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We estimated the reactive nitrogen (Nr) lost per unit food Nr consumed for organic food production in the United States and compared it to conventional production. We used a nitrogen footprint model approach, which accounts for both differences in Nr losses as well as differences in productivity of the two systems. Additionally, we quantified the types of Nr inputs (new versus recycled) that are used in both production systems. We estimated Nr losses from organic crop and animal production to be of comparable magnitude to conventional production losses, with the exception of beef. While Nr losses from organic vegetables are possibly higher (+37%), Nr losses from organic grains, starchy roots, legumes are likely of similar magnitude to conventional production (+7%, +6%, −12%, respectively). Nr losses from organic poultry, pigmeat, and dairy production are also likely comparable to conventional production (+9%, +10%, +12%, respectively), while Nr losses from organic beef production were estimated to be higher (+124%). Due to the high variability and high uncertainty in Nr efficiency in both systems we cannot make conclusions yet on the statistical significance of these potential differences. Conventional production relies heavily on the creation of new Nr (70%-90% of inputs are from new Nr sources like synthetic fertilizer), whereas organic production primarily utilizes already existing Nr (0%-50% of organic inputs are from new Nr sources like leguminous N fixation). Consuming organically produced foods has little impact on an individual's food N footprint but changes the percentage of new versus recycled Nr in the footprint. With the exception of beef, Nr losses from organic production per unit N in product are comparable to conventional production. However, organic production requires the creation of less new Nr, which could reduce global Nr pollution.

Biological soil amendments of animal origin (BSAAOs), including untreated (e.g., raw or aged manure, or incompletely composted manure) and treated animal products (e.g., compost), are used for crop production and as part of soil health management. Application of BSAAO's must be done cautiously, as raw manure commonly contains enteric foodborne pathogens that can potentially contaminate edible produce that may be consumed without cooking. USDA National Organic Program (NOP) certified production systems follow the 90-or 120-day interval standards between applications of untreated BSAAOs and crop harvest, depending on whether the edible portions of the crops are in indirect or direct contact with the soil, respectively. This study was conducted to evaluate the survival of four foodborne pathogens in soils amended with BSAAOs and to examine the potential for bacterial transfer to fresh produce harvested from USDA NOP certified organic farms (19) from four states. Only 0.4% (2/527) of produce samples were positive for L. monocytogenes . Among the untreated manure and compost samples, 18.0% (42/233) were positive for at least one of the tested and culturable bacterial foodborne pathogens. The prevalence of non-O157 STEC and Salmonella in untreated manure was substantially > that of E. coli O157:H7 and L. monocytogenes . Of the 2,461 soil samples analyzed in this study, 12.9% (318) were positive for at least one pathogen. In soil amended with untreated manure, the prevalence of non-O157 STEC [7.7% (190) and L. monocytogenes (5.0% (122), was > that of Salmonella (1.1% (26)] or E. coli O157 [0.04% (1)]. Foodborne pathogen prevalence in the soil peaked after manure application and decreased significantly 30 days post-application (dpa). However, non-O157 STEC and L. monocytogenes were recovered from soil samples after 90 and 120 dpa. Results indicate that produce contamination by tested foodborne pathogens was infrequent, but these data should not be generalized outside of the specific wait-time regulations for organic crop production and the farms studied. Moreover, other sources of contamination, e.g., irrigation, wildlife, environmental conditions, cropping and management practices, should be considered. This study also provides multi-regional baseline data relating to current NOP application intervals and development of potential risk mitigation strategies to reduce pathogen persistence in soils amended with BSAAOs. These findings contribute to filling critical data gaps concerning occurrence of fecal pathogens in NOP-certified farming systems used for production of fresh produce in different US regions.

IntroductionBiological soil amendments, including raw or untreated manure, are currently used to improve soil fertility, especially in organic operations that prohibit use of synthetic fertilizers. However, addition of untreated manure may pose a risk of contamination of fresh produce by pathogens of public health significance, including Listeria monocytogenes . Organic growers follow United States Department of Agriculture (USDA) National Organic Program regulations for raw manure use, which stipulate that harvest should commence no earlier than 90- or 120-days post-application, depending on direct contact between the edible portion of the produce and the soil. To inform the protection that such time-intervals provide, this study explored the farm-level risk factors associated with L. monocytogenes prevalence in USDA-certified organic farm soils amended with untreated manures.MethodsA longitudinal, multi-regional study was conducted on 19 farms in four states (California, Minnesota, Maine, and Maryland) over two growing seasons (2017 and 2018). Untreated manure, soil, irrigation water, and produce samples were collected and cultured for L. monocytogenes. Mixed effect logistic regression was used to investigate risk factors associated with L. monocytogenes prevalence in soil.Results and DiscussionResults showed that multiple factors influenced the odds of a soil-positive sample, including temporal [year (OR = 0.19), sampling day (OR = 0.09–0.48)] and weather-related [temperature range (OR = 0.48)] variables, manure characteristics [season of application (OR = 0.04, summer), presence of L. monocytogenes (OR = 2.89) and other pathogens in manure (OR = 5.24)], farm management factors [water source (OR = 2.73, mixed), number of year-round staff (OR = 0.02)], and soil characteristics [concentration of generic Escherichia coli (OR = 1.45), moisture (OR = 0.46), organic matter (OR = 7.30), nitrate (OR = 3.07), potassium (OR = 0.09) and calcium (OR = 2.48)]. This study highlights the complexity of L. monocytogenes prevalence in soil and contributes science-based metrics that may be used when determining risk-mitigation strategies for pathogen contamination.

IntroductionBiological soil amendments of animal origin (BSAAO), including untreated amendments are often used to improve soil fertility and are particularly important in organic agriculture. However, application of untreated manure on cropland can potentially introduce foodborne pathogens into the soil and onto produce. Certified organic farms follow the USDA National Organic Program (NOP) standards that stipulate a 90- or 120-day interval between application of untreated manure and crop harvest, depending on whether the edible portion of the crop directly contacts the soil. This time-interval metric is based on environmental factors and does not consider a multitude of factors that might affect the survival of the main pathogens of concern. The objective of this study was to assess predictors for the prevalence of Shiga-toxin-producing Escherichia coli (non-O157 STEC) in soils amended with untreated manure on USDA-NOP certified farms.MethodsA longitudinal, multi-regional study was conducted on 19 farms in four USA regions for two growing seasons (2017–2018). Untreated manure (cattle, horse, and poultry), soil, and irrigation water samples were collected and enrichment cultured for non-O157 STEC. Mixed effects logistic regression models were used to analyze the predictors of non-O157 STEC in the soil up to 180 days post-manure application.Results and discussionResults show that farm management practices (previous use with livestock, presence of animal feces on the field, season of manure application) and soil characteristics (presence of generic E. coli in the soil, soil moisture, sodium) increased the odds of STEC-positive soil samples. Manure application method and snowfall decreased the odds of detecting STEC in the soil. Time-variant predictors (year and sampling day) affected the presence of STEC. This study shows that a single metric, such as the time interval between application of untreated manure and crop harvest, may not be sufficient to reduce the food safety risks from untreated manure, and additional environmental and farm-management practices should also be considered. These findings are of particular importance because they provide multi-regional baseline data relating to current NOP wait-time standards. They can therefore contribute to the development of strategies to reduce pathogen persistence that may contribute to contamination of fresh produce typically eaten raw from NOP-certified farms using untreated manure.

The use of biological soil amendments of animal origin (BSAAOs) to improve soil fertility and quality plays an important role in organic agriculture in the U.S. However, organic practices, such as untreated manure application, may introduce foodborne pathogens and consequently increase the risk of fresh produce contamination. Certified organic farms follow the USDA-National Organic Program (NOP) standards, which stipulate a 90- or 120-day waiting period between incorporating raw manure into the soil and crop harvest, depending on whether the edible portions of the crops come into indirect or direct contact, respectively, with the soil. To determine knowledge, attitudes, behaviors, and practices of organic farmers related to use of biological soil amendments, we employed three evaluation tools: a national workshop held at the University of California-Davis (UC-Davis); multiple in-person focus groups (listening sessions) conducted around the United States, and an online survey. Results reveal that untreated BSAAOs (untreated manure and immature composted manure) are critical tools in organic production for managing soil fertility and improving soil quality. Overall, organic producers surveyed in this study agreed that there is a need for more science-based data to evaluate and establish an appropriately protective time interval between untreated manure application and crop harvest to reduce the risk of surviving foodborne pathogens contaminating organic fresh produce. This study highlights the need for development of outreach and educational tools intended to help organic producers implement mitigation strategies to reduce food safety risks related to BSAAOs in organically grown produce covered by the Produce Safety Rule (PSR) of the U.S. Food and Drug Administration Food Safety Modernization Act (FSMA). This study informs and will aid prioritization of research (e.g., on a time interval protective of fresh produce food safety when soil is amended with animal-biological amendments in organic fresh produce systems) and outreach programs (e.g., GAPs, food safety programs, soil testing, pre-harvest food safety mitigation strategies, and organic rules and regulations) aimed at improving food safety for organic vegetable, fruit, and nut growers who use animal-based soil inputs, including amendments and rotational grazing.

Conventional cotton production has been associated with the extensive use of agricultural chemicals, leading to environmental and health problems, decreased effectiveness of pesticides and higher costs of production. Organic bans the use of most pesticides while providing premiums for growers, and therefore may be a beneficial alternative for growers. Unfortunately, there has been a paucity of research examining the specific practices used by organic cotton growers and the environmental aspects of those practices. This study surveyed organic cotton producers and processors to document specific approaches and techniques used in organic cotton production and processing, the environmental impacts of those techniques and challenges facing organic cotton growers. We discuss the environmental impacts of organic management techniques and methods for conserving water and reducing dependence on irrigation. We also highlight the challenges to organic production identified in the survey, including management for weeds, insects and diseases, genetic contamination of organic crops from genetically modified cotton, organic seed availability, climate change, chemical drift and marketing of organic cotton. Finally, we suggest that investing in research to produce higher-yielding organic varieties, improved methods for organic weed management, and supporting carbon-sequestering practices will improve conversion to organic production.

Excess reactive nitrogen (Nr) in the global system has led to a wide variety of environmental and human health problems. To minimize the negative impacts of nitrogen loss from agriculture, we need to develop more sustainable farming systems that can efficiently produce food for humans while balancing ecological functioning and reducing Nr losses. This paper looks at recent research examining Nr losses in organic systems, using conventional Nr losses in the United States (U.S.) as a baseline to identify leverage points for reducing Nr loss. The paper discusses the sources of Nr used in organic versus conventional farming and highlights the importance of increasing the use of recycled Nr to prevent additional Nr loss to the environment. Specifically, we note that organic production is advantageous when it comes to the creation of new Nr because of its reliance on recycled sources of Nr, improved ability to access nutrients in the soil, and higher residue recycling rates. We also highlight areas where additional research, policies, and protocols are needed to improve Nr efficiency, including increasing organic yields, increased recycling of processing waste, matching nutrient flows, reducing and recycling edible food waste, and examining potential benefits and risks of land application of sewage sludge in organic systems.

This article explores the symbolic connection between marriage and space in Emilia Pardo Bazán’s Los pazos de Ulloa (1886). Although marriage was an effective strategy of social and subjective control in nineteenth-century Spain, it is my contention that this institution also provided the grounds for subversive intervention—for undermining the basic tenets of patriarchal society and the modern nation-state. In particular, this article asserts that the intersection between marriage and social space can be unmoored from the interlocking regulations of domestic and political legislation and recast as a destabilizing force within the society it is supposed to uphold. I interpret marriage as a liminal construct whose meaning fluctuates as it alternates between the “civilized” locus of the city and the “barbaric” countryside. The multilayered nature of marriage in the novel provides the grounds to detach these spaces from their univocal meanings as established by the self-appointed artisans of the modern nation in Spain. The reader is confronted throughout Los pazos de Ulloa with symbolic spaces that underscore the gaps of such regulations, pointing towards the possibility of creating social meaning and individual identities beyond the bounds imposed by male-dominated values and the related constraints associated with liberal political theory.

This special issue presents the outcomes from “ Designing sustainable and circular agricultural systems for the year 2100 ,” the joint scientific workshop of ISOFAR, the Thünen-Institute, and INRA-Morocco, which was held from November 14 to 16, 2019 in Marrakesh, Morocco. Nineteen scientists from a broad array of background and nationalities came together with the understanding that food security globally is at risk, especially in the post-2050 timeframe. Current concepts, strategies, measures, and scientific efforts carried out by governments, NGOs, businesses, and societies do not deliver satisfying solutions for how to sustainably produce enough healthy and affordable food to support the global population. With the economic and social impact of the Covid-19 pandemic in 2020, it became even more evident that food security is a challenge. This workshop took an innovative approach to addressing the challenges of future agriculture by considering sustainable, circular agricultural systems. Participants presented research results on algae-based food, edible insects, mushrooms, novel concepts for nutrient management, bioreactor-based farming, sustainable food culture, as well as sensor- and remote-controlled automatic food production. This special issue presents the papers contributed to the workshop and the results of the discussions.