Tag: vertical grow system

The sprouted stem fragments rested on a floating plastic mesh supported by a ring of plastic pipe, on the surface of each trash can’s nutrient solution. A sheet of opaque white plastic was wrapped around and over each trash can to block out sunlight preventing algae growth and high temperatures in the nutrient solution. The nutrient solutions in the containers were monitored two times per week during a 48-week growth period. Each check consisted of the following: addition of enough deionized water to bring the can’s nutrient solution level up to a 100-L mark, determination of the can’s electrical conductivity in full volume. A concentrated Hoagland solution was added to re-establish the conductivity of the nutrient solution to its original value. The pH was adjusted to 5.7. The harvest dates were partially determined by the growth of the plants as the experiment progressed. Harvested plants were separated into apical meristems, green leaf blades, brown leaf blades , green leaf sheaths, brown leaf sheaths , stems, rhizomes, and roots. Plant parts were dried to a constant weight at 60 C. Biomass of the tissue was determined and sub-samples were ground in a Wiley mill to pass a 0.5 mm mesh screen . The nitrogen and carbon contents of the tissues were determined using an organic elemental analyzer . Stem fragments with meristems can root and regenerate new Arundo plants , as has been reported earlier by . There were significant patterns in rooting success of meristems on Arundo stems throughout the growing season. In the winter months of November through January, rooting is low, and success percentage lies below 20%, with the exception of 28 ± 12% rooting for meristems from hanging stems in January . Nearly all meristems rooted from March through September. The speed with which meristems rooted showed a related pattern through the growing season . In the period with the lowest rooting success, t50 had the highest values,dutch buckets system indicating the slowest rooting.

Rooting was most rapid in the months of May through July, a time window that was more narrow that the period in which rooting is most successful.There are no significant differences between the results in plain water and half-Hoagland nutrient solution . The rooting success and speed pattern is similar in soil, but the single replicate meristems do not allow for inclusion in the two-way ANOVA. When compared within each sampling, the rooting success of meristems from hanging stems was significantly higher than that of meristems from upright stems . When split for rooting medium, there was no significant different in rooting success between hanging and upright meristems over time in plain water , but the differences remain significant in the nutrient solution and in soil . Like with rooting success, rooting speed of hanging meristems was significantly faster when compared to that of the upright meristems of the same sampling date . When separated among rooting media, the difference in the speed with which rooting occurs was most pronounced in plain water , but still exists in the nutrient solution and soil . Though these differences in rooting success and the speed of rooting may be statistically significant, they generally are too small to be ecologically significant. Stem diameter at the node where the meristem is placed is an indicator of relative height on the stem, and the age of the meristem. Within stems, there was no relation of rooting success or speed with the diameter of the stem at the point of the meristem, so the older meristems on an Arundo stem do not root better or faster than the younger meristems on Arundo stems.When the temperature of the rooting environment was controlled at 28/15 °C for 14/10 h during the entire growing season the seasonal patterns of rooting success and speed remained, and differences between the seasonal rooting patterns of the fragments from hanging and upright stems emerged . The overall patterns differed slightly from those in the greenhouse experiment, with the lowest rooting by both stem type fragments in February through March. The rooting percentages increased in April, and the highest rooting rates occurred from July through September at 80 – 92% for both stem types.

In October the rooting of the upright stem fragments decreased more than that of those from hanging stems. The lowest rooting rates of the stem fragments from upright stems were 0 – 10% in February and March, while the rooting rates of the hanging stem fragments only decreased to 30% . The positive influence of the seasonal effect in the months of July – September on the rooting rates of both stem types masked the difference that emerged in the Winter and Spring months. The rooting by meristems from upright stems benefits more from this seasonal effect that of meristems from hanging stems. The seasonal effect on the rooting rates of the stem types could be related to a number of environmental factors that change during the growing season, such as temperature, light intensity, and daylength. determined that stem fragments sampled at the same time, but stored at different temperatures, displayed different sprouting percentages when potted and regenerated at the same temperature in a single greenhouse. We hypothesize that the different ambient temperatures prior to sampling in our experiment was an ecophysiological equivalent of the experimental factor “storage temperature” in the Boose and Holt study, and one of the factors involved in the seasonal pattern of A. donax stem fragment rooting.The seasonal differences in the rooting percentages and speed between meristems from upright and hanging stems that was striking under controlled temperature conditions had been much less pronounced in the greenhouse rooting experiment. The results of the greenhouse rooting experiment show that the temperature at the time of rooting influence the effects of the seasonal factor. Environmental effects, such as temperature and inundation, are known to affect the success of invasive plants with either negatively or positively In the greenhouse experiment, the temperatures of the rooting medium varied with the ambient temperatures and solar irradiation, while the temperature of the rooting environment in the growth chamber experiment was the same throughout the growing season. The greenhouse, the temperature of the rooting media in the winter ranged from 0.5 – 2 °C at night to 19 –21 °C during the day. In the spring and summer, solar irradiation increased these temperatures to 16 -18 and 28 – 34 °C, respectively. To test the effect of the temperature at rooting, we tested the rooting of fragments of hanging A. donax stems at different temperatures in April and May, a period that in the year-round temperature controlled experiment the success rates were 45 ± 10% in 1998, and 45 ± 21% in 1999. In this test using constant temperatures, no rooting occurred at 10 °C during the 40 days of the experiment .

At 15 °C, rooting was better than at 10 °C , but significantly less than at 17.5, 20, and 22.5 °C . In the greenhouse experiment, the seasonal pattern of rooting success was present, but the inherent advantage of fragments of the hanging stems in the winter months was masked by the negative effect of the lower temperatures of the rooting media. The temperatures chosen for the year-round temperature controlled experiment were selected to reflect the temperature conditions in the habitats invaded by A. donax in Southern California in the months of April and May. From the results of this April constant temperature experiment, it appears that the lower night temperature in the 28/15 °C for 14/10 h experiment led to a reduction in rooting success from the maximum possible in that month. This reemphasizes the effect of in situ temperature on the success of stem fragment meristem rooting, and the ecological danger of the floating stem fragments in shallow waters. The inherent seasonal pattern observed in the year round temperature controlled experiment may have resulted from cycles in the concentrations of the plant growth regulators that play a role in the growth of the side shoots, and the apical dominance of the top of the main stems. One of the growth regulators that plays a major role in the regulation of apical dominance is indole-3-acetic acid. The effect of IAA on the rooting of axillary bud on A. donax stem fragments throughout the growing season was tested through the use of exogenous IAA in the rooting medium,dutch buckets and the determination of endogenous IAA levels in the shoots that grew from the axillary buds. When the stem fragments and their axillary buds were exposed to 5 and 10 µM IAA in the rooting medium, the difference between the hanging and the upright stems disappeared. The main effect of the exogenous IAA was a significant improvement of the rooting percentage and speed of the upright stem fragments in the winter and spring periods, so that the difference between the two stem types was minimized. The exogenous IAA had little effect on the rooting success and speed of the hanging stem fragments . At 20 µM exogenous IAA, the highest concentration applied, the success rate and the speed of upright stem fragment rooting decreased from the optimum observed at 5 and 10 µM, almost down to the percentages and t50 observed in the absence of the hormone . The IAA in the rooting medium may have reached the axillary bud through the vascular bundles of the main stem piece, directly through the cuticle of the bud itself, which was positioned immediately below the rooting medium surface, or both. In early studies into the effect of IAA onplant growth, the growth regulator was sometimes applied to the leaf tissues, and the position of the axillary bud in the rooting medium could have resulted in a similar situation. There is a striking similarity between the seasonal pattern of the endogenous IAA levels in the shoots that grow from the hanging and upright stem fragments and their seasonal rooting patterns. The lowest IAA levels for both stem types occurred in the spring, and the highest levels in late summer . At the time that the endogenous IAA levels are low, levels in the shoots from the upright stem fragments are significantly lower than in those from the hanging stems. As the IAA levels in the shoots increase with the progression of the growing season, the levels in the shoots from the upright stem fragments increase more than in those from the hanging stems, and the difference between the shoots of the two stem types disappears . The role of this IAA is unclear. Although studies have also shown more complicated mechanisms , IAA produced in the main stem apex plays an important role in the apical dominance, and the growth of side shoots. A difference between the rooting and the endogenous IAA patterns is that the seasonal pattern of endogenous IAA concentrations in the new shoots runs approximately one month behind that of the rooting success. This makes it less likely that the IAA concentrations in these new shoots, of which the growth is initiated prior to root growth, is the direct cause of the rooting of the stem fragments. It is possible that both the rooting pattern and the endogenous IAA pattern result from seasonal variation in another factor, possibly the concentrations of another plant growth regulator. Preliminary enzyme kinetics results have shown higher NADP-dependent indole- 3-acetatealdehyde oxidase activity in the new shoots that developed from the hanging stems in April than in those from the upright stems . This indicates that the IAA measured in the new shoots may be the product of de novo synthesis in these shoots, rather than a trace of the IAA that may have been stored in the main stem fragment that was used in the experiment. IAA plays an important role in tracheary cell differentiation and xylem regeneration . The support for the formation of the vascular system by IAA and its promotion of the formation of adventitious roots may be related, but no causal relationship was determined in this study.

Plant and rhizosphere metabolomics thus provide a snapshot of the entire plant-associated metabolome, that can be directly correlated with real-time functional footprint of the cellular state. The need for measuring metabolite levels in plants in response to ENMs was realized early on by the nanotoxicology community. However, most studies evaluated the total content of classes of metabolites such as sugars, phenolics, flavonoids, chlorophylls, non-enzymatic antioxidants, lignin, etc. using less sensitive biochemical assays . In some studies, profiling of specific classes of compounds like carbohydrates, fatty acids, and amino acids was also performed . However, based on the evaluation of a few metabolic parameters, a comprehensive understanding of the underlying mechanisms of ENM transport and effects is rather limited and biased by author’s interpretations. To address these challenges and identify the crucial role of the affected metabolites in response to ENMs, it is important to increase the analytical coverage of the plant metabolome.Metabolomic analysis can be categorized as untargeted or targeted, the choice of which depends on the scope of the study . Key factors that separate untargeted from targeted metabolomics are: extent of sample preparation required; number of metabolites detected; level of quantification; and extent of data processing post acquisition. Untargeted metabolomics is a discovery-based approach that screens the entire pool of metabolites in an organism. In nanotoxicity studies, untargeted metabolomics can be used to discover unknown metabolites of significance and identify markers in order to generate hypothesis on biological pathways involved in response to ENM exposures . Metabolite identification is based on available literature or in house experimental database,grow strawberry in containers and the quantitation is either relative or semi-quantitative, aided with extensive data processing . However, untargeted metabolomics also suffers from practical challenges.

Plant metabolites span over a broad range of composition and physio-chemical properties, which makes it challenging to extract and identify all of them simultaneously with acceptable recovery using a single analytical procedure. In addition, low molecular weight plant metabolites differ by several orders of magnitude, ranging from femto- or picomolar to millimolar concentrations , which present sensitivity and accuracy challenges for the detection of less abundant metabolites . Targeted metabolomics, on the other hand, focus on selected classes of chemically characterized and biologically annotated metabolites. Targeted metabolomics is hypothesis-driven, in which a defined set of known metabolites are analyzed with significantly higher selectivity and sensitivity, focusing on a specific biochemical question. Calibration and isotopically-labelled internal standards are used for absolute quantitation of the metabolites under investigation. Metabolomic analysis demands careful attention to details at each analytical step including sampling, metabolite extraction, storage, instrumental analysis, data processing, and interpretation for factual representation and reproducibility.Hence, a robust experimental design, randomization, efficient reporting of experimental details as per the Metabolomics Standards Initiative guidelines, and submission of results in data repositories are highly advisable, to ensure reproducibility and consistency of the metadata obtained from metabolomic analysis . To compensate for the qualitative and quantitative variations among plant samples, biological replicates are essential, which results in more powerful statistical analysis. However, in case of high variability and limited sample availability, sample pooling is a common procedure to represent the population, which nonetheless should be reported and considered during data analysis . Although these requirements are quintessential for any metabolomic experiment, nanotoxicity studies should also consider ENM stability in the exposure media throughout the experiment duration, environmentally or agriculturally relevant dosing, ambient fluctuations, use of appropriate positive and negative controls, and comparison with ionic and bulk-particle controls to identify nano-specific effects.

Representative techniques and key challenges in each step of the metabolomic analysis in ENM-plant interaction research are summarized below .In a metabolomic study, a robust sampling protocol is critical in order to obtain maximum information from the plants exposed to ENMs. Some of the factors considered during sampling are: scope of the study, route of exposure , kinetic of ENM transport in the species under investigation, growth stage of the plant and time of the day when harvesting is done. Different plant organs such as root, leaf or fruit have distinct metabolic footprint owing to varying cellular organization. Thus, to prevent loss of information about chemical signaling across organs, it is necessary to analyze them separately. The metabolite profile of a tissue also varies significantly depending on the growth stage of the plant; hence, results from an ENM exposure study in a germinating seedling cannot be extended to compare or interpret metabolic events in the plant in its vegetative or matured stage, or vice versa. Tissues collected from untreated and ENM-treated plants should be immediately quenched in liquid nitrogen or freeze-dried to capture the metabolic state of the plant at the desired moment. Prior to freezing, tissues may be washed with water at room temperature, if necessary; cold or hot solvents must be avoided to prevent leakage of intracellular metabolites. Frozen tissues are ground to homogenous dry powder using precooled homogenizing apparatus, and appropriate extraction methods must be used depending on the analytical technique used. To prevent loss of unstable metabolites and to maximize analytical recovery through all the steps of extraction, adequate sample storage and handling is important. In untargeted analysis, the aim is to broaden the coverage of metabolites and maximize identification. The most common strategy is to extract a wide range of metabolites in solvent mixtures, such as methanol/ methyl tert-butyl ether/water or methanol/chloroform/water, followed by separation of the polar and non-polar metabolites by biphasic partitioning . Each phase is collected for analysis using suitable analytical platforms. In targeted analysis, specific extraction protocols are optimized to retain the metabolites of interest. Additional sample processing such as filtration or solid phase extraction are also used to reduce matrix effects and remove undesired metabolites.However, GC-MS is best suitable for volatile and thermally stable metabolites, and requires derivatization/ chemical modification of polar metabolites such as sugars, amino acids and organic acids .

In contrast, LC-MS allows analysis of polar and high molecular weight metabolites without any derivatization. For untargeted analysis, LC is hyphenated with high resolution MS like time-of-flight or Orbitrap mass analyzers with electrospray ionization . Nevertheless, LC-MS also suffers from drawbacks due to ion suppression, differential adduct formation and retention time shifts due to matrix effects. Different analytical approaches are however complementary, and can be used together to obtain a comprehensive coverage of metabolites with high confidence. Extraction of plant metabolites in solvent mixtures results in an immediate loss of inter- and sub-cellular resolution. Advances in MS imaging techniques have made it possible to map metabolites in intact plant tissues at sub-cellular level and connect the spatial complexity of the plant molecular organization to phenotypical features. Some techniques that have been hyphenated with MSI for imaging metabolites in plant specimens are matrix-assisted laser desorption/ionization and laser ablation electrospray ionization . However, these approaches have not yet been utilized in ENM plant interaction studies.In targeted metabolomics, low resolution MS such as linear ion traps or triple quadrupole are predominantly used . Advances in QqQ in single reaction monitoring mode allows robust absolute quantification of metabolites with high sensitivity and selectivity, even at trace levels with relatively high throughput. Column chemistry and its retention mechanism are extremely critical for targeted analysis of metabolites using LC-MS; and hence, reverse phase and hydrophilic interaction liquid chromatography are used to cover broad range of metabolites with contrasting polarity . Targeted analysis is particularly useful as a follow up from untargeted analysis, in order to focus on specific metabolic pathways or testing application of ENMs in pathogen defense, nutrient acquisition, photosynthetic efficiency or productivity.Data processing in metabolomics comprises baseline correction, feature extraction, spectral alignment across samples, identification and interpretation . Post data-acquisition, baseline correction is performed on the datasets to remove low frequency artifacts and aberrations across multiple samples that could be generated by experimental or instrumental variation. As chromatographic retention time may vary between samples, spectral alignment is performed across the dataset, which may precede or follow feature extraction process. In MS-based studies, peak-based algorithms are used to extract and quantify all relevant chromatographic and spectral information for all known and unknown metabolites in each sample. Upon detection, related ions indicative of a single-component chromatographic peak are identified and grouped . Several open source and commercial MS reference and MS/MS library matching databases are available; but the databases on plant metabolites is limited and they are not fully optimized for all analytical platforms. Electron ionization fragmentation patterns and indexed retention times for an extensive array of compounds using GC-MS and NMR spectral library are available; however, LC-MS data lack standardization in the available resources . However, due to an increasing number of studies in plant metabolism, high quality spectral and chromatographic data are continuously being added to and curated within these spectral libraries, which will eventually improve the routine peak identification in non-model plants. Software such as XCMS, PRIMe, MeltDB etc. are used for data processing including feature detection, retention time correction, alignment, annotation, statistical analysis, and data visualization. Another online tool, Metabo Analyst,hydroponic nft system is used to process identified metabolites for data normalization, statistic alanalysis, and visualization . Statistical analysis of the metabolomics data helps to identify features that are differentially regulated compared to control samples. The identified markers are then projected on to the available metabolic networks, which can be used in a phenotypic context to generate mechanistic hypothesis.Kocide-3000 is a commercial micron-sized pesticide, composed of copper hydroxide 2) nanosheets, which can be applied using aerial or ground spray in the field. Zhao et al. investigated the metabolomes of lettuce, cucumber, maize and spinach plants chronically sprayed with Kocide .

Twenty four-days-old lettuce plants were foliar sprayed with 1050, 1550, 2100 mg/l Kocide twice a week for four weeks . Although the chronic exposure did not induce overt response, metabolomic analysis of the leaves revealed differential accumulation of 50 metabolites ultimately affecting six biological pathways, including Gly/Se/Thr metabolism, Ala/Asp/Glu metabolism, TCA cycle, pantothenate and CoA biosynthesis, glycolysis or gluconeogenesis, and pyruvate metabolism. Chronic exposure to Kocide deteriorated the antioxidant defense mechanism in the lettuce plants expressed by decreasing levels of phenolic compounds like cis-caffeic acid, chlorogenic acid, 3,4- hydroxycinnamic acid. Dehydroascorbic acid, its oxidation products and GABA levels were also diminished at high exposure concentrations, suggesting impairment of the antioxidant system in lettuce. A chronic exposure of spinach leaves for 7 days to 1000 mg/l Kocide also resulted in depreciated levels of antioxidant or defense associated metabolites, including ascorbic acid, a-tocopherol, GABA, threonic acid, b-sitosterol, 4-hydroxybutyric acid, and ferulic acid, resulting in the perturbation of phenylpropanoid and ascorbate/aldarate pathways . However, the decreased levels of antioxidants and activation of antioxidant defense system in spinach leaves were driven by Cu ion release. In addition to amino acids , accumulation of phytol, a chlorophyll degradation product, was also decreased in Kocide-exposed spinach leaves, similar to Kocide-exposed maize and cucumber leaves . Metabolomic response in artificial soil-grown three-weeks old cucumber and maize plants exposed to 100 and 1000 mg/lKocide by foliar spray for a week was compared; however it is to be noted that the final dose in maize plants were higher than the cucumber plants due to hydrophobicity of maize leaves . In maize leaves, Kocide treatment induced accumulation of glycolysis and TCA intermediates thereby enhancing energy metabolism and enhance branched chain amino acids accumulation, which play important role in oxidative phosphorylation energy source. Kocide resulted in increased levels of polyphenols such as 4-hydroxycinnamic acid, 1,2,4-benezenetiol, and their amino acid precursors , thereby activating shikimate phenylpropanoid pathway in maize leaves suggesting induction of antioxidative processes. In cucumber plants, Kocide significantly affected the Arg/Pro pathway intermediates . In both plants, Kocide exposure resulted in reduced levels of unsaturated fatty acids and increased saturated fatty acid indicating an alteration of plasma membrane homeostasis.Metabolomic studies suggest that the toxicity effects in plants exposed to nAg is primarily attributed to the released Agþ ions . In 7-day old Arabidopsis thaliana plants, a 24 hexposure to 1 mg/L of citrate-nAg, polyvinylpyrrolidone -nAg and AgNO3 via roots resulted in alteration in six, three, and nine metabolites respectively, which were identified as fatty acid derivates.

Over the 6 years of study, except perhaps for 2013 when we focused on other study priorities, we never experienced ideal conditions to adequately test the flood extension concept. We were either in a severe drought, during which the Yolo Bypass did not flood from the river, or we experienced severe and sustained flooding, which made it impossible to contain flood waters within study fields. Based on these experiences, studying the concept of flood extension appears to depend on the occurrence of moderate flood events at the right time of year , provided fields are appropriately designed to hold water and allow efficient immigration and emigration of potentially large numbers of juvenile salmon. However, significant outreach and communication is necessary with landowners to maintain floodwaters on their fields during the natural drainage period. Because these events cannot be predicted well ahead of time, these communications—and availability of robust infrastructure—need to be constantly maintained even outside the flood extension period. As suggested in the previous section, such potential actions would need to be taken in a way that maintains hydrologic connectivity and salmon access, so that salmon can successfully locate potential managed habitats, use them for rearing, and then successfully emigrate from them at the appropriate time. Timing of such potential manipulations is critical because previous sampling has shown that salmon quickly emigrate from the floodplain during large scale drainage events , leaving relatively low densities of salmon in remaining ponded areas to potentially benefit from flood extension. Although our use of hatchery salmon gave us more experimental options during drought conditions, the use of these fish resulted in additional challenges. Our approach relied on a non-traditional use of hatchery salmon, which required a suite of permits and approvals to execute the project. As noted above, the project coincided with a major drought, so access to hatchery salmon was limited as a result of low salmon population levels. In addition, use of hatchery salmon affected the time-period when we could conduct experimental work. We were unable to test salmon response to early season flooding ,ebb and flow tray because the hatchery salmon were too small to receive coded-wire tags as required under our permit conditions.

Similarly, the timing of our work was affected by the availability of holding tanks at our partner hatchery , and by the availability of transport staff and vehicles to move salmon to our study site. While we were able to assess many important biological metrics in our study, direct measurement of the population-level effect of floodplain rearing on agricultural habitats proved elusive. A traditional approach to addressing this question involves inserting CWTs into very large numbers of experimental salmon and estimating the population response from expanded CWT recaptures in the ocean fisheries. Recoveries of CWTs in adult salmon from experimental releases made in the Yolo Bypass have generally been very low , making it difficult to get a high level of resolution with which to reliably compare survival rates, including with values in the literature. Although CWT recoveries could potentially be improved by increasing the number of tagged salmon, the effort required even to collect a single data point would be substantial and is limited by the availability of surplus hatchery salmon. A related issue is that it is difficult to design a survival experiment that provides a useful comparison to other management strategies or migration corridors. For example, it is challenging to assess the incremental survival value of flooded agricultural habitat versus adjacent perennial channels . Telemetry can partially address this issue, but current acoustic tagging technology does not allow estimates of survival once smolts emigrate from the estuary, and is also limited in the size of salmon that can be tagged. Ultimately, addressing the question of population-level effects will likely depend on a combination of measured field data, incorporating new methodologies for assessing survival to adulthood , and fish population models.Our observations must be considered within the constraints of the infrastructure in the Yolo Bypass during the time of our field work. In the intervening years since our field studies, there has been a substantial amount of progress in improving Yolo Bypass infrastructure to support native fishes. During 2017-2018, an inflatable dam fish barrier and collection facility was constructed at Wallace Weir at Knights Landing Ridge Cut . This facility can enhance potential water distribution options for managed flooding studies under relatively low flow conditions when only Yolo Bypass tributary flows are available, including sources from Colusa Basin, which may not always have suitable water quality for juvenile salmonids.

It is important to note, however, that these local water sources are not useful unless there is improved connectivity with the Sacramento River, allowing wild juvenile salmon to access seasonal habitat throughout the Yolo Bypass. To that end, the joint Environmental Impact Statement/Report was finalized in 2019 for a project that will improve connectivity between the Sacramento River and Yolo Bypass with a proposed notch in Fremont Weir . This proposed facility would allow managed flows at lower Sacramento River stages than the current weir structure, thereby increasing the frequency and duration of seasonal inundation, and providing improved access to the floodplain from the Sacramento River fish migration corridor. This upgrade is required as a condition of the 2009 Biological Opinion for Salmonids for long term operation of the federal and state water projects . Our study did not specifically address these new facilities or their operations, and how the concept of managed agricultural floodplain habitat can be integrated into the primary purposes of these improvements. Hence, potential use of flooded agricultural fields as juvenile salmon rearing habitat should be evaluated in light of both a modified hydrology and local land use and infrastructure changes. Additional research is needed to address the efficacy and suitability of different potential water sources, hydrology timing, connectivity with the Sacramento River, and related issues, such as the effects of operations on land use and other species or life stages .Using conservation easements to protect farmland from urbanization is a relatively new application of a technique that has been used in land preservation programs in the United States for about a century. Landowners who voluntarily sell easements or donate them for tax benefits, in effect give up development rights on their land in perpetuity while still retaining basic ownership . Only in the past 20 years in California, and slightly longer in several other states, have state and local programs employed easements for the express purpose of keeping farmland in production. The more traditional uses have been for preserving land with natural resource or recreational values, such as riparian areas, wetlands, habitat and trails. Thousands of agricultural acres — primarily grazing land — have been covered by environmentally oriented easements over the years. In part this is because farmland is a form of open space, a passive environmental amenity. But protecting agricultural production with easements intended to protect more specific natural resources, such as habitat and riparian areas, is more difficult for much of California’s farmland, because orchards, vineyards, vegetable cultivation and other intensive crop production constitute a “working” rather than “natural” landscape. While sustainable agriculture offers considerable promise for minimizing the impacts of farming on natural resources, intensive crop production still generally involves chemical applications, the use of heavy machinery and other industrial like activities.

We address it only in the context of conservation easements, by examining the agendas of local organizations with land conservation objectives. We identify 34 California organizations that emphasize farmland protection to varying degrees, and examine the mix of agricultural and other conservation purposes in their missions, drawing primarily from open-ended phone and personal interviews with program managers and from mission statements.The 34 California programs that fit our standards for having an interest in farmland protection include 30 nonprofit land trusts and four open space districts. Land trusts are nonprofit, community organizations founded and run by volunteers and small staffs, while open space districts are local government entities governed by publicly elected boards . All four of the state’s open space districts are included on this list. But the 30 land trusts are only a small portion of the more than 130 land trusts that operate throughout California, according to the 1998 directory of the national Land Trust Alliance . Among 20 different types of resource conservation purposes noted in the directory for individual California trusts , farmland/ranches ranked eighth in the frequency of mention. The top mentions were watersheds/water quality, rare species habitat, scenic views, wetlands, river corridors, trails and forests/timberlands. To select 30 farmland-oriented land trusts, we first identified 37 organizations that cited a farmland or ranch purpose in the LTA directory. Next, we added about 10 other trusts identified as having an agricultural orientation by other sources such as state and foundation programs, the American Farmland Trust and our own files. Finally, after speaking with program managers and reviewing mission statements, we narrowed the list down to 30 trusts. The final list does not include land trusts that acquired easements on grazing acres or other farmland primarily for environmental,4×8 flood tray rather than agricultural purposes. The two essential selection criteria were an expressed interest in the preservation of farmland as an agricultural resource and the intention to use conservation easements. For our purposes the farmland criterion encompasses both cropland and rangeland. The few California trusts that have forestry or growing of trees as their only “agricultural” activity were not included. Otherwise, we defined “farmland” and “agriculture” broadly. For example, one manager for a coastal land trust described the scope of his agricultural program as including, “all agricultural uses in accordance with sound and generally accepted agricultural management practices, such as breeding, raising, pasturing and grazing of livestock; production of food and fiber; breeding, raising and boarding horses, bees, poultry and other fowl; and planting, raising, harvesting other agricultural, horticultural and forestry crops.” In applying the second selection standard, use of easements, we emphasized intention rather than accomplishment. It was not necessary for an organization to have actually acquired specific easements. Rather, we deemed it sufficient to express an intention to acquire easements for farmland protection in the future. One justification for this liberal approach was recognition of how difficult it is for a new land trust to complete its first easement transaction, primarily due to funding limitations and landowner resistance . The trusts we identified are located in 29 of California’s 58 counties .

A few operate in more than one county, and the California Rangeland Trust has a statewide orientation with an emphasis on the Sierra foothills and Central Coast hillsides. Twenty-one of the 34 programs are concentrated in coastal areas, with 14 in the Bay Area alone . The Central Valley has nine and Sierra foothill counties have two. Least represented in relation to area and population, Southern California has only two organizations on our list, in Ventura and San Bernardino counties. No such programs are located in the major counties of Los Angeles, Orange, Riverside and San Diego.Both nonprofit organizations and public agencies are legally able to acquire and hold conservation easements on private properties that restrict their future use. The key is their noncommercial and public interest character, which under federal law allows them to accept contributions of money or land interests as tax deductions. Nonprofit land trusts specifically qualify under section 501 of the Internal Revenue Code. But the California land trusts and public agencies have distinctly different forms and operational procedures. Land trusts are independent, nongovernmental entities with no formal accountability to the community or its political bodies. Volunteer boards of directors, who fill their own vacancies, govern them and a number have small staffs and membership or donor rolls. Because of their grassroots origins, flexibility, citizen participation and conservation credentials, land trusts are an attractive alternative to local government as the major mechanism for acquiring and holding easements . No California county and city governments directly operate agricultural easement programs, although they frequently require the donation of easements as mitigation for approving development projects. The open space districts and several regional conservancies organized by state government are the only public agencies in California with active easement programs. Unlike the nonprofits, the districts are accountable to their communities via separately elected governing boards or are extensions of county government and the elected board of supervisors.

The data came from 661 respondents to a statewide survey fielded between May and July 2016, which achieved an overall response rate of 28% . In addition to UC Cooperative Extension professionals, the survey included people from organizations that are part of the knowledge network engaged in outreach, education and communication: producer groups, nongovernmental organizations, consultants, resource conservation districts, government agencies and others. While some respondents did manage farms, we were not targeting farmers but rather those who develop and deliver information to farmers. It would be useful for future research to extend the survey to farmer populations, specific consultant groups such as pest control advisors, and agricultural knowledge networks in other countries and U.S. states. Using the framework of the diffusion of innovation theory, our analysis tested the following hypotheses: extension professionals who perceive a greater relative advantage are more likely to adopt ICT; less likely to adopt ICT are extension professionals who perceive ICT as incompatible with their values and social norms, extension professionals who perceive ICT as too complex or time consuming and extension professionals who are uncertain about how to measure ICT effectiveness or strategically target audiences. In addition, we tested how demographic factors may be linked to ICT adoption, with the expectation that the patterns would be similar to the patterns in the general population. To pursue the possibility of an extension gap,ebb and flow table we tested whether UC employees had a lower ICT adoption rate relative to other types of extension professionals.We tested our hypotheses by first constructing dependent variables for the number of ICT platforms used and the frequency of social media use. The survey assessed ICT adoption by asking respondents if they used blogs, websites, email, mobile applications, Facebook, Twitter, Pinterest, Instagram or LinkedIn to communicate or learn about sustainable agriculture. We constructed a yes/no variable for each ICT platform. To zero in on the frequency of use for just the social media platforms , we followed the Pew Internet Survey in establishing the following categories of use: several times a day, once a day, a few days a week, every few weeks, or less often.

Importantly, the focus was on using social media for professional communication about sustainable agriculture, not personal use of social media. To analyze how perceptions about the attributes of ICT are related to ICT behavior, we constructed a social media frequency scale that calculated the average frequency of social media use across all five platforms, plus an “other social media” category. The scale ranged from 1 = do not use any social media to 6 = use all social media several times per day, with mean = 2.01. To calculate the number of total ICT platforms used, not just the social media platforms, we summed the number of platforms respondents checked; the numbers ranged from 0 to 9, with mean = 3.81. We then estimated multivariate models with social media frequency and total number of ICT platforms as dependent variables, and the four attributes of innovations as independent variables . Respondents’ perception of social media’s relative advantage was measured by averaging their responses to six statements related to its capacity to reach audiences and help extension professionals coordinate professional activities. These statements form a reliable scale ranging from 1 = strongly disagree on all statements to 5 = strongly agree on all statements, with mean = 3.71. Respondents’ perception of compatibility was measured in their responses to four statements: social media risks spreading fake news, there are positive incentives for its use, most colleagues use it, and it involves too much interaction with trolls. The response options did not form a reliable scale, so we included each statement as a separate variable in the analysis. Perception of social media complexity was measured in responses to these four statements: it takes too much time, it’s technically difficult to use, best practices are well known, and the large number of platforms is confusing. Again, the response options did not form a reliable scale, so we included each statement as a separate variable in the analysis. Lastly, respondents’ perception of the measurability of social media’s effectiveness was assessed. One statement suggested it was easy to measure effectiveness; the other statement suggested it was easy to identify appropriate audiences for social media. Responses were averaged into a reliable scale that ranged from 1 = strongly disagree on both statements to 5 = strongly agree on both statements, with mean = 2.32. To test the effect on ICT adoption of users’ demographic characteristics, we used the same dependent variables as described above, and we estimated the same models using the following demographic independent variables: sustainability attitude , age , income , UC system , male and education .

Figure 1 reports the overall adoption rates for the ICT platforms. In decreasing order of use, email was used by 92% of the respondents, followed by websites and Facebook , with Instagram and Pinterest having the lowest adoption rates. While the results for the most popular platforms echo the results for the general population, Twitter and LinkedIn were used relatively more by extension professionals because they are specifically intended for information dissemination and professional networking. Figure 2 reports the average temporal frequency indicated by each respondent for using just social media. For the general population, Pew reports that 55% of Facebook users and 23% of Twitter users access their accounts several times per day. In contrast, our sustainable agriculture stakeholders in California access Twitter and Facebook at the lower rates of once a day or a few days per week. The lower frequency of use for LinkedIn most likely reflects that the content changes more slowly than the events communicated on Twitter and Facebook. Figure 3 plots the coefficients from an ordinary least squares regression model for social media frequency and a Poisson model for number of ICT platforms , with the variables arranged in order of decreasing magnitude from the social media frequency model. Relative advantage had the strongest positive relationship with both the frequency of social media use and number of ICT platforms. Respondents who thought most of their colleagues used social media also used more ICT platforms, more frequently.Interestingly, the attributes of innovations were less important for the number of ICT platforms used than for the frequency of social media use, where the capacity to measure effectiveness and identify the audience had a positive influence and lack of time and concern about fake news had strong negative effects. The existence of professional incentives, confusion about the number of platforms and knowledge about best practices were unimportant in both models. Figure 4 suggests some demographic variables behaved in ways consistent with the general population: ICT and social media use was higher among female, younger and wealthier respondents. The results also corroborated the technology gap described earlier: UC employees used fewer ICT platforms and used social media less frequently than other respondents. More educated respondents also used social media less frequently, which contrasts to the general population, where educational levels are positively correlated with social media use. In the context of professional extension activities, UC system employees or those with advanced degrees may be stressed for time, perceive social media as incompatible with norms of scientific knowledge sharing or lack professional incentives.

The breakdown of UC respondents was 35% campus faculty, 13% Cooperative Extension specialist, 22% Cooperative Extension county advisor, 6% other academic title, 10% student/ postdoctoral scholar, 11% staff and 3% other. Sustainable agriculture stakeholders in both developed and developing countries are quickly catching up to the information revolution that has transformed society in the 21st century. Our results confirmed the usefulness of diffusion of information theory, which frames the debate about the benefits and risks of ICT in terms of innovation attributes related to relative advantage, compatibility, complexity, observability and trialability. Extension professionals clearly recognized the relative advantages for ICT in terms of quickly communicating with a more diverse and distant audience, but with less potential to coordinate on-the-ground activities. Extension professionals are more likely to capitalize on these relative advantages if their colleagues are also using ICT, and they have good tools for measuring effectiveness. The most important barriers for widespread adoption of ICT were time constraints, technical complexity and incompatibility between norms of scientific discourse and the reality of trolls and misinformation on the internet. These results support some concrete recommendations for organizations seeking to increase the use of ICT and make it more effective for extension professionals. Resources could be invested in developing a community of practice for aspiring ICT users interested in using ICT for outreach, with leadership from extension professionals with an established reputation for successful innovation. Communities of practice are one of the organizational concepts in e-eXtension, and are defined as informal networks of professionals with a common goal who regularly interact to share information and expertise . They can help creatively solve problems, transfer knowledge and develop professional skills and are effective where the network of individuals is distributed across many administrative units or system components, as is the case with extension professionals experimenting with ICT. A sponsoring organization can help foster a community of practice by identifying potential members,flood table providing organizational infrastructure for interaction and measuring effectiveness with appropriate metrics. Such a community of practice should document the potential advantages of ICT and provide information about best practices. It would increase awareness about how many extension professionals are using ICT, which would help create a community norm. The community of practice should include a diverse set of stakeholders, including digital technology specialists from outside of agriculture who are knowledgeable about different types of tools, altmetrics and social media strategies that are effective in digital communication. It is also important for agricultural extension organizations, including land-grant universities, to establish clear guidelines for recognizing the value of ICT as an extension tool that complements traditional communication strategies and ways of extending knowledge. If extension professionals know what counts in terms of documenting their professional activities for job performance evaluation, they are less likely to be confused and view ICT as a risky endeavor. Developing such guidelines would benefit from consultation by outside specialists with expertise in digital tools and measurement. The risks of misinformation and credibility may be some of the most important for extension organizations to address at a strategic level.

Such organizations typically desire to be perceived as impartial providers of evidence-based information. Social media platforms recognize that legitimate knowledge exists outside of Cooperative Extension but also provides a gateway for misinformation. At the individual level, the risk is not so much that a particular extension professional may make a mistake in communicating their own research, but rather they may unintentionally spread misinformation from others and be required to invest additional resources in sorting accurate social media information from misinformation. At the institutional level, social media’s democratization of information creates the fear of messages being corrupted, misinterpreted or simply lost in the wash of real information and misinformation. In both cases, it is important to avoid damaging the reputation of providing high-quality science communication. However, Bastos et al. provide some evidence that may mitigate these fears. Examining the topology of Twitter networks connected with UC Agriculture and Natural Resources Twitter users, Bastos et al. found that communities focused on specialized agricultural topics formed centralized networks in which a relatively small number of expert nodes collected and broadcast information to a large audience. In other words, relative to more general users and nonspecialists, technical experts become more central in the online networks and serve as important information hubs for specialized and technical issues. This suggests that social media communication is not completely incompatible with the traditional extension goal of providing hubs of expertise. Further research is needed to increase confidence in our results and recommendations. More systematic comparison between extension professionals and their clientele would corroborate the extent and nature of the technology gap. While our findings are relevant for extension professionals involved in sustainable agriculture, it would be important to generalize the research to other types of agricultural sectors, compare different commodity groups, directly survey farmers and extend the research to natural resource managers. Using big data approaches to monitor the dynamics and effectiveness of communication is also an important effort going forward.

The factors to which models respond vary among models and evolve as modelers attempt to make them more comprehensive and universally applicable. In contrast, some researchers who want to apply them do not have all needed inputs, or they may want to embed a crop model into economic or other models for analyzing responses across scales. Some researchers have used more comprehensive crop models to create reduced form crop models that have much fewer input requirements, run fast, and produce responses needed for specific applications . For example, Chikowo et al. used the APSIM cropping system model to generate parameters and variables needed to operate a much simpler field scale crop model . The reduced form summary model responds to nitrogen and phosphorus levels for different soil characteristics and management inputs. Dzotsi et al. used a similar approach, showing that reduced maize, peanut, and cotton models parameterized from the DSSAT CSM model accurately reproduced DSSAT results across time and space. Reduced form crop models allow researchers to produce situation specific summary models that approximate the responses of a more comprehensive model for use in broader scale analyses that may involve socioeconomic, livestock, and environmental sustainability components. Reduced-form crop models can be interpreted as the “production function” that is the foundation of economic production models , and can be linked to economic models to create “hybrid” models for policy analysis and impact assessment . Keating et al. demonstrated a similar process of summary model development, building from the foundation of a comprehensive set of crop soil and management system simulations. They developed a summary model from thousands of APSIM simulations with three key parameters that captured 88% of the variation in space and time of key water balance variables.A central element driving production, profitability, and efficiency in livestock systems is animal performance. Hence, the most commonly used livestock models are those that predict animal meat and milk productivity. Precursors to performance models have existed since the 1940s when the first feed requirements for livestock were developed . Since then,grow lights many have been built and refined regularly across the US and Europe . Nutrient requirements models are the workhorse of the feed industry for ration formulation and for recommending changes in feed management to farm advisors. These models are often based on a mixture of statistical regressions derived from experimental data plus mechanistic principles of the energetics and protein metabolism of mammals.

They also need an estimate of feed intake, perhaps the most important parameter. While these models are good for calculating feed requirements, dynamic models of digestion are more accurate at predicting the nutrient supply to animals under a wide range of conditions from the high-yielding dairy cow to the smallholder goat , because they predict intake more accurately, and they can deal with more complex diets and their interactions. Some models also predict methane production by ruminants and manure quantity and quality, which are important for estimating GHG emissions and the role of livestock in nutrient cycles. These models are typically used to answer ‘what if’ questions around the impacts of different feeding practices or changes of animal types on animal performance . Herd dynamics models follow herd evolution over time in terms of animal numbers and herd structure. Herd dynamics models usually start by splitting a herd into cohorts of different ages or weight, and sex. These cohorts are specified with different mortality, reproductive,selling and replacement rates. Adult females produce offspring at specified reproductive rates, which grow or die, become part of the next cohort, and get sold, and the cycle continues. The best of these models include interactions between animal nutrition and reproduction to drive reproductive and mortality parameters stochastically. This feature is important as feed availability or supplementation strategies have significant impacts on herd reproduction and performance. Some applications of herd dynamics models include estimating optimal stocking rates and carrying capacities, assessing the impacts of reproductive technologies and/or reductions in mortality, and predicting removal of biomass from crop or pasture systems. These models are also widely used by livestock epidemiologists for estimating impacts of diseases on herd mortality and morbidity. They have also been used with dynamic programming for optimizing replacement decisions in commercial dairy herds , or in linear programming applications for studying optimal sales policies, herd sizes, etc. Biological simulation models are sometimes used as input output coefficient generators for linear programming models to aid in the selection of management strategies in livestock systems .These models represent whole livestock farms and their key components . The complexity of some livestock systems justifies the need to build whole-system models using simulation and optimization techniques to represent different components and their interactions . For example, grazing management strategies cannot be defined without also considering herd and nutritional management, since herd dynamics or feed supplementation practices determine the grazing intensity, use of forage, and subsequently animal performance.

Thus, simulations of the biology of livestock enterprises include flexible models representing pasture growth, structure and quality; individual animal performance to test nutritional strategies; and population dynamics describing management practices at herd or flock level , which subsequently determine animal numbers and their age or physiological state classes .Biologists have been building mathematical models to describe the population dynamics of agricultural weeds, pests and diseases for more than a hundred years. Recent progress in modeling these components is discussed by Donatelli et al. ; here we focus more on broad concepts and general state of progress. The diversity of modeling approaches that constitute the current state of science can be categorized in different ways. The first and most obvious is by production type and threat. Thus there are models that describe the dynamics of weeds, diseases and pests that are threats to arable crops, the diseases of livestock, and the diseases of fish used in aquaculture. While threats such as pests and diseases have been recognized since pre-history, the complexities of the microbial communities on the crop surface and in the soil around plants, and in the gut and rumen, are only just becoming more fully understood. Models of the mixture of beneficial and pathogenic organisms that these systems contain have not yet been developed. A broad distinction can be made between mechanistic and non-process-based pest and disease models. The former include explicit biology while the latter use a purely statistical approach. The choice of modeling approach depends greatly on the intended application. For example, a farm manager may want to know when to apply a prophylactic insecticide against a common insect pest. For this purpose, future insect population density may be best predicted by a statistical model containing independent biological variables such as crop stage, and dependent weather variables such as temperature and rainfall. In some cases, information about the pest itself may be included in the model, for example from pheromone or other traps monitored by the farmer or in the case of mobile insects from publicly-operated monitoring networks. A different statistical application is the use of climate-matching models to predict future pest problems. The current distribution of an organism is modeled using a set of predictors including climate. The distribution of the organism after climate change is then estimated by mapping the “climate envelope” using scenarios developed from global climate models. There is now a broad literature on the strengths and weaknesses of this approach, particularly challenging the assumption that organisms are able to move easily to track climate. Important recent advances in statistical models of pest dynamics have included the application of modern spline and neural net estimation techniques, and in the use of personal computers and mobile devices. Mechanistic models incorporate at least some information about the biology of the crop and pest species concerned. The models may be highly abstract – summarizing, for example, a pest population by a single state variable such as density – or, alternatively, highly complex with individual pests each represented by numerous attributes. The simplest models sacrifice realism for mathematical tractability and general insights, while models of intermediate complexity include more biological detail but are constructed in such a way that simpler analytical models can be recovered as limiting cases to help interpretation. Pest and disease models also vary in the degree to which they explicitly incorporate stochastic processes and in whether they treat a population as homogeneous or spatially variable. An important area is the coupling of pest and disease models with crop models . Donatelli et al. review issues involved and existing major projects that have attempted to bridge this gap.

They also propose a road map to improve pest and disease modeling focusing on improving the data resources available for parameterization and validation, bettering the coupling of crop to antagonist models,led grow lights and creating a community of researchers that can collaborate to share expertise and produce community tools.Mechanistic models can be used to predict near-future pest and disease threats in similar ways to statistical models. As was discussed with crop models, they may be more successful than statistical models if biological insights can substitute for missing data or if they can aid prediction by suggesting a model structure that simple statistical fitting would miss. Consider, for example, the response of an insect to daily temperature. Higher temperatures may elevate growth and reproduction, and thus result in more pests, a pattern that could be derived with sufficient weather and population data. Alternatively, the physiological response of the insect could be modeled, which might improve the model’s predictive power or allow insect dynamics to be predicted in data-poor systems . Several schools of physiological modeling exist. However, we are not aware of any formal comparison of different process and statistical approaches to the same problem. An area where biological insights have proven fruitful has been in disease spread through commercial livestock populations. An understanding of how animals interact, and more importantly how they are moved around, can provide critical advice to policy-makers. Current state-of-the-art livestock models incorporate data on movements of animals between individual farms coupled with modern Bayesian parameter estimation. However, the type of data needed for such approaches is prohibitively expensive to obtain or politically unacceptable for many countries to collect . Modeling has also proved valuable in assessing possible pest risks and in guiding general policy development. The basic epidemiological number is the number of secondary cases of a disease that are expected to happen when a primary case occurs in a susceptible population. Calculation of R0 for prevalent human diseases has proved useful in prioritizing investment in control strategies and vaccine development. Today, sophisticated mathematical tools are available for calculating R0 for complex structured populations, for spatially extended populations, and in the presence of stochastic effects . Probably the most sophisticated applications of population genetics to weed, pest and disease issues in agriculture are models of the evolution of resistance to pesticides, and of the dynamics of plant diseases. Evolutionary models can be broadly categorized as genetic or phenotypic. Although phenotypic models have been explored in agriculture , the vast majority of evolutionary models have been genetic. Based on theoretical analyses, areas of fields have been set aside unsprayed or not planted with modified crops that express an insecticide in order to slow the rate of spread of resistance . The genetic basis of plant-pathogen interactions have been resolved for a number of major systems, which has allowed detailed analysis of strain dynamics and how disease spread may be slowed by judicious use of a range of different crop varieties. State-of-the-art work in genetic models of weeds, pests and diseases includes using the avalanche of data that modern high-throughput DNA measurement technologies are providing, and modeling how novel genetic interventions may be used to suppress pest populations. Some of the most sophisticated pest monitoring software now includes specific economic variables with parameters such as commodity prices that can be updated dynamically. The farmer may make different decisions about pest management depending on current market conditions. More generally, a goal of many people working to increase the sustainability of agriculture is to reduce chemical inputs by practicing “integrated pest management”. The models required to support such work are challenging to construct, but some of the most advanced incorporate economic elements as well as various biological processes.Linear economic optimization models of farm systems, developed in the 1950–60s, provide a basis for prescriptive farm management advice .

To decipher the molecular defect in d53, we isolated D53 by a map-based cloning approach. Using an F2 population of ~ 12,000 plants generated from the cross between Ketan Nangka and the mutant, we further delimited the D53 locus to a 34-kb DNA region on the BAC clone OSJNBa0032J07, which contains three putative genes . Sequence analysis revealed a single-nucleotide substitution and 15 nucleotides deletion in the third exon of LOC_Os11g01330 in d53, which resulted in an amino acid substitution and deletion of five amino acids . To verify that this mutation caused the tillering dwarf phenotype, we generated transgenic plants expressing the wild type or mutant D53 gene under the control of rice Actin1 promoter, in a wild-type background. Strikingly, all transgenic plants expressing the mutant d53 gene showed a more exaggerated tillering phenotype than those expressing the wild-type D53 gene. The severity of tillering phenotype in these transgenic plants was correlated with the expression level of the transgene. Notably, overexpression of the wild-type D53 gene also caused a moderate increase in tillering, compared to the vector control plants . These observations suggested that the D53 protein acts as a repressor in the SL-mediated branching-inhibition pathway and that the dominant tillering phenotype of the d53 mutant was most likely caused by a gain-of-function mutation in d53. To further confirm this, we generated D53 knockdown transgenic plants using a RNA interference approach. As expected, reducing D53 expression in d53 background drastically reduced the tiller number . Taken together, these data support the proposition that d53 mutation enhanced D53 activity in repressing SL signaling. D53 is predicted to encode a protein of 1131 amino acids. A BLAST search identified a closely related homolog of D53 with 96.6% amino acid sequence identity in the rice genome. In addition, D53 homologs were found in other monocots and dicots, but not in lower plants, animals or microbes, indicating that D53- like proteins are specific in higher plants . Sequence analysis by the HHpred structure prediction server revealed that D53 shares a similar secondary structure composition, despite low primary sequence homology, to proteins of the class I Clp ATPases family, hydroponic channel which are characterized by an N-terminal domain, a D1 ATPase domain, an M domain, and a D2 ATPase domain36.

Notably, the D2 domain of D53 contains a highly conserved linear sequence, FDLNL, which closely matches the ETHYLENE RESPONSE FACTOR-associated amphiphilic repression motif , which is known to interact with the TOPLESS family of proteins and involved in transcriptional repression37 . Real-time PCR analysis revealed that D53 was widely expressed in the examined rice tissues . D53 promoter driven GUS reporter gene assay showed that GUS staining was observed in vasculature in roots, shoots, leaves, leaf sheaths, nodes, internodes and young panicles, preferentially in the parenchyma cells surrounding the xylem . Moreover, D53 expression was up-regulated by GR24 treatment in wild-type plants, but down-regulated in six d mutants, suggesting that expression of D53 is regulated by SLs signaling . The D53-GFP fusion protein is exclusively localized to the nucleus in rice protoplasts and the pActin::D53-GFP transgenic root cells . Previous studies have identified the F-box protein D3 and the α/β hydrolase D14 as two key components of SL signaling in rice10,12, of which D14 and its orthologues in Arabidopsis and Petunia have been proposed to directly participate in SL perception 19,27,28. Yeast two-hybrid assay showed that both D53 and d53 could physically interact with D14 in the presence of GR24 . Domain deletion analysis indicated that the D1 domain of D53 was essential for the GR24-dependent D53-D14 interaction. Interestingly, its binding activity was inhibited by the M and D2 domains, although their negative effect can be overcome by the N domain . We verified the D53-D14 interaction in N. benthamiana leaf cell nucleus both in the presence or absence of exogenously applied GR24 using a bimolecular fluorescence complementation assay . The observed interaction between D53 and D14 in the absence of exogenously applied GR24 might be due to the effect of endogenous SLs present in the tobacco leaf cells. Consistent with the previously reported GR24-depedent interaction between DAD2 and PhMAX2A in yeast19, our in vitro pull down assay also revealed a direct physical interaction between D14 and D3 in a GR24- dependent manner . Furthermore, using recombinant GST-D3-OSK1 fusion protein as the bait, our in vitro pull-down assay showed that D14 could be more efficiently coimmuno precipitated from d3 plant extracts in the presence of exogenously applied GR24 . Together, these results suggest that SLs may act to promote complex formation among D14, D3 and D53, linking D53 to the hormone-perception components of the SL signaling pathway. To investigate how SL regulates D53, we performed a set of additional experiments. Both western blot analysis and fluorescence microscopy examination showed that GR24 treatment induced rapid degradation of the D53 protein in wild-type cells, but not in d3 and d14 mutant cells . We further showed that D53 was degraded by the proteasome, as a proteasome inhibitor, MG132, but not other protease inhibitors, effectively blocked GR24-induced D53-GFP degradation . Notably, unlike the wild-type D53-GFP fusion protein, the mutant d53-GFP fusion protein appeared to be stable in the presence of GR24 . Interestingly, we noted that D53-GFP and D53-LUC were still degraded in the d53 mutant cells, but not in d3 or d14 mutant cells , indicating that the D53 degradation pathway was still operational in the d53 mutant.

Together, these results suggest that SL triggers proteasome-mediated degradation of D53 in a D14- and D3-dependent manner. Importantly, the insensitivity of d53 protein to SL-triggered turnover is consistent with the observed dominant gain-of-function mutant phenotype of d53. To provide genetic support for the functional relationship between D53, D3 and D14, we generated d3 d53 and d14 d53 double mutants. The d3 mutant had more tillers and it was shorter than the d14 and d53 single mutants . The d14 d53 double mutants exhibited a dwarf tillering phenotype resembling the d14 and d53 parental plants, whereas the d3 d53 double mutant exhibited a dwarf tillering phenotype resembling d3 . The lack of obvious additive effects among these mutants suggests that D3, D14 and D53 act in the same signaling pathway. To further test their epistasis relationship, we knocked down D53 gene expression in the d3 and d14 backgrounds. As shown in Fig. 4g and Extended Data Fig. 9b–d, the mutant phenotype of d3 and d14 was restored to nearly wild type levels, demonstrating that D53 acts downstream of D3 and D14, and that accumulation of D53 protein is responsible for blocking SL signaling and conferring the dwarf tillering phenotype in these mutants. It has been speculated that perception of SLs triggers the degradation of putative repressors by the SCFMAX2 ubiquitin ligase complex to suppress shoot branching21,29,30. In this study, we established that D53 acts as a repressor of SL signaling in rice. Consistent with the previous observation of GR24-dependent interaction between DAD2 and PhMAX2 , we found that GR24 also promotes the interaction between D14 with D53 and D3 . Further, we showed that D53 is targeted for degradation by the proteasome in a D14- and D3-dependent manner . Together, these data collectively support the notion that SL perception by D14 acts to promote ubiquitination of D53 by the D14-SCFD3 ubiquitin ligase, and subsequent degradation of D53 by the proteasome, leading to the propagation of SL signal and downstream physiological responses . Our findings revealed a remarkable similarity between the hormonal perception and signaling mechanism of SL and several other classes of plant hormones, including auxin, jasmonate and gibberellin25,38–40 . Interestingly, a recent study reported that a D53 homologue in Arabidopsis, SMAX1, acts downstream of MAX2 in repressing the seed germination and seedling photomorphogenesis phenotypes of max2, but not the lateral root formation, axillary shoot growth, or senescence phenotypes of max2 . Further, as observed for D53, three closest homologs of D53 in Arabidopsis were also induced by GR24 treatment41, suggesting that D53 and its homologues play a broad role in regulating different developmental processes and that the D3/D53 functional module is conserved between monocots and dicots. Consistent with this notion, the SL-analogous compounds karrikins also employ a MAX2 and KAI2 – dependent pathway to regulate seed germination and seedling growth29,42. The identification and characterization of D53 in SL signaling now set the stage for further dissection of the mechanisms by which SLs regulate plant form and its complex interactions with parasitic weeds and symbiotic arbusular mycorrhizal fungi3 .According to the United Nations, the population of the world is expected to grow in the next century, which in turn encourages the development of innovative techniques to ensure agricultural sustainability. Agriculture on productive land is threatened not only by high levels of urbanization, uneven water distribution, hydroponic dutch buckets and inclement weather, but also is threats to biodiversity that have unfavorable environmental impacts.

Due to the anticipated drastic population growth and constraints on resources in the upcoming decades, only 10% of the demand for food is estimated to be met by expansion of productive lands, with the remainder relying on new techniques that can achieve higher yields. Therefore, developing novel methods to augment the ratio of crop production over used land is a vital issue. In recent years, the indoor vertical farming systems with artificial light are found to be a viable solution to resolve the in-creasing demands of future agricultural products. The IVFS are promising alternatives to open field or greenhouse agriculture because they have precisely monitoring environmental parameters and are insensitive to outdoor climates, which can boost annual sales volume per unit area up to 100 times compared to that of open lands. Furthermore, employment of light emitting diodes as light sources can initiate and sustain photosynthesis reactions and the optical wavelength, light intensity, and radiation intervals can further enhance growth quality. Recently, many studies have been carried out to investigate how environmental parameters, such as closed-loop control, ultrasound, and electro-degradation, affect hydroponic cultivation of leafy vegetables in these systems. One of the most influential factors affecting growth in IVFS is to maintain a uniform air flow at an optimal air current speed over plants canopy surfaces.It has been found that inducing a horizontal air speed of 0.3–0.5 m s−1 boosts photosynthesis through more efficiently exchanging species between the stomatal cavities in plants and the flow of air. Lee et al. studied the effects of air temperature and flow rate on the occurrence of lettuce leaf tip burn in a closed plant factory system. Furthermore, it was observed that the relative humidity of the air flow can significantly influence calcium transportation in lisian thus cultivars. According to Vanhassel et al., higher levels of relative humidity can significantly decrease the occurrence of tip burn. Therefore, it is vital to maintain relative humidity in the desired range to ensure even distribution of calcium in lettuce leaves. Over the past few years, researchers have been trying to develop techniques for improving uniformity over cultivation zones. Regardless of the recent progress, the control and automation systems of IVFS bring additional costs, which makes systematic experimental investigation and optimization a challenge. Computational fluid dynamics has been utilized as a reliable tool to numerically simulate complex physical phenomena. Markatos et al. developed a CFD procedure to study velocity and temperature distribution in enclosures using buoyancy-induced physics. Stavrakakis et al. investigated the capability of three Reynolds Averaged Navier-Stokes models to simulate natural ventilation in buildings. Papakonstantinou et al. presented a mathematical model for turbulent flow and accordingly developed a 3- D numerical code to compute velocity and temperature fields in buildings. A novel gas-liquid mass transfer CFD model was developed by Li et al. to simulate the absorption of CO2 in a micro-porous micro-channel reactor. Yuan et al. visualized the air paths and thermal leakages near a complex geometry using a transient thermal model with buoyancy-driven convection, conduction and thermal radiation heat transfer and flow field near a vehicle structure. In the context of agriculture, researchers have extensively employed CFD analysis for study of ventilation, air flow, and microclimate in indoor systems. Zhang et al. developed a CFD simulation to assess single-phase turbulent air stream in an indoor plant factory system and achieved the highest level of flow uniformity with two perforated tubes.

The Pajaro Valley Water Management Agency formed in 1984 to manage existing and supplemental water supplies within the basin. PVWMA has implemented policies and an assortment of strategies to address groundwater overdraft while maintaining agricultural productivity and meeting water demands in the area, which have risen steadily in the past 50 years along with population, agricultural acreage, and groundwater extraction, with pump age rising from 7.5 million m3 in 1964 to 13.5 million m3 in 2009 . Agricultural land predominates in the valley and was estimated at 10,000 ha in 2006, compared to 5,000 ha for urban and rural municipalities . Crops include berries, vegetable row crops, grapes, apples, and cut flowers, and production has developed into a multi-million dollar agricultural sector with crop yields valued at over $800 million in 2011, and the region ranks fifth for total agricultural production in California . Large corporations, such as Driscoll’s, California Giant, and Martinelli’s & Company helped the area to become one of the top ranked farming cities in the country, and this agroindustrial pressure creates a unique economic environment worth studying, which includes high-value crops, a recycled water system, and an aquifer recharge basin.Although crops shift yearly due to numerous factors such as traditions, preference, economic profit, etc., the total area of agricultural land has remained consistent since 1989 . Agricultural demand for Pajaro Valley was divided into inland and coastal regions. Given the extent of the historic seawater intrusion and coastal access, agricultural demand for Pajaro Valley was divided into inland and coastal regions that are delineated by the CDS and Highway 1 . This study defined inland crops as strawberries, vegetables , bush berries , vine grapes, artichokes, apple trees, cut flowers, and other crops and coastal crops as strawberries,ebb and flow trays vegetables, artichokes, cut flowers, and a small number of other crops. These crop assignments were adapted from the 2012 PVWMA data in the Basin Management Plan Update .

Overdraft of the Pajaro Valley groundwater basin has depleted the aquifer storage and led to saltwater intrusion from Monterey Bay into freshwater aquifers, causing water quality degradation and unsustainable storage levels. Seawater intrusion has been observed up to 4.8 km inland and could potentially reach farther if over extractions continue . PVWMA is executing several measures as part of a Basin Management Plan to address the imbalance of water demands and supplies. The CDS was implemented in 2009 to supply irrigation water to farms in coastal areas with compromised groundwater supplies. Water from the CDS serves in lieu of local groundwater and helps to reduce coastal seawater intrusion by reducing groundwater pumping near the coast through the delivery of a mixture of groundwater from farther inland in the basin, water recovered from a locally managed recharge system, and wastewater from the Watsonville Area Water Recycling Project. This facility and its conveyance system can produce ∼4.934 million m3=year , which includes recycled water, Harkin Slough recovery wells, and blend wells. PVWMA also increased groundwater supplies through the Harkins Slough Project, a managed aquifer recharge and recovery basin. The project aims to replenish a shallow aquifer by infiltrating water diverted from the Harkins Slough in the winter to provide an alternative solution to the overuse of groundwater. Water demand and supply challenges of this area provide a unique opportunity to develop strategies for improved water allocation and conservation. This study uses the coupling of a simulation and optimization model to provide a unique approach to sustainable groundwater management and could be integrated into future decision-making processes and groundwater sustainability plans.A GBM was built and calibrated to represent the water supply, water use, and groundwater storage of Pajaro Valley groundwater basin. An optimization model was built to determine crop acreages that maximize agricultural profit given water availability constraints. The models were coupled to estimate the aquifer storage and assess the sustainable carrying capacity of Pajaro Valley groundwater basin by using the outputs from the optimization model as inputs into the groundwater box model.Data sources for inflows included land use data and Harkin Slough recharge inflows obtained from PVWMA and precipitation and reference evapotranspiration obtained from the California Irrigation Management Information System. An estimate of evapotranspiration was developed based on data from the National Solar Radiation Database and the Hargreaves-Samani equation whenever ETo data was unavailable . Monthly crop coefficients values were obtained from Hanson et al. . In this study, the agriculture water demand was estimated using potential evapotranspiration, which can differ from the actual evapotranspiration. The application efficiency was assumed to be spatially uniform throughout the valley.

The percentage of irrigation use for gravity, sprinkler, drip, and other methods were obtained from the California Department of Water Resources and average application efficiencies were obtained from Sandoval-Solis et al. . Data sources for outflows include population data for the City of Watsonville, and rural municipalities that were retrieved from the US Census Bureau , and water use per capita for indoor and outdoor consumer water use from 1999 to 2015 was obtained from Cahill et al. . WUPC from 1966 to 1999, was assumed as the fixed value of the 1999 WUPC. Similarly, WUPC from 2016 to 2040 was assumed to be the same value as in the year 2015. Rural WUPC was estimated to be 29% of the City of Watsonville, based on the urban-rural population ratio. The acreage factors and acreage share percentage were obtained from Lin et al. . Well production data for the City of Watsonville, agricultural wells and recycled water was provided by PVWMA. Linear regression models were used to fill gaps when input data for specific periods were missing. Table S1 shows the model equations.Based on Eq. , at a given time, a groundwater basin has a certain amount of water that might increase or decrease based on the change of storage. If the total inflows are greater than the total outflows, the positive change will increase the groundwater storage. Conversely, if the outflows exceed the inflows, then the negative change will result in the decrease in groundwater storage. In this study, net groundwater storage is defined as the average change of storage for a determined period, and the change of storage is calculated every year by subtracting the inflows minus the outflows. GBM inflows ranged from 24.6 to 96.6 million m3=year, and outflows ranged from 40.7 to 98.6 million m3=year. In contrast, PVHM inflows ranged from 16 to 103 million m3=year, and outflows ranged from 30.8 to 90 million m3=year. Groundwater pumpage is dominated by agricultural use and was 13.5 times greater than urban and rural water demands. Recharge to the aquifer from precipitation is 6.2 times greater than recharge due to excess irrigation. Fig. 2 shows the net change in groundwater storage of the GBM and PVHM.The optimization model was built to estimate a series of optimal acreages that maximize economic profits. Profits were estimated as yearly benefits , which were the difference between crop revenue and the costs of production for that crop. All prices were adjusted using the consumer price index for 2015. Crop revenues were calculated based on crop incomes from crop reports and economic contributions of Monterey County from 1966 to 2014 and the annual crop and livestock reports of Santa Cruz County base.

COP components of the model were obtained from budgets published through current cost and return studies from the University of California Cooperative Extension . These budgets were used to determine annual costs per acre for each crop including operational, cultural, and overhead costs that covered land preparation, plant establishment, fertilization, pest management, harvest, labor, equipment costs, property taxes, irrigation, sanitation, and management salaries. The price of water was removed from each budget because it was included separately in the optimization equation for specific circumstances in Pajaro Valley. COP budgets for crops grown in the California central coast region were used for strawberries, vegetables, bush berries, artichokes, and apple trees, while the COP budget for grapes grown in the upper San Joaquin Valley was used for vine grapes. The UCCE has not published a COP budget for cut flowers in California; therefore estimates were made based on COP budgets developed by the Cooperative Extension at Penn State University. Based on budget availability, each crop was treated slightly differently. The COP for strawberries was found by taking the average of two budgets, one for each year of production . The COP for vegetables was determined based on budgets for various types of lettuce grown in this region because lettuce is commonly used in rotation with strawberries . The COP for bush berries was calculated through consideration of the budgets for raspberries and blackberries,4×8 flood tray including an establishment year, the first year of reduced production, and four subsequent years of steady production . The COP for artichokes was based on a single production year . The COPs for apples and vine grapes were based on a 25-year life of an apple orchard and vineyard, respectively . The first year of establishment for vineyards is the most expensive, with subsequent years costing one-third of the initial price. The COP of the other crop group was based on the budgets of alfalfa, wheat, and beans . Table 2 shows the COP budgets and revenue figures. All crops show economic benefit except for vine grapes, for which revenue remains below the break-even point. From the year 2000 to 2010 vine grapes had economic benefits, but not from 2010 to 2015 where COP exceeded revenues. Vine grapes have become less economically viable in recent years because of inexpensive imports from Australia, competition from corporate farms in other regions of California, and the fact that harvest standards often change in harvest time, hang time, and Brix standards .

The cost of water in Pajaro Valley was defined by the price of water and the energetic cost for pumping. Annual rates published by the City of Watsonville and PVWMA set water prices, which differ based on user location and water source . Water prices ranged from $101 to $338 per acre-ft and increased with an average yearly rate from 3% to 9.5% . The energetic cost of pumping was estimated to range from $0.18 to $0.20 kWh for an average well depth of ∼90 m for domestic wells, and ∼131 m for municipal wells .The coupled model determined the optimal crop pattern by maximizing net economic benefits while constraining agricultural water and land use, which decreased groundwater overdraft. Both scenarios began in the year 2000 with approximately ∼8,000 ha and 62.5 million m3=year of water use. For the next 15 years, the trend increased to ∼8,500 ha and 64.1 million m3=year for the baseline scenario and these values were maintained until 2040. The optimized scenario decreased water use to 49.3 million m3=year for ∼6,315 ha . The crop acreages that gained the most economic revenue and water use were bush berries, cut flowers, strawberries, and vegetables. These crops were allocated within their maximum allowable acres. The lowest crop revenues were for apple trees, vine grapes, artichokes, and others, reflecting their minimized acreages. The optimal land use had a total acreage reduction of 15%. The objective function was to maximize the net revenue from agricultural production while determining the optimal crop pattern for the available water. A similar objective function is observed in other studies. Mainuddin et al. determined the irrigation plan by optimal crop area allocation and groundwater requirement by maximizing the net economic benefit in Thailand. Benli and Kodal developed a linear model that allocates optimally available resources, rearranges crop patterns, and maximize economic crop revenue. These studies showed a decrease in available water corresponded to the upper limits of acreages of higher values crops, which is consistent with the finding from this study that crop acreages increase or decrease relative to the change in their economic profit. Regarding economic benefit, the baseline scenario showed total revenue of $274 million, which increased to $289 million in the optimized scenario using the same allotment of water . The net difference between the optimized and baseline scenario is shown in Table 4, where the pattern of higher revenue for the optimized scenario is observed even when the available water was reduced to 60 million m3. However, if available water is reduced to 50 million m3, revenue is reduced to ∼$239 million. In general, annual revenue decreased by 2.4% on average, which translates to ∼$5 million loss per reduction of 1.2 million m3 of available water.

Moreover, despite clearly being a developing country, China’s de minimis exemption for product-specific support is equivalent to only 8.5% of the total value of production of a basic agricultural product . Moreover, some measures, such as investment subsidies for all farmers and input subsidies for the poor and other resource-scarce farmers, that are generally available for policy makers to use in developing countries, are not allowed in China . Because of its Socialist background and the difficulty that the world has had in assessing the scope of the government’s intervention into business dealings of all types, China agreed to a series of measure governing the way that they will deal with the rest of the world in cases of anti-dumping and countervailing duties. Most simply, special anti-dumping provisions will remain for 15 years. According to these provisions, in cases of anti-dumping China will subject to a different set of rules that countries can use to prove their dumping allegations. In addition, the methods that countries can use against China to enforce anti-dumping claims when they have won will differ from most of the world. In essence, this set of measures makes it easier for countries to bring, prove and enforce dumping cases against China. It should be noted, however, that that although the rules differ from those governing trade among other countries, China will get the same rights in their dealings with other countries, a element that could help them in some cases with their dealings with dumping matters when they concern their partners’ exporting behavior. China’s WTO commitments and privileges associated with the measures in other parts of the agreement also will directly or indirectly affect its agriculture. For example, on agricultural chemicals, China has committed to replace quantitative import restrictions on three types of fertilizers by TRQs. Tariffs will be cut on accession and further cuts will be phased in by 2005 in almost all industrial products, . Furthermore, China will reduce significantly its non-tariff measures and eliminate all quotas, tendering and import licensing on non-farm merchandise by no later than 2005. For textiles and clothing, however, the current ‘voluntary’ export restraints will not be completely phased out until end of 2008, meaning that the expansion of exports may not expand as fast as they would under a less restrictive regime.

Substantial commitments to open up services markets in China also have been made. While substantial institutional and marketing reforms implemented in agriculture since the late 1970s will help facilitate the response of households to the changes that will arise with the implementation of WTO and, flood table more generally in China’s overall transition to the post accession WTO regime, China still requires considerable reform to meet its WTO membership commitments . In fact, the government has realized for a considerable time that it faces a real challenge. In fact, in many instances, officials are taking this challenge as an opportunity to stimulate and accelerate its on-going reforms in both international and domestic policies. Policy responses as a result of WTO accession are expected take one of two forms. One is a policy response that is required of China in order for it to be able to keep the nation’s commitments and to adjust its domestic policies to be consistent with those promulgated by the WTO’s rules. The other is a response that will consist of introducing some new set of measures that are allowed under the new framework that could help to boost China’s economy and minimize adverse shocks that arise as part of the accession. Identifying the two kinds of policy changes is essential to study how China’s WTO accession will affect the ways that policy makers respond after accession.Many of the most important changes that will occur because of WTO will be in the area of legal and legislation changes. China reserves the right to use a transitional period of one year from the date of accession to amend or repeal any institution, regulation, law or legal stipulation in its current economic policies in order to make them consistent with the spirits of nondiscrimination and transparency. The government recognizes this and has already started to make a concentrated effort to rectify existing legal rules and legislation in the late 1990s. To provide a general guidance for ministerial and local government authorities to amend or repeal the relevant regulations, laws and policies, the State Council decreed two important Regulations in January 2002: the Regulations on Formulation Process of Laws; and the Regulations on Formulation Process of Administrative Laws. Essentially, a guide for local governments and ministries, these new regulations were issued with the aim of transferring many government functions toward the market and directing the government to take a more regulatory, indirect role in commerce and trade. It tries to limit the role of government and emphasizes that the role of government is primarily one to provide social and public services. The regulations also seek to simplify administrative processes and increasing the transparency of regulations and policies.

For example, during the last stage of WTO negotiation, each ministry formed its leading group or committee to work on all of the laws and regulations under its jurisdiction. These committees typically were comprised of decision makers and experts who had the mandate of cleaning up all existing regulations and preparing a proposal for amending or repealing those laws and regulations that are not consistent with the WTO rules and China’s commitments to its WTO accession. Local governments also had similar committees. Ministries and provincial government are also working closely with its corresponding law and regulation committee under the Standing Committee of the National People’s Congress for those laws and regulations to be amended or repealed by the People’s Congress. Several recent experiences involving amending laws and regulations and creating new institutions related to agriculture demonstrate the effectiveness of these committees and China’s overall commitment to its WTO obligations. For example, China’s Patent Law was re-amended on July 1, 2001. Many of the associated regulations also were redone. Moreover, a new set of regulations on Plant Variety Protection was put into effect in 1999 when China became the 39th member country of UPOV. Soon after passage, government agencies quickly proposed and implemented detailed regulations facilitating the implementation of PVP. The MOA and State Forest Bureau also created a new set of institutions, a series of Plant New Variety Protection Offices. Finally, China’s Seed Law was issued in 2000. Hence, the rights of new plant varieties are now protected by both the PVP and Seed Law. To assist in the initial implementation of these laws the government has set up an IPR Affairs Center under the Ministry of Science and Technology. In order to fulfill its legal obligations related to agriculture, MOA also has repealed several regulations since 2000 that sought to subsidize certain types of enterprises and apply different rules in agricultural input industries to different economic actors. Officials have eliminated the Regulations on the Development of Integrated Agricultural, Industrial and Commercial Enterprises under State Farms and the Regulations on the Development of Rural Township and Village Owned Enterprises . Seed Management Regulations that gave monopoly powers to local seed companies and Pesticide Field Trial Rules that discriminated against foreign companies were abolished. Despite the above substantial efforts, China still requires considerable institutional reform. There are still a number of laws and rules that treat domestic and foreign companies and individuals differently. These changes still need to be changed to allow China to fulfill the legal obligations that they are committed in its Protocol of Accession to WTO. It may be even a greater challenge to build up the nation’s capacity for effective implementation of the amended and new laws.

Reforms and liberalization in China’s trade laws and regulations are perhaps the most advanced, in part, because of its strategic role in the economy . Through nearly 20 years reform, China’s foreign trade regime has gradually changed from a highly centralized, planned and import substitution regime to a more decentralized, market-oriented and export promotion one . These changes in trade and other policies have significantly affected the total and composition of China’s trade in favor of the products in which China has a comparative advantage. On the other hand, as argued by Martin , while China’s trade policies in most areas have been transformed in the reform era, trade in many agricultural goods remains under relatively non-transparent state trading arrangements. Accession to the WTO will be a critical time for China to push its trade reform in agricultural sector, including both tariff and non-tariff measures. Changes in tariff policy are more straightforward and simpler than non-tariff policy reforms. China followed its tariff reduction schedule specified in the Protocol on the first day of 2002. Average tariff rate was reduced from 15.3% in 2001 to 12%. For agricultural products the tariff reduction was from 21% to 15.8%. China has also started to implement its three years of transition of progressively liberalize the scope and availability of trading rights for agricultural products as discussed in the last section. Export subsidies have been ordered to be completely phased out on the first day of 2002. Compared to the trend of tariff reduction in the past decade, the tariff changes due to China’s WTO accession should present relatively few problems. Significant reforms will,however,rolling benches be required in the area of non-tariff measures. Among various aspects of non-tariff barriers, state trading could be a particular important area to consider when reforming China’s agricultural trade policy. China has agreed to phase out restrictions on trading rights for all products except those under TRQ trade regime that will implement a more gradual approach in phasing out the state-trading regime . After three years of WTO accession, the private sector is supposed to dominate the trade of almost all agricultural products. There are provisions to keep the state involved in three commodities, however: wheat, maize and tobacco. The measures for Technical barriers to trade and sanitary and phy-sanitary as well as institutional arrangements to fulfill the agreement on Trade-Related Intellectual Property Rights are the other important issues which China has to deal with. The Agreements on TBT and SPS focus on using internationally accepted standards to discipline the use of standards as protectionist devices. This rules-based approach can be valuable in improving policy formulation, but is likely to require investment in strengthening standards related institutions. Comprehensive adoption of these measures should lead to improved policies and, by basing policies on a scientific approach, move away from the time-consuming and inefficient approach of resolving these issues on a political basis. China will undoubtedly struggle in its effort to create a fully transparent and open trade regime with respect to non-tariff barriers. The case of labeling requirements for GMO imports, most conspicuously soybeans, shows how frustrating and protracted the creation of any set of regulations and institutions can be. In June 2001, the government suddenly announced that in response to concerns about the presences of GMO foods in the nation’s import basket, it would require that all goods contained GMOs from there on out would require labeling. Unfortunately, no one in the world who was shipping to China had a system in place to do so. China did not tell any one what was the process to apply for a permit for importing labeled commodities or the place to learn about the process. Initially, trade in soybeans was thrown into disarray. China’s traders lost money, soybean users faced tremendous losses, and prices threatened to rise sharply. Even when facing such a crisis, there was no way that any agency could clarify the matter or announce a plan. Instead, the government postponed any decision to an unspecified future date and trade has since continued.2 The point of this is, however, that even when there is a crisis facing the external sector is often is difficult to rapidly come up with effective and transparent regulations and implementing processes. After 20 years of reform, China’s agriculture has become much more market-oriented . Traders moved products around the country with increasingly regularity and factors adjusted more rapidly. By the late 1990s, only grain, cotton, and to some extent silkworm cocoon and tobacco, were subjected to price interventions. But even in these cases, their markets, especially those for grain, have been shown to have become increasingly competitive, integrated and efficient overtime .

We can look at the effects from only two recessions, 2001 and the Great Recession, because the CPS does include certain key variables prior to 1994. It also lacks a variable on bonus payments. In contrast to the NAWS, the CPS data does not record whether an immigrant is undocumented. Therefore, we focus on immigrants in general and form interaction terms between immigrant status and the recession dummies. Otherwise, we use as similar a set of demographic variables as possible. Table 4 presents the regression results for the ln wage and weekly hours in the three sectors. In none of these three sectors did either recession affect the wages of non-immigrants or of immigrants. Presumably, wages are sticky in these sectors, partially due to union and other contracts and minimum wage laws. The unemployment rate had a statistically significant effect only in the construction sector, and that positive effect is small, as in the agricultural sector. The 2001 recession did not affect the weekly hours in these sectors. The Great Recession reduced weekly hours by 1.3 hours in the hotel sector but not in the other sectors. Thus, for most employed workers in these three sectors, weekly hours remained constant during recessions. This result contrasts with that in the agricultural sector where weekly hours rose substantially during recessions.But they most often use traditional technologies, despite the existence of more modern alternatives. This puzzle has sparked extensive research to understand which barriers constrain technology adoption. Researchers have focused most particularly on credit and insurance markets failures and on information frictions . Focusing on the latter, decades of research show that knowledge indeed plays an important role for adoption . Recognizing this, governments have invested heavily in dispatching agricultural extension workers throughout rural areas to transmit information from scientists to selected farmers — with the hope that information will then flow to others via social networks. But these public-sector efforts are widely recognized as having had limited impact . In advanced economies, by contrast,berry pots private businesses have become the main source of information about technological innovations for potential clients. Farmers rely on commercial input dealers not only to purchase inputs but also to be informed about available technological options.

These dealers are in turn informed by the companies whose products they sell and by public agricultural agencies and research institutions . In developing countries, could there similarly be a greater role for private business-motivated entrepreneurs in the public agricultural extension system? The optimal boundary between government and private entities in the provision of public services is an extensively studied topic in economics . Empirical research has found that outsourcing public service delivery to private firms can improve provision in many sectors such as potable water, health, food distribution, and education . Unlike these sectors, developing country agriculture has yet to see a large role for private business in delivering public services. Agriculture thus offers an opportunity to study whether private input suppliers can internalize benefits from the spread of information and become agents in the delivery of public services. Our experiment provides information on new technologies to local input suppliers , rather than to selected farmers as in the business-as-usual approach. Specifically, we give agrodealers access to a new seed variety for their own learning. Taking this business-oriented approach to agricultural extension could influence farm-level adoption in different ways. On the one hand, input suppliers — unlike contact farmers — have economic incentives to spread information. They stand to reap profits when suggesting the use of new inputs to farmers. Repeated interactions with farmers over time may discipline them into providing high-quality recommendations benefiting their clients.1 On the other hand, agrodealers might purposefully under-provide quality . Or they may recommend products that maximize their own profits instead of customer welfare, as has been observed in numerous other sectors . These concerns about securing through agrodealers adoption of the right technologies by the right farmers are akin to concerns about the quality of public services provided by the private sector . Therefore, our analysis seeks to answer both whether informed agrodealers increase adoption and whether they do so for the farmers that stand to benefit the most from the innovation. We study these questions with an experiment where information services are provided to local seed dealers. Our sample consists of 72 blocks, spread across 10 districts in the Indian state of Odisha.

We consider the dissemination of Swarna-Sub1, a new and profitable flood-tolerant rice variety that reduces the damage caused by flash flooding.We partnered with the government extension service to support their conventional activities in 36 control blocks. This included providing seed minikits to the contact farmers on whom they rely to use the new technologies and spread information about them in their social networks. It also involved carrying out large-scale “cluster” demonstrations where many farmers grow the new variety on contiguous pieces of land, and organizing farmer field days to share results from demonstrations. These are all activities the government extension service would do with adequate resources, but we supported them as part of the experiment to make sure that they were carried out and that our control group reflects business-as-usual activities at their best. We provided the exact same quantity of seeds and the same information to input dealers in the 36 treatment blocks. We did not support any conventional extension activities as was done in the control blocks. These dealers are highly local, small-scale businesses, selling seeds and sometimes other inputs such as agro-chemicals. They were free to choose how to use the demonstration seeds. The key distinction between this treatment and the standard mode of agricultural extension is that information constraints are being relaxed on the supply side, rather than on the demand side for new technology. The treatment tries to leverage the natural incentives created by the marketplace for private businesses to transmit information to their clients. Turning to the results one year later, we find that the dealer-based approach to the diffusion of information increases adoption of Swarna-Sub1 — the variety being introduced — by over 56 percent, i.e. from 6.3 to 9.8 percent of farmers. We further find that the average farmer in the treatment blocks is cultivating 69 percent more land with the variety, and the cultivated area of adopters increases on the intensive margin by about 9 percent. Consistent with these results on farm-level adoption, we find that the treatment triggered a supply-side response.

The magnitude of this response is similar to the increase in adoption. By the 2018 season, two years after the new seeds had been introduced, dealers in treatment blocks were about 59 percent more likely to have Swarna-Sub1 in stock. There is also some evidence that informing agrodealers causes a change in local input production. Treatment blocks were producing 40-50 percent more Swarna-Sub1 seeds during the three years after the intervention. An immediate next question is whether farmers induced to adopt in the dealer treatment are those with relatively higher expected returns. Dealers may invest little in promoting a particular input to the right farmers if something else provides them higher profit margins. Dealers in our setting principally sell seeds that are produced by the state-run seed corporation — that fixes both wholesale and retail prices equally for all seed varieties. This aspect of our setting eliminates a differential price motivation for dealers promoting the new technology. We consider a different possibility where dealers might encourage adoption by farmers with the greatest potential benefits if they want to maintain a good reputation as providers of high-quality advice. To consider this, we test for treatment-effect heterogeneity according to past flood exposure — an important determinant of returns.We find that the treatment effects of dealer-based extension are largest for households that are expected to have the highest returns. We would not expect this type of heterogeneity if dealers were sharing information indiscriminately or without considering the possible benefits for farmers. This offers a first piece of evidence that dealers are concerned with their reputation when sharing information. We then explore whether dealers proactively promote the new variety and what might explain their behavior. For this, we sent “secret shoppers” to around 300 dealers to inquire about new rice varieties in the third season of the study — two years after the seeds were introduced. We find direct evidence that the treatment changes what dealers say to farmers coming into their shops. Dealers in treatment blocks are about 25 percent more likely to mention Swarna-Sub1 when listing the new varieties to consider. When specifically asked for a recommendation,hydroponic grow system we find that dealers are less likely to recommend older types of seeds and in some cases more likely to recommend trying SwarnaSub1. These findings suggest that relaxing information constraints on dealers leads them to share this information with farmers. As a final piece of evidence, we ran an experiment to test whether business incentives and reputational concerns motivate dealers to spread information. In partnership with a local NGO, we revisited dealers during the fourth season to further solicit recommendations. Each dealer was randomized into one of two treatments. In the first treatment, someone visited the dealer and asked which farmers, locations, and varieties would be best for a demonstration where farmers would cultivate a new variety and then the NGO would organize a meeting with other villagers to explain its attributes. Importantly, the name of the dealer giving the recommendation would be advertised during the meeting. We refer to this treatment as the reputation treatment because the dealer’s identity would be publicly displayed as part of the demonstration. In the second treatment, the program was presented as one where the NGO would not name the dealer and would collect the harvest after the demonstration and redistribute it as seeds to other farmers. This treatment reduces the salience of reputation for the dealer and lowers their business motivation by reducing the demand that would be created by the demonstration.

We find that priming dealers to consider their reputation and business motivation changes the advice they give. In particular, it causes them to suggest different locations, types of farmers, and seed varieties. Starting with location, when presented with a candidate list of villages for the program, dealers in the reputation treatment are more likely to suggest a village not on that list. Most of this is explained by treatment dealers being more likely to suggest their own villages. Dealers in the reputation treatment also spend more time thinking of which farmers to recommend. They are more likely to suggest neighbors or other people in their own village. Finally, the reputation treatment causes dealers to recommend less common seed varieties. Taken together, these findings suggest that business interests and reputational concerns play a role in the information sharing process for dealers.These results help interpret the findings in our main experiment. Concerns over market share and reputation could be factors causing dealers to promote an improved seed — even if it does not provide them with higher profit margins. In sum, we present the first evidence on how leveraging private agents on the supply side of input markets can help disseminate agricultural technology more effectively than the conventional methods used by the public sector. An important channel through which this happens is that dealers, when they gain information, spread it actively to farmers. Importantly, the gains from leveraging agrodealers are largest in areas where the technology delivers the highest benefits to farmers. Reputational concerns may be one of the factors that motivates dealers to match the technology to farmers with the highest expected returns. These results contribute to the literature on public-private partnerships by showing how using private-sector input suppliers to spread knowledge can improve the delivery of public services.Moreover, it does so at a lower cost compared to expanding the current practices used in the public sector. It is cheaper to visit a small handful of dealers compared to carrying out large-scale demonstrations and training. Our findings contribute to the literature on agricultural technology adoption in the developing world.Several studies consider different methods to improve the provision of extension services. For instance, cell-phone-based monitoring of extension workers can help solve agency problems and increase the number of farmers reached . Alternatively, researchers have considered efforts to better select, incentivize, and train the farmers that the extension service partners with . Finally, field days to share information from demonstrations is a commonly used technique . This literature has focused on ways of reaching more farmers via the traditional channels — either through direct outreach or by learning from the contact farmers that were trained by extension workers.

The settlers participated in organized, communal holiday events such as Hanukkah, Purim and the annual Passover Seder. There were bar and bat mitzvahs that celebrated the coming of age of Jewish boys and girls, as well as funerals that honored those who passed. Indeed, settlers had “established a religious burial society and created a small Jewish cemetery” that served the colony.The 1950 figures, again culled from the Rosenzweig Report in Bruman’s Field Book III, divulge that DORSA allocated monies totaling $7,900.00 to subsidize various functions and administrative arms at the colony. This included $400.00 for ‘Religious Purposes,’ but also $3, 500.00 for the school and $1,000.00 for the Hospital. The Sosúa Council had responsibility for administrative oversight at the colony, and the settlers made monthly contributions to the Council that were from 1% to 3% of their income. Bruman noted that the Loan Cooperative filled the basic banking needs of the Sosúa settlers. The cooperative functioned as a bank and clearing house for all financial transactions at the settlement. Indeed, all “money transactions of the Sosúa Cooperative were made through the Loan Cooperative.”Sosúa also had its entrepreneurs who began private enterprises at the colony. One of Rosenberg’s key goals for Sosúa was the establishment of small crafts and niche businesses to create revenue streams aside from a farm-based income. They included a turtle-shell business that made arts and crafts goods, which were then sold throughout the country, a haberdashery which made shirts and pants, a cobbler who also made slippers, several restaurants, and a cinema which had its own ‘Cine bar’ selling refreshments. Also included among the fledgling businesses were a plumber and a dentist whose services were not paid for by DORSA. The colony’s reliance on agriculture as its primary source of income did not pan out, and showed that a shift to dairy products was necessary if the colony was to become self-sustaining and profitable. That change came with the addition of cattle, dairy cows,ebb flow and pigs. In about four years since its first refugees arrived in May 1940, Sosúa’s dairy industry had grown into a thriving business with national importance.

The new emphasis on dairy and meat products, made it clear that Sosúa’s initial focus on agriculture had been a failure. Sondheimer wrote that “It was soon seen that the best source of cash income was from milk production. The original plan was revised,” and the economic focus shifted to dairy products and meat processing. Each settler who joined the Cooperativa Industrial Lechera, C. por A. or CILCA by its initials, founded in late 1941, and the Ganadera meat cooperative founded in 1945, became shareholders with one share in each of the enterprises. The Ganadera “slaughtered meat, tenderized beef and ham, and produced bologna, frankfurters, and sausages.”Both CILCA and Ganadera became award-winning anchor businesses that drove the economy of Sosúa. Indeed, their products were sold throughout the island with CILCA butter “in constant demand [because] it is considered the best butter produced in the Republic.” Rosenzweig noted that “out of the 27,000 total acres of the settlement, 18,000 were judged suitable for grazing. Sondheimer’s report of 1944 noted that the improvement in the breeds of animals was done through “the judicious introduction of [imported and superior] breeding stock.” The inferior, native breed of cattle was cross-bred with imported Holstein, Zebu and Senegal bulls, which translated into heartier and heavier calves, and increased yields of milk and meat.The CILCA C. por A. is, at the time of this writing in 2016, still in business, although no longer wholly owned by Jewish settlers/stockholders. It remains a visible reminder of Sosúa’s success as an agricultural colony founded by Jewish refugees fleeing the violence of war torn Europe more than half a century earlier. The Ganadera, Compania Industrial Ganadera C. por A. also enjoyed phenomenal success, with their meat products sold throughout the island and elsewhere. Indeed, from its inception as a small, local Jewish co-op, it experienced increased sales and profits throughout its life. By 1950 it had an annual turnover of an impressive $200,000, whereas in the preceding year, 1949, its receipts were $164,000.The turnover at CILCA C. por A. was equally impressive. In 1949 the receipts totaled $198,000, and by 1950 they jumped to over $245,000. The hapless Jewish refugees who arrived in Sosúa in 1940, built a business empire that is today valued at over millions of dollars, this in spite of the tremendous odds that were stacked against them.

People without a country and land to call their own, a people who had their personal possessions and wealth confiscated, and who were involuntarily pushed out of their homeland, were the success of an experiment happening leagues away from the madness then infecting most of the world.The end of the colony paralleled that of World War II. Many refugees had arrived at Sosúa with no intention of staying on as farmers or ranchers. Some did not want to remain in the Dominican Republic at all, and were among the first to flee the colony when they had the chance. Some who had connections and/or family in the United States, moved there directly after the war. A few chose to return to their European homeland, still reeling from the effects of more than six years of conflict. Then again, some migrated into other Latin American countries such as Brazil, Argentina and Chile. Some remained at Sosúa, yet moved from the homestead farm to the administrative hub at El Batey to be closer to ‘downtown’ and its attractions. Today only a small museum resides at the site of the original colony, reminding those who now come in search of tropical dreams, that this was once a Promised Land for some ‘hapless’ Jewish refugees who had escaped the Nazi terror.Rosen had developed a successful agricultural settlement model in Crimea based on the three-point plan discussed earlier. However, what worked so well in the Crimea failed miserably at Sosúa. It must be noted that the Bolivian haven for Jewish refugees at Buena Tierra in the Yungas region was, according to the historian Leo Spitzer, also an abject failure. Such failures, on the other hand, can be considered as successes given that they had achieved their original objective: saving lives. Buena Tierra was cobbled together from three formerly profitable but now derelict haciendas: Charobamba, Santa Rosa, and Polo Polo in the semitropical Yungas region to the northeast of the capital city of La Paz. As with Sosúa, Buena Tierra included a professional agronomist who did detailed surveys of available tracts of land on which to settle the Jewish refugees. Bolivia also had, as in the Dominican Republic, a president, Germán Busch Becerra , who came from the ranks of the military. After a military coup, Busch seized the presidency in July of 1937. Busch was born in the Beni Province to a physician father who had emigrated from Germany at the beginning of the twentieth century and a Bolivian mother of Italian heritage.98 Busch also wanted to establish agricultural settlements in Bolivia, some years before the conference at Évian took place. Busch’s chief reason for supporting agricultural settlements was that Bolivia was held hostage by fluctuations within the international commodities markets where it had to purchase essentials.

Bolivia, under Germán Busch, struggled to become self-reliant and feed itself. Busch’s strategy was to avoid any of the pitfalls inherent in the international commodities markets.99 The Bolivian president’s ally, Mauricio Hochschild was a billionaire mining magnate and naturalized Bolivian. Both men saw the wisdom of having “European immigrants as agriculturalist colonists to cultivate and exploit the vast, potentially rich, but largely undeveloped semitropical and tropical areas of the country.” The recruitment took place through Bolivian Consular officials stationed in Europe, who “were instructed to attract prospective agricultural immigrants with an offer of free land, free transportation within the country, and a one-year maintenance allowance.” This experiment resulted in the founding of the Colonia Busch. The colony failed from the start,greenhouse benches yet it also provided a model for future colonization of the Yungas by Jews who had fled war-torn Europe in droves.100 In early 1940 Hochschild and officials from the Joint founded the Sociedad Colonizadora de Bolivia, or SOCOBO, which oversaw the development of Jewish agricultural settlements, including the training of the would-be settlers. SOCOBO functioned much like its Dominican twin DORSA. It was a legal corporation that entered into agreements and contract negotiations with government officials. It also handled, along with officials from the Joint, the logistics involved in getting Jewish refugees into Bolivia, and then supplying them with the necessary funds, housing, seeds and farming equipment to begin life anew as Bolivian farmers. Much faith was put in the word of Felipe Bonoli, the Italian agronomist and naturalized Argentine who had past success in Argentina establishing a settlement of Italians on the land. Bonoli had gone to the Yungas region to report on the state of the land and the feasibility of purchasing the properties. The plan was to combine the three derelict haciendas into one large settlement and rename it Buena Tierra. The Yungas region is in the lush semitropical Andean lowlands, an area with plenty of rivers for irrigation. The three haciendas were once thriving farming concerns “on which coffee, cocoa, mangoes, oranges, tangerines, bananas and coca had once been cultivated,” yet had been abandoned by their former owners.Bonoli had deemed the properties suitable for settlement as their fertile soil could be recycled and put into cultivation and pasturage. Bonoli was also taken by the physical beauty of the semitropical, lush Yungas, as were investigators for the REC. Echoing the sentiments of Rosenberg and Rosen about the natural beauty of Sosúa, REC investigator Walter Weiss gushed with praise for the Yungas site; “Not only is the soil long-rested and fertile with mountain streams running in sufficient quantities [but] nowhere in our far West have I seen more wonderful panoramas.”

Members of the REC and the Joint believed that Buena Tierra would be attractive to the refugees as a sight for settlement. The pioneers would have land, low-cost housing and opportunities not available elsewhere on the continent. Recall that most Latin American countries closed their doors to Jewish refugees who came in search of a safe haven, so the list of places in which to immigrate was very short indeed. In addition to the difficulties one encountered fleeing Europe, were the difficulties of getting to the extremely isolated colony. The trip from the capital of La Paz was a ‘terrifying one.’ One left La Paz, altitude 11,000 plus feet, ascended an additional 3,000 feet to La Cumbre, and then began the hair-raising descent into the Yungas and its ‘green, lushly vegetated valleys.’In a masterful bit of understatement, Spitzer noted that “travel on this road is not an easy journey to undertake.” This was aptly illustrated by the numerous crosses that dotted the narrow road, put there to mark the spot of the frequent, fatal crashes that happened to careless travelers. The lack of a network of passable roads accessible by automobile or truck further enhanced the colony’s isolation. It was essential to build a network of roads that would connect the colony with the outside world, one which would facilitate access to domestic markets and ports. Bolivia was in the main dependent on imported goods and foodstuffs for clothing and food. Bolivians consumed rice from India, drank coffee grown and processed in neighboring Colombia and Brazil, and used wheat grown in Canada and Argentina to bake their bread and pastries.It was hoped that agricultural colonies such as Buena Tierra could put Bolivia on the path to feeding itself and, in the process, become self-sustaining. The money saved by reducing costly imports would be invested in settlement schemes such as Buena Tierra. Money would also come from the Jewish philanthropies such as the Joint, and the recently founded protection society known as the Sociedad de Protección a los Imigrantes Israelitas, or by its acronym SOPRO. The SOPRO had offices in several large Bolivian cities, including one in the famous silver mining center of Potosí, that provided aid to Jewish refugees, many of whom had arrived with just the clothes on their backs. It may be recalled that the Nazis had imposed the onerous Flight Tax on Jews emigrating from Third Reich lands beginning in the 1930s, causing the financial ruin of many. So, as in the Dominican Republic, the majority of the Jewish refugees who made it to the safety of Bolivia were penniless.