Tag: cultivo del frambueso

Due to such unexpected effects, accurately predicting the consequences of specific CECs, even in model insects, is not yet possible. This problem is exacerbated by a lack of information regarding effects of pharmaceuticals and other CECs on the microbial communities of any terrestrial insects. Arthropods, such as insects and crustaceans, rely on hormones to grow, develop, mate, and produce pigmentation . However, many pharmaceuticals, especially mammalian sexhormones, are structurally similar to chemicals that these organisms rely on for growth and development. These pharmaceuticals then bind to receptors and either over express or suppress their counterparts’ natural function. This has been seen in birds, reptiles, and arthropods where endocrine disruption occurs, primary and secondary sexual characteristics are modified, and courtship behaviors are changed . Although most arthropod hormones do not closely match those of mammals, their molting hormone is very similar in structure to the mammalian female sex hormone 17β-estradiol. In crustaceans, mammalian hormones have been known to cause both increased molting events and inhibition of chitobiase, the enzyme responsible for digestion of the cuticle during insect molting . In insects, 17α-ethinylestradiol, a common synthetic birth control hormone, has been shown to alter molting and lead to deformities of C. riparius . In addition to these effects,macetas de plástico pharmaceuticals have been shown to have delayed cross-generational effects . The cabbage looper is a well-studied polyphagous insect native to North America and is found throughout much of the world . T. ni are yellow-green to green in color and can complete their life cycle in as little as 21 d depending on temperature . This species is a pest on many agricultural crops including crucifers and a variety of other vegetables in both field and greenhouse settings .

Currently, there is little to no information regarding pharmaceutical effects at the concentrations found in reclaimed water on the growth or microbial community composition of any terrestrial herbivore. Many herbivores can be exposed to these contaminants after the CECs enter surface waters, soil, and plants from wastewater reuse and unintended discharge. To investigate the function of the gut microbes in insects, several studies have used antibiotics applied at high doses . There is also no information regarding effects of CECs when translocated through plants to terrestrial insects. To test the hypothesis that common pharmaceuticals affect mortality, development, and microbial communities of T. ni, we conducted a series of bio-assays in artificial diet and on a key host plant utilizing surface water concentrations of common important pharmaceuticals. We used a culture-independent approach by performing a 16S rRNA gene survey on both diet and whole-body insects. Any effects would have potentially important implications from agricultural perspectives. Also, as there is currently no information on effects of CECs on terrestrial insects acquired through a plant matrix, our findings would have possible interest for integrated pest management research.In our study, CECs at concentrations found in reclaimed wastewater were shown to increase mortality of T. ni, especially on artificial diets contaminated with antibiotics, hormones, and a mixture of the chemicals. The mortality effect was also evident when T. ni were reared on plants grown in antibiotic-containing hydroponic growth media. Because plants grown in the hydroponic system contained quantifiable levels of ciprofloxacin in the leaf tissue , and the antibiotic treatments significantly changed the microbial community of the insect , we think this is possibly a cause of the mortality but we cannot exclude direct effects of the CECs on the insects or indirect effects through the plants. Ciprofloxacin is a quinolone topoisomerase IV and DNA gyrase inhibitor that acts by stabilizing the DNA-topoisomerase IV and DNA-girase so that it is no longer reversible . This blocks DNA replication and eventually causes cell death of bacteria.

However, unlike bacteria, when higher-level organisms evolved, the A and B subunits of the topoisomerases fused, creating homodimers that cannot be targets of ciprofloxacin , and thus damage to the ribosomes of insects is not a possible mechanism of toxicity. Interestingly, we did not see the increased time to adulthood in T. ni reared on plants compared with those reared on contaminated artificial diet. We postulate the discrepancy is possibly due to a number of factors such as dilution of CECs, as they were acquired from the water by the plants or there was bio-degradation of the chemicals occurring in the plant or by photo degradation. However, recent studies have shown pharmaceutical concentrations in surface waters, which appear to remain constant over the course of several years . More studies would be needed to determine how CECs at concentrations found in reclaimed water for agriculture would interact with current IPM strategies , and how soil matrices would affect the chemical acquisition and translocation by plants. Many insects rely on microbial communities and endosymbionts to grow and develop; however, it has been shown that Lepidoptera species do not have a vertically transmitted microbial community. In addition, because the effects of microbial communities on T. ni survival and development have not been documented, we present these data only to show that microbial communities change when exposed to CECs, and not as a proven factor influencing survival. We found significant shifts in the microbial community in the various life stages examined within the control treatments notably from third instar to subsequent life stages. A similar result has been reported for mosquitoes and other insects . However, there is one family, Lactobacillaceae, which appears in all treatments and life stages in high proportions, except for adults. They are fairly common in insects and can be responsible for at least 70% of the bacterial community .

Lactobacillaceae is responsible for ∼42% of the bacteria in all life stages, followed by Pseudomonadaceae, Alcaligenaceae, and Enterobacteriaceae. Lactobacillaceae have been shown to act as beneficial bacteria in Drosophila ; however, its function in T. ni is still unknown. Alcaligenaceae has been shown to be present in other moths , but Lepidopterans are not thought to have a functional microbiome . There are clear patterns regarding the changes in microbial community proportionality according to the heat map . In controls, third-instar microbial communities are relatively evenly spaced by family. The microbial community becomes predominately Lactobacillaceae for sixth instars and pupae. Once the insects reach the adult stage, their most predominant family is Pseudomonadaceae. This pattern holds in the acetaminophenand caffeine treatment groups as well. Interestingly, the other treatment groups do not share this pattern. For antibiotic- and hormone-treated T. ni, Lactobacillaceae is the predominant microbial family in the immature stages, but at the adult stage microbial community reverts to predominantly Pseudomonadaceae. We suspect that this is because,cultivo del frambueso once the larvae undergo metamorphosis and shed their gut contents in preparation for pupation, they are no longer exposed to the pressures exerted by the CECs on the microbial community. Fig. 3 provides a visual indication of the changes in the bacterial communities over time. The increase in β diversity after eclosion could be due to the larvae no longer being exposed to CECs or diet-borne bacteria after being moved to sterile containers. Also, when bacteria are lost as larvae digest their gut contents during pupation, the microbial β diversity could change. Interestingly, the hormone-treated T. ni follow a similar pattern to those exposed to antibiotics, but their ellipses are always much smaller, suggesting the entire insect population is showing a uniform response within their microbial communities. However, in the mixture-treated insects, larvae displayed a greater average diversity in their microbial community structure than either pupae or adults. This finding has not been shown in any single category of treatment, and we suspect the microbes exposed to mixtures could be experiencing potential interactive effects among chemicals . Such interactions should be the focus of future studies along with investigations of plant rhizosphere bacteria, particularly since we found a difference in the Bradyrhizobiaceae family for all treatments. These results show that a terrestrial insect pest of commercial crops can be affected by CECs found in reclaimed wastewater for agricultural use. Our results suggest that CECs found in wastewater can impact T. ni growth and development, survivorship, and alter their microbial communities. Because T. ni is a common agricultural pest found around the world, feeds on a wide variety of plants, and has a history of developing pesticide resistance, its ability to deal with toxins is likely higher than many other insects.

In addition, the responses we observed to CECs could have interesting implications for IPM practices on plants such as lowering the amount of pesticides needed or increasing susceptibility to insect pathogens, as has been shown in mosquitoes . These potential effects may be understated because some insects cannot detect the presence of the pharmaceuticals . However, we do not recommend purposefully exposing crops to CECs specifically for the control of insects because our study documented that these pharmaceuticals are translocated into crops and we do not yet know their possible effects on humans if consumed . We specifically want to note that ingestion of these compounds through uptake and translocation by a plant is not the only way T. ni or any other insect would be exposed to these compounds. Overhead sprinkler irrigation could cause contact absorption by the plants or insects, and simply drinking water on leaves at contaminated sites could expose insects to higher concentrations than were found in plant tissues. In fact, the ciprofloxacin concentration used was less than one-third of the highest rate . We urge caution in extrapolating to plants growing in soil, because variation in soil type and potential soil bacterial degradation could affect persistence [although soil bacteria are often negatively impacted by CECs ]. However, CEC exposures are considered pseudopersistent because they are reapplied with each irrigation. Thus, the effects reported here are likely to be conservative. Additional studies with other insects, particularly those with other feeding strategies, will be necessary before any patterns can be discerned.The majority of these associations are with arbuscular mycorrhiza fungi which penetrate into root cortex cells to form highly branched structures . The investment of photosynthetic carbon by plants to AMF is rewarded with increased nutrient availability made possible by the extended hyphal network in the soil. For instance, up to 90% of phosphorus uptake in plants can be contributed by symbiosis with AMF . AMF networks in the soil also influence water retention and soil aggregation further impacting plant growth . Moreover, next-generation sequencing technologies and advances in imaging techniques have greatly improved our knowledge on the taxonomical and functional properties of fungal communities in the rhizosphere . However, these methods are optimized for fine scale analysis and are not capable of assessing the foraging capabilities of hyphal networks which can span across centimeter to meter scales. Toward this end, several researchers have used compartment setups with physical barriers created by 20–37 µm nylon membranes which restrict movement of roots but not mycorrhizal fungi. This separation creates root-free and plantfree soil compartments connected only by mycorrhizal fungi to examine the transport of various compounds across these compartments. Using this set up, the importance of mycorrhizal fungi in the flow of different elements such as carbon , nitrogen and phosphorus between plants, soil and microbes over centimeter distances have been validated. Repeated disruption of the hyphal connections also led to a decreased resistance in plants to drought stress . The membranes can also be placed horizontally to create different depth gradients to investigate hyphal contributions to water uptake . In some studies, an additional 1.5–3 mm air gap is created between two membranes with a wire net to restrict solute movement between two chambers . A common feature of these set ups is the size-exclusion membranes which proved to be critical in distinguishing fungal hyphae processes in the rhizosphere soil. In addition to AMF interactions, a split root set up, which separates the roots of one plant into halves, can be introduced to investigate the systemic response of plants . In essence, the split-root system directs the growth of the roots to generally two different growth conditions and enables the investigation of whether a local stimuli have a local or global response which can be observed at the root or shoot level .

Farmers and worker advocates argued over the details of a revised AgJOBS program that included earned legalization throughout 2000, with farmers wanting more days of farm work to qualify for eventual immigrant status, and worker advocates fewer days. After the November 2000 elections, some worker advocates, noting that both U.S. President Bush and Mexican President Fox favored a new guest worker program, agreed to a compromise that won the endorsement of the United Farm Workers and the National Council of Agricultural Employers. Under this December 2000 compromise, unauthorized workers who did at least 100 days of farm work in the preceding 18 months could qualify for temporary legal status, and they could convert this temporary legal status into an immigrant status if they did at least 360 days of farm work in the next six years. The compromise included freezing the minimum wage that had to be paid to foreign workers for several years and giving farmers the option of providing a housing allowance rather than housing to workers. The AgJOBS compromise came close to Congressional approval in December 2000, but was blocked by those opposed to any type of amnesty for unauthorized foreigners. The atmosphere changed in 2001, especially after U.S. President Bush and Mexican President Fox met in Mexico in February 2001 and agreed to establish a migration working group that was charged with creating “an orderly framework for [Mexico-U.S.] migration that ensures humane treatment [and] legal security, and dignifies labor conditions.” Senator Phil Gramm became the leading proponent of the guest worker-only approach, favoring a program that would permit unauthorized Mexicans already in the U.S. to obtain seasonal or year-round work permits: seasonal workers could return to the U.S. indefinitely,macetas de plástico and year-round workers could remain in the U.S. three years, and then they would have to stay in Mexico at least one year before returning legally. U.S. employers and guest workers would pay social security taxes to a trust fund that would reimburse U.S. hospitals that provided emergency medical care for injured guest workers; the balance of the social security taxes paid would be placed in individual IRA-type accounts that workers could receive when they surrendered their work permits to U.S. consulates in Mexico.

Gramm’s proposal covers Mexicans employed in all U.S. industries, but does not include a path to immigrant status. The other extreme is legalization. Under a plan embraced by the AFL-CIO and many church and ethnic groups, unauthorized foreigners in the U.S. from any country, and employed in any industry, could become immigrants, and then sponsor their families for admission. Rep. Luis V. Gutierrez introduced a bill that would grant immigrant status to all persons who were in the U.S. at least five years, and temporary legal status to those in the U.S. less than five years. When unauthorized foreigners reach the five-year U.S. residence mark, they could apply to convert their temporary status to an immigrant status.Only unauthorized foreigners who have worked in the U.S. would be eligible, and they must continue working to maintain their temporary legal status and to eventually become immigrants. Earned legalization appeals to those who associate immigration with work in the U.S., and allows Mexican President Fox to keep his promise of improving conditions for the migrants he calls “heroes” for working in the U.S. and sending remittances to Mexico. A spokesperson said President Bush supports “a new temporary-worker program that would allow for some of the [unauthorized] workers to achieve permanent residency status over a period of time.” In 2003, it appears that Democrats, unions and immigrant rights groups will settle for earned legalization, but they oppose new temporary worker programs, while Republicans and most employers favor new temporary worker programs, but oppose an easy transition to legal immigrant status.Many human activities have had a significant effect on the environments in which they take place, and agriculture is no exception. California’s natural waterways have been greatly modified to enable conveyance of water to its farmlands as well as its cities, and to provide facilities for flood control, navigation, and hydroelectric power generation. Most of the natural wetlands in the state have been drained and transformed into fertile, highly productive agricultural land. Farmers have introduced many new species of plants and animals to California and in the process changed many of its ecosystems. While modifications of California’s environment have generated immense good, they have also increasingly become a cause of concern.

Over the last half-century many policies and regulations have been introduced to control some of the effects that California agriculture has had on its environment.Two main types of policy intervention have been made. First, numerous policies have sought to control agricultural externalities. These center on issues such as reducing groundwater contamination from animal waste; worker safety, environmental contamination, and food safety problems associated with pesticide use; water-logging problems associated with excessive irrigation and lack of drainage; air pollution from agricultural waste burning such as rice, and earth mining activities; and odor pollution associated with livestock. A second set of policies has specifically attempted to preserve ecosystems and species. These policies identify and protect the environmental amenities that may be threatened or damaged by agricultural activities. Environmental policies affecting California agriculture have continually evolved over the last fifty years. The evolution has been affected by changes in technology as well as by changes in the political environment and public beliefs and preferences. For example, new knowledge about the impact of agricultural chemicals on human health and the environment, the discovery of new methods of pest control, and the introduction of new monitoring or pollution-detecting strategies have led to changes in environmental laws and regulations affecting agriculture. Similarly, changes in the relative political power of environmental groups or various farm groups and/or changes in public perception and concern about certain environmental issues have led to changes in regulations. Farming in California is subject to policy-making and regulation by a wide variety of agencies. In addition to traditional agencies in the U.S. Department of Agriculture, they include other federal agencies such as the U.S. Environmental Protection Agency and the U.S. Fish and Wildlife Service; state agencies such as the California Environmental Protection Agency, California Department of Food and Agriculture, California Department of Public Health, State Air Quality Control Board, and State Water Quality Control Board; and county and municipal agencies. These many agencies that control various aspects of California’s environment have operated under a complex set of policies that are not necessarily consistent and are subject to modification. The complexity and the changing nature of environmental policies in California have provided an ample background for research in agricultural and environmental economics. Agricultural economists have assessed the impacts of various policy proposals, attempted to provide an economic rationale for proposed policies, and introduced proposals for policy reform and modification. Some of this research may have affected the existing policies and regulations in California; some has provided general background knowledge for the body of literature in agricultural and environmental economics. A survey of the environmental policies affecting California agriculture identifies some of the difficulties that policy makers are faced with in their attempts to establish environmental regulations. Problems with detecting and monitoring agricultural pollutants have sometimes led to overly strict policing of agricultural activities that are likely to cause environmental side effects. For example,cultivo del frambueso a chemical may be banned or its use restricted even though policy makers may be concerned only with the environmental side effects of some of its residue. Similarly, animal production in a certain area may be restricted or limited even though the only local concern may be with the waste that the animals are producing. The evolution of new technologies will likely help to develop policy measures that will relate more to specific environmental side effects rather than to the general related activities . Establishment of straightforward and efficient policies is influenced by difficulties in measuring the impacts of externalities. The assessment of health risk effects and environmental side effects associated with pesticide use, for instance, is subject to much uncertainty. These uncertainties have contributed to the constant debates and controversies regarding environmental regulation affecting agriculture. One of the challenges facing the scientific community is to provide data to reduce such uncertainties. As Baumol and Oates have suggested, uncertainty regarding outcomes has led to policies that aim to reach a target level of environmental quality based mainly on biological or ecological criteria, even in instances where balancing marginal benefits with marginal costs might be more appropriate. Another practical difficulty in determining environmental quality is its multi-dimensionality. The same chemical can cause several types of environmental problems—worker safety, food safety, groundwater contamination, or damage to wildlife. The benefits of chemicals, as well as the magnitude of their environmental side effects, can vary significantly according to crop and location. The way a chemical is applied can alter its impact on the environment; a chemical sprayed from an airplane is likely to generate more environmental side effects than one applied by low-pressure, precise-application techniques. Thus the social costs associated with the use of certain chemicals may vary significantly across locations and applications, and policies such as uniform taxation or direct regulation of agricultural chemical use may be economically inefficient in many situations. Efficient regulation of the environmental side effects of agriculture may call for policies that vary by location and agricultural activity, and the need for flexibility may also provide a challenge in terms of design and implementation. Much of the economic research on the environmental regulation of agriculture has simply estimated the economic impacts of proposed regulation. However, some research has also suggested improvements in policy design and demonstrated how changes in policy instruments might result in attaining environmental objectives at much lower economic costs. This chapter discusses some of the major environmental issues arising from California agriculture, and describes the conclusions of recent economic research that has analyzed the efficacy of various approaches to handling these issues. The diversity of problems and policy issues is illustrated here through discussion of control of animal wastes, pest control and the regulation of pesticides, endangered species protection, climate change, and the growing role of agricultural land as a source of recreational amenities.California is the United States’ major dairy producer, and is home to approximately one-sixth of the nation’s dairy cow population. These 1.64 million cows account for over one-fifth of all milk produced in the United States . Although the United States milk cow inventory decreased by approximately 130,000 head between 1997 and 2001, the number of milk cows in California increased by 14 percent during this time. Milk production per cow has also increased by approximately five percent during the same period . In short, California dairy production has been increasing both in scale and efficiency in recent years. Until recently, the dairy industry in California had been closely concentrated near the larger population centers in Los Angeles and Northern California. The largest dairy-producing region in the state had been the Chino region near Riverside, not far from Los Angeles. These patterns were in accordance with the models of agricultural land use first developed by Johann von Thünen almost 200 years ago. Von Thünen modeled the allocation of land uses around a city as a function of the economic return, or “rent” to the land, which in turn is a function of transportation costs. In the city’s core, urban uses such as residences and industry will determine the highest value of the land. Von Thünen hypothesized that dairying and other intensive farming industries would be located immediately outside of the urban core, because they had the highest transportation costs, both in absolute terms and in terms of the losses that would be suffered by any delays in getting easily spoiled products to market. Less intensive industries such as forestry, extensive field crops, and ranching would be located further outside of the central city. The allocation of land predicted by von Thünen’s model does not take environmental externalities into account, however. Recent studies suggest that when the cost of environmental quality is taken into account, then the location of various activities have to balance transportation and pollution costs . Thus, pollution-intensive industries either have to reduce their pollution or relocate farther away from the city.

The phase-out of methyl bromide has proven to be a daunting task for the California strawberry industry. Not only are strawberry producers faced with the likelihood that methyl bromide will no longer be available to them by 2015, but they also must deal with increasing regulatory stringency on the use of all soil fumigants. While fumigants face an uncertain future in California, barrier films can help trap fumigants in the soil and reduce the likelihood of environmental or health impacts associated with fumigants in the atmosphere. It appears very likely in the near future that barrier films will be the only type of film approved for use with fumigants in California.Potential methods of strawberry production that do not use fumigants include growing plants in substrates and using steam treatments or anaerobic soil disinfestation. All of these systems are being evaluated on a much larger scale, from 1 to 10 acres, with different soil types, to determine commercial feasibility and cost effectiveness. It is not likely, nor is it desirable from a pest management perspective, that one nonfumigant system will dominate on a large percentage of the strawberry acreage. Multiple production systems, using fumigants and nonfumigants, would allow producers to rotate treatments to suppress soil pests.Increasing global temperatures coupled States . Long with unpredictable changes in climate term drought in California and other regions threaten food security globally . California has experienced United States has caused growers to abandon extreme drought conditions for several years,macetas de plástico fruit crops and seek alternatives with less causing fruit growers to face water limita- water demand in the short term. Options fortions affecting production and leading to mitigating long term drought in California hundreds of millions of dollars in crop rev- have included crop abandonment, stress irenue losses in 2016 alone .

To lessen the impacts of climate new plantings change and increasing temperatures on food and utilization of lower quality secondary security, it is important to utilize diversified water sources. cropping systems to reduce vulnerability to It has been proposed that physiologists and extreme climatic events as experienced in breeders focus on increasing the efficiency California and other regions of the United of water use in agriculture . Improving production efficiency and drought tolerance through cultivar or variety selection has been proposed in tree crops, such as citrus Prunus species , dates , and coffee . Because tree crops can have a considerable amount of variability in terms of physiological traits, it is useful to study diversity in crop species to determine if there are cultivars that use water more efficiently or are able to be productive in stressful conditions. Because pomegranate is a drought tolerant crop, especially once established , it is a candidate crop for growers wishing to switch from more water intensive species, such as avocado, citrus or almond. Pomegranate is a drought tolerant crop that has been grown in California since the Spanish missionaries arrived from Spain and planted mongrel seeds at missions up and down the coast . The pomegranate variety collection located at the United States Department of Agriculture – Agricultural Research Service National Clonal Germplasm Repository, Davis, CA conserves about 200 genotypes of pomegranate sourced from all over the world, many of which have unique phenotypic traits . Experiments have demonstrated differences in morphology and vegetative growth traits, including differences in relative chlorophyll content, plant vigor, and branching habit, which can be observed during propagation and in the field . Although available literature on pomegranate physiology is scarce, research has shown that there can be differences among cultivars for many physiological traits of pomegranate in other collections, including transpiration rate, stomatal conductance, water use efficiency, photosynthetic rate and chlorophyll content . The objectives of this study were 1) to evaluate four unique pomegranate cultivars for physiological field performance in a semi-arid agroecosystem during morning and afternoon hours; and 2) to determine if there are differences among cultivars for physiological traits that would be conducive to commercial crop production in drought conditions.‘Wonderful’ is the industry standard in many countries and was chosen as a control in the experimental cultivar field trial.

The other cultivars were selected for their unique phenotypes. ‘Eversweet’ is a dwarf-like cultivar bred for coastal climates, with pink fruit peel and aril color, and soft seeds. ‘Haku Botan’ is an ornamental Japanese cultivar that has an upright growth habit with double white flowers and darker green foliage than most other pomegranate cultivars and lacks visible anthocyanin pigments in stem, leaves and fruit. The fruit is very acidic and very light yellow in color. ‘Parfianka’ is an internationally-renowned cultivar that has a bright red peel and arils with soft seeds and a balanced sweet-tart flavor. The tree is extremely thorny and has a bushy, highly branched growth habit with smaller leaves than other pomegranate cultivars. ‘Wonderful’ is commercially widely-grown, and in the USA it accounts for approximately 90- 95% of production. It is a highly vigorous, thorny tree that has high yield with red fruit and red seeds with moderate seed hardness and a sweet-tart flavor. The growth habit is willowy, with a tendency to sucker at the base of the tree. Photosynthesis measurements. During fruit development , an infrared gas analyzer was used to measure maximum rates of net CO2 assimilation , stomatal conductance , and transpiration during the morning and afternoon . Morning photosynthetically active radiation ranged from 1500-1600 µmol m-2·s-1 photosynthetic photon flux density , while afternoon PAR was 1990 µmol m-2·s-1 PFD. Morning measurements were pooled for the four cultivars, which occurred on 22, 23 Aug. 2015 and 26 June 2016. Afternoon measurements were taken on 30 June 2016, which was representative of a typical summer afternoon in Riverside . Gas exchange characteristics were measured on two leaves per tree and a minimum of three trees per cultivar. All leaves were collected for leaf area, which was quantified on a leaf area meter to normalize photosynthesis data . Only the most recently fully-formed, sunexposed leaves were selected for this study. Cuvette temperatures were allowed to vary with field conditions. Leaves were measured in a chamber that provided 1500 µmol m-2·s-1 . Instantaneous water-use efficiency was calculated as A·E-1 and intrinsic water use efficiency was calculated as A·gs -1. Stem water potential measurements. Predawn and midday stem water potential measurements were recorded for each data tree. For predawn water potential, non-actively growing shoots were covered with a plastic bag for 10 min before being pruned, placed in a sealed plastic bag and kept in a cooler bag until transferred to an indoor environment for plant moisture stress measurements with a pressure chamber .

For afternoon stem water potential measurements, canopy-shaded nonactively growing shoots were covered with a plastic bag for 10 min before being pruned, placed in a sealed plastic bag and kept in a cooler until immediately transferred to a cool lit, indoor environment. Stem water potential was immediately measured after being removed from the cooler bag. One stem was measured from three individual trees per cultivar, for a total of three trees, for predawn and midday stem water potential. Statistical analysis. All variables were analyzed with Analysis of Variance . When ANOVA indicated significant differences, post-hoc comparisons were performed utilizing Tukey’s honestly significant difference with an experiment-wise type 1 error rate of α = 0.05. Relationships between all variables were analyzed using linear regression , with relationships among parameters determined using general regression with Minitab Software, version 16 . Block was coded as a random effect and interaction terms were included in the models. For the purposes of this work, the R2 value is the proportion of variation in one variable that is explained by the variation in the regressor variable. Regression models were fit to determine differences in slope coefficients and constants among variables. The focus of this review is on water use and water recycling in container-grown production of greenhouse and nursery specialty crops. The majority of information and insights in this review also have applicability to containerized edible crops grown in open air or under protected culture. In container-grown crop production, water application frequency varies from multiple times per day to once every few days depending on the production system, crop producer, growing season, and environmental conditions, such as rainfall. Use of containers has grown in popularity with nursery growers over the past 50 years because crops can be produced more rapidly and economically and the root zone is easier to modify when compared with field production . Ruter showed that total biomass increased by 27% by growing Betula nigra under pot-in-pot conditions compared with above ground container production,cultivo del frambueso which was likely due to more favorable root zone conditions. Container-grown plants also weigh less and therefore are easier to move and ship, allowing more flexibility at an operation and improving shipping efficiency. Containerization allows growers to sell plants throughout the year regardless of soil conditions or plant growth stage, which increases productivity per unit area. Field operations typically apply lower rates of fertilizer and water on a per meter or per hectare basis compared with container production because soil matrices are typically more chemically and water buffered . Field production also has wider plant spacing compared to both container production in nurseries and greenhouses . As inventories are sold, containerized plants can be consolidated to make room for additional plants, while field operations cannot be consolidated. This greater density of ornamental container-grown crop production results in both higher revenue and increased material and input costs compared with field production. Irrigation must be applied more frequently in containerized production systems compared to field soils, because plant available water is lower within containers filled with soilless substrates, which have high porosity and restricted root volumes . Any water, or agrichemicals applied in excess of the capacity of the container, are unable to be utilized by the plant, or fall outside of the container will likely leach and run off and may eventually impact surface water and groundwater .

Concerns persist that as runoff leaves an operation, sediment and agrichemical contaminants will also be exported . Some growers capture and reuse all or a portion of production runoff, whereas other growers allow runoff to drain from their operations to the surrounding ecosystem. Grower hesitation to capture and reuse runoff can usually be attributed to a reluctance to change practices because of concerns about the opportunity cost of lost production area, installation costs of containment and treatment systems, management costs for treatment technology, reintroduction of disease-causing organisms or plant growth regulators, phytotoxicity of reintroduced pesticides, or land characteristic restrictions . In this review, we will discuss these challenges, as well as potential solutions to these issues and limitations Greenhouses are typically characterized as covered or enclosed systems with the capacity to control environmental factors that impact plant growth, including temperature, humidity, irrigation, and light. Operation sizes typically range from a few hundred square meters to 5 ha but can exceed 10 ha. Greenhouse operations tend to be highly intensive production systems on a per unit area basis, but due to smaller container sizes are typically smaller than container-nursery operations. They typically use precise irrigation applications and can have a high degree of environmental monitoring and control. Thus, greenhouse operations typically require less water per unit area than open-air container or pot-in-pot nurseries . This higher degree of control capability can lead to higher distribution uniformity and water use efficiencies. However, efficiencies also depend on irrigation application method , application decisions , and system design and maintenance. The typical higher efficiency irrigation used in greenhouse operations requires higher-quality water and regular maintenance to avoid emitter clogging and subsequent plant loss or damage. Nursery container operations place containers at or below ground level . Plants are grown on various combinations of bare ground, gravel, landscape fabric, or other surfaces that are often graded to reduce standing water directly below containers. Nursery container operation sizes can vary from less than a hectare to thousands of hectares. Irrigation is typically applied overhead using impact sprinkler heads or similar-type heads. Larger containers are often irrigated using micro-irrigation via drip emitters or spray stakes. Although micro-irrigation is more labor intensive to maintain, the necessity of wider plant spacing due to canopy size makes overhead irrigation inefficient due to wind drift and decreased interception efficiency .