Month: March 2024

We estimated a total of 19.9 and 21.8 tera-liter of water consumption via evapotranspiration over the agricultural land in California’s Central Valley in 2014 and 2016 water years , respectively . In the water year 2014, the top eight crop types accounted for 75% of total crop consumptive water use in the valley, including almond , rice , grapes , alfalfa , corn , walnuts , pistachios , and tomatoes . Overall, rice was the second largest water consumer after almonds, although it only used 7.6% of cropland, due to its highest annual evapotranspiration rate of 1,109 mm yr−1, on a per unit area basis . Pasture, walnut, almonds, citrus, and alfalfa also had relatively high evapotranspiration rate  . In contrast, wheat consumed the least amount of water per area among major crops, whereas pistachio, tomato, corn, cotton, and grapes had a moderate evapotranspiration rate between 600 and 800 mm yr−1. As the second and third largest cropland use in the valley, grapes, and corn used less total water than rice but similar water with alfalfa, walnuts, and fruits.Across the valley, the mean annual evapotranspiration rate varied by 35% over all agricultural pixels in 2014, mostly due to the diversity of the crop types. We also found high ariability of evapotranspiration rate within each crop type, especially over orchards such as almond, pistachios, and walnut, with a CV higher than 20% , most likely due to differences in planting density, age, canopy structures, and stressors among orchards . For example, the almond evapotranspiration rate varied by 34% , and the rate for pistachio varied by 59% in 2014. Wheat also had a very high variability , different from other annual crops, which typically had a much lower variation of evapotranspiration rate than perennial crops. For all major crop categories, the difference in CV between 2014 and 2016 was <7.2%. Compared to 2014, total crop consumptive water use increased by 9.6% in 2016 , with an evapotranspiration rate of 856 mm yr−1,containers size for raspberries although the reference evapotranspiration from Spatial-CIMIS decreased by 4%. This increase in evapotranspiration was mostly caused by land-use changes with higher irrigated areas and crops with higher averaged water consumptive use .

Total irrigated agriculture land use increased by 7.0% in 2016, partly due to a 2,370 km2 land-use conversion from fallow/ idle lands in 2014 to cropland in 2016. A large portion of fallow land conversion grew rice , wheat , and perennial crops in 2016, leading to an increase of total water use by 1.3 tera-liters. Another major land-use change was the conversion from annual crops to high water demand orchards, including almonds, walnuts, citrus, or grape in 2016, accounting for 1.5% of 2016 cropland and decreasing water use by 0.07 tera-liters due to the low evapotranspiration rate of young orchards.Variability of evapotranspiration rate among GSAs was primarily driven by non-meteorological drivers. Across GSAs, we found that the evapotranspiration rate highly correlated with net radiation and actual Priestley-Taylor coefficient . Many of these factors were regulated by land-use types, vegetation cover, and plant water stress status. In contrast, EToF was the dominant driver of evapotranspiration rate variability among GSAs , mostly driven by crop types, e.g., rice with EToF of 0.61 , tomato 0.33 , almond 0.52 , and pistachio 0.37 summarized at the GSA scale. Even for the same crop type, EToF varied significantly among GSAs for some tree crops and wheat 0.36 . The average almond EToF , e.g., ranged from 0.25 in the City of Tracy GSA in Tracy county to 0.75 in Rock Creek Reclamation District GSA in Chico county. Pistachio’s EToF was much lower in the majority of the western San Joaquin Valley areas , probably due to the plant stress caused by salinity . Citrus EToF had an IQR of 0.16 at the GSA scale. In contrast, the mean EToF showed much smaller variation among GSAs for the majority of annual crops such as alfalfa 0.54 , rice 0.61 , pasture 0.57 , and cotton 0.35 . Within each GSAs, the annual EToF also showed large spatial variation, with a mean CV of 31% across all agricultural fields; Some GSAs with a lower evapotranspiration rate had the highest variability , mostly located at and around the Westlands Water District region in the western-Fresno and Kings county.

In addition to crop diversity within each GSA, significant variation of EToF was also found for each tree crop type, such as almonds and pistachios , with IQRs of CVs among GSAs greater than 15%. For examples, the CVs of pistachio EToF within each GSAs had a mean of 34% and an IQR of 33% across GSAs, with the largest within-GSA variation found in the Central Delta-Mendota GSA; In the Southeast Kings GSA, CV of Pistachio EToF is 29%, much lower than its neighbor, Tri-County Water Authority GSA . Other types with highly variable EToF included almond, citrus, walnut, and wheat. In contrast, EToF was more homogeneous within GSA for alfalfa with a mean CV of 17% and IQR of 6% , and rice . About 39 GSAs had >60% of agricultural land areas planted with perennial crops including almond, pistachio, citrus, walnut, and grape in 2014, which accounted for 76% of total agricultural water use by these GSAs and 27% of Central Valley’s total agricultural water use in 2014 . These GSAs will likely face greater vulnerability to prolonged drought due to the high cost of fallowing productive orchards. When dividing the total consumptive use of perennial crops by the GSA area , we found that some small and medium-size GSAs, such as Delano-Earlimart Irrigation District GSA, Madera Water District GSA, and New Stone Water District GSA, will need to reserve a much greater depth of groundwater storage to maintain the orchards during drought.Our study showed that the semiempirical Priestley-Taylor algorithm, when calibrated with ground measurement data over diverse crop types and driven by Landsat Analysis Ready Data, improved the accuracy of the older 1 km MODIS-driven PT-0 model . The crop-specific Priestley-Taylor optimization performed consistently between the testing and independent data sets, and slightly better than the PT-JPL method . The generalized Priestley-Taylor optimization had a similar overall performance with PT-JPL when driven by the same input data. However, relatively larger uncertainties were found during nongrowing seasons, from November to March, when the evapotranspiration rate was relatively low. This was partly due to the limited field measurements data during winter and early spring for optimizing the sensitivity of actual Priestley-Taylor coefficients to the moisture content.

Moreover, our Priestley-Taylor approach does not separate soil evaporation and plant transpiration. This introduces uncertainty in evapotranspiration estimates during non-growing seasons when evapotranspiration is mainly driven by evaporation from the soil due to minimal canopy coverage or leaf area. For example, we did find that PT-JPL better captured the peak of the actual Priestley-Taylor coefficient for the corn site during the dormant season , when PT-JPL’s estimates showed that soil evaporation was the most significant component. The uncertainty of our refined Priestley-Taylor approach here is similar to the DisALEXI model, as shown by the report from the Sacramento-San Joaquin Delta intercomparison project . For additional reference, Anderson et al. reported that DisALEXI had an RMSE of 1.09 mm day−1 at site number 1 and 1.24 mm day−1 at site number 24 when compared to daily measurements. Being a process-based model, DisALEXI does not depend on land-use maps and field measurements for calibration once validated. The semiempirical Priestley-Taylor approach, however, has the advantage of easy implementation,big plastic pots compared to other more sophisticated and computationally more expensive approaches.At a regional scale, the annual mean values of per-area water use of major crop types in the Central Valley estimated here are generally within the ranges reported in the literature . For example, DWR’s water portfolio and balances data set, as part of DWR’s 2018 Water Plan, reports that water requirement by corn ranges from 390 to 835 mm yr−1 in 2014 across sub-regions of all planning areas in the Central Valley . Burt et al. estimated that corn in the Central Valley conventionally used 813 mm yr−1 in a typical precipitation year. Our regional average of corn evapotranspiration was 16% more than DWR’s average corn water requirement over planning areas . Larger differences were found for alfalfa, pasture, wheat, almonds, pistachio, and vineyard, for which our regional averages were 30%–65% lower or higher than DWR’s values. Over all 30-m pixels of agricultural lands in Central Valley , the average annual evapotranspiration rate, estimated here, is higher than the estimates over the whole Central Valley by the BESS biophysical process-based model forced with 1 km satellite observations . The discrepancy is likely due to the scale effect and differences in land cover maps. Larger pixels likely contain other land-use areas such as fallow, urban, water, and natural vegetation. Nonetheless, our estimates in 2014 align with the values reported in Schauer and Senay based on the SSEBop remote sensing evapotranspiration model driven by Landsat thermal data. Our estimation of 19.6 tera-liter water consumption in 2014 was equivalent to 74% of DWR’s estimate over all planning areas within the Central Valley, which was derived from CalSIMETAW . Among the planning areas, the discrepancies ranged from –53.4% to −18.5%, with the most significant disagreement occurring in the southern and center-east of the San Joaquin Valley .

Similarly, previous studies in the Sacramento-San Joaquin Delta, a subset of the Central Valley, showed that remote sensing estimates are lower than CALSIMETAW’s estimates by 6–24% . Over this Delta area, our crop-specific Priestley-Taylor method in this study estimated 1.20 tera-liter in 2016, very similar to the DISALEXI’s estimate of 1.16 tera-liter in the water year 2016; both were about 80% of CalSIMETAW’s estimates of 1.49 tera-liters, based on the published data summary table in Medellín-Azuara et al. . Two factors may have caused the discrepancy in regional estimates between PT-UCD and CalSIMETAW. First, CalSIMETAW’s crop-coefficient approach implemented at a regional scale may overestimate actual evapotranspiration, because it did not account for the impacts of planting variabilities such as orchard age distribution and planting density, field conditions such as salinity and disease, and crop management like deficit irrigation. Second, the land-use map used by CALSIMETAW was different from the DWR’s land-use map that we used here. For example, CALSIMETAW estimated 13.7, 23.9, and 23.9 km2 of corn, alfalfa, and pasture in PA 704 in 2014, in contrast to our DWR’s map-based estimates of 18.2, 21.4, and 9.3 km2 of corn, alfalfa, and pasture.Currently, California’s GSAs employ various approaches to estimate evapotranspiration in their water budget accounting and management plan development, causing systematic inconsistencies among GSAs. For example, the Olcese GSA near Bakersfield estimates monthly evapotranspiration from 1993 to 2015 using the METRIC method version by the Irrigation Training & Research Center at the California Polytechnic State University; North Kings GSA uses CA DWR’s crop coefficients to estimate annual evapotranspiration rate over detailed analysis units from 1998 to 2010, while the Delano and Yuba GSAs use crop coefficients published by ITRC in 2003 and derived from an SEBAL-based evapotranspiration map in 2009, respectively. Our study shows that the fractional of reference ET , or similarly crop coefficients, for most crops, varies spatially across and even within GSAs, and for some crops, EToF changes considerably between years. More consistent estimates with known uncertainty from a calibrated or thoroughly evaluated approach are needed to ensure consistent quantitative information for data-driven decisions for water planning. Our optimized Priestley-Taylor approach driven by remote sensing observations provides an efficient way to capture both spatial heterogeneity and temporal dynamics of water balance. In particular, we found that orchards and wheat generally had a greater spatial variability of evapotranspiration and crop coefficients than other major crop types, across the Central Valley, within, and among GSAs. Age distribution and other stressors such as salinity likely contributed to such evapotranspiration variability for tree crops . Among three major nut tree crops, pistachio had the lowest mean annual evapotranspiration rate , followed by walnut and almond . Coincidentally, 26% of pistachio acreages in 2014%, 18% of walnut in 2015%, and 15% of almond in 2014 across California were non-bearing orchards . The high variability of wheat water use is likely due to cultivar and end-use for the crop .

To date, few MAR site suitability studies have conducted a sensitivity analysis or validation of recommended sites . Previous MAR suitability assessment studies have used indirect methods to validate MAR locations , while few have used numerical models and in situ observations . With this study, we propose to guide selection of suitable MAR sites by ensuring quantifiable benefits to groundwater levels, storage, water quality, and land subsidence. Although water management agencies maintain multiple MAR basins in the southern CV, most of these facilities have not been implemented to benefit the domestic water supply to rural communities. The Tulare Irrigation District has a 42 ha MAR basin located south of the Okieville community that has been operational since the 1940 . The recharge basin overlays the capture zone of the community’s southern groundwater wells. Its location was accurately identified by this study as suitable Ag-MAR location . Data from Okieville domestic wells show groundwater quality improvements from MAR, including lower nitrate, uranium and arsenic concentrations, which are well below the groundwater concentrations of nearby communities . These indicate that our methodology has positively identified locations where recharge can improve the drinking water supply of rural communities in a region of our study area. Although many studies have used GIS-based MCDA for MAR suitability studies, there is no consensus on appropriate criteria, weights, and methods as these are generally dependent on the study objective, data availability,planting blueberries in containers and local experience . The assignment of weights to each thematic layer or feature is one of the most subjective factors of MCDA and thus, one of the main sources of uncertainty .

To address this issue, AHP is increasingly used to convert subjective assessments of relative importance into a set of weights , though sometimes the relative importance of themes may not be discernable . In this study, local experts in hydrology and human ecology similarly recommended the use of equal weights for thematic layers in both the site suitability and community vulnerability analyses. However, future iterations of these analyses will require the active involvement of local stakeholders , a process that may benefit greatly from the integration of AHP into the GIS-based MCDA . One main difficulty when estimating suitable recharge areas is the spatial and temporal variability of the physical system. We acknowledge that our analysis mainly uses land surface characteristics to determine suitable Ag-MAR sites, while subsurface characteristics were not directly included. Other factors not accounted for in our analysis include water availability, water quality, unsaturated zone transport, and willingness of landowners to flood agricultural land. Although robust quality control measures were taken, the accuracy of our results relies on the integrity of input data. Issues of accuracy and completeness of proprietary, hand-digitized, or self-reported data are inevitable, hence field-level studies of local surface and subsurface characteristics should be completed as part of project scoping and pilot testing. They are also essential to assess soil surface conditions, the presence of potential unprotected wellheads, capacity of connected surface water conveyance systems, feasible Ag-MAR water application amounts , and cropping and agro-chemical application history to determine potential legacy contaminant loading in the unsaturated zone that could be mobilized by recharge . Although nitrate loading to groundwater has been assessed at larger scales in California’s CV , parcel-level data on fertilizer application rates and nitrogen removal by crops is not publicly available, preventing the assessment of legacy nitrate loading in the unsaturated zone.

Future improvements of this methodology should include the addition of contaminant transport modeling or site-specific simulation of drinking water contaminants to address this gap. Climate projections and impacts on surface water availability for recharge require further investigation . As shown by Bachand et al. , despite its semiarid climate, the southern CV faces frequent flood risks. Along the Kings River, flows have exceeded the flood stage almost once every 7 years in the last 4 decades, creating total losses exceeding $1.2 billion . Kocis & Dahlke showed that excess surface water from high flows occur on average every 4.7 out of 10 years with total amounts reaching up to 1.6 km3 between November and April in years when high flows are available. Water scarcity is expected to increase as the southern CV experiences more frequent and longer droughts and more frequent extreme events during wet years . Integrated water management solutions like Ag-MAR are urgently needed to stabilize groundwater supplies in the region.Motorized UAS were introduced as a potential remote sensing tool for scientific research in the late 1970s. However, due to a variety of limitations these platforms had few practical applications . For years, UAS technology was led by military needs and applications. The relatively few applications in research and agriculture included deployments in Japan for crop dusting and in Australia for meteorological studies . In the past decade, several factors have greatly increased the utility and ease of use of UAS, while prices have fallen. Consumer demand drove the hobby craft industry to make major improvements in UAS vehicles. Integrating improved battery technology, miniature inertia measurement units , GPS and customizable apps for smartphones and tablets has delivered improved flight longevity, reliability, ease of use and the ability to better utilize cameras and other sensors needed for applications in agriculture and natural resources . Innovations in sensor technology now include dozens of models of lightweight visible-spectrum and multi-spectrum cameras capable of capturing reliable, scientifically valid data from UAS platforms .

Meanwhile, the Federal Aviation Administration has helped facilitate increased UAS use, with rule changes adopted in August 2016 that lowered what have previously been significant regulatory obstacles to the legal use of UAS for research and commercial purposes . UC faculty throughout California are using UAS in a wide range of agricultural and environmental research projects — from grazed range lands to field crops and orchards, forests, lakes and even the ice sheets of Greenland . UAS also have become a part of the curriculum across the UC system, and are increasingly used by campus staff in departments from facilities to athletics to marketing . UAS are already in wide use in agriculture, and the sector is projected to continue to account for a large share — 19% in the near term, per a recent FAA report — of the commercial UAS market in the United States. The use of UAS for research, particularly remote sensing and mapping, is soaring: A search in Scopus finds 3,079 articles focused on UAS or UAV applications in 2015, compared with 769 in 2005. Across all commercial uses, the FAA estimates 2016 sales of commercial UAS at 600,000 units and expects that figure to balloon to 2.5 million units annually as soon as 2017 . Despite the growing ubiquity of UAS, a variety of practical and scientific challenges remain to using the technology effectively. Collecting and processing data that is useful for management decisions requires a disparate range of skills and knowledge — understanding the relevant regulations, determining what sensing technology and UAS to use for the problem at hand, developing a data collection plan, safely piloting the UAS, managing the large data sets generated by the sensors, selecting and then using the appropriate image-processing and mapping software, and interpreting the data. In addition, as highlighted in the research cases presented below, much science remains to be done to develop reliable methods for interpreting and processing the data gathered by UAS sensors, so that a user can know with confidence that the changes or patterns detected by a UAS camera reflect reality. The UC Agriculture and Natural Resources Informatics and GIS program has recently incorporated drone services into the portfolio of support that it offers to UC ANR and its affiliated UC Agricultural Experiment Station faculty.Working closely with UC Office of the President, Center of Excellence on Unmanned Aircraft System Safety , IGIS has also developed a workshop curriculum around UAS technology,container growing raspberries regulations and data processing, which is open to members of the UC system as well as the public. Please check the IGIS website to learn about upcoming training events around the state in 2017, including a three day “DroneCamp” that will intensively cover drone technology, regulations and data processing.When a tree is stressed — whether due to pest infestation, nutrient deficiency or insufficient water — its leaves change. These changes may be detectable in the visible light spectrum — a shift in a leaf’s shade of green. They can also be “seen” in other bands of the electromagnetic spectrum — for example, a change in the texture of a leaf’s waxy coating may alter how infrared light is reflected.

Different types of stress generate unique electromagnetic “signatures.” If these signatures can be reliably correlated with specific causes, a UAS could be deployed to quickly scan a large orchard for signs of trouble, enabling early detection and treatment of pest infestations and other problems. Christian Nansen, a professor of entomology and nematology at UC Davis, leads a team working to refine this monitoring technique. They use hyperspectral camera, which generates a very high-resolution signature across a wide range of wavelengths. One of the challenges is that the electromagnetic signatures often contain high degrees of data “noise” — due to shadows, dust on leaves, differences between leaves and other factors — making it difficult to discern a clear signal associated with the stress that the tree is experiencing. To address this problem, Nansen’s team is refining a combination of advanced calibration, correction and data filtering techniques. As entomologists, they are also working to understand in fine detail the interactions between different pest species and tree stress, and how those affect the electromagnetic signature of a tree’s leaves .Rapid detection of water stress can help farmers optimize irrigation water applications and improve crop yields. In an orchard, precise assessments of water stress typically require manual measurements at individual trees using a device known as a pressure bomb that measures water tension in individual leaves. Tiebiao Zhao, a graduate student at UC Merced’s Mechatronics, Embedded Systems and Automation Laboratory, is collaborating with UC ANR Merced County pomology farm advisor David Doll with the goal of developing UAS-based tools to assess water stress across a large almond orchard at a high level of accuracy. Water stress can be detected by relatively low-cost multi-spectral cameras due to changes in how the canopy reflects near-infrared light. This project is building a database of canopy spectral signatures and water-stress measurements with the objective of developing indices that can be used to reliably translate UAS imagery into useful water-stress information. In a related experiment, Zhao is working with Dong Wang of the USDA Agriculture Research Service San Joaquin Valley Agricultural Sciences Center to detect the effects of varying irrigation levels and biomass soil amendments on crop development and yield in onions. As in Zhao’s almond experiment, the researchers are comparing spectral signatures gathered by low-cost UAS-mounted multi-spectral cameras with ground-truth data to better understand the relationship between the two .The Greenland ice sheet covers 656,000 square miles and holds roughly 2.3 trillion acre-feet of water — the sea level equivalent of 24 feet. As the climate warms, ice sheet melt accelerates; therefore, understanding the processes involved is important. This knowledge can help to refine predictions about the ice sheet’s future and its contribution to global sea level rise. A team of researchers led by UCLA professor of geography Laurence Smith is using UAS-based imaging technologies to map and monitor meltwater generation, transport and export. The group’s UAS carry multiband visible and near-infrared digital cameras that capture sub-meter resolution data, from which the researchers create multiple orthomosaics of the ice surface and perimeter over time. They are using the data to analyze a number of different cryohydrologic processes and features, including mapping rivers on the ice surface from their origins to their termination at moulins — vertical conduits that connect the ice surface with en- and sub-glacial drainage networks — and melt water outflow to the ocean. The team is also generating digital elevation models of the ice surface to extract hydrologic features, micro topography and drainage divides. In addition, they are working towards mapping ice surface impurities and albedo at high resolution using multi-band visible and near-infrared images.

For these simulations, the concentrations of dissolved species in background precipitation and in groundwater at the bottom model boundary were fixed, with compositions described in Table 2 to yield similar vertically distributed NO3 – concentrations as were measured in the soil cores. Flooding scenarios were then started from the initially steady flow and biogeochemical conditions developed as described above and run for 60 days. For these simulations, a free surface boundary was implemented for scenario S1 where 68 cm of water was applied all at once. In contrast, a specified flux boundary condition was imposed for the scenarios S2-S3, where floodwater applications were broken up over a week. The flood water composition is discussed in Section 2.3.5. The groundwater composition was taken from analyses reported by Landon and Belitz for a groundwater well located near our study site. For simplicity, the background recharge from rainfall was assumed to have the same composition as groundwater except that it was re-equilibrated under atmospheric O2 and CO2 conditions prior to infiltration. In addition, the concentrations of N species in the background recharge were set to values determined from our own analyses of N at the top of soil cores. The composition of the flood water was set to that of the background precipitation diluted by a factor of 100 for most constituents except for Cl-1 . Ratios of NO3 – to Cl-1 were used to trace the difference between dilution and denitrification effects on NO3 – . Denitrification and N2O production were simulated as aqueous kinetic reactions coupled to the fate of pH, CO2, Fe, S, NO3 – , and NH4 + based on the Spearman correlation analyses discussed above . Apart from pH and nitrate species, Fe and S have been linked to denitrification through chemolithoautotrophic pathways in addition to heterotrophic denitrification , and are therefore included in our reaction network.

Heterotrophic denitrification of NO3 – to N2 was represented via a two-step reduction process of NO3 – to nitrite and NO2 – to dinitrogen . Additionally,blueberry pot chemolithoautotrophic reduction of NO3 – to N2 with Fe and bisulfide as electron donors were implemented. Further, dissolved organic carbon was observed throughout the nine-meter profile at our field site, and CO2 and N2O profiles showed strong correlation . Therefore, DOC degradation was simulated using Monod kinetics, although individual DOC components were not simulated consistent with other modeling studies . In particular, we considered a single solid phase of cellulose in equilibrium with acetate as the source of DOC. Parameters for cellulose dissolution were calibrated using the total organic carbon concentrations obtained for each cluster. Biodegradation of acetate was coupled to multiple terminal electron acceptors, including NO3 – , Fe and SO4 2- which follow the hierarchical sequence of reduction potential of each constituent implemented by using inhibition terms that impede lower energy-yielding reactions when the higher energy yielding electron acceptors are present. These microbially mediated reactions and their kinetic rate parameters are shown in Table 5. Rates for denitrification were calibrated using the results from the acetylene inhibition assays as described above. Enzymes involved in denitrification include nitrate reductase, nitrite reductase and nitrous oxide reductase. To remain conservative in our estimates, we chose values typical for oxygen inhibition of nitrous oxide reductase L -1 ), the most sensitive to oxygen of the enzymes . Spearman rank correlation indicated that pH, DOC, S, NO3 – , and Fe exhibit significant correlation with N2O and therefore, these geochemical species were included in the reaction network. Cluster analysis was used to further detect natural groupings in the soil data based on physio-chemical characteristics, textural classes and the total dataset. Cluster analysis revealed three clusters representing distinct depth associated textural classes with varying levels of substrates and biogeochemical activity. Table 5 shows the median and range for N2O, CO2, NO3 – -N, Fe, S and total organic C for each of the clusters.

The first cluster is dominated by sandy loams within the top meter with highest median values of total N2O, total CO2, NO3 – -N, Fe, and total organic C concentrations, indicative of greatest microbial activity and denitrification potential. The second cluster is dominated by silt loams below one meter and had average values of total N2O, total CO2, NO3 – -N, Fe, and total organic C concentrations when compared to the other groups. The third group is dominated by sands and sandy loams below 1 meter and had the lowest median values of total N2O, total CO2, NO3 – -N, Fe, and total organic C concentrations amongst all groups. The clusters were thus automatically grouped by decreasing levels of denitrification and microbial activity. While most concentrations followed a decreasing concentration trend from cluster 1 to 3, the highest median values of S were associated with cluster 2. Liquid saturation profiles and concentration of key aqueous species predicted at different times for the homogeneous sandy loam column are shown in Figure A1. The sandy loam vadose zone is computed to be 32% saturated with near atmospheric concentrations of O2. As a result of oxic conditions, model results demonstrate significant residual NO3 – concentration within the vadose zone . Evolving from these conditions, Figure A1d shows that with flooding scenario S1, water reaches depths of 490 cm-bgs and saturation levels reach 40% in the sandy loam column. Deeper in the column, lower saturation and only small decreases in O2 concentration are predicted . Calculated concentration profiles show that O2 introduced with the infiltrating water is persistent at shallow depths down to 100 cm-bgs, below which O2 declines slightly as floodwater moves below this zone. Model results further indicate higher NO3 – reduction in the shallow vadose zone including the root zone with 35% of NO3 – being denitrified . Overall, this scenario results in NO3 – concentration persisting at depth. While other redox reactions, such as iron reduction and HSreduction of NO3 – to N2, may be important, conditions needed to induce these reactions were not realized in the sandy loam vadose zone due to the high pore gas velocities of the homogenous sandy loam allowing for large amounts of O2 to penetrate the profile from the incoming oxygenated water. In comparison to the homogenous sandy loam column, the predicted water content is higher and O2 concentration is 53% lower in the vadose zone of the homogenous silt loam column at steady state . This result is expected because of the difference in porosity,nursery pots with silt loams having higher water holding capacity and lower pore gas velocities compared to sandy loams.

Consequently, lower NO3 – concentration and lower NO3 – :Clratio are predicted in the silty loam vadose zone as compared to the sandy loam column . It is interesting to note that while greater NO3 – loss and denitrification are predicted for the silty loam vadose zone, carbon concentration associated with the shallow vadose zone are comparatively lower than for the sandy loam column. Moreover, the calculated pH is lower and iron concentrations are higher in the silt loam profile below the top meter when compared to the same depths within the sandy loam column . This suggests that chemolithoautotrophic reactions could be more important for these finer textured sediments. While both heterotrophic and chemolithoautotrophic reactions would be expected to result in a pH decrease , the greater decline in pH and concomitant increase in Fe+3 concentration suggests the importance of Fe and S redox cycling associated with the chemolithoautotrophic reactions in silty loam sediments . Evolving from these steady state conditions, scenario S1 suggests that denitrification is enhanced as floodwater infiltrates into the silt loam column. Model results indicate that saturation increases to 80% from 1 to 4 m depths and O2 decreases from 2.1 x 10-4 mol L-1 to 1.7 x 10-4 mol L -1 , resulting in 43% of the NO3 – being denitrified for this scenario . In comparison to the homogeneous profiles, the sandy loam with silt loam channel stratigraphy has higher calculated water contents and slightly lower O2 concentration within and surrounding the silt loam channel than the homogenous sandy loam column under steady state conditions . Calculated NO3 – concentrations are also similar between the homogenous sandy loam column and SaSi case, except for within and below the silt loam channel where lower NO3 – concentration was predicted . For scenario S1, water content for the SaSi case increased in a manner similar to the homogenous sandy loam, except for within the silt loam channel, which increased from 60 to 81%. Figure 4 further demonstrates that the infiltrating floodwater resulted in an increase in NO3 – concentration between 1 and 3 m within the sandy loam textured soil, but a decrease elsewhere. Within the channel itself , lower nitrate and NO3 – :Clratio are predicted, suggesting higher rates of denitrification . Overall, the model results indicate that an average of 37% of the NO3 – concentration is denitrified in the SaSi case 60 days after flooding, with 35% denitrification occurring in the sandy loam matrix and 40% occurring within the silt loam channel. This suggests that the silt loam channel acts as a denitrification hotspot. Furthermore, the silt loam channel has lower carbon and higher Fe+3 concentrations similar to the homogenous silt loam column again suggesting the importance of both heterotrophic and chemolithoautotrophic denitrification in these finer textured sediments. In comparison to the SaSi case, calculated water saturation and O2 profiles were markedly different between the homogenous silt loam column and the silt loam with sandy loam channel under steady state conditions . In particular, the sandy loam channel has lower calculated water content than the homogenous silt loam column . Further, greater gas flux within the channel resulted in 11-19% higher O2 concentration that penetrated deeper into the vadose zone as compared to the homogeneously textured column. NO3 – concentration are also estimated to penetrate deeper into the vadose zone in the SiSa case due to the high permeability of the sandy loam channel . While carbon concentration also penetrated deeper in the vadose zone in the SiSa case, higher calculated O2 concentration did not allow for comparable rates of denitrification below 1 m in this case as observed in the homogenous silt loam profile. This is further confirmed by the lower NO3 – :Clratio, which indicates that transport processes dominate biogeochemical fluxes within this column . With scenario S1, the calculated water content increased to 48% saturation while the O2 concentration remained the same within the channel. The high permeability channel allowed for NO3 – to move faster and deeper into the vadose zone. Overall, calculated denitrification was lower in the SiSa case as compared to the homogeneous textured column. In the simplified ERT stratigraphy, similar patterns were observed such that high permeability channels transported water, O2, and NO3 – faster and deeper into the subsurface than low permeability regions . As a result, concentration profiles showed significant variability across the modeled domain even under steady state conditions. For example, the calculated O2 and NO3 – concentrations are an order of magnitude lower in the shallow vadose zone below the limiting layer than within the preferential flow channel. Higher NO3 – :Clratio within the channel further confirms that preferential flow paths transport higher quantities of dissolved aqueous species without their being impacted by other processes such as denitrification . Dissolved carbon in particular is predicted to have a lower concentration in the preferential flow channel and the matrix surrounding the channel than below the limiting layer. In contrast, the Fe+2 concentration is estimated to be higher in the matrix surrounding the preferential flow channel and below the limiting layer . For scenario S1, model results indicate that NO3 – moved through the preferential flow path faster and deeper into the profile, while the limiting layer acts as a denitrification barrier as evidenced by the decrease in NO3 – :Clratio. The highest denitrification was estimated to occur in the matrix adjacent to the preferential flow channel , followed by intermediate nitrate reduction below the limiting layer and far away from the channel , while the lowest denitrification was estimated to occur within the channel itself .

In 2007, Food and Drug Administration officials advised consumers to discard toothpaste manufactured in China after discovering it contained ethyleneglycol, a chemical agent used in antifreeze.In China, the toxic ingredient melamine found its way into milk, infant formula, and pet food, sickening 294,000 children and causing at least 6 deaths.Ingredients are entering the United States from more than 100 countries with the dollar value doubling over the past decade to $80 billion in 2006. Once these ingredients are incorporated into processed foods, it is difficult and often impossible to trace them back to their source.As American food policies encourage the production of few crops and rely heavily on global imports for the rest, more cases of contamination are likely without aggressive policing and controls.Farm policies encouraging mass production have resulted in highly centralized farm practices that are more likely to result in environmental degradation. For example, fossil fuels are used to manufacture and transport fertilizer and pesticides over long distances; the raw and then finished products are then further transported, often back to their original locations; source water is also transported for agriculture use; and used water is commonly contaminated by chemical fertilizers and pesticides with resulting downstream “dead zones.” Ground and surface waters can also be polluted by antibiotics from CAFOs and by antibiotic-resistant bacteria, and soil is depleted through overuse and lack of crop rotation. CAFOs generate enormous amounts of waste and air pollution, and they are perhaps the most egregious example of environmental degradation exacerbated by US farm policies. The savings to large livestock producers feeding their animals cheap subsidized grains have driven down the price of meats,growing blueberries in pots resulting in consolidation of livestock operations. Diversified farmers, using their own farm products and labor to raise livestock, are unable to compete with concentrated livestock industries that benefit from cheap inputs and economies of scale without regard to resulting environmental damage.

CAFOs lack sewage treatment plants, yet, because a pig produces about 4 times as much solid waste as a human, a typical CAFO of 5000 swine produces waste equivalent to a city of 20,000 people.This waste is expensive to transport, store, and dispose. Storage pits for livestock or poultry manure can leak into groundwater and streams; such pits become even more problematic if sited in a flood plain or below the water table. CAFOs generally produce more waste than can be used on nearby fields as fertilizer.Levels of phosphorus and nitrogen in the waste often exceed what the crops can utilize or the soil can retain. Correspondingly, excess nutrients contaminate surface waters and streams, causing algal overgrowth in nearby water bodies that devastate underwater ecological systems. Many feed ingredients used in CAFOs pass directly through the animal into manure,including carcinogenic heavy metals , antibiotics, nitrogen, and phosphorus. The manure also contains dust, mold, pathogenic bacteria, and bacterial endotoxins that contaminate air and water. Generally accepted livestock waste management practices do not adequately or effectively protect water resources from contamination with excessive nutrients, microbial pathogens, and pharmaceuticals present in the waste.Additionally, toxic gases, vapors, and particles are emitted from CAFOs into the environment, including ammonia, hydrogen sulfide, carbon dioxide, malodorous vapors, and particles contaminated with a wide range of microorganisms.The negative impact of CAFOs on nearby communities is a frequently voiced concern and is being increasingly documented. Finally, CAFOs contribute to the health threat of antibiotic resistance. Because large numbers of animals are kept in crowded conditions, microbes spread easily. Though physicians receive negative attention for contributing to antibiotic resistance by over prescribing antibiotics, antibiotics used to produce livestock account for the largest portion of antibiotic usage in the United States—between 60% and 80% of total non–therapeutic antimicrobials produced in the United States are used in US livestock operations.

The World Health Organization recently called for phasing out the use of antimicrobial growth stimulants for livestock and fish production.WHO recommended that therapeutic antimicrobial agents be available only by prescription for human and veterinary use. Additionally, concern about the risk of an influenza pandemic led WHO to recommend that regulations be promulgated to restrict the colocation of swine and poultry CAFOs on the same site and to set substantial separation distances. Aware that CAFOs present significant environmental and health risks, legislators have addressed them in recent Farm Bills. But rather than discouraging their practices, the Farm Bill directed hundreds of millions of dollars to CAFOs through the conservation title and rejected amendments, such as the Farm Ranch Equity Stewardship and Health Act, that would increase support for farmer’s using environmentally friendly practices. Under the Environmental Quality Incentives Program, CAFOs are eligible for up to $450,000 to build storage facilities for animal sewage.Though 3 out of 4 farmers interested in Farm Bill conservation programs are rejected for lack of funds, it is antithetical to the protection of the environment and health to provide funds that enable the current operation of CAFOs rather than providing incentives for them to shift toward sustainable practices.The price of food to consumers does not contain the true costs of its production. The true costs include the cost of environmental cleanup, the costs to human health of toxic exposure and a lack of clean water sources, the costs of overusing fossil fuels, as well as the cost to future generations of growing food with the loss of severely depleted agricultural land.Population experts anticipate the addition of another roughly 3 billion people to the planet’s population by the mid-21st century. However, the amount of arable land has not changed appreciably in more than half a century. It is unlikely to increase much in the future because we are losing it to urbanization, salinization, and desertification as fast as or faster than we are adding it . Water scarcity is already a critical concern in parts of the world . Climate change also has important implications for agriculture.

The European heat wave of 2003 killed some 30,000 to 50,000 people . The average temperature that summer was only about 3.5°C above the average for the last century. The 20 to 36% decrease in the yields of grains and fruits that summer drew little attention. But if the climate scientists are right, summers will be that hot on average by midcentury, and by 2090 much of the world will be experiencing summers hotter than the hottest summer now on record. The yields of our most important food, feed, and fiber crops decline precipitously at temperatures much above 30°C . Among other reasons, this is because photosynthesis has a temperature optimum in the range of 20° to 25°C for our major temperate crops, and plants develop faster as temperature increases, leaving less time to accumulate the carbohydrates, fats, and proteins that constitute the bulk of fruits and grains . Widespread adoption of more effective and sustainable agronomic practices can help buffer crops against warmer and drier environments , but it will be increasingly difficult to maintain, much less increase, yields of our current major crops as temperatures rise and drylands expand . Climate change will further affect agriculture as the sea level rises, submerging low-lying cropland,drainage gutter and as glaciers melt, causing river systems to experience shorter and more intense seasonal flows, as well as more flooding . Recent reports on food security emphasize the gains that can be made by bringing existing agronomic and food science technology and knowhow to people who do not yet have it , as well as by exploring the genetic variability in our existing food crops and developing more ecologically sound farming practices . This requires building local educational, technical, and research capacity, food processing capability, storage capacity, and other aspects of agribusiness, as well as rural transportation and water and communications infrastructure. It also necessitates addressing the many trade, subsidy, intellectual property, and regulatory issues that interfere with trade and inhibit the use of technology. What people are talking about today, both in the private and public research sectors, is the use and improvement of conventional and molecular breeding, as well as molecular genetic modification , to adapt our existing food crops to increasing temperatures, decreased water availability in some places and flooding in others, rising salinity , and changing pathogen and insect threats . Another important goal of such research is increasing crops’ nitrogen uptake and use efficiency, because nitrogenous compounds in fertilizers are major contributors to waterway eutrophication and greenhouse gas emissions. There is a critical need to get beyond popular biases against the use of agricultural biotechnology and develop forward-looking regulatory frameworks based on scientific evidence. In 2008, the most recent year for which statistics are available, GM crops were grown on almost 300 million acres in 25 countries, of which 15 were developing countries . The world has consumed GM crops for 13 years without incident. The first few GM crops that have been grown very widely, including insect-resistant and herbicide-tolerant corn, cotton, canola, and soybeans, have increased agricultural productivity and farmers’ incomes. They have also had environmental and health benefits, such as decreased use of pesticides and herbicides and increased use of no-till farming .

Despite the excellent safety and efficacy record of GM crops, regulatory policies remain almost as restrictive as they were when GM crops were first introduced. In the United States, case by-case review by at least two and sometimes three regulatory agencies is still commonly the rule rather than the exception. Perhaps the most detrimental effect of this complex, costly, and time-intensive regulatory apparatus is the virtual exclusion of public-sector researchers from the use of molecular methods to improve crops for farmers. As a result, there are still only a few GM crops, primarily those for which there is a large seed market , and the benefits of biotechnology have not been realized for the vast majority of food crops. What is needed is a serious reevaluation of the existing regulatory framework in the light of accumulated evidence and experience. An authoritative assessment of existing data on GM crop safety is timely and should encompass protein safety, gene stability, acute toxicity, composition, nutritional value, allergenicity, gene flow, and effects on non–target organisms. This would establish a foundation for reducing the complexity of the regulatory process without affecting the integrity of the safety assessment. Such an evolution of the regulatory process in the United States would be a welcome precedent globally. It is also critically important to develop a public facility within the USDA with the mission of conducting the requisite safety testing of GM crops developed in the public sector. This would make it possible for university and other public-sector researchers to use contemporary molecular knowledge and techniques to improve local crops for farmers. However, it is not at all a foregone conclusion that our current crops can be pushed to perform as well as they do now at much higher temperatures and with much less water and other agricultural inputs. It will take new approaches, new methods,new technology—indeed, perhaps even new crops and new agricultural systems. Aquaculture is part of the answer. A kilogram of fish can be produced in as little as 50 liters of water , although the total water requirements depend on the feed source. Feed is now commonly derived from wild-caught fish, increasing pressure on marine fisheries. As well, much of the growing aquaculture industry is a source of nutrient pollution of coastal waters, but self contained and isolated systems are increasingly used to buffer aquaculture from pathogens and minimize its impact on the environment . Another part of the answer is in the scale-up of dryland and saline agriculture . Among the research leaders are several centers of the Consultative Group on International Agricultural Research, the International Center for Biosaline Agriculture, and the Jacob Blaustein Institutes for Desert Research of the Ben-Gurion University of the Negev. Systems that integrate agriculture and aquaculture are rapidly developing in scope and sophistication. A 2001 United Nations Food and Agriculture Organization report describes the development of such systems in many Asian countries. Today, such systems increasingly integrate organisms from multiple trophic levels . An approach particularly well suited for coastal deserts includes inland seawater ponds that support aquaculture, the nutrient efflux from which fertilizes the growth of halophytes, seaweed, salt-tolerant grasses, and mangroves useful for animal feed, human food, and bio–fuels, and as carbon sinks .If done on a sufficient scale, inland seawater systems could also compensate for rising sea levels.

The garden was built but a few years later it lay fallow. He continued, “But if we’d gone around the block and just gotten everybody together and said, “What do you need? What do you want?” who knows?” He wondered if a neighborhood-based decision to build a garden, a community-art project, or some other use would have had a more engaging and lasting presence. Ultimately, Betcher does not want to see more legislation or advocacy purely for gardens, but instead advocacy that promotes neighborhood-based land use decision making processes. Gentrification has been a primary issue for organizers now working under the banner of “right to the city”. Activists have resisted displacement of low-income people and people of color, and have fought for residents’ voices in decision making about the use of land . The Right to the City national alliance states in their platform that they fight for “The right to land and housing that is free from market speculation and that serves the interests of community building, sustainable economies, and cultural and political space” . As Voicu and Been document in their analysis of the impact of gardens in New York neighborhood property values, community and urban gardens can increase property values and thus contribute to gentrification trends. The New Yorker publication sparked several organizations and projects to engage in further conversation on gentrification. About a year before SFUAA’s member Antonio Ramon-Alcala spearheaded the alliance’s release of a position statement on gentrification . The statement both recognized that urban agriculture and gentrification are tied up in urban processes of change, and rejected gardening as a cause though maybe a “Trojan horse” of displacement. The alliance advocates asking critical questions of themselves and believes they “can and should link up our struggles with those of others. Ultimately,gallon pot many of these struggles are about local community control over public resources, and that is a much larger battle.”.

An article published in the Atlantic Magazine, after the passage of AB 551 policies in San Francisco, critiqued gardening in a housing-stressed city and again stirred conversation amongst gardeners and Bay Area residents . San Francisco Housing Development Corporation and others expressed dismay that urban gardens are being promoted in a city with such a shortage of affordable housing and gentrification pressures. Yet, SPUR, formerly the San Francisco Planning and Urban Renewal Association and a strong proponent of development, does not agree with the dichotomy, arguing the legislation promotes growing on land that is not likely to be sold for development in the near future . As an urban planning organization SPUR has promoted housing construction, commercial construction, and many other land uses in tandem since its inception in 1910. SPUR gained ground as an influential San Francisco institution after WWII when the organization, led by business-class leaders, pushed for the city’s revitalization through targeted neighborhood demolition of primarily African American communities . Today SPUR remains an influential organization in San Francisco, just opened a branch in San Jose, and plans to open an office in Oakland, making their position on affordable housing and gardening one of importance in the region. For Doria Robinson the issue was clear: “Improve the areas with the people who are there. That’s the key. People who are wanting to gentrify are saying, “You don’t want to develop, you want it to be run down for ever so you can be the queen” We’re like that’s not what is up, we want our hoods to be better, we want them to be beautiful and thriving, and whatever, but we want to be there! To experience this, we want to be a part of this renaissance, not watch it.” . For this reason, Urban Tilth has worked with other organizations engaged in discussions with project managers of the newly proposed University of California Richmond Bay laboratory, research, and teaching campus to insist on community benefit packages and a say in the development process.

In San Francisco’s Bayview/Hunters Point, Betchel again warned, “I worry that one day people are gonna look at these newly fenced in locked, spaces with people they don’t recognize who come across town because they don’t have any land there, inside, bickering about weeds in their raised beds and say, ‘That’s no better than the Google bus that’s around, that’s just disempowering’” . But Betchel, Robinson, and others remain hopeful that urban agriculture as a movement will not turn a blind eye to this tension. As Cadjii explains, it’s just a question the movement needs to be uncomfortable with and yet sit with.Gardeners assert their projects can be part of a broader landscape of movements attempting to reassert community power in societal decision-making around land use and social well being. Organizations like Phat Beets work with neighbors to resist evictions and fight the Oakland gang injunction. Yet they also recognize that urban garden projects can increase property values and become an attractive attribute for real estate interests, thus contributing to gentrification. As gardeners work with other community-based movements they contribute to the coalitional aspirations of those working, conceptually and on the ground, with “the right to the city”. Resiliency is a debated term both in ecology and in the work of gardeners. Much academic work has explored the meaning of resiliency in ecological, agroecological and socio-natural systems, exploring concepts of system integrity, capacity to recover from disturbance or shocks, and stability of systemic basic functions. Originating from work of ecologists who were dissatisfied with climax models of ecosystem function, resiliency thinking gained popularity in the 1970s and later for ecological economists analyzing socio-ecological systems . I will refer to agroecologists, Miguel Altieri and C.I. Nicholls’s use of the term. World peasant farmers still inhabiting agroecological systems offer hope for resilience and varied solutions during change and uncertainties arising from times of disturbance such as peak oil and climate change . Gardeners contextualize the need for resiliency in both the increasing impacts of climate change and the uncertainty of urban social change. In San Francisco, Berkeley, and Oakland activists concern about resiliency is mirrored in city priorities. The three cities were selected to be part of the first group in the Rockefeller Foundation’s 100 Resilient Cities initiative, in which the cities have appointed “Chief Resilience Officers to set priorities and an agenda for a more resilient future” .

Two dominant narratives of resilience expressed by urban gardeners can be traced in the first case to movement and organizing strategies, and in the second case to permaculture. Movement Generation, a Bay area environmental and social justice organization that works with many garden projects, including Urban Tilth and PODER, uses resilience-based organizing as a core principle of their work. In a PowerPoint presentation, Movement Generation explained their resilience-based organizing approach. To address the economic, racial, and ecological injustices caused by a capitalist economic system, Movement Generation’s approach advocates for organizing that engages resistance to power structures that continue to oppress, resiliency strategies to survive ecological and social change,gallon nursery pot restoration of ecosystems and communities that sustain us, and re-imagination of narratives of how we can live. Drawing inspiration from the Black Panthers and MST, they argue that neither conventional campaigns nor isolated projects for community improvement are enough. Instead they value pairing resistance and resilience. The second narrative derives from resiliency in the context of permaculture, also takes a holistic approach to socio-ecological change. For permaculturalists resiliency refers to “the ability of a system to hold together and maintain its ability to function in the face of change and shocks from the outside” . Resiliency lies at the heart of permaculture goals but the tactics to achieve it are often debated as evidenced in the case of the Hayes Valley Farm and interim use. For some resiliency is the ability to build projects and energy in short period of time in response to changes in political or ecological forces. One permaculturalist explained this position as, “Currently we are exploring multiple strategies for gaining access to marginalized space for the establishment of urban agriculture elements – interim-use agreements for public land, the Streets Parks Program, agreements with private land owners. Fundamentally, we are characterizing our organization as lightweight and nimble.” . Many of these strategies contribute to urban land use and decision-making that maintain the authority of owners and their power to use land for financial gain through development. For others, resiliency meant resisting structural forces that did not permit long-term relationships to be developed with the land, which is essential for building social and ecological systems of resiliency. But the majority of permaculturalists take a middle path. While recognizing the potential ecological consequences of not having tenure security they believe there are benefits to be gained. Doria Robinson, of Urban Tilth, is a partner with Movement Generation and a permaculturalist. While she ultimately believes that urban agriculturalists and their broader communities would be better served by secure tenure, Robinson also describes the benefits of gardening on insecure land, “I think we need to be vulnerable… If you are in a reciprocal relationship with the land, you put yourself in a vulnerable spot… And to give back to the land, even if we don’t know ultimately if it’s going to be worth it” . Beyond improving lives and environments in the short-term, tenure insecurity requires people to realize their vulnerability and embrace generosity towards the socio-natural landscape. A primary function of social movements can be to reform and rearticulate state institutions in favor of movement actors .

Food movement activists in the Bay Area have engaged in collaborative food policy councils and other alliances to lobby and advocate for municipal policy change. They have used the resources and specialties of local university urban planning programs to change local regulations regarding gardening. As discussed in Chapter Two, urban agriculture is gaining the attention of planners and city governments across the nation, in no small part due to food movement activism. In the last six years several national publications have documented best practices from various municipalities, making recommendations to planners regarding food system and urban agriculture zoning use definitions, specific areas of policy change, and mechanisms for empowering gardeners and food movements . In the Bay Area, city governments and planners in San Francisco, Oakland, and San Jose have collaborated with movement actors to enact recent changes to city code, general plans, and municipal programming, extending the reach of urban agriculture in all three cities. Urban agriculture is of interest to a variety of city agencies not only for its potential impact on sustainability and resiliency, food security, mental health, and community beautification and safety, but also for its impacts on economic development , city branding, and urban entrepreneurialism. How these collaborations have unfolded over the last five years speaks to both the trajectory of urban governance that food movement actors are supporting and to the emergence of dominant social movement strategies that shape land and property through city policy. The context in which these three Bay Area municipalities operate has developed over three decades of urbanization heavily influenced by the processes of neoliberalism. While environmental values and protection have had a strong hold in Bay Area politics for the last century , the growing entrepreneurial practices of American cities have created new challenges and opportunities for gardeners. Increasingly since the 1970s, US urban parks have been funded and managed through public-private ventures, such as the financial aid and volunteer labor support San Francisco Parks’ received from the San Francisco Parks Alliance, formerly the San Francisco Parks Trust and Neighborhood Parks Council . For urban agriculturalists in Oakland and San Jose, community gardens have increasingly become the territory for public-private partnership experiments. These partnerships are emblematic of an entrepreneurial urban form that decreases government spending while seeking to attract, directly or indirectly, investment and growth . In San Francisco, alliances between advocates and policy makers have promoted San Francisco as a city on the forefront of urban food production. At the same time the city is in crisis over housing availability, affordability, and rapid social dislocation of low-income residents; economic investment and growth are skyrocketing. Tensions over strategies advocating for entrepreneurial urban policies, such as AB 551 or the Recreation and Parks Department’s recent Pay to Play, both of which were discussed in my introduction, have elicited fiery debate amongst movement actors and city residents in the summer and fall of 2014.

For these social justice scholars, the universal ideal can be abandoned without being completely lost. Harvey calls for strategic employment of ideals appealing to better processes that are contextualized in concrete geographic, historical and institutional terms . For DuPuis et al, a reflexive approach allows activists to “speculate on some possible practices and processes that might lead to better local food systems” . Food sovereignty actors increasingly have sought justice through translocal connections, pointing to reflexive politics committed to valuing equity, autonomy, and difference. For gardeners who engage with the food sovereignty movement, the land access strategies they engage are conceptually and practically connected to global land struggles against capitalist agricultural and urbanization processes. Urban agriculturalists in the Bay Area connect local struggles for community management of land to broader injustices of urban land decisions and development driven by finance capitalism. The Occupy the Farm organizing discussed in the introduction is an example of this work, yet the urban agriculture movement is not universally committed to food sovereignty. The differing commitments of urban gardeners and their landing strategies are discussed in the next chapter. Throughout the history of urban agriculture, gardeners have adopted a range of strategies from squatting, working with municipal and other public agencies to increase access to public space,black plastic planting pots and renting vacant land to find space to cultivate. The tenure insecurity of these organized garden projects has been and continues to be immense. In their national survey of urban agriculture projects McClintock and Simpson identified a variety of tenure strategies used by contemporary garden organizations .

Looking across the urban gardening movement, the strategies for land access and secure tenure frequently appear to be disorderly, grabbag approaches to gardening. Yet, many gardeners would like to see urban agriculture as a more consistent and permanent feature in the urban landscape. For these gardeners, their land access and tenure strategies are filled with meaning and intention. Gardeners recognize that their strategies are bounded or to some degree shaped by contemporary property relations. Their assessment that property relations are a determining dynamic for the future of their gardens is acute. Many gardeners also contend that they are active participants in shaping the property relations that may determine the fates of their projects. Gardeners stress their projects are making a real impact on how local municipalities are embracing urban gardening as land use, how residents view the use of land for food production, and how gardening can challenge the priority of land value for development. I term the process of decision making gardeners that take in manifesting a land access strategy “landing.” Landing is a process of creating closure, when utopian desires are enacted on the land and preexisting property relations. Through landing gardeners recreate old or develop new socio-spatial relations, setting direction, and foreclosing on other possibilities if only for the moment. This chapter examines the landscape of strategies of land access and tenure used by over fifty garden groups in the Bay Area and analyzes the ideologies behind them. In this this chapter I analyze primary material from interviews and other sources to tell the stories of landing and the property relations gardeners create and contest. In claiming that today’s gardening will persist into the future, urban agriculturalists believe their strategies will move gardening beyond its previously held position as an interim use of land. Furthermore, they contend urban agriculture can be a long-lasting means to construct new social, spatial, and ecological relationships. As such some gardeners wish to and do contribute to enactments of property that challenge neoliberal and ownership based relations of land use that they see as a barrier to better urban forms. Yet, the opposite is a more pervasive trend.

Urban agriculture in the Bay Area continues to be a movement focused on momentary gains, acceptance of impermanence on particular sites, and goals other than enacting anti-capitalist land politics and spatial production. To understand gardeners’ land claims, we must first understand something about private property as it is institutionalized and practiced in the US. Emphasis on private property within contemporary economic policy revives liberal and utilitarian arguments that assert property is a stabilizing and productive social force . Neo-utilitarians draw from Bentham’s thesis that when individuals have clear and secure ownership they feel free to participate in economic activity . Bentham’s assertion is part of what Joseph Singer terms “the ownership model.” Singer argues that this model of property has become the dominant and guiding view of property in social and political life . The ownership model identifies property as a set of rights over particular things and the holder of those rights is the property owner . The set of rights imply that owners have the freedom to use the property, sell it or otherwise transfer title, exclude others from its use, and experience security that others will not attempt to take their property without the owner’s consent. The conditions of full and liberal ownership are an ideal that is frequently not met . The role of government is to attempt to establish legal frameworks in which full and liberal ownership may occur, thus giving owners a sense of security and empowerment. Within the ownership model both space and property are represented as “fixed, natural, and objective” . Property rights rely on spatial boundaries for their enforcement. As such, the freedom to property is conceived as a negative freedom, a freedom from either state or private intrusion . Thus, the model rests almost entirely on the dichotomy between private ownership and state ownership with little explanatory power for situations between or outside of these categories. Nonetheless, the ownership model remains dominant in its influence over property law as practiced in contemporary neoliberal urban spaces . Additionally, the ownership model presents property as static with only two moments of importance: the creation of the right and the transfer of that right. Objective representation of property, space, and law make current property relations “appear prepolitical, obvious, and unproblematic” .

The enforcement of property is possible through the assertion of claims as rights. Blomley cites Laclau and Mouffe as arguing that rights offer a means of acknowledging and measuring power relations in their political and conditional contexts . To demand access to those rights can produce powerful language of “naming, blaming, and claiming” . Rights, as enforced by the state, can be used as a powerful tool of oppression or in the least cause confusion within populations. States choose which rights warrant protection. As we will see in the next section,drainage pot when particular communities value aspects of property other than those protected by law, disjuncture and/or conflict can occur. From perspectives like those of Gibson-Graham that de-center capitalist relations, property can take on complex meanings, as alternative property dynamics may exist within our current society that are not completely outside capitalism nor completely capitalist . The ownership model sits side by side with resistant practices. In these perspectives, property, rather than being a static object, is a dynamic social relation. In the edited volume: Privatization: Property and the Remaking of Nature-Society Relations, the complex, varied and sometimes contradictory results of private property relations are demonstrated through several case studies . Similarly public property often has multiple and overlapping meanings . Following Gibson-Graham’s lead, Blomley calls this is a process of “unsettling” . In Unsettling the City: Urban Land and the Politics of Property, Blomley argues for the need to “depict property ‘at its loose ends’” thus destabilizing property as it is conceived in the ownership model, which occupies a hegemonic place in today’s society . Similarly in an effort to describe private property as untotalized, Rose describes property relations as plural, interrelated and unfixed . She coins the term “unreal estate” to describe when people make property claims or recognize others’ claims despite their knowledge that these claims are legally illegitimate. Hardt andNegri describe the commons as a project beyond the public/private dichotomy. Blomley offers this example: in Vancouver private gardeners are planting beyond their yards by taking over the soil in the space between the sidewalk and street. In particular, an artist collective used this space to place an old bathtub and other creative planters as a way to disrupt ideas of normal use of the space. The legal categories of private and public space had little relevance to these gardeners who used land in their daily practices. By analyzing these property practices, we can see property enacted more as a continual and somewhat open process of doing rather than a closed collection of laws . Property is manifested through story telling or complicated forms of communication, what Rose calls “persuasion”. Here she examines the cultural question of how particular stories and ideas of property are created and maintained through concrete practices. Recent analysis of environmental networks also shows the power of the narrative-network in creating communities of change .

Ingerson challenges the notion that most land in US cities is either private or public by suggesting that the actual practices of new experimental forms of ownership such as land trusts, neighborhood managed parks, limited-equity housing cooperatives, and community supported agriculture do not neatly fit into a public/private dichotomy. Instead these forms promote collective claims, management and ownership, forming what Ingerson called urban commons. As Blomley argues, “rather than settling social life, property emerges as a site for moral and political ambiguity, contest, and struggle” . Thus property can become both a site of resistance, a tool of resistance, and that which must be resisted. For the gardeners in this dissertation, property is all three: a place to enact other worlds, a tool to draw attention to contemporary social problems, and an obstacle to the work gardeners desire to do. Landing describes how property becomes a political tool, site, or instigator of conflict. The following section explores these landing strategies. Through description of landing, I analyze enactments of property in the actions and discourses of urban gardeners themselves. In my study of Bay Area urban gardeners and organized garden projects, I found a variety of land tenure arrangements are represented, . The forty organized garden projects represented are only a sample of the hundreds of projects across the region. This selection contains many of the most prominent projects as well as some that are fairly unknown and captures the variation in garden organization and tenure arrangements while documenting major trends. The descriptions that follow demonstrate the diversity of the urban agricultural projects currently existing in the region. Of the thirty seven garden projects that were not part of municipal run community gardening programs, twenty-two were non-profit organizations, six were businesses, social enterprises or private enterprises designed to engage the broader community, eight were community groups or collectives not affiliated with nonprofits, and two were sponsored governmental programs. Twenty-two of the garden projects used or were located on public land, twelve projects used private land they did not own, and eleven projects used land the gardeners or participants owned. Several projects included more than one garden and used different tenure strategies for the different garden sites. All but five of the garden projects were started after 2000.While the sample size in this project is not large enough to draw conclusions from cross tabulations, it is noteworthy that several private businesses used the personal properties of their managers or of individuals who were personal connections. Given the large variation in landowners for parcels used by non-profits and unaffiliated community groups, if a larger sample size were surveyed I do not believe there would be significant correlations between governance and tenure strategy. Alternatively the diversity of strategies employed by gardeners of differing aims and institutional support points to the broader conclusion of this dissertation, namely: that gardens occupy interim spaces in an urban fabric driven by development interests. My focus is to describe how these representative projects approached the questions of land access and tenure.For many gardeners, already preserved or recently acquired areas of public land offer an optimistic and strategic means towards greater tenure security. Using public land for long-term gardening is one form of activist engagement with the state. Yet, garden project advocates engage the state spaces and resources in multiple ways all shaping public opinion on the use of public space. This section explores these strategies including land inventories, and community garden programs and public private partnerships.

In 1977 the Boston Urban Gardens was formed through a coalition of black community organizers, white activists, and other Boston residents to better coordinate gardening efforts in the city . In Oakland, the Black Panther Party grew gardens for subsistence on open spaces and on the properties of facilities used for BPP activities . Nationally, community garden received significant support and became increasingly institutionalized by the end of the 1970s. Between 1976 and 1993 the USDA ran an Urban Agriculture Program in 26 cities providing technical and financial support to gardeners. In 1982, $17 million worth of food was produced by community gardeners supported by the Urban Agriculture Program . In 1979 the American Community Gardening Association was formed at a conference of community gardeners from across the nation. Their early mission included publicizing the work of gardens, providing mechanisms for information exchange and establishing deeper relationships between gardening groups . In the 1980s the ACGA was deeply concerned with land tenure, a sentiment we will see reflected in the San Francisco League of Urban Gardeners as well. The May 1982 and fall 1987 issues of the Journal of Community Gardening, the ACGA’s national publication, were devoted to the topics of site permanence, advocacy to change the place of gardening in city master plans and housing developments, and opinions on gardeners organizing to secure sites through ownership, land trusts, and long-term leases . In 1982, Diane Gonsalves argued community gardens should not be made portable stating, “the displacement of gardens undermines the commitment of the gardeners,plant pot with drainage depriving neighborhoods of an important stabilizing factor, in much the same way that housing displacement does” .

Gonsalves laments that gardens “remain invisible to planners. Architects, politicians, and policy makers” and “are treated like carpets that can be rolled up and moved elsewhere atwill” . In spring 1983, the ACGA published an infographic on tips for saving a garden entitled “Stop the Bulldozers!” . On the other hand, in the 1987 ACGA publication on land tenure, Gerson was advocating for gardeners to accept that gardeners will sometimes lose sites: “When it comes time to leave, you do so. Regrettably. But you don’t cry, whine, or fuss, nor do you encourage your gardeners to do so” ). Gerson argued that ‘creating a fuss’ damages the reputation of community gardening at large, and in an environment where “developers will win 98% of the time” gardeners need to know gardens are not forever. During this period from the late 1960s to the 1970s, collective urban gardening experienced a revival across the country. But by the mid-1980s community gardening was in decline. Shifts in federal and state funding left many gardening programs without the funds to support their staff or work. Yet, the commitments and sometimes projects of this era have survived to the present. During the community gardening period, San Francisco Bay Area urban agriculture communities started to develop as a vanguard leading many conceptual and political efforts to support gardening and urban improvement through agriculture. Home gardening was embraced as a key piece of sustainability of the rapidly growing communal living movement in the Bay Area. By 1971 there were more than 300 communes in the region connected by the weekly newsletter Kaliflower in which articles described home gardening techniques among other things . Kaliflower authors drew inspiration from the Diggers, a spin off from the San Francisco Mime Troupe who advocated for community self-sufficiency and practices such as dumpster diving, labeled “garbage yoga”, and theater aimed to “politicize a new way of living in the city” .

Urban communes became the launching ground for a network of Food Conspiracies, collectives who pooled food stamps, bought bulk food and shared other food resources, and later the San Francisco People’s Food System . In Berkeley, community activist Helga Olkowski and doctoral student William Olkowski, Helga’s husband, created many opportunities for Bay Area residents to learn about sustainable living. Together they developed classes at UC Berkeley on food growing, promoted the use integrated pest management across the Bay Area, started the first recycling center in the US, and help start Antioch College West, an alternative college in San Francisco with a focus on ecology. For six years, William Olkowski conducted research and education on the UCB Gill Tract Farm in Albany, now the site of an urban garden and land battle . The Olkowskis are potentially best known for the publication of two books on urban food production: The City People’s Book of Raising Food and Integral Urban House: Self-reliant Living in the City. The latter was one of the first books on “urban homesteading Lower down on the peninsula, John Jeavons and his colleagues at Ecology Action in Palo Alto started an urban farm in 1971 to conduct research on intensive food production methods. Ecology Action grew food and taught ecological agricultural practices on this farm until their lease ran out in 1980. Jeavons, a former student of UCSC’s Orin Martin, lamented, “like so much other agricultural land in the United States, our lovingly tended beds succumbed to the press of urbanization” . While their farm was initially imagined as a piece of the urban Bay region, the difficulty of maintaining land access pushed Ecology Action to find a permanent site in Northern California. Their bio-intensive method of food production requires long-term soil building, ideally over a 50-year period, and other practices that were not viable in land markets dominated by short-term leases and the loss of land to development.

However, by the 1980s, another force in bio-intensive and sustainable local agriculture was growing as a commercial venture in both rural and urban California. In 1982 the renowned Berkeley restaurant, Chez Panisse started growing and buying local produce . By 1986, Chez Panisse and fourteen other high-end restaurants were buying from a small urban farm, Kona Kai Farms Market Garden, in an industrial neighborhood in Berkeley . Sustainable gardening and local food sources for commercial purposes were deeply connected to the Bay Area environmental movements of the sixties, seventies, and eighties. In addition to experiments in home agriculture as connected to sustainable and often communal living, the Bay Area was enlivened with other acts to reimagine urban relationships to land, food, and people. In 1969 in Berkeley, People’s Park became a national example of a continued community occupation of land leading to the creation of community gardens, open space, and much more . In a decades-long, often violent struggle, student activists, environmentalists and social justice advocates occupied UC Berkeley land in what was considered a revolutionary act to create space for humans and nature in resistance to development. In San Francisco, artists from the San Francisco Mime Troupe, inspired by the diggers, started an urban farm as a piece of “life theater.” Here art, agriculture, and community gathering were combined to radically rethink human-nature relations . Another urban farm, the Farm, was created when project leaders, Sherk and Wickert, leased 1.5 acres of land by the side of the freeway. Community activists worked with the Trust for Public Land and the city eventually agreed to buy 5.5 acres and develop it into a park. Between 1974 and 1987 “The Farm” or Crossroads Community included artists, poets, punks, vegetables, livestock,pots with drainage holes and many others in an experiment in non-hierarchical radical ecology. At the same time, the lot next to The Farm became a key gathering space for low rider cars and Chicano cultural activists. People’s Park was an inspiration to Low Riders looking to carve out a space of their own in the mission district . After 1980, diminishing funds for community arts projects and shifting use of the space led to the decline of The Farm as it had been. The City was not accepting of the radical vision of the space and began development of a more traditional urban park, which still exists today as Portrero Del Sol Park and adjacent community gardens. During the 1970’s, Community garden programs housed under municipal departments began popping up across the country. Over forty percent of contemporary community gardening programs began in 1975 . Many of California’s contemporary community gardening programs were initiated in this period. In 1977 the California Council on Community Gardening stated “Community gardening improves the quality of life for all people by beautifying neighborhoods; stimulating social interaction; producing nutritious food; encouraging self-reliance, conserving resources; and creating opportunities for recreation and education” . San Jose’s first community garden was started in 1976 by a coalition of residents from senior associations, the Food Bank, San Jose State University students in environmental studies, UC Cooperative Extension, and San Jose Parks and Recreation. The 5-acre garden, located on land previously used for a City nursery, was named Mi Tierra and was led and tended by mainly Mexican-American residents . A year later the City started its official community gardening program. In 1993 Mi Tierra was evicted when the San Jose Ice Center was built on the land, and Mi Tierra became Nuestra Tierra community garden on another site. The garden was moved again in 2000 when the land was scheduled to be made into a golf course . This has been a common story for San Jose gardens; all of the community gardens started in the seventies have been moved from their initial sites when the City or other landholder developed the land.

In 1999 when the 25-year-old West Side Garden was evicted in order to build a library, Lilyann W. Brannon with the help of other gardeners fought the prospect of loosing more garden land. Lilyann W. Brannon, a prominent environmental activist and leader of the United New Conservationists, an environmental group started in the seventies at San Jose State University, objected to the City’s position that a community garden is an interim use until development takes place. She advocated that the City zone sites for permanent community gardens, stating: “I would like to see some dignity given to the urban agriculture” . John Dotter, San Jose community garden program director for many years, noted that community gardens and cultural gardens have been an essential space in San Jose for many groups of immigrants to continue the expression of agricultural and community identities . In a valley with rich history of farming in Japanese, Mexican, and other ethnic communities, gardens bridge rural and urban immigrant communities.In addition to San Jose, both Oakland and San Francisco initiated community garden programs in the seventies. In 1973, the San Francisco Board of Supervisors created a community gardening program under the Department of Public Works Street Tree Program and hired a coordinator to run the gardens . The greenhouse at the Laguna Honda Hospital, the site of the former victory garden, was put to use growing plants for distribution to community gardens. At the same time the coordinator assisted residents in finding sites for gardens and in obtaining insurance. When the Comprehensive Employment Training Act began providing federal funding for positions for urban improvement, San Francisco hired CETA workers to run community garden and art projects. By 1975 fourteen full-time workers were employed . Using CETA funding, Contra Costa County hired seven staff members to develop a gardening program inspired by San Francisco’s program . The state of California hired a community gardening coordinator to be housed under the Office of Appropriate Technology and published a 1977 report on the state of community gardens . The significant energy across the state was funneled into the creation of the California Council for Community Gardening , a precursor to the American Community Gardening Association . The Council organized statewide conferences, a communication network, and information sharing forums. By 1979 there were 75 community gardens managed by the San Francisco Department of Public Works. However due to the passage of Proposition 13 and the end of CETA funding, the community gardens program had already begun its decline. By 1980 the community garden program was no longer functioning . The Contra Costa program lost all but one staff member. The California Council for Community Gardening began its decline and folded in 1985. Organizer Mark West wind concluded the project ultimately did not continue because “each of us was too dedicated to our primary focus – our own projects in our own communities” . In San Francisco, Pam Pierce, Steve Michaels, and other gardeners continued the work of helping to support gardens under the name of the Urban Agriculture Coalition .

In July 2006 in South Central Los Angeles, over 300 gardeners were evicted after public land became private through backroom deals. This eviction became perhaps the most publicized and scandalous urban farming land dispossession in U.S. history. Three years later in Albany, CA in the face of UC Berkeley’s plans to develop their last plot of urban agricultural land, a coalition of over thirty groups began a fifteen-year process resulting in an urban garden and community-university partnership. Today activists struggle to maintain access to the land for the future. Both of these cases, despite being gardens on public land engaging hundreds of community members, demonstrate the insecure access to land gardeners struggle with across cities in the US. Their stories are telling. The Los Angeles South Central Farm garden site, which was over ten acres, was obtained by the City of LA in the mid-1980s through eminent domain for the purpose of creating a trash incinerator facility . Local citizens successfully opposed the building of the incinerator, and in response to the 1992 social uprising spurred by the Rodney King beating and long term effects racism and poverty in south central LA, the site was purposed as a community garden. The local food bank saw the garden as a means to address a lack of food retailers and social marginalization of residents. Garden construction began in 1994. Gardeners, mainly recent Mexican and Central American immigrants and Latinos, farmed 350 plots, producing rich agroecological environments with fruit trees, dense plantings of vegetables and flowers,growing strawberries vertical system and difficult to find herbs and culinary ingredients.

Gardeners came to the farm to grow food for their families, practice or learn agricultural traditions from those still practicing their knowledges, feel more at home and socialize, and support family businesses . In a study of the farm’s biodiversity, Peña estimated there were 100-150 plant varieties, many varieties of which were difficult to find in the US outside of huertos familiares in Latino communities. In 1995, the development company that had lost the property to eminent domain in the 80s made its first attempt to buy back the property, but the City Council did not approve the deal . The developer sued arguing that he was denied his right to buy back the land that was taken with the purpose to build a trash incinerator. In 2004 the gardeners were given their eviction notices after the city as a result of an out-of-court settlement sold the property back to the developer for $5.05 million . In response to the eviction notices, the gardeners organized to form the South Central Farmers Feeding Families. The gardeners and their allies went through a roller coaster journey of successes then eventual failure in the courts. Local residents, internationally known actors, and city politicians supported the effort to keep the gardeners on the land. In April 2006, the Trust for Public Land and LA Mayor Villaraigosa’s office negotiated an option to buy the land, but the developer was now seeking $16.3 million for the property . When the coalition raised the funds to meet the asking price, the developer rejected the offer and, starting in June, barred gardeners from the land and demolition begun . Mares and Peña argue that the struggle over South Central Farm represented a turning point for the environmental justice movement. Latino immigrants had reproduced village-based forms of community self-organization, integrated agricultural traditions into a new place, and challenged undemocratic urban planning and policy. Many city officials had expressed support for the South Central Farmers, a group of Latino residents, including many undocumented immigrants. Still, in the end the city sided with an interpretation of the case as a simple matter of a developer’s right to his property .

The incident demonstrated that many local government officials who claimed to support the work of gardeners would only go so far in standing up to business interests, despite arguments that the sale of the city land was illegal . Gardeners who assumed city land would be secure from development saw the land sold out from under them. Despite the eventual development of the land, the gardeners’ resistance to claims by the developer galvanized a community and demonstrated their political power .In Berkeley, urban agriculture advocates struggled for fifteen years to gain a tenyear agreement for a garden on public land. In 1997 after learning of UC’s plans to develop a large tract of agricultural research land for commercial purposes, a coalition of over 30 groups began resisting the development and proposed instead an urban agriculture research and education center. For over seven decades the farm was used by the Division of Biological Control for research on integrated pest management, but in 1998 a research agreement was made between the UC Department of Plant and Molecular Biology and Novartis, a biotechnology corporation, which granted Novartis the right to license discoveries in exchange for a $25 million donation to the department . As a result, by 2001 the DBC was no longer allowed to use the land and was defunded by the university. Students, faculty and others organized against this “biotech buyout”, leading to the infamous tenure battle of Ignacio Chapela.1 At the same time students, faculty, and community partners were organizing to try to gain a better foothold for sustainable agriculture research at the University. Starting in the mid-1990s, the University of California Berkeley decided to sell the development rights to the unused south side of Gill Tract that was adjacent to UC Berkeley family student housing. UC students, neighbors, and urban garden advocates led by Peter Rosset and others at Food First organized to resist the development and advocated for the creation of a sustainable urban agriculture training center 1997.

The UC moved ahead with planning the development at the same time it was seeing unprecedented tuition hikes, increased recruitment of out-of-state students, and increased investment in real estate and development on UC campuses . In 2004 the UC Regent’s released a Master Plan for Developing the University Village with details of Capital Projects Division’s plans to develop the entire tract with a shopping center, senior center complex, and recreation and open spaces . The Associated Students of the University of California and the Student Organic Garden Association at UC Berkeley released statements opposing the development of the land and supporting the creation of a garden/farm . Between 2004 and the early 2010s, the UC sought the necessary zoning changes and approvals from the city of Albany as well as solicited interested developers, including Whole Foods and Sprouts grocery stores.The occupation initially lasted three weeks during April 2012, until UC police stepped in to end the occupation. The land was reoccupied in May, 2013, when protesters again cleared grasses, tilled, and planted. This occupation was broken up by UC police, re-established, and then raided again. At the same time students and garden advocates were working with faculty, such as Miguel Altieri, and the College of Natural Resources,growing vegetables in vertical pvc pipe to develop a community-university partnership for use of the land. Today that partnership project manages a collectively run garden called the Gill Tract Community Farm located on part of the northern portion of the land. In addition, UC faculty continue to conduct agricultural experiments on the north side, while the south side is still slated for development. Occupy the Farm persists as a movement and many of the original occupiers now garden as a part of the partnership. OTF activists have also developed a connection with the MST 2 , organizing events that connect food and land sovereignty work in the global south to the struggle for the Gill Tract Farm. Occupy the Farm works to highlight the UC’s shift towards increasing privatization while little support is given to projects that support local agriculture, food security, or otherwise serve the local ecological and human communities. For example, OTF activists protested the December 2013 hiring of Robert Lalanne as the first ever ‘vice chancellor for real estate’ for UC Berkeley. On October 1, 2014, members of OTF and the Cal Progressive Coalition occupied the office of Capital Projects holding a sit-in until Chancellor Dirks met with the occupiers and provided several important documents about the Gill Tract development, which activists had been promised in May . This action was conducted as a part of a call for National Days of Action for Land and Food Sovereignty put forth by the US Food Sovereignty Alliance. The idea for these days of action came out of meetings at the second US Food Sovereignty Alliance Annual Assembly in 2013. The first was held in Oakland in 2011.

Organizing around land and food in the US context arose as an important theme for Alliance members, as well as for researchers. Food First initiated the Land & Sovereignty in the Americas’ Collective, which in October 2014 released its first informational brief on land and resources grabs in the US . OTF and others engaged in these actions have sought to bring land politics to the forefront of the struggles for sustainable agriculture and food sovereignty. These two urban agriculture projects aimed to enact better food systems, both as a part of contemporary food movements and as a part of the local struggles of their immediate geographic communities. The South Central Farm arose in the mid-1990s in Los Angeles in the same time and place as the community food security movement, as a solution to the hunger and lack of healthy food options in a majority African American, Latino, and Mexico and Central American immigrant community. Organizing for use of the Gill Tract Farm began in 1997 and for nearly two decades has focused on the need for public educational resources to be allocated towards sustainable agriculture. Advocates have stressed the environmental significance of preserving one of the last pieces of farmland in the East Bay. In 2010 the advocacy received a new boost of energy when Occupy the Farm activists identified the farm as important to the broader community project of reclaiming commons. Due to the intensity of their struggle, both of these stories gained positions of prominence in contemporary food movements. These examples demonstrate the fact that gardeners are most frequently not the owners or decision makers of land use choices for the parcels of land that they farm. This disconnect of land ownership and use has led to a significant problem for contemporary urban agriculture: tenure insecurity even on public land. But the stories go beyond highlighting struggles for tenure strictly for gardening. Both stories incite both outrage and debate in gardening communities on the topics of how urban space can and should be used in recreating food systems. Urban agriculturalists construct and define urban utopian projects that intend to reconfigure the city in more ideal forms. Ultimately, each project made food activists distinguish their positions on the appropriate uses, governance, and ownership of urban land in situations where gardeners are not immediately empowered to make land use decisions. Gardens are part of  socio-ecological processes that create urban space, and gardeners are a part of the urban movements that struggle for ideal landscapes. Drawing on Lefebvre, urban political ecology understands space as socially produced through a history of practices, representations, and experiences . Gardeners change the production of urban spaces through actions like advocating for use of public lands, changing investors’ decisions on buying particular parcels, or passing legislation to increase access to space for gardens. Adopted as a strategy for change in various movements, community gardens in urban settings can have multiple and contrasting meanings of community and garden . Gardeners debate the questions: What kind of city do we want to live in? How do we want to eat and work, interact with nature, and engage with our neighbors and governmental agencies within that city? Can gardens help us transform cities today or prefigure new cities of our futures? Can we change the economic, political, social, ecological landscapes of cities through garden projects? These questions are central to the project of urban political ecology, which serves as a guiding framework for this dissertation. Urban political ecology brings together theories of production, space, justice and agency to understand socioecological landscapes .

The first uses a lagged dependent variable approach and the second employs a difference-in-difference framework. Both approaches yield similar estimates, indicating that during the period under examination the subsidy increased support for the incumbent party by 6.2% to 7.5%. While this increase might seem relatively modest, we emphasize that this result is the estimated effect of receiving the subsidy in a single year of a multi-year program and that the individual effects of the subsidy are likely to be attenuated because non-recipients may have also benefitted indirectly, for example through reduced food prices. The main contribution of this paper is to add to the growing empirical literature on the political benefits of poverty-reduction programs . We draw from the new wave of agricultural subsidy programs in Africa to demonstrate that such programs can alter political preferences even in settings like Malawi, where entrenched ethno-regional partisan ties might be expected to limit the political effects of government sponsored programs. In doing so, the paper also contributes to the literature specifically related to the political economy of agricultural subsidies . The findings have important implications for the larger literature on distributive politics and on our understanding of voter behavior in Africa. The conventional wisdom in scholarship on patronage and clientelism, particularly in Africa, is that ruling parties build and maintain support by channeling material favors to core supporters . One of the key debates in the empirical literature on voter behavior in Africa’s emerging democracies is whether government performance affects voters’ political preferences in contexts where social identities, particularly ethnicity, are salient. The analysis presented here shows that distributive programs need not be targeted to core supporters to be politically beneficial to incumbents,greenhouse benches suggesting that leaders in Africa’s emerging democracies may be able to enhance their support by implementing anti-poverty programs that do not discriminate against non-partisans or out groups at the local level.

Should incumbent leaders expect to reap political rewards from implementing targeted antipoverty programs? On the one hand, the answer may seem obvious. The theoretical literature on retrospective voting suggests that voters reward parties that implement desired policies . To the extent that distributive programs lead to real improvements in welfare, voters may well compensate the incumbent at the ballot box. Studies from emerging democracies in the developing world find evidence of such a link. De la O shows that in Mexico a large-scale anti-poverty cash transfer program that provided benefits to lowincome families increased voter turnout and support for the incumbent party. In Brazil, Zucco reports similar effects when examining a cash transfer program aimed at low income families with children. Manacorda et. al show that a short-term poverty relief program in Uruguay had similar effects, increasing support for the incumbent party that launched the program. Pop-Eleches and Pop-Eleches examine a program that distributed coupons to poor families for the purchase of reduced-priced computers and found that beneficiaries were significantly more likely to support parties of the governing coalition. Finally, Harding and Harding and Stasavage present evidence from Ghana and Kenya that voters reward incumbents for improving roads and expanding access to primary education. There are at least two channels through which targeted subsidy programs like the agricultural subsidy we examine in this paper might affect voter preferences. First, retrospective theories of economic voting suggest that when such programs have a positive effect on individual economic welfare, voters will reward the party responsible for implementing the program. Agricultural programs are generally highly visible initiatives that have a direct effect on material well-being for large numbers of citizens. In Malawi, for example, studies have shown a strong positive relationship between expanded fertilizer use resulting from the subsidy program and crop yields . Others have linked the subsidy to dramatic increases in maize output that reduced food insecurity and brought down the price of maize in local markets .

Existing studies suggest that subsidy programs have contributed to improved evaluations of incumbent job performance in Malawi and elsewhere . This is important, because, as Harding and Stasavage argue, voters are more likely to reward incumbent leaders for programs that can be directly attributed to those political actors. The clientelism literature suggests an alternative mechanism through which subsidy programs might affect voter behavior. In contexts where the distribution of valued benefits is controlled by party agents, citizens may trade their vote for material transfers . By this logic, the receipt of subsidy coupons might be expected to strengthen patron-client bonds, solidifying support for the party that controls access to state largess. However, for reasons described below, we expect the clientelist mechanism to be less relevant in the Malawian context that we study because of weak local-level party infrastructure. At the same time, there is reason to be skeptical about anti-poverty programs’ power to influence political preferences, particularly in African contexts where voter preferences are often driven by ethnic and regional identities. Longstanding approaches to political behavior in Africa suggest that voters hold strong preferences for candidates and parties associated with their own ethnic communities and only trust co-ethnics to deliver benefits to their group . Where ethnicity underlies political preferences, voters may be unresponsive to material transfers and may be hesitant to give incumbents credit for distributive programs, even when such programs do not discriminate by ethnicity or partisanship.Moreover, the clientelism literature suggests an additional reason why voters may be unmoved by anti-poverty programs: where local monitoring systems are weak, voters may simply accept government favors but continue to vote according to pre-existing preferences . The existing empirical literature from African cases has so far offered mixed findings on the connection between government performance and voter preferences. Several recent studies provide evidence in favor of retrospective voting theories . Other studies, however, suggest that in some cases ethnicity can trump performance . With the exception of Harding and Harding and Stasavage , these works tend to focus on broad performance measures, rather than specific antipoverty programs. As such, we still know relatively little about the potential effect of particular policy initiatives. There is good reason to be skeptical about the political effects of anti-poverty programs in the Malawian context in particular. In four of five elections after the return to competitive politics in 1994, electoral results exhibited a clear ethno-regional character, with voters in the North, Center, and South lining up en masse behind the party associated with their regions and the ethnic communities in each area . Likewise, the incumbent party at the time of our study – the DPP – was particularly weak. The incumbent president, Mutharika, came to power in the 2004 election as the hand-picked successor of the retiring president, Bakili Muluzi. Mutharika was elected as the head of the United Democratic Front party, over which Muluzi continued to preside after the 2004 election. Subsequent power struggles led Mutharika to abandon the UDF and launch the DPP in 2005. As a new party, the DPP lacked even minimal infrastructure and was poorly suited to monitor clientelist exchanges at the local level. The principal contribution of this article is to show that anti-poverty programs,plant benches particularly in the form of a targeted agricultural subsidy, can affect political preferences even when ethno-regional identities are politically salient and parties lack the ability to monitor distributive exchanges.Intervening in agricultural markets has long been a central political strategy used by African leaders to build and maintain support. In the period following independence African leaders implemented a variety of agricultural policies – tariffs, price controls, subsidies, credit schemes, and so forth – to reward favored constituencies . These interventions favored urban residents and rural notables, not ordinary farmers who posed little threat to incumbent leaders. By the 1990s, governments across the continent had removed or scaled back these programs in response to fiscal constraints and donor pressure to reduce the role of the state in the economy.

In recent years, however, large-scale subsidy programs have reemerged in several countries as initiatives to combat stagnant agricultural productivity and chronic food insecurity . One estimate suggests that seven leading African countries presently spend over US$ 2 billion per year on subsidy programs . Malawi’s Agricultural Input Subsidy Programme was launched in response to a sharp decline in rainfall in the 2004/05 growing season3 that that left an estimated 4.9 million Malawians vulnerable to hunger and food insecurity . The AISP targeted poor subsistence farmers starting with the 2005/06 season. The program represented a massive expansion of efforts to alleviate food insecurity that had been initiated earlier in the decade . The program is often heralded as a success: one report, for example, credits the AISP with taking Malawi from having a 43% food deficit in 2005 to achieving a 53% food surplus in 2007—becoming a net food exporter in just two years . These claims, however, have been challenged by those questioning the validity of such statistics and by those who have studied household-level data to measure the program’s enduring effects and its ability to reduce food insecurity and poverty . The AISP’s core objective was to increase resource-poor smallholder farmers’ access to improved agricultural inputs to achieve food self-sufficiency and to increase smallholder farmers’ incomes through increased food and cash crop production . Beneficiaries received coupons to be redeemed at government-designated retailers for either seed or subsidized fertilizer. The AISP distributed three types of coupons: a fertilizer coupon, a seed coupon, and what was referred to as a flexible coupon, which could be exchanged for a variety of seed options. The program grew in subsequent years, reaching an estimated 65% of farm households at its peak in 2008/09 at a cost of approximately USD $285 million in that year, equivalent to 16% of the government’s annual budget or about $22 per citizen in a country were GDP per capita is less than $300 . Allocation decisions4 are made at the national level by officials from the Ministry of Agriculture. District allocations are based on the amount of land under cultivation and the number of farm families per district, information that is provided by village-level officials and cross-checked by agricultural extension agents. At the village level, allocation was jointly determined by the Ministry of Agriculture, District Development Committees, Area Development Committees, and Traditional Authorities. Individual beneficiaries were supposed to be identified through use of the farm household register and open meetings held by Ministry of Agriculture staff. These committees submitted to Ministry of Agriculture staff a list of names of those in need, from which the Ministry of Agriculture selected beneficiaries. District officials then transferred coupons to representatives of village committees , and these committees distributed coupons to beneficiaries. Given the multiple actors involved in the identification of recipients and the delivery of coupons, there were a number of opportunities for the government to engage in targeting.The literature on distributive politics offers contrasting views on whether incumbents should be expected to target rewards to core supporters , swing voters or some mix of the two. Empirical studies from other contexts find evidence consistent with both models . With specific regard to targeting in agricultural input subsidy programs in African countries, relevant studies found evidence of political targeting toward opposition strongholds in Ghana , core support areas in Zambia , and an absence of targeting with respect to patterns of prior electoral support in Malawi .6 More work is needed to identify the conditions under which leaders adopt alternative allocation strategies. Regardless of whether the Malawian government may have sought to reward core supporters or to court potential swing voters through the allocation of subsidy coupons across districts, we expect that the ability to target individuals at the local level was constrained in Malawi by the relatively high degree of ethnic homogeneity at the village level.The prerequisite for individual targeting is that party agents must be able to identify core supporters, opposition supporters, and possible swing voters. In most election years, ethnicity serves as a useful predictor of electoral preferences , making it possible to identify core and swing districts based on ethnic demography. However, because rural villages have little ethnic diversity, ethnicity is much less useful for identifying core and swing individuals within villages.Two additional features of the Malawian context limit the potential for village-level targeting. First, during the period under study partisan orientations were abnormally fluid, making ethnicity even less useful as a marker of party allegiances.

These groups bring together their expertise, tools, and infrastructure in a research program supported by the NSF to create and translate to practice precision agriculture technologies and systems. The Center activities are positioned to deliver outputs in agricultural-specific IoT sensor, robotics, energy, communication, and data science technologies and their integrated systems, that are responsive to the scale, environment, and socioeconomics of farming. The research program outcomes are structured to build needed fundamental knowledge, technologies, and systems with increasing complexity and scale over time and to establish trusted relationships between researchers and stakeholders to realize precision agriculture systems that contribute to a food, energy, and water secure future. The impacts of market liberalization on welfare in rural areas of less developed countries have received increasing attention from both researchers and policy makers as relatively poor countries become integrated into world markets and trade pacts. Overwhelmingly, the view of researchers and policy makers alike has been that, in less developed countries , urban residents win but rural populations lose from the elimination of own-import tariffs on agricultural commodities. The urban gain results from lower consumption costs, while the rural loss is the consequence of increased competition with imported agricultural and livestock goods, depressing both profits and wages in a sector in which LDCs presumably have a comparative advantage. This raises serious welfare concerns, because many of the world’s poor live in rural areas. An interesting corollary to this argument is that agricultural support policies in developed countries adversely affect welfare in rural LDC households by depressing world prices for farm goods . In this paper we use a disaggregated rural economy-wide modeling approach to explore the rural welfare impacts of own-country agricultural tariff reforms called for in the Central American Free Trade Agreement in four Central American countries: El Salvador, Guatemala, Honduras, and Nicaragua .

Our rural economy-wide model for each country consists of a series of interacting micro agricultural household models. Inasmuch as an agricultural household model can be viewed as a computable general equilibrium model for an individual rural household group , the disaggregated rural economy-wide model is really a nested CGEM. To facilitate comparison,dutch buckets for sale we model the same rural household groups in each of the four countries . We use the nested rural CGEMs to simulate the impacts of country-specific agricultural provisions in CAFTA on the income of each rural household group. We also perform a welfare analysis in which the economy-wide model is used to estimate the transfers that would be required to maintain all rural household groups at their pre-CAFTA welfare levels. This transfer differs from a conventional compensating variation by taking into account rural economy-wide impacts of the trade policy shock on household resource allocations, rural wages and subsistence production.Two considerations have tended to reinforce the view that agricultural trade reforms negatively affect rural welfare in LDCs. First, many rural households produce grain, for which high-income countries have a comparative advantage in production. Removing protection on grain imports thus leaves the rural economy vulnerable to competition from foreign grain producers. The combination of generous support programs for grain farmers in high-income countries with LDC tariff reform, from this perspective, inflicts damage on the LDC rural economy. Second, the effects of agricultural reforms in high-income countries are likely to be muted because in many cases LDCs already have preferential access to developed country markets for their agricultural exports. LDCs are net exporters of tropical products, for which competition with developed countries generally is not an issue. Preferential treatment covers a large share of developing country exports to the European Union and the United States, reaching over 90% of all agricultural exports to these regions for some LDCs .

The most notable preferential agreements include those between the E.U. and its members’ former colonies in Africa, the Caribbean and the Pacific, and the Everything but Arms agreement; and between the United States and Africa and Latin America via the Africa Growth and Opportunity Act and the Caribbean Basin Initiative. Because of this, the argument goes, LDCs stand to gain less than they lose from the liberalization of agricultural trade. In fact, some LDCs may lose from trade liberalization as a result of preference erosion . These considerations have been salient in the contentious debates over agricultural policy that characterized the Uruguay Round in the late 1980s and 1990s and currently plague multilateral trade negotiations under the Doha Development Agenda . Some evidence from aggregate economy-wide models suggests that the impact of agricultural trade reforms in LDCs would be positive; however, the reasons lie mostly in the effects that such reforms would have on the non-agricultural sector. Tangermann reports the finding from a GTAP model that full agricultural liberalization by high-income countries would enhance the non-agricultural terms of trade for developing countries, thus leading to income gains. However, Anderson and Valenzuela , using a GTAP model, find negative effects of own-country agricultural trade reforms on agricultural value-added in all the developing countries they considered. The implication of these findings would seem to be that the more narrowly one focuses on the LDC rural economy and on own-country tariff reforms, the greater the likelihood of finding negative welfare impacts of agricultural trade liberalization. Micro agricultural household theory suggests that the impacts of agricultural market liberalization on LDC rural welfare are not clear cut, even if LDC producers do not acquire greater access to high-income markets for their agricultural output. As producers or suppliers of factors to farms, rural household lose when the price of goods they produce decreases. However, rural households also are consumers, and it is not uncommon to find that most producers of protected goods in LDCs are not net sellers of these goods prior to reforms. Like urban households, they stand to benefit as consumers. Whether the negative production or positive consumption effect dominates is an empirical question, and the answer is likely to be different for different rural household groups. Even on the production side, a decrease in price may benefit households that are engaged in other crop activities if factor prices decrease. Even the impacts of agricultural trade reforms on factor prices are ambiguous; they depend on the relative factor intensities of the directly and indirectly affected activities.

Understanding the impacts of agricultural trade reforms on LDC rural economies thus requires an economy-wide modeling approach that embeds within it a micro-economic focus capturing both the heterogeneity of rural households and the diversity of activities in which these households participate. GTAP and other economy-wide models are useful to explore aggregate impacts of trade policy reforms; however, their high level of aggregation precludes a rural micro focus.CAFTA represents an ideal case for studying the potential impacts of agricultural trade reforms on rural welfare. In EGHN,hydroponic net pots the majority of farm households cultivate food grains. All benefit from preferential access to U.S. markets for their agricultural exports, and all are net importers of grain. Prevailing tariffs on grain imports range from 15% to 40% in El Salvador, from 20% to 35% in Guatemala, from 15% to 45% in Honduras, and from 10% to as high as 62% in Nicaragua. Tariffs on livestock products in the four countries range from 15% to 164% . With the exception of white corn, all of these tariffs would be phased out, either immediately or gradually, under CAFTA. 1 The stakes are high from a rural welfare point of view. Rural poverty ranges from 62% of all rural residents in El Salvador to 86% in Honduras. CAFTA would be implemented in a context of generally deteriorating agricultural trade balances. Between 1990 and 2003, both Guatemala and Honduras experienced a decrease in their positive agricultural trade balances while in El Salvador a surplus gave way to a steep deficit . Only in Nicaragua did a positive surplus increase, due primarily to increases in bean and meat exports. In all four countries, maize and rice imports and fruit and vegetable exports increased sharply. Sugar exports increased, but in two out of the four countries , traditional agricultural exports as a whole contracted.Maize production decreased in Guatemala and Honduras, increased slightly in El Salvador, and rose sharply in Nicaragua. Rice production contracted in El Salvador, Guatemala and Honduras while rising in Nicaragua. Beef output stagnated in El Salvador and Guatemala, fell in Honduras, and rose in Nicaragua; beef imports increased as did imports of poultry . Milk production rose in all four countries, and except in Nicaragua, milk imports increased, as well. Changes in land use mirror these trends . Between 1978 and 2001, the land area cultivated in basic grains decreased in Honduras, did not change significantly in El Salvador and Guatemala, and increased in Nicaragua. In contrast, land in other crops, including non-traditional fruits and vegetables, increased in all four countries. Only in Nicaragua did the number of cattle increase. CAFTA would be implemented in a context of demographic transformation, as migration shifts rural population internally, to cities, and internationally, mostly to the United States. Nevertheless, rural population shares remain high by international standards. In 2003, the rural share of the economically active population was 56% in Guatemala, 46% in Honduras, 42% in Nicaragua and 38% in El Salvador.

The shares of population living in rural areas ranged from 43% in El Salvador to 60% in Guatemala. According to the U.S. Census of Population, the number of EGHN-born persons living in the United States nearly doubled from 1990 to 2000, from 771,600 to 1,342,000. The rural migration response potentially has an important influence on how agricultural trade policy reforms affect rural poverty. Two other considerations are critical when modeling rural welfare effects of trade policy shocks: the heterogeneity of rural households and the diversification of these households’ activities and income sources.Tables 3a-3d present the classification of rural household groups that we use to capture the heterogeneity of the rural population in each Central American country, the criteria used to create the household categories, and the number of households in each country and in the data bases used to estimate the models. Landless households represent the largest number of rural households in all but Guatemala, where more than half of all rural households are subsistence producers. In all four countries, rural households without land depend primarily on salaries, both agricultural and non-agricultural, and remittances from internal and international migrants. Subsistence households produce basic grains on small holdings, principally for home consumption. Because they do not participate in markets, the implicit value of their grain output is given by shadow prices that are endogenously determined for each subsistence household group. In our DREMs as in the micro agricultural household models of Strauss and De Janvry, Fafchamps, and Sadoulet , these households are modeled as autarkic; basic grain production is equal to demand. A novelty of the DREM is its ability to represent differences in market articulation as well as in demands, production technologies, and activity mixes among different rural household groups. Production decisions in commercial households, which produce primarily for markets, are guided by market rather than shadow prices. Marketed surplus from these households is simply the difference between output and demand, as in the staple agricultural household model described by Singh, Squire, and Strauss . All household groups participate in markets for other agricultural and non-agricultural commodities and for factors, either as buyers or sellers . They differ with respect to incomes, activity mixes, demand patterns, and technologies. Average per-capita incomes, human capital and landholdings vary widely across countries as well as rural household groups. Landless households have an average annual income of US$347 per capita in Honduras and $877 in El Salvador, where we were unable to disaggregate landless households by schooling. Landless low-education households had an average per-capita income of $502 in Nicaragua and $576 in Guatemala. Average incomes of subsistence producer households range from $359 to $510 , and those of small commercial producers, from $409 to $479 . The highest incomes are found in large commercial households in El Salvador $1,909 and Nicaragua . With the exception of high-skilled landless households, rural household heads in all four countries have low levels of completed schooling, ranging from 1.3 years to 3.5 years .