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Aim: As climate change increases the frequency and severity of droughts in many regions, conservation during drought is becoming a major challenge for ecologists. Droughts are multidimensional climate events whose impacts may be moderated by changes in temperature, water availability or food availability, or some combination of these. Simultaneously, other stressors such as extensive anthropogenic landscape modification may synergize with drought. Useful observational models for guiding conservation decision‐making during drought require multidimensional, dynamic representations to disentangle possible drought impacts, and consequently, they will require large, highly resolved data sets. In this paper, we develop a two‐stage predictive framework for assessing how drought impacts vary with species, habitats and climate pathways. Location: Central Valley, California, USA. Methods: We used a two‐stage counterfactual analysis combining predictive linear mixed models and N‐mixture models to characterize the multidimensional impacts of drought on 66 bird species. We analysed counts from the eBird participatory science data set between 2010 and 2019 and produced species‐ and habitat‐specific estimates of the impact of drought on relative abundance. Results: We found that while fewer than a quarter (16/66) of species experienced abundance declines during drought, nearly half of all species (27/66) changed their habitat associations during drought. Among species that shifted their habitat associations, the use of natural habitats declined during drought while use of developed habitat and perennial agricultural habitat increased. Main Conclusions: Our findings suggest that birds take advantage of agricultural and developed land with artificial irrigation and heat‐buffering microhabitat structure, such as in orchards or parks, to buffer drought impacts. A working lands approach that promotes biodiversity and mitigates stressors across a human‐induced water gradient will be critical for conserving birds during drought. [ABSTRACT FROM AUTHOR]

Drained agricultural peatlands occupy only 1% of agricultural land but are estimated to be responsible for approximately one third of global cropland greenhouse gas emissions. However, recent studies show that greenhouse gases fluxes from agricultural peatlands can vary by orders of magnitude over time. The relationship between these hot moments (individual fluxes with disproportionate impact on annual budgets) of greenhouse gas emissions and individual chamber locations (i.e. hot spots with disproportionate observations of hot moments) is poorly understood, but may help elucidate patterns and drivers of high greenhouse gas emissions from agricultural peatland soils. We used continuous chamber-based flux measurements across three land uses (corn, alfalfa, and pasture) to quantify the spatiotemporal patterns of soil greenhouse gas emissions from temperate agricultural peatlands in the Sacramento-San Joaquin Delta of California. We found that the location of hot spots of emissions varied over time and were not consistent across annual timescales. Hot moments of nitrous oxide (N2O) and carbon dioxide (CO2) fluxes were more evenly distributed across space than methane (CH4). In the corn system, hot moments of CH4 flux were often isolated to a single location but locations were not consistent across years. Spatiotemporal variability in soil moisture, soil oxygen, and temperature helped explain patterns in N2O fluxes in the annual corn agroecosystem but were less informative for perennial alfalfa N2O fluxes or CH4 fluxes across ecosystems, potentially due to insufficient spatiotemporal resolution of the associated drivers. Overall, our results do not support the concept of persistent hot spots of soil CO2, CH4, and N2O emissions in these drained agricultural peatlands. Hot moments of high flux events generally varied in space and time and thus required high sample densities. Our results highlight the importance of constraining hot moments and their controls to better quantify ecosystem greenhouse gas budgets. [ABSTRACT FROM AUTHOR]

Policies that improve drought resilience have heterogeneous effects on agricultural land values. We examine the value of surface water transfers and groundwater resources in a hedonic analysis of agricultural parcels in California. We find that parcels in irrigation districts, which engage in interbasin surface water transfers, experience an increase in value in subsequent years, but the gains are short-lived and unevenly distributed. Value of groundwater stock is higher in parcels outside irrigation districts. We also find that policies to restrict groundwater-substitution-based transfers, which aimed to reduce groundwater open-access externalities, have not been a deterrent against transfers in all areas. [ABSTRACT FROM AUTHOR]

Climate change is expected to impact the spring phenology of perennial trees, potentially altering the suitability of land for their cultivation. In this study, we investigate the effects of climate change on the bloom timing of almond orchards, focusing on California, the world's leading region for almond production. By analyzing historical climatic data, employing a model that considers hourly temperatures and fall non-structural carbohydrates to predict bloom dates, and examining various Coupled Model Intercomparison Project Phase 6 (CMIP6) scenarios, we assess the potential impacts of climate shifts on plant phenology and, consequently, on land suitability for almond farming. Our findings reveal that, within the next 30 years, the land suitable for almond production will not undergo significant changes. However, under unchanged emission scenarios, the available land to support almond orchard farming could decline between 48 to 73% by the end of the century. This reduction corresponds with an early shift in bloom time from the average Day of Year (DOY) 64 observed over the past 40 years to a projected earlier bloom between DOY 28–33 by 2100. These results emphasize the critical role climate shifts have in shaping future land use strategies for almond production in Central Valley, California. Consequently, understanding and addressing these factors is essential for the sustainable management and preservation of agricultural land, ensuring long-term food security and economic stability in the face of a rapidly changing climate. [ABSTRACT FROM AUTHOR]

In this paper, we examine the implications of groundwater sustainability policies on agricultural land retirement and how retired land can be repurposed to minimize social, economic, and environmental harms, while maximizing potential benefits. Globally, as water resources are strained by increasing agricultural demand and biophysical factors, policies are enacted to restrict groundwater pumping for irrigated agriculture in order to stem social, economic, and environmental harm. However, little is known about the implications of land retirement on ecosystems and people, and how this land can be best repurposed. Using Kern County, CA, as a case study, we draw from 23 qualitative interviews with stakeholders in the agricultural, water, and conservation sectors to understand the impacts of sustainable groundwater management policy and options for land repurposing. Stakeholders in our study outlined both positive and negative impacts of such policies across the region, including increased financial costs of agricultural production, crop type switches to perennial crops such as trees and vines, and improved communication and collaboration among stakeholders. Stakeholders discussed options for land repurposing to maximize ecological, social, and economic benefits, including habitat restoration, installation of solar farms, grazing, groundwater recharge, temporary fallowing, and recreation and parks. Finally, we propose recommendations to maximize the benefits and minimize the harms from the retirement and repurposing of agricultural land: (1) increasing regional planning and cross-stakeholder communication for strategic land repurposing, (2) minimizing the burden of policies that may restrict land repurposing options, and (3) ensuring financial incentives exist for landowners to repurpose their land. [ABSTRACT FROM AUTHOR]

California sea cucumbers (Apostichopus californicus) are often abundant at oyster farms in British Columbia, Canada both on the suspended gear as juveniles and on the seafloor beneath them as a mixture of juveniles and adults. Their natural abundance, high value, and potential to mitigate benthic organic loading has led to an interest in their coculture with oysters. Whether farmed sea cucumbers ought to be contained to physically separate them from wild stocks is debated. The present three-year field study examined the movement of wild California sea cucumbers on/off an operational oyster farm (~3000 m2) to help inform future sea cucumber aquaculture development. Sea cucumber effects on organic loading, immigration to/emigration from the farm, and the efficacy of various containment-material mesh types and sizes were examined. Juvenile and adult sea cucumber densities on the farm steadily increased from the end of winter through the end of summer, likely due in large part to juveniles falling off the suspended oyster gear, which occurred at an average rate of ~780 ind d−1 (for the whole farm) in the summer months. The largest increase in abundance on the farm was observed between January and March/April, when the population increased by 100–350 ind d−1. Between late summer and early winter, sea cucumbers emigrated from the farm at a rate of 50–90 ind d−1, neither juvenile nor adult densities on the farm changing appreciably over the winter. The sea cucumber density showed a progressive decrease in the first 20 m from the farm, after which the animals were scarcely noticed. Apostichopus californicus did not significantly decrease sediment organics beneath the farm compared to a nearby control site, but such an effect may have been lost due to their seasonal feeding cycles and/or the presence of other benthic grazers that were not part of our exclusion trial. Overall, our findings suggest that the separation of farmed and wild California sea cucumbers on a shellfish farm can only be guaranteed through containment, given the dynamic immigration and emigration patterns of wild stocks. Through laboratory trials, we found that individuals of A. californicus were able to squeeze through mesh as small as 32% of their contracted width and could escape fenced areas (90 ± 4% escape from nylon fencing and 40 ± 8% escape from VexarTM fencing) unless the fencing extended above the water surface (where there was no escape from either type). [ABSTRACT FROM AUTHOR]

Promoting wildlife habitat on working agricultural land is a growing conservation priority, and agri‐environment schemes are using payments for environmental services (PES) to reach these privately owned lands. PES can be ecologically effective, but also expensive, putting pressure on these schemes to be cost‐effective, maximizing the conservation value of their limited resources. This study assesses the cost‐effectiveness of four PES schemes in California that paid rice growers to provide temporary flood habitat on their working lands in support of shorebirds. It examines whether the schemes (1) paid for flood habitat only when needed (targeting); (2) paid for habitat that was actually delivered and would not otherwise be provided (additionality); (3) sacrificed as little habitat as possible when the habitat competed with production (ag/wildlife balance); and (4) fostered a commitment among growers to maintain the habitat after payments ended (permanence). Results show that the schemes fell short in each of the four goals, and they expose several factors that undermined their cost‐effectiveness. First, variable weather patterns altered the date in which the shorebird‐habitat gap emerged year‐to‐year, creating a dynamic and unpredictable target for the schemes to address. Second, growers' views on the compatibility of the flood habitat with their rice production varied widely and changed rapidly as the agricultural calendar progressed, making it a challenge to mitigate potential ag/wildlife conflicts. Third, water for flood habitat is expensive, and growers proved unwilling to shoulder that expense once payments ended. These results highlight the need for schemes to adopt design elements that can add flexibility, such as cancelation clauses, so that they can adjust to dynamic targets and adapt to changing ag/wildlife relationships. Results also suggest that PES schemes operating on working lands may require long‐term external support. That finding amplifies the imperative that schemes use their conservation resources cost‐effectively. [ABSTRACT FROM AUTHOR]

Coccidioidomycosis is a typically respiratory fungal disease that, in the United States, occurs primarily in Arizona and California. In California, most coccidioidomycosis cases occur in the San Joaquin Valley, a primarily agricultural region where the disease poses a risk for outdoor workers. We collected 710 soil samples and 265 settled dust samples from nine sites in the San Joaquin Valley and examined how Coccidioides detection varied by month, site, and the presence and abundance of other fungal species. We detected Coccidioides in 89 of 238 (37.4%) rodent burrow soil samples at five undeveloped sites and were unable to detect Coccidioides in any of 472 surface and subsurface soil samples at four agricultural sites. In what is the largest sampling effort undertaken on agricultural land, our results provide no evidence that agricultural soils in the San Joaquin Valley harbor Coccidioides. We found no clear association between Coccidioides and the greater soil fungal community, but we identified 19 fungal indicator species that were significantly associated with Coccidioides detection in burrows. We also did not find a seasonal pattern in Coccidioides detection in the rodent burrow soils we sampled. These findings suggest both the presence of a spore bank and that coccidioidomycosis incidence may be more strongly associated with Coccidioides dispersal than Coccidioides growth. Finally, we were able to detect Coccidioides in only five of our 265 near-surface settled dust samples, one from agricultural land, where Coccidioides was undetected in soils, and four from undeveloped land, where Coccidioides was common in the rodent burrow soils we sampled. Our ability to detect Coccidioides in few settled dust samples indicates that improved methods are likely needed moving forward, though raises questions regarding aerial dispersal in Coccidioides, whose key transmission event likely occurs over short distances in rodent burrows from soil to naïve rodent lungs. Author summary: Valley fever (coccidioidomycosis) is a fungal disease of humans that, in California, most commonly occurs in the San Joaquin Valley. Valley fever is caused by infection with Coccidioides fungi, of which nearly all cases occur though inhalation of airborne spores. Many cases of Valley fever in the San Joaquin Valley occur amongst agricultural workers, though only one other study has attempted to detect Coccidioides in agricultural soils. Furthermore, Valley fever cases follow a seasonal pattern, though no other work has determined whether the abundance of Coccidioides fungi in the environment follows a similar pattern. Here, we undertake what is the largest survey of Coccidioides amongst agricultural soils. Additionally, we provide the most comprehensive monthly survey of Coccidioides, spanning an entire year, amongst soils in the natural environment, namely, within rodent burrows, an environment where Coccidioides is commonly found. We were unable to detect Coccidioides in any of the agricultural soils we sampled, nor did we find a seasonal pattern in Coccidioides detection in the rodent burrow soils we sampled on undeveloped land. Finally, we found few associations between Coccidioides and other soil fungi, and no significant association with the structure of the greater soil fungal community. Taken together, our findings challenge assumptions regarding the prevalence of Coccidioides in agricultural soils and the relative importance of seasonal growth versus dispersal of Coccidioides in the environment. [ABSTRACT FROM AUTHOR]

Background: The Salmonella enterica serovar Newport red onion outbreak of 2020 was the largest foodborne outbreak of Salmonella in over a decade. The epidemiological investigation suggested two farms as the likely source of contamination. However, single nucleotide polymorphism (SNP) analysis of the whole genome sequencing data showed that none of the Salmonella isolates collected from the farm regions were linked to the clinical isolates—preventing the use of phylogenetics in source identification. Here, we explored an alternative method for analyzing the whole genome sequencing data driven by the hypothesis that if the outbreak strain had come from the farm regions, then the clinical isolates would disproportionately contain plasmids found in isolates from the farm regions due to horizontal transfer. Results: SNP analysis confirmed that the clinical isolates formed a single, nearly-clonal clade with evidence for ancestry in California going back a decade. The clinical clade had a large core genome (4,399 genes) and a large and sparsely distributed accessory genome (2,577 genes, at least 64% on plasmids). At least 20 plasmid types occurred in the clinical clade, more than were found in the literature for Salmonella Newport. A small number of plasmids, 14 from 13 clinical isolates and 17 from 8 farm isolates, were found to be highly similar (> 95% identical)—indicating they might be related by horizontal transfer. Phylogenetic analysis was unable to determine the geographic origin, isolation source, or time of transfer of the plasmids, likely due to their promiscuous and transient nature. However, our resampling analysis suggested that observing a similar number and combination of highly similar plasmids in random samples of environmental Salmonella enterica within the NCBI Pathogen Detection database was unlikely, supporting a connection between the outbreak strain and the farms implicated by the epidemiological investigation. Conclusion: Horizontally transferred plasmids provided evidence for a connection between clinical isolates and the farms implicated as the source of the outbreak. Our case study suggests that such analyses might add a new dimension to source tracking investigations, but highlights the need for detailed and accurate metadata, more extensive environmental sampling, and a better understanding of plasmid molecular evolution. [ABSTRACT FROM AUTHOR]

The monitoring of agronomic parameters like biomass, water stress, and plant health can benefit from synergistic use of all available remotely sensed information. Multispectral imagery has been used for this purpose for decades, largely with vegetation indices (VIs). Many multispectral VIs exist, typically relying on a single feature—the spectral red edge—for information. Where hyperspectral imagery is available, spectral mixture models can use the full VSWIR spectrum to yield further insight, simultaneously estimating area fractions of multiple materials within mixed pixels. Here we investigate the relationships between VIs and mixture models by comparing hyperspectral endmember fractions to six common multispectral VIs in California's diverse crops and soils. In so doing, we isolate spectral effects from sensor- and acquisition-specific variability associated with atmosphere, illumination, and view geometry. Specifically, we compare: (1) fractional area of photosynthetic vegetation (Fv) from 64,000,000 3–5 m resolution AVIRIS-ng reflectance spectra; and (2) six popular VIs (NDVI, NIRv, EVI, EVI2, SR, DVI) computed from simulated Planet SuperDove reflectance spectra derived from the AVIRIS-ng spectra. Hyperspectral Fv and multispectral VIs are compared using both parametric (Pearson correlation, ρ) and nonparametric (Mutual Information, MI) metrics. Four VIs (NIRv, DVI, EVI, EVI2) showed strong linear relationships with Fv (ρ > 0.94; MI > 1.2). NIRv and DVI showed strong interrelation (ρ > 0.99, MI > 2.4), but deviated from a 1:1 correspondence with Fv. EVI and EVI2 were strongly interrelated (ρ > 0.99, MI > 2.3) and more closely approximated a 1:1 relationship with Fv. In contrast, NDVI and SR showed a weaker, nonlinear, heteroskedastic relation to Fv (ρ < 0.84, MI = 0.69). NDVI exhibited both especially severe sensitivity to unvegetated background (–0.05 < NDVI < +0.6) and saturation (0.2 < Fv < 0.8 for NDVI = 0.7). The self-consistent atmospheric correction, radiometry, and sun-sensor geometry allows this simulation approach to be further applied to indices, sensors, and landscapes worldwide. [ABSTRACT FROM AUTHOR]

Since the early 1990s when much of the population of the Tricolored Blackbird (Agelaius tricolor) began nesting in fields of triticale grown for dairy silage in the San Joaquin Valley, many colonies have been destroyed inadvertently during harvest. After previous inconsistent efforts, in 2015 a Regional Conservation Partnership Program brought the dairy industry, Natural Resource Conservation Service, Audubon California, California Department of Fish and Wildlife, and other partners together in an effort to stem the losses. The program located colonies and compensated farmers for crop value lost when the harvest was delayed until after the blackbirds fledged and encouraged creation of alternative nesting habitat to attract nesting birds away from agricultural fields. Before 2015, data on the numbers of colonies in silage fields, and on the blackbirds' productivity conserved and lost, are complete only for 2005-2009, when only 43% of colonies encompassing 60% of the monitored nestings avoided destruction. From 2015 to 2022, 93% of colonies representing 96% of nesting attempts were conserved, and the number of birds nesting in silage increased by as much as 100,000. The program's success resulted from the adequacy of federal funding, protection provided by the species' listing as endangered by the state of California, and effective communications and cooperation among the partners and within the dairy industry. Protection of colonies in silage fields since 2015 likely contributed to the substantial increase in the numbers of birds nesting in this habitat and perhaps to an increase in California's Tricolored Blackbird population as a whole. Continued effort is needed to achieve the species' recovery. [ABSTRACT FROM AUTHOR]

Agricultural waste grains are significant for providing nutrients for wintering waterfowl in California. Rice and corn comprise 56% of their nutrient needs in the Central Valley and changes to agricultural practices, such as postharvest treatments, could impact these food resources. Currently, limited data exist on how postharvest treatments in rice and corn fields affect the abundance of waste grain, yet these data are essential to determine the carrying capacity of agricultural lands for wintering waterfowl. To address this knowledge gap, we estimated the abundance of waste grain (kg/ha) using dry field transects, dry field soil cores, and flooded field (wet) soil cores. In 2016 and 2017, we sampled 84 rice fields and 47 corn fields. Our results indicate that the abundance of waste rice varied significantly among postharvest treatments. Fields that received no postharvest treatment (stubble left standing; no incorporation of straw) had the greatest amounts of waste rice, whereas fields that were disced, disced and rolled, or burned provided the least amount of waste rice. The average abundance of waste rice across all postharvest treatments was 320 kg/ha in dry fields (arithmetic mean; geometric mean = 228 kg/ha; soil core samples). Estimates of waste rice in flooded fields averaged only 169 kg/ha (geometric mean 98 kg/ha; soil core samples), significantly lower than in the same fields prior to flooding. Variation in the abundance of waste corn was greater than that of waste rice. Fields that did not receive any postharvest incorporation had the greatest abundance of waste corn, 233 kg/ha on average (arithmetic mean; geometric mean = 72 kg/ha), whereas fields that were incorporated (disced or disced and rolled) contained significantly lower abundance of waste corn, averaging 50–60 kg/ha (arithmetic mean; geometric mean = 5–10 kg/ha). The average, across all postharvest treatments, was 159 kg/ha of waste corn (geometric mean = 25–34 kg/ha). Our results suggest that postharvest practices affect the abundance of waste grain in rice and corn fields; changes in these practices could impact food availability for wintering waterfowl. Our results also indicate that the method of sampling waste grain can influence estimates of residual grain abundance. [ABSTRACT FROM AUTHOR]

Farmland birds can suppress insect pests, but may also consume beneficial insects, damage crops and potentially carry foodborne pathogens. As bird communities shift in response to farming practices, so too do the benefits (services) and costs (disservices) from birds. Understanding how and why ecosystem services and disservices covary can inform management interventions that enhance synergies, avoid trade‐offs and promote multifunctionality.We investigated how farmland diversification practices influence the services and disservices provided by wild birds on 21 California strawberry farms. Specifically, we coupled 285 bird surveys, metabarcoding and other molecular analyses of ~1,000 faecal samples representing 55 bird species (mostly passerines) to determine which individuals consumed pests, natural enemies, and crops and carried foodborne pathogens. Then, we explored how farming practices shape ecosystem service bundles, or suites of consistently co‐occurring services/disservices.Avian services and disservices were shaped by interactions between local farming practices and landscape context. We found that the amount of semi‐natural habitat surrounding each farm was the single most important driver of ecosystem services, with the best outcomes (highest multifunctionality) occurring on farms surrounded by semi‐natural habitat.Bundles were primarily influenced by landscape context. Increasing semi‐natural habitat around farms was associated with more multifunctional bird communities that maximized services and minimized disservices. However, not all trade‐offs were minimized in landscapes with more semi‐natural habitat, suggesting that specific farming contexts can exacerbate or mitigate trade‐offs as bird communities shift in response to diversification practices.Synthesis and applications. Though growers are often pressured to remove non‐crop habitat to reduce food‐safety risks, our work suggests that conserving habitat can support bird conservation, mitigate food‐safety risks and decrease crop damage from birds. More broadly, by considering the multiple roles that communities play in ecosystems, managers can simultaneously maximize services and minimize disservices to achieve multifunctionality. [ABSTRACT FROM AUTHOR]

Mitigation of greenhouse gas emissions from agriculture requires an understanding of spatial‐temporal dynamics of nitrous oxide (N2O) emissions. Process‐based models can quantify N2O emissions from agricultural soils but have rarely been applied to regions with highly diverse agriculture. In this study, a process‐based biogeochemical model, DeNitrification‐DeComposition (DNDC), was applied to quantify spatial‐temporal dynamics of direct N2O emissions from California cropland employing a wide range of cropping systems. DNDC simulated direct N2O emissions from nitrogen (N) inputs through applications of synthetic fertilizers and crop residues during 2000–2015 by linking the model with a spatial‐temporal differentiated database containing data on weather, crop areas, soil properties, and management. Simulated direct N2O emissions ranged from 3,830 to 7,875 tonnes N2O‐N yr−1, representing 0.73%–1.21% of the N inputs. N2O emission rates were higher for hay and field crops and lower for orchard and vineyard. State cropland total N2O emissions showed a decreasing trend primarily driven by reductions of cropland area and N inputs, the trend toward growing more orchard, and changes in irrigation. Annual direct N2O emissions declined by 47% from 2000 to 2015. Simulations showed N2O emission variations could be explained not only by cropland area and N fertilizer inputs but also climate, soil properties, and management besides N fertilization. The detailed spatial‐temporal emission dynamics and driving factors provide knowledge toward effective N2O mitigation and highlight the importance of coupling process‐based models with high‐resolution data for characterizing the spatial‐temporal variability of N2O emissions in regions with diverse croplands. Plain Language Summary: Nitrous oxide (N2O) is the third most important greenhouse gas and an important ozone‐depleting substance. It is challenging to quantify N2O emissions from croplands in regions with highly diverse agriculture. In this study, a process‐based biogeochemical model, DeNitrification‐DeComposition (DNDC), was applied to quantify spatial‐temporal dynamics of direct N2O emissions from California cropland, which has a wide range of cropping systems. DNDC simulated direct N2O emissions from nitrogen (N) inputs from synthetic fertilizers and crop residues during 2000–2015. Simulated direct N2O emissions ranged from 3,830 to 7,875 tonnes N yr−1, representing 0.73%–1.21% of the N inputs from synthetic fertilizers and crop residues. Simulated annual direct N2O emissions from California cropland declined by 47% from 2000 to 2015. This decreasing trend could be explained by reductions of cropland area and associated N inputs, the trend toward growing more orchard crops, and changes in irrigation. This study characterized spatial‐temporal dynamics of N2O emissions from California cropland, and provided knowledge toward effective N2O mitigation. It also highlights the importance of coupling process‐based models with high‐resolution data to quantify the spatial‐temporal variability of N2O emissions in regions with complicated agricultural systems. Key Points: Direct nitrous oxide (N2O) emission from N inputs of fertilizers and residues ranged from 3,830 to 7,875 ton N yr−1 from 2000 to 2015 in California croplandSimulated annual direct N2O emission decreased by 47% from 2000 to 2015, primarily driven by changes in land use and farming managementCoupling model with environmental and activity database improved characterization of direct N2O emissions from California cropland [ABSTRACT FROM AUTHOR]

As has long been the case for conventional agriculture, organic agriculture is increasingly characterized by the consolidation of production into the hands of larger operations. Using historical pesticide applications records from the California Pesticide Use Report (PUR), this study identified individual organic fields, to document the occurrence of cropland consolidation, and assess the correlation between cropland consolidation and pesticide use. Our results show that pesticide use is correlated with the consolidation of organic cropland. Farms with more organic acreage applied sulfur and fixed copper pesticides more frequently after controlled for the crop type and field size. As the result, larger farms had greater environmental impacts on surface water and smaller impacts on soil and air because sulfur and fixed copper are more toxic to fish and algae, and less toxic to earthworms and have lower Volatile Organic Compound (VOC) emissions than other pesticides used in organic fields. [ABSTRACT FROM AUTHOR]

Excessive groundwater extraction is exacerbated by worsening droughts under climate change. Among agricultural users, well-drilling activity is not evenly distributed. The number, diameter and depth of new agricultural wells were analysed in this study in relation to farm size and land cover class during California's 2012–16 extreme drought. The results show smaller farms drilled at higher rates, whereas larger farms drilled at comparatively greater depths and with wider wellbores. Sections dominated by permanent crops drilled at 2.4 times the rate of those dominated by annual crops, and at 24.7 times the rate of forest and rangeland dominated sections. [ABSTRACT FROM AUTHOR]

Aim: California's Central Valley, one of the most productive agricultural regions worldwide, is home to a high number of at‐risk species due to habitat conversion. Amplifying the issue, the Central Valley faces severe droughts, creating water scarcity in surrounding natural areas. At least 14 insectivorous bat species live in this region, and prior studies show mixed results regarding the impact of agriculture and drought on bats. The aim of this study was to investigate how bats use agricultural areas during drought. Location: Central Valley, California, United States. Methods: We deployed ultrasonic acoustic detectors at 274 sites from March through July of 2016, the final year of an extreme drought, and 2017, one of the wettest years on record. We identified bats to species, used single‐species occupancy models including biologically relevant covariates and created spatial projections of ecoregion‐wide occupancy for each species. Results: We modelled occupancy for eight bat species. Long‐distance migrants in the study area contracted their geographic range during the drought, while resident species did not. Five of the eight bats in this analysis were more likely to occupy areas with orchard crop cover. Lastly, arid‐adapted bats used cultivated landscapes during the drought but retracted their range after the drought ended. Main conclusions: Migratory bats appeared to shift occupancy more during drought than resident bats, possibly because of lower roost fidelity. Additionally, the effects of drought on some bat species in the Central Valley may be buffered by agricultural landscapes acting as drought refugia. Overall, this study demonstrates the benefits of broad‐scale acoustic studies which can serve as a tool to track changing bat distributions on the landscape and provide baseline occupancy for acoustically detectable species. [ABSTRACT FROM AUTHOR]

Interregional free-trade of agricultural products is expected to transfer embodied (virtual) water from more to less water-productive regions. However, irrigation in semi-arid to arid regions may significantly push up agricultural productivity but cause local water scarcity. This may result in a puzzle: inter-regional trade may save overall water consumption but lead to more severe local water scarcity. An analogous puzzle may exist for farmland, for instance, trade may save farmland but not address farmland scarcity. To test the existence of these two important puzzles, we applied environmentally extended multi-regional input-output models to obtain the inter-regional virtual agricultural water and land transfer across 48 states of the conterminous U.S. and estimated their agricultural land and water footprints in 2017. Such a detailed analysis showed that while the land-abundant Midwestern states exported a sizable amount of virtual farmland to other densely populated areas and foreign nations, the water-stressed Western U.S. and Southwestern U.S. states, like California, Arizona, and New Mexico, exported considerable amounts of water-intensive crops such as fruits, vegetables and tree nuts to the Eastern U.S. and overseas, thus worsen the local water scarcity of those water scarce states. Our analysis highlights a critical dilemma inherent in an economic productivity-focused incentive regime: It frequently leads to increased withdrawal of scarce water. Therefore, resource scarcity rents need to be reflected in inter-regional trade with the support of local environmental policies. • Interstate trade mitigates coastal U.S. cropland scarcity but worsens water issues. • The Southwest states export significant virtual water via water-intensive crops. • Conflict between high economic productivity and water use exists in California. • Underpricing of water boosts farming of high-profit, water-intensive crops. • Policies needed for balancing land and water use, ensuring sustainable agriculture. [ABSTRACT FROM AUTHOR]

Targeted conservation approaches seek to focus resources on areas where they can deliver the greatest benefits and are recognized as key to reducing nonpoint source nutrients from agricultural landscapes into sensitive receiving waters. Moreover, there is growing recognition of the importance and complementarity of in-field and edge-of-field conservation for reaching nutrient reduction goals. Here we provide a generic prioritization that can help with spatial targeting and applied it across the conterminous US (CONUS). The prioritization begins with identifying areas with high agricultural nutrient surplus, i.e., where the most nitrogen (N) and/or phosphorus (P) inputs are left on the landscape after crop harvest. Subwatersheds with high surplus included 52% and 50% of CONUS subwatersheds for N and P, respectively, and were located predominantly in the Midwest for N, in the South for P, and in California for both N and P. Then we identified the most suitable conservation strategies using a hierarchy of metrics including nutrient use efficiency (proportion of new nutrient inputs removed by crop harvest), tile drainage, existing buffers for agricultural run-off, and wetland restoration potential. In-field nutrient input reduction emerged as a priority because nutrient use efficiency fell below a high but achievable goal of 0.7 (30% of nutrients applied are not utilized) in 45% and 44% of CONUS subwatersheds for N and P, respectively. In many parts of the southern and western US, in-field conservation (i.e., reducing inputs + preventing nutrients from leaving fields) alone was likely the optimal strategy as agriculture was already well-buffered. However, stacking in-field conservation with additional edge-of-field buffering would be important to conservation strategies in 35% and 29% of CONUS subwatersheds for N and P, respectively. Nutrient use efficiencies were often high enough in the Midwest that proposed strategies focused more on preventing nutrients from leaving fields, managing tile effluent, and buffering agricultural fields. Almost all major river basins would benefit from a variety of nutrient reduction conservation strategies, underscoring the potential of targeted approaches to help limit excess nutrients in surface and ground waters. • Overlaying surplus with conservation opportunities provides novel prioritization. • Nutrient use efficiency can guide conservation strategies. • Reducing in-field N and P inputs was the priority in ∼44% of US subwatersheds. • Stacking in-field and edge-of-field conservation in ∼30–35% of US subwatersheds. [ABSTRACT FROM AUTHOR]

Governance of global natural resources is increasingly hybrid, with complementary public and private sector initiatives layered on landscapes to improve environmental outcomes. The challenge of polycentric land use governance is alignment of goals across diverse governance mechanisms when agricultural producers, public agencies, and corporations have distinct motivations. This case study of soil carbon governance on California rangelands explores a new payment for ecosystem services (PES) initiative led by the food and agriculture industry, called the Ecosystem Services Market Consortium (ESMC). Applying hybrid governance theory to agricultural lands, we conduct an ex-ante policy evaluation of potential policy impact based on (i) alignment between corporate sustainability goals and ranchers' priorities and (ii) complementarity of the ESMC market with existing public and private policies enabling rangeland conservation. We found corporations developing the PES market to be motivated by carbon insetting, the objectives of which converge with ranchers' goals of preserving soils. Each policy offers distinct benefits and challenges, with synergies around climate change adaptation and soil health. As a new policy tool, carbon markets like the ESMC are positioned to meet demand for soil health financing, support resilience and ranch productivity, and improve ranchers' access to soil health data for adaptive management. Given carbon markets' outcome-based payment structure, we highlight the importance of complementary governance mechanisms that mitigate upfront risk with financial and technical support during the transition period, including Farm Bill cost-share programs and private sector financing tools. This policy evaluation highlights the challenges and opportunities surrounding rangelands soil carbon governance, particularly the trade-offs that ranchers, corporations, and society at large must consider for landscape-scale conservation programs. [ABSTRACT FROM AUTHOR]

Imperial County, California, is a high-need, medically underserved area that has some of the worst overall health outcomes of all California counties. Given this and the high depression and anxiety rates in agricultural occupations, Imperial County farmers and ranchers may be at an increased risk of stress and poor mental health outcomes. An exploratory mixed methods assessment was used to collect information from 24 farmers and ranchers in Imperial County. Survey topics included questions about farm or ranch operations, farm-related stress, mental health, community support, and health behaviors. The results indicate that most respondents perceive unpredictable factors, such as government regulations, as the most impactful stressors related to their farm or ranch operations. Additionally, depression symptomatology scores were positively correlated with respondents' ability to obtain credit. Efforts to understand farm-related stress and how community support can help Imperial County farmers and ranchers mediate adverse physical and mental health effects through formal and informal networks are considered. [ABSTRACT FROM AUTHOR]

The licensed cannabis industry represents one of the top five most economically valued agricultural commodities in California, yet farming largely remains on remote, environmentally sensitive, "marginal" lands. Using mixed methods, this paper examines the determinants of this marginalization, their embedded elaboration, and their relation to historical policy regimes. We used Generalized Additive Models (GAMs) to determine the most important predictors of licensed cannabis industry development since the inception of a statewide licensing program in 2018 and to compare the distribution of licensed cannabis to other forms of rural agriculture, including vineyards and pasture, to understand landscape factors and environmental sensitivity of land uses. We found that a county's median income and the extent of traditional (non-cannabis) agriculture, as measured by the proportion of on-farm (non-cannabis) employment, were both negatively associated with its amount of licensed cannabis agriculture. Ethnographic data suggests that cannabis is often excluded from traditional agricultural areas, through formal local-level bans, restrictive zoning, high "prime" farmland values, and cultural exclusions from other powerful resource users. The resulting relegation to "marginal" lands foments conflicts with amenity land users and environmentalists, even as it partly supports "legacy" cultivators whose farms were established under prior policy regimes. Results suggest that cannabis is more likely to be grown under conditions that introduce regulatory hurdles, including farming on steeper slopes, with natural streams onsite, and without access to large groundwater aquifers for irrigation. Our findings suggest that failure to allow licensed cannabis farming in traditional agriculture regions has led to a self-fulfilling prophecy wherein cannabis cultivation is largely relegated to environmentally sensitive areas where cultivation activity has an elevated tendency for environmental impacts., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interestsChristopher Dillis reports financial support was provided by California Department of Cannabis Control. Margiana Peterson-Rockney reports financial support was provided by California Department of Cannabis Control. Michael Polson reports financial support was provided by California Department of Cannabis Control., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The selection of locations and practices for energy crops requires the economics to be planned and the carbon intensity of the fuel to be assessed. This study develops a framework for selecting near‐optimal cropland sites to minimize the cost to produce a targeted quantity of an energy crop, considering soil properties, fertilizer management, and spatio‐temporal trends in crop yield and soil emissions. DayCent, a biogeochemical model, simulates site‐level crop yield, and soil emissions. As a case study, this framework is applied to a 2.08 × 108 L year−1 capacity barley‐to‐ethanol biorefinery that selects cultivation sites from winter fallow cropland in the mid‐Atlantic region of the USA. The framework implements carbon crediting as per California's Low Carbon Fuel Standard. Our analysis finds the biorefinery's strategy on co‐products significantly influences its life‐cycle carbon intensity ranging between 0.74 gCO2e MJ−1 for all co‐product use and 59 gCO2e MJ−1 for no co‐product use. Coastal counties in Delaware show low soil emission and high yield, but higher transportation distances increase the carbon intensity of these distant croplands. When co‐products are used, the least intensive fertilizer management with fertilizer applications in spring is identified as the cost‐optimized choice for the biorefinery. It is also the option economically favored by growers, suggesting that detailed monitoring of these practices might not be needed to assure the adoption of low‐emission cultivation practices. However, the framework might demonstrate different results for other biofuel‐crop scenarios or different locations. The framework presented can assess the performance of a biorefinery prospectively and improve investors' confidence in the biofuel industry. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Intensive use of external inputs in specialized industrial farming systems has created significant socio-ecological externalities, including water and air pollution from nutrients and pesticides, soil erosion and depletion of carbon stocks, biodiversity loss and rising production costs. Ecological intensification is a strategy for reducing reliance on inputs by intentionally designing agroecosystems to harness biological processes and ecological relationships for the sustainable functioning of the system. Incorporating perennials and diversifying systems are two avenues for achieving ecological intensification, and both are characteristics of agroforestry. This preliminary report uses examples of agroforestry in the US state of California as a proof of concept to explore the agronomic and economic feasibility and sustainability benefits of agroforestry in intensive irrigated and temperate farming systems. An exploratory study of farmers experimenting with agroforestry systems and other agricultural professionals identified eight different variants of agroforestry systems being practiced on prime agricultural land in California, ranging from simple use of winter cover crops in orchards to multi-storied cropping systems with integrated grazing. Respondents noted benefits of reduced inputs and production costs, and better nutrient cycling, soil health and pest control. Trade-offs and challenges included increases in labor requirements and management complexity. Knowledge gaps included lack of guidance in biophysical systems design, lack of clarity about economic tradeoffs, and lack of information about ecosystem services benefits. In light of interviewees' responses, we discuss the constraints and factors needed to foster the successful expansion of agroforestry systems in California and other regions characterized by industrialized farming. [ABSTRACT FROM AUTHOR]

Current California agricultural practices strive to comanage food safety and habitat conservation on farmland. However, the ecology of foodborne pathogens in wild bird populations, especially those avian species residing in proximity to fresh produce production fields, is not fully understood. In this repeated crosssectional study, avifauna within agricultural lands in California were sampled over 1 year. Feces, oral swabs, and foot/feather swabs were cultured for zoonotic Salmonella spp., Escherichia coli O157:H7, and non-O157 Shiga toxin-producing E. coli (STEC) and characterized by serotyping and pulsed-field gel electrophoresis. Of 60 avian species sampled, 8 species (13.3%, bird groups of sparrows, icterids, geese, wrens, and kinglets) were positive for at least one of these foodborne pathogens. At the individual bird level, the detection of foodborne pathogens was infrequent in feces (n=583; 0.5% Salmonella, 0.34% E. coli O157:H7, and 0.5% non-O157 STEC) and in feet/feathers (n=401; 0.5% non-O157 STEC), and it was absent from oral swabs (n=353). Several subtypes of public health importance were identified, including Salmonella enterica serotype Newport, E. coli O157:H7, and STEC serogroups O103 and O26. In late summer and autumn, the same STEC subtype was episodically found in several individuals of the same and different avian species, suggesting a common source of contamination in the environment. Sympatric free-range cattle shared subtypes of STEC O26 and O163 with wild geese. A limited rate of positive detection in wild birds provides insights into broad risk profile for contamination considerations but cannot preclude or predict risk on an individual farm. [ABSTRACT FROM AUTHOR]

As the frequency and duration of droughts persist in Southern California, we may witness more agricultural land sales among both agricultural producers and non-agricultural users. How is this related to land value? Do the same factors that increase land value also increase the likelihood of land sales? We analyze the extent to which short-run weather shocks associated with California droughts (2007-2009 and 2011-2016) influence the sale and value of agricultural parcels. We employ a population- averaged panel logistic analysis and a Ricardian model across 17 years (2000-2016) of parcel data in Riverside County, California. The history of farming in Riverside County extends to over a century, with many growers holding senior water rights. The western part of the county is experiencing rapid population growth, increasing the pressure for agriculture-to-urban water transfers. Persistent drought would only exacerbate the viability of farming in the region. Although we do not find a significant relationship between the likelihood of selling farmland and precipitation variability, we do find that precipitation variability reduces the value of farmland. We also find that increase in population rate decreases the likelihood of land sales while increasing land value. It would be insightful to determine the extent to which different attributes that contribute to land value also contribute to the likelihood of selling agricultural land. In particular, it would be insightful for appraisal methodologies to incorporate drought persistence into the existing frameworks. [ABSTRACT FROM AUTHOR]

The California Fish and Game Commission listed the Swainson's Hawk (Buteo swainsoni) as a state threatened species in 1983 in response to population reductions and habitat loss across the state. Human population increases, urbanization, and shifts in agricultural land use have the potential to affect California's Swainson's Hawk population. In 2005 and 2006, we conducted surveys to estimate the abundance and density of Swainson's Hawk breeding pairs in California's Great (Central) Valley, using a random sampling design stratified across dense, medium, and sparse nesting density strata. The sampling units comprised 2.59-km2 (1-mile2) US Public Land Survey System Sections, and the 2-yr survey covered an aggregate total of 682 sampling units (268 in 2005, 414 in 2006). Separate surveyors conducted independent surveys of 29 sampling units in 2006; based on these data, the estimated probability of detecting a single pair (if present) following the multiple-visits protocol was 0.81 (95% CI: 0.58–0.93). After applying this detection-probability correction and using generalized linear modeling of habitat associations to extrapolate density estimates throughout the study area, we estimated that the Great Valley supported 3218 (95% CI: 2271–4165) breeding pairs of Swainson's Hawks in 2005–2006. Our modeling of habitat associations showed crop diversity, alfalfa, and native vegetation as positively associated with the density of Swainson's Hawk breeding pairs, and orchards/vineyards negatively associated. Counts of breeding pairs were also highest in the middle latitudes of the Great Valley, which spans approximately 660 km from north to south. The predictive density model results had some areas of disagreement with the density strata used as basis for the stratified sampling design. To monitor the population status of this species throughout California, we recommend that our 2-yr sampling approach be expanded throughout the state and repeated every 5–10 yr. We also suggest this approach be used to monitor other special status raptor species to track population trend and distributional changes over time. [ABSTRACT FROM AUTHOR]

Groundwater aquifers provide an important "insurance" against climate variability. Due to prolonged droughts and/or irrigation demands, groundwater exploitation results in significant groundwater storage depletion. Managed aquifer recharge (MAR) is a promising management practice that intentionally places or retains more water in groundwater aquifers than would otherwise naturally occur. In this study, we examine the possibility of using large irrigated agricultural areas as potential MAR locations (Ag‐MAR). Using the California Central Valley Groundwater‐Surface Water Simulation Model we tested four different agricultural recharge land distributions, two streamflow diversion locations, eight recharge target amounts, and five recharge timings. These scenarios allowed a systematic evaluation of Ag‐MAR on changes in regional, long‐term groundwater storage, streamflow, and groundwater levels. The results show that overall availability of stream water for recharge is critical for Ag‐MAR systems. If stream water availability is limited, longer recharge periods at lower diversion rates allow diverting larger volumes and more efficient recharge compared to shorter diversion periods with higher rates. The recharged stream water increases both groundwater storage and net groundwater contributions to streamflow. During the first decades of Ag‐MAR operation, the diverted water contributed mainly to groundwater storage. After 80 years of Ag‐MAR operation about 34% of the overall diverted water remained in groundwater storage while 66% discharged back to streams, enhancing base flow during months with no recharge diversions. Groundwater level rise is shown to vary with the spatial and temporal distribution of Ag‐MAR. Overall, Ag‐MAR is shown to provide long‐term benefits for water availability, in groundwater and in streams. Key Points: Agricultural managed aquifer recharge at low recharge rates over large areas offers benefits to groundwater storage and seasonal base flowLonger recharge periods allow for more recharge than short, fixed windows of recharge that accommodate high recharge ratesMaximum groundwater level rise is sensitive to recharge timing and recharge locations [ABSTRACT FROM AUTHOR]

As small- and medium-sized farms struggle to remain viable in a competitive global economy, the expanding specialty food industry provides a potential marketing opportunity. These farms raise many of the farm products that can become the key ingredients in value-added foods. Little research exists about processed specialty foods made from locally/regionally sourced ingredients produced by small- and medium-sized farms. This study investigates the benefits, barriers and challenges for small- and medium-sized farmers who want to sell products to specialty food manufacturers (SFMs). This paper analyzes 240 survey responses from dairy, meat, fruit/vegetable/nuts and grain specialty manufacturers and 60 in-depth interviews of these manufacturers and farmers in California, Minnesota, Wisconsin, Washington and Oregon. We found that almost half of the manufacturers surveyed source primary ingredients directly from farms or from their own farm. More than half of the farms that supply these key ingredients are small or medium-sized, indicating that many farms in this category are already successfully supplying SFMs with key ingredients. The key benefits manufacturers receive from working with these farms included quality assurance, trust, and traceability. Key obstacles to such farmer/manufacturer transactions are: cost, inability to meet volume requirements, unreliable supply and lack of year-round supply. The nature of relationships between manufacturers and farmers emerged as a theme that influences the success of small- and medium-sized farms as ingredient suppliers. Whether they were large or small, most manufacturers purchased their key ingredients from multiple suppliers in order to reduce their risk. Overall, we find evidence that the specialty food industry is an emerging market channel for small- and medium-sized farms. We also find that to be successful suppliers of SFMs, farmers need to have processes in place to ensure the quality of their products; provide the specific attributes the manufacturer requires for its ingredients and be willing to communicate frequently with the manufacturer. [ABSTRACT FROM AUTHOR]

This article, titled "Trans Icons from the Farm," explores the complexities of gender and identity in animals. The author discusses various examples, such as a hen that becomes a rooster, a hermaphrodite goat, and a female stockdog that exhibits male-like behavior. The author challenges the notion of fixed gender identities and celebrates the fluidity and mutability of gender in the animal kingdom. The article is written by Mukethe Kawinzi, a shepherd who has experience with goats on the open range in coastal California. [Extracted from the article]

Crop-type composition and configuration at field and landscape scales are known to impact ecological functions in agricultural landscapes. However, links between regional farmland structures (e.g., variable farm size, ownership, configuration, etc.), which are important determinants of farm-level management decisions, and subsequent changes in agroecosystem impacts, remain understudied. Objective: To investigate these dynamics, we examined relationships between changing farm structures, as indicated by farm consolidation and persistence, and concurrent changes in crop diversity and agricultural resource use between 2002 and 2018 in Kern County, California. Methods: We integrated parcel-level datasets documenting farm size, operatorship, crop cover, pesticide usage and evapotranspiration rates for 2002 and 2018. We then applied seemingly unrelated regression analyses to quantify potential relationships between these key variables. Results and conclusions: In our study area we observed low (28%) persistence of farm operators from 2002 to 2018 and farm consolidation, as evidenced by a 43% increase in farm midpoint size in the studied time period. We further found significant associations between farm structures and agro-environmental outcomes. A doubling in farm size was associated with an 8% increase in crop diversity, but also with an 18% increase in pesticide-use and a 7% increase in water use at the farm level, raising concerns about the impact of large farms on landscape-scale resource use. Both crop diversity and water use were higher in persistent farms (8% and 11%, respectively) than in replaced or emergent farms. Our findings illustrate how regional shifts in farm size and operatorship may link to changes in crop diversity and resource use. Given continued concerns about the impacts that landscape simplification, pesticide use, and water shortages may have on agroecosystems both in our study region and beyond, our study highlights regional farm structure dynamics as a key element to investigate further and to consider in policies aiming to increase the sustainability of future agricultural landscapes. [Display omitted] • We study structural shifts in our study area by analyzing changes in farm size and operatorship from 2002 to 2018. • We then assess potential links to changing farm-level crop diversity, pesticide and water use through regression analysis. • Our data indicates high operator turnover and farm consolidation across Kern County, driven by emerging farms. • Persistent farms had higher crop diversity and water use; large farms had higher crop diversity and pesticide & water use. • Our findings highlight regional farm structure dynamics as a key element to investigate further. [ABSTRACT FROM AUTHOR]

Interactions between pathogenic and nonpathogenic fungal species in the tree canopy are complex and can determine if disease will manifest in the plant and in other organisms such as honey bees. Seasonal dynamics of fungi were studied in an almond orchard in California where experimental release of the atoxigenic biopesticide Aspergillus flavus AF36 to displace toxigenic Aspergillus strains has been conducted for five years. The presence of the vegetative compatibility group (VCG) YV36, to which AF36 belongs, in the blossoms, and the honey bees that attend these blossoms, was assessed. In blossoms, A. flavus frequencies ranged from 0 to 4.5%, depending on the year of study. Frequencies of honey bees carrying A. flavus ranged from 6.5 to 10%. Only one A. flavus isolate recovered from a blossom in 2016 belonged to YV36, while members of the VCG were not detected contaminating honey bees. Exposure of pollinator honey bees to AF36 was detected to be very low. The density of several Aspergillus species was found to increase during almond hull split and throughout the final stages of maturation; this also occurred in pistachio orchards during the maturation period. Additionally, we found that AF36 effectively limited almond aflatoxin contamination in laboratory assays. This study provides knowledge and understanding of the seasonal dynamics of Aspergillus fungi and will help design aflatoxin management strategies for almond. The evidence of the low levels of VCG YV36 encountered on almond blossoms and bees during pollination and AF36’s effectiveness in limiting aflatoxin contamination in almond provided additional support for the registration of AF36 with USEPA to use in almond in California. [ABSTRACT FROM AUTHOR]

Impacts of climate change threaten California farmers in a number of ways, most importantly through a decline in freshwater availability, concurrent with a rise in water demand. In coastal California, the growing season of economically important crops, such as strawberries, overlap with the occurrence of summertime coastal fog, which buffers the summer dry season through shading effects and direct water inputs. The impacts of coastal fog on plant physiology have been extensively studied in natural ecosystems. Yet, very few studies have evaluated its direct effects on crop water use and demand, which has potential to curtail groundwater use. We established two sites on large, conventional strawberry farms along a coastal-inland gradient in the Salinas Valley, California, where we monitored variation in microclimate conditions and measured strawberry plant physiological responses to foggy and non-foggy conditions between June–September 2015. Spatial analysis of coastal low clouds and fog from satellite imagery was preformed to quantify and characterize fog events at seasonal and diel time scales. We found strong agreement between field and satellite-derived observations of coastal fog events. Canopy-level conductance and whole-plant carbon uptake were reduced by 60% and 30%, respectively, on foggy compared to clear-sky days. Leaf-level photosynthesis and stomatal conductance were 30% lower on foggy compared to clear-sky days, which was driven by reduced photosynthetically active radiation and cooler temperatures during fog events. Taken together, we found that whole-plant water use efficiency increased significantly during foggy periods, and these patterns were driven by changes in the radiation balance and atmospheric water stress. Our results provide evidence that the shading effect by fog is a primary influence on crop water use efficiency in coastal agricultural fields during summer. The outcome of our research can inform estimates of how much irrigation water may be reduced during foggy periods without sacrificing crop yields on coastal agricultural lands. [ABSTRACT FROM AUTHOR]

Land ownership is one of the primary determinants of how agricultural land is used, and property size has been shown to drive many land use decisions. Land ownership information is also key to understanding food production systems and land fragmentation, and in targeting outreach materials to improve agricultural production and conservation practices. Using a parcel dataset containing all 58 California counties, we describe the characteristics of cropland ownership across California. The largest 5% of properties -- with "property" defned as all parcels owned by a given landowner -- account for 50.6% of California cropland, while the smallest 84% of properties account for 25% of cropland. Cropland ownership inequality (few large properties, many small properties) was greatest in Kings, Kern and Contra Costa counties and lowest in Mendocino, Napa and Santa Clara counties. Of crop types, rice properties had the largest median size, while properties with orchard trees had the smallest median sizes. Cluster analysis of crop mixes revealed that properties with grapes, rice, almonds and alfalfa/ hay tended to be planted to individual crops, while crops such as grains, tomatoes and vegetables were more likely to be mixed within a single property. Analyses of cropland ownership patterns can help researchers prioritize outreach eforts and tailor research to stakeholders' needs. [ABSTRACT FROM AUTHOR]

The article offers information on how University of California (UC) Global Food Initiative-funded projects operated by the UC Sustainable Agriculture Research and Education Program (SAREP) are helping food hubs bridge the gap of small farms with big buyers in 2017. Food hubs are aimed to enable mid-scale and small farms to efficiently reach more distant and larger market channels such as corporate kitchens, hospitals, and campuses and school districts.

Quantitative evaluation of best management practice (BMP) effectiveness can help stakeholders to make better watershed management decisions. However, such evaluations are always challenging as they require complex algorithms to simulate the relevant hydrological processes, crop growth and the corresponding pollutant transport pathways in order to evaluate potential BMPs and select the best one for the specific field conditions. In this study, a web-based interface (CalBMP) was developed to predict BMP effectiveness in California, focusing on pesticide modeling at the field scale. With built-in databases for soil, weather, crop, pesticides, and BMPs, users can run simulations for baseline and BMP scenarios using their site-specific field conditions by simply providing the field information, such as zip code, soil, crop management, and pesticide application data. CalBMP uses PRZM5 + , a USEPA model, to simulate pesticide transport and fate at the field edge. The CalBMP simulations were validated based on measurements from an alfalfa field study. The results indicated that the CalBMP interface could reasonably simulate the runoff and adsorbed pesticide loss leaving the field with default parameters from previously known field parameters or public databases. CalBMP underestimated sediment erosion, possibly due to uncertainties in field measurements or inaccurate simulation of the temporal distribution of flood irrigation. CalBMP is likely to underestimate pesticides with greater solubility, such as diuron, because PRZM5 + uses the simplified instantaneous equilibrium sorption model. In addition, a strawberry field study was adopted to demonstrate the capability of the CalBMP interface for simulating BMP effectiveness (pesticide reduction percentage in the main pathways) with easy-to-understand graphs and tables. The results indicated that users can easily compare and review the results from multiple scenarios, which could facilitate the decision-making process for mitigating the amount of active ingredient bifenthrin leaving the field. The CalBMP tool provides useful information on pesticide runoff potential and BMP selection at the field scale. With increasingly stringent regulations for water quality protection, CalBMP will add to the growers' toolbox for minimizing the environmental impacts from their inevitable pesticide usage. [Display omitted] • An online best management practice (BMP) modeling tool was developed and validated. • It could help stakeholders identify water quality risks from pesticide use. • It is open access and greatly aid in BMP selection to reduce pesticide runoff. [ABSTRACT FROM AUTHOR]

Pesticide exposure has been associated with adverse health effects. We evaluated relationships between proximity to agricultural insecticide applications and insecticides in household dust, accounting for land use and wind direction. We measured concentrations (ng/g) of nine insecticides in carpet-dust samples collected from 598 California homes. Using a geographic information system (GIS), we integrated the California Pesticide Use Reporting (CPUR) database to estimate agricultural use within residential buffers with radii of 0.5 to 4 km. We calculated the density of use (kg/km2) during 30-, 60-, 180-, and 365-day periods prior to dust collection and evaluated relationships between three density metrics (CPUR unit-based, agricultural land area adjusted, and average daily wind direction adjusted) and dust concentrations. We modeled natural-log transformed concentrations using Tobit regression for carbaryl, chlorpyrifos, cypermethrin, diazinon, and permethrin. Odds of detection were modeled with logistic regression for azinphos-methyl, cyfluthrin, malathion, and phosmet. We adjusted for season, year, occupation, and home/garden uses. Chlorpyrifos use within 1–4 km was associated with 1 to 2-times higher dust concentrations in both the 60- and 365-day periods. Carbaryl applications within 2–4 km of homes 60-days prior to dust collection were associated with 3 to 7-times higher concentrations and the 4 km trend was strongest using the wind-adjusted metric (p-trend = 0.04). For diazinon, there were 2-times higher concentrations for the 60-day metrics in the 2 km buffer and for the CPUR and wind-adjusted metrics within 4 km. Cyfluthrin, phosmet, and azinphos-methyl applications within 4 km in the prior 365-days were associated with 2-, 6-, and 3-fold higher odds of detection, respectively. Agricultural use of six of the nine insecticides within 4 km is an important determinant of indoor contamination. Our findings demonstrated that GIS-based metrics for quantifying potential exposure to fugitive emissions from agriculture should incorporate tailored distances and time periods and support wind-adjustment for some, but not all insecticides. [ABSTRACT FROM AUTHOR]

Agriculture dominates California's San Joaquin Valley with over five million acres of farmland produces 400 different commodities ranging from nuts, tree fruits, vines, and row crops. During dry years agricultural production in the San Joaquin Valley uses about 53% of total applied water in the state. Implementation of California's Sustainable Groundwater Management Act (SGMA) will restrict groundwater pumping, likely reducing irrigated agricultural land use resulting in conversion to alternative land uses. To promote collaborative and inclusive efforts to repurpose agricultural land, California's legislature established a funding program administered by the Department of Conservation, the Multibenefit Land Repurposing Program (MLRP), in 2021. To ensure that land repurposing plans under the MLRP and SGMA represent San Joaquin Valley community needs this paper examines public perceptions of future land uses under SGMA through a phone survey. Respondents (n = 197) were recruited through a stratified random sample of mobile numbers registered within communities in the San Joaquin Valley classified as disadvantaged communities (DACs) (n = 32). Our results show that most respondents were somewhat (33%) or not at all (54%) familiar with SGMA, highlighting the need for outreach efforts to overcome barriers to representation, translation, and education about future water and land use decisions. Survey respondents identified secure water supplies (e.g., groundwater recharge) (35%) and less-water intensive agriculture (27%) as their top land use priorities to address groundwater overdraft under SGMA, indicating that the status quo for land use is preferred to alternative land uses. Preference for maintaining agriculture as primary land use (27%), we correlated with agricultural identity and lack of interest in community or global benefits such as schools and climate change mitigation. The findings from this study underscore the local variability in land use values and the importance to engaging local communities in land use decision-making, especially as they relate to changing current practices toward a more climate-resilient but agriculturally productive future with less land and less water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The article discusses the challenges of the Sustainable Groundwater Management Act in the diversity of the California farms. Topics mention including the possibilities of threatening the diversity of the California state's farming operations, increased pumping operational and capital costs and needs of assistance in developing good information on surface groundwater interactions.