Two solid state anaerobic digesters (SSADs), 15 L each, were set up for co-digestion of switchgrass with primary digestate of a liquid anaerobic digester (LAD) and the recirculating leachate. Both the LAD and two SSADs were operated at 50°C. The results showed that the bioreactors were not started up stably until day 16 and day 47 for reactors A and B, respectively. The supplement of LAD digestate or injection of sodium hydroxide (NaOH) into the recirculating leachate readily reinitiated the biogas production to normal daily high rates of the two individual SSADs, one on day 16 and the other on day 47. In contrast to reactor A, there was a longer lag phase for bioreactor B, however, it showed 46.2% [77.9 vs 53.3 L kg−1 volatile solid (VS)] more cumulative biogas yields, and higher reduction rate of total solid, VS, cellulose and hemicellulose of 29.5, 31, 40.6 and 15%, respectively, which was likely due to optimized pH and NaOH pretreated switchgrass during start-up period. Methane contents of biogas increased gradually and stabilized at 50% for both reactors, indicating a normal operation of anaerobic digestion lasted for at least 100 days. The determined parameters of digested residues met China organic fertilizer standard (NY 525-2012) except for high moisture and low total nutrient contents. Therefore, the product of SSAD has the potential value of organic fertilizer. It is concluded that the LAD digestate can be reused as inoculums by co-digestion with agricultural residues for biogas and organic fertilizer production in SSAD.

The global population is projected to be enormous by the mid-21st century, whereas, most essential crops being sustained by the rain-fed agriculture are threatened by climate change. Therefore, the study investigated the projected near-future effect of rainfall variability on rot incidence and yam production in humid tropical Nigeria. Production data from the Food and Agriculture Organization and the Nigeria National Bureau of Statistics showed the significant increasing trend in the annual yam output. The field survey conducted in 2018 showed that the maximum percentage of rot incidence occurred in July. Climate Research Unit observational rainfall data from 1979 to 2018 showed the nonsignificant trend in the interannual rainfall variability; however, it showed low variability and a significant decreasing trend in the July rainfall. A pathogenicity test on yam samples confirmed rot by fungi, bacteria and nematodes as virulent pathogens, whereas, the nutritional qualities of the rotted yams were indicated. Monthly rainfall and rot incidence showed positive correlation (r = 0.84, significant at 99% from t-test). The positive characteristic impact values indicated that increase (decrease) in the monthly rainfall corresponds to increase (decrease) in the magnitude of monthly percentage rot incidence. Thus, the significantly decreasing rainfall reduced the quantity of rot incidence and consequently increased the annual yam production for the period. Selected CoOrdinated Regional Downscaling EXperiment-Africa models and the ensemble mean showed a good measure of agreement with observational rainfall in the historical experiments. The efficiencies of the bias-corrected outputs in the representative concentration pathway (RCP) 4.5 and 8.5 indicated improved ‘reasonable’ performances. Bias-corrected projections of the July rainfall showed an increasing trend in both the RCPs, which indicate a potential increase in rot incidence and the consequent decline in annual yam production. The findings are imperative in sustaining the global food supply.

Chickpea (Cicer arietinum L.) is an economically and ecologically important food legume crop. Ethiopia has a large collection of chickpea germplasm accessions; but, it has not been extensively characterized for desirable sources of agronomic and symbiotic significance for use in breeding programs. A study was conducted at two locations (Ambo and Ginchi) in 2009/2010 to characterize and evaluate Ethiopian chickpea germplasm accessions for symbiotic and agronomic performance. One hundred and thirty-nine germplasm accessions were evaluated with 16 other genotypes including non-nodulating reference checks. Differences among genotypes, locations and genotype by location interaction effects were significant for a number of characters. A number of accessions better performing over the improved genotypes were identified for both symbiotic and agronomic characters. The amount of fixed nitrogen ranged from 13 to 49% in foliage, 30 to 44% in grain and 28 to 40% in total above-ground biomass. Grain yield performance varied from 31 to 70 g per 5 plants and seed size ranged from 82 to 288 g per 1000 seeds. For both symbiotic and agronomic characters, landraces were found to be overwhelmingly superior to introduced genotypes, except for seed size, where the best genotypes were all from exotic sources. The result indicated that Ethiopian chickpea landraces have better genetic potential for improving a number of symbiotic and agronomic characters over the varieties currently in use. Selection of best individuals within and among the accessions would be expected to be effective.

What is the role of Northeastern agricultural products in the US food system? This paper presents a typology that categorizes where agricultural production and distribution of a specific geographic area, in this case a multi-state region, fits within the US food system. The place of each food is defined based on its production volume, scope of distribution, market timing and agro-ecological niche. Six distinct roles that a region might play in supplying food are identified: (a) the region is a national production center, (b) the region is a seasonally important supplier, (c) regional production and distribution is the primary scale for supplying a food, (d) the product occupies an agro-ecological niche, (e) a product is a co-product of another industry in the region, and (f) the product is marketed explicitly for its geographic provenance as a local or regional product. Illustrative examples of each role are provided from the research of the Enhancing Food Security in the Northeast (EFSNE) regional food systems project. The examples draw from a variety of methodological approaches including regional self-reliance analysis, product case studies, supply chain models, and examination of spatial and temporal patterns in crop and livestock production and marketing. While presented in the context of the Northeast, the typology would likely be valuable for characterizing other regions of the country. We need such a typology to better understand and communicate the value of geographically dispersed agricultural production to creating a resilient food system, thereby improving our decisions of how to respond to future agricultural challenges

In order to increase ecological horticulture in Sweden, it is necessary to increase productivity while reducing working hours. To improve the relevance of research results as a base for such transitions, a Participatory Learning and Action Research (PLAR) group was added to a conventional research project that aimed to find options for using green manure as a multifunctional tool in vegetable production. The project consisted of four work packages looking at different aspects of a system of interest defined by researchers. The PLAR group sought to evaluate the agronomic outcome of the conventional research outputs but came to add qualitative experience of using the different manuring methods tried. The article reports on the evaluation of the PLAR activities as well as on issues of cooperation and understanding The difficulties and constrains that arose revealed the limitations of conventional research as a means for supporting ecological horticulture transitions, but using PLAR as an ‘add on method’ is also shown to be inadequate for helping producers effect the transitions required. Discussion on the robustness of the data generated and the stability of the approach show the importance of using approaches that are fit for practice when extending research to develop ecological horticulture to include participation with practitioners. Moving from conventional research approaches to trans-disciplinary approaches is not easy and includes the need to relate the contextual knowledge of farmers to the abstract knowledge of scientists.

Although research on the consumers of farmers' markets spans four decades, no prior study has reviewed the most important characteristics of this consumer segment. Our study collects all the survey-based empirical information available in academic journals listed by WoS and Scopus. Based on the outcomes of 103 studies from 21 countries, consumers are described according to their sociographic characteristics and economic, environmental, and social parameters. Results clearly indicate a homogeneous group, with minor variation mainly due to regional specificities, and identify 27 very typical characteristics. The study identifies key implications for managers and policymakers and provides an agenda for further research.

Positive relationships between plant species diversity, soil microbial function and nutrient cycling have been well documented in natural systems, and these relationships have the potential to improve the production and sustainability of agroecosystems. Our objectives were to study the long-term effects of planted species composition and nitrogen (N) fertilization on soil microbial biomass C, extracellular enzyme activity, changes in total soil C, soil fertility and aboveground biomass yield in mixtures of native prairie species managed with and without N fertilizer for bioenergy production at four sites in Minnesota (MN), USA. Species were sown into mixture treatments and composition was not maintained (i.e., no weeding) throughout the duration of the study. Species mixture treatments at establishment included a switchgrass (Panicum virgatum L.) monoculture (SG), a four-species grass mixture (GM), an eight-species legume/grass mixture (LG) and a 24-species high diversity forb/legume/grass mixture (HD). Species diversity and aboveground productivity were similar for most mixture treatments at final sampling after 11 or 12 years of succession. Despite this homogenization of productivity and diversity throughout the study, the effects of planted species diversity and a decade of succession resulted in some differences in soil variables across species mixture treatments. On a peat soil in Roseau, MN, soil enzyme activities including β-glucosidase (BG), cellobiohydrolase (CBH) and phosphatase (PHOS) were highest in HD compared to GM treatments. On a sandy soil at Becker, MN, total soil C increased in all treatment combinations at the 0–15 and 15–30 cm depth intervals, with SG showing greater increases than HD at the 15–30 cm depth. Final soil pH also varied by species mixture at the Becker and Roseau sites, but differences in treatment comparisons varied by location. Nitrogen fertilization did not affect any response variable alone, but interacted with species mixture treatment to influence PHOS and total soil C at Becker. The inconsistent effects of species mixture and N fertilization on soil biological and chemical properties observed across sites highlight the importance of local soil and climate conditions on bioenergy and ecosystem service provisioning of perennial bioenergy cropping systems.

This paper presents a novel approach to multi-criteria sustainability performance assessment of horticultural crops. The crops are ranked by the decision-making method ELECTRE IV with environmental, energy and technological criteria. In total eight indicators are taken into consideration and calculated based on primary data collected from over 260 farms in northern Iran. Additionally, Data Envelopment Analysis is used to calculate the technical efficiency and potential for energy saving by different management of the production units. The novel contribution of this study is the comparison of several horticultural products (oranges, kiwis, persimmons and tangerines), when most of the previous studies have focused on one product. Moreover, novel calculations of the carbon footprint are presented for oranges, tangerines and persimmons. This paper also includes the first study on the environmental impact of persimmon fruit's production. The obtained results show that energy efficiency for orange, tangerine, kiwi and persimmon products: 1.1, 0.84, 0.53 and 1.22, respectively. In each hectare of kiwi orchards, the amount of CO2 emissions of 1219 kg and the ecological footprint of 3.21 hectares have been calculated, which is statistically significant compared to orange, tangerine and persimmon. The chemical and fuel inputs have the greatest potential for reducing energy consumption in the studied products. Results of ELECTRE IV showed that kiwi is the most sustainable selection for the studied region followed by orange, persimmon and tangerine, respectively. Kiwi has also relatively low technical efficiency. This means that this product has the greatest potential for a reduction of energy consumption, while maintaining the same amount of crop. It is recommended to include the development of kiwi orchards in the policies of Guilan, but with more careful management of the production inputs.

Biochar is considered a promising option for the development of sustainable agroecosystems, due to its diverse agronomic and environmental benefits. In this context, the aim of this study was to carry out a bibliometric analysis on biochar research in Brazil within an agricultural context, including investigating the raw materials most employed for its production in the country. The analysis was conducted based on a search for scientific articles (peer-reviewed papers) at the Web of Science database (WoS Core Collection) from 2003 to 2020 specifically in Brazil. A performance analysis was carried out by applying a descriptive and metric approach concerning research constituents (authors, institutions, countries and keywords) and science mapping to clarify scientific collaborations and cognitive and intellectual structure patterns regarding the biochar domain in Brazilian research, using the VOSviewer software. The obtained studies were also analyzed individually to classify the different raw materials employed in biochar production. A total of 261 scientific articles met the screening criteria, indicating that the beginning of biochar publications in Brazil took place in 2003, increasing until 2015 and peaking in 2021. Institutions and authors with the highest publication contributions were the Brazilian Agricultural Research Corporation (EMBRAPA) (Novotny E.), São Paulo University (USP) (Cerri C.) and Federal Lavras University (UFLA) (Melo L.). The United States, Spain, Australia, Germany and the Netherlands present the most collaborations on biochar research with Brazil. The biochar domain was highly associated with the following keywords: biochar, pyrogenic carbon, pyrolysis, charcoal, immobilization, black carbon, soil fertility and soil and characterization. Raw materials of plant origin were the most employed in biochar research in Brazil, with wood residues being the most studied and residues originated from the sugar-energy industry (straw, bagasse and filter cake) identified as exhibiting high potential for future studies. Poultry litter is the most promising animal waste for biochar production, while the use of biosolids can be innovative, contributing to the consolidation of biochar as an option for serious urban waste sanitary management problems.

The effects of the farming system (conventional-organic-abandoned) and soil management (native cover crop vs tillage) on vascular plant species were analyzed in sloping olive groves (>20%) in 20 different locations in Andalusia, SE Spain. The soil management techniques included Organic Tillage (OT), Organic Cover Crops (OC), Conventional Tillage (CT), Conventional Non-Tillage (CNT), Abandoned Cover Crops (AC) and Abandoned Woody (AW). Data for the vascular plant species were recorded through three line transects of 30 m with a bar perpendicularly touching every 1 m of the measuring tape. Environmental variables were also recorded at plot level to assess their influence. Dependent variables, such as species abundance, richness and diversity indexes were studied using univariate analysis (one-way ANOVA, Kruskal–Wallis test) while multivariate statistics (ANOSIM, SIMPER, DCA) were used for analyzing the data matrices. We found that the different combinations of farming system and soil management affect biological diversity in terms of individual abundance, plant cover, species richness and diversity, species and family composition. Life forms and species distribution patterns are also affected. The main environmental variables affecting the plant taxa were those related with soil and climate characteristics, slope, olive age and intensive land uses at landscape level, including the percentage of artificial surfaces. The lowest levels of biodiversity (e.g., species richness) were found in the tilled olive groves (CT = 8.1 sp. ± 2.2, OT = 10.0 sp. ± 5.4). Surprisingly, the organic tilled groves (OT) were very poor in species compared to those with native plant cover (OC = 27.9 sp. ± 3.0). The latter, however, showed similar species richness to the abandoned olive groves (AC = 21.2 sp. ± 3.7, AW = 27.2 sp. ± 3.0). Possible solutions for increasingly uncompetitive sloping olive groves include conversion to organic with native plant cover or abandonment for rewilding.

This paper examines how certified organic cotton initiatives (COCIs) influence community capitals in rural Peru, Tanzania and India using the community capitals framework (CCF). Case study analyses, including qualitative interviews of farmers, expert interviews and participatory observations, were conducted in Northern Peru, Northern Tanzania and Eastern India. The results show slight changes in community capitals in Peru, while comprehensive changes and spiraling-up effects were triggered by certified organic cotton farming initiatives in Tanzania and India. These community developments strongly depended on set measures, such as the extent of (1) partnership (e.g., contract farming), (2) input support (e.g., seeds, loans, community infrastructure), (3) capacity building (through training and advisory services), (4) group formation and (5) formation of cooperatives. Favorable environmental conditions and supporting local institutions facilitated spiraling-up effects, while social preconditions (e.g., gender inequality) strongly limited these effects. The research showed that COCIs have considerable potential to trigger spiraling-up effects in rural communities. However, the capacity strongly depends on the respective initiative and its ability to involve and empower farmers, i.e., to build up human and social capital.

Acacia dealbata Link is one of the main invasive species in southwestern Europe and a resource with potential value for agriculture. Our objective was to assess the value of A. dealbata vegetative aerial biomass used as green manure and as a tool for weed control in maize crops through three sequential experiments. In 2017, an experiment was carried out with acacia green manure vs inorganic fertilization of pots sown with a field corn and a sweet corn hybrid with strong and weak nutrient demand, respectively. Nutrients were not released from acacia green manure at an appropriate timing, and maize suffered nutrient deficit. In 2018, a pot experiment was made outdoors incorporating acacia green manure at different times before maize sowing, and we found that a 4-month period was required for maximum nutrient release from acacia green manure. In 2019, an early and a late-field experiments were performed by incorporating acacia green manure 4 months before maize sowing. Physiological and agronomic data were recorded in maize, along with soil data, for all years, and weed data the last year. Altogether, most effects and interactions between genotype or environment and fertilization treatment were not significant, and some deficiencies caused by acacia green manure fertilization depend on genotype and environment. Incorporation of acacia green manure 4 months before maize sowing partially controlled weeds and replaced inorganic fertilization. However, deficiencies should be corrected with additional weed control practices and fertilization treatments, according to the nutrient demand of the crop and the soil environment.

Intensifying crop–fallow systems could address increased weed control costs, increased land or rental costs, reduced crop diversity, and degraded soil properties in water-limited environments. One strategy to intensify such systems could be the insertion of a short-season crop during fallow. But, how this strategy affects soils, crop production, and farm economics needs further research. Thus, we studied the impacts of replacing fallow in a winter wheat (Triticum aestivum L)–corn (Zea mays L.)–fallow system with a short-season spring crop [field pea (Pisum sativum L.)] on crop yields and economics from 2015 to 2019 and 5-yr cumulative effects on soil properties using an experiment in the west-central US Great Plains. After 5 yr, replacing fallow with field pea increased microbial biomass by 294 nmol g−1 and plant available water by 0.08 cm3 cm−3, and reduced bulk density by 0.1 g cm−3 and cone index by 0.73 MPa in the 0–5 cm depth. It had, however, no effect on other soil properties. Field pea yield averaged 2.24 Mg ha−1. Field pea reduced subsequent crop yield by 15–25% in two of three crops compared with fallow. However, economic analysis showed replacing fallow with field pea may improve net income by $144–303 ha−1, although income across the 5 yr differed by $65 ha−1 in favor of fallow. Replacing fallow in winter wheat–corn–fallow rotation with a short-season spring crop offers promise to improve some near-surface soil properties while increasing net economic return during fallow under the conditions of this study.

Organic matter is a key element of soil fertility. However, in-soil stocks of organic matter are in decline in specialized crop farms. Reintroducing organic fertilizers could be a way to increase or at least maintain organic matter stocks in these soils. Straw/manure exchanges between crop farms and livestock farms could improve overall land fertility and thus the long-term income of farmers. Here we used a bioeconomic model to estimate the agronomic and economic benefits of straw/manure exchanges as part of a strategy to improve soil fertility. Iterative simulations were run with prices of farmyard manure varying from €0 to €20 ton−1 to identify the price at which a crop farm can buy manure and sell straw without degrading its net income (manure ceiling price) compared to purchasing mineral fertilizer only and ploughing back straw. Parallel simulations were run to identify the price at which a livestock farmer can sell manure and buy straw without degrading its net income (manure floor price) compared to keeping all manure on the farm and buying straw on the market. The key new contributions of this study are that it (i) considers the characteristics of manure beyond its short-term fertilizing value, i.e., better mineralization of humus and a 10% increase in crop yields, (ii) estimates both the economic and agronomic benefits of manure and (iii) assesses the impacts of uncertainties on manure effects and prices. The results show that it is profitable for a French farmer in a conventional field crop system to buy manure at a price between €10 ton−1 in the short term and €18 ton−1 in the long term. The results also show that it is still economically advantageous for a livestock farmer to sell part of their manure, even at a very low price. This study shows that it is possible to better distribute manure resources over a territory in a way that enriches the soils of crop farms without degrading the soils of livestock farms.

Exotic crops—plant species grown in relatively small quantities and not traditionally cultivated in a country or region—are often intimately linked with the ethnic origins of their maintainers and are a principal source of culinary and nutritional diversity for many people. Recognizing that a wealth of exotic crop diversity and associated knowledge is held by small-scale growers in the UK, Garden Organic initiated the Sowing New Seeds project to capture and preserve some of this valuable resource by building a seed collection and knowledge base. To establish a sample of this diversity and knowledge, we undertook a survey at 31 allotment sites in the Midlands region of the UK with the objectives of identifying the exotic crops cultivated, characterizing the demography of those who grow them, understanding their direct use values, and assessing their potential indirect use value for the diversification and improvement of other crops. Results reveal that 26% of the food crops recorded are exotic and that they are grown by people belonging to 13 different ethnic groups. The majority save their own seed, indicating that these crops are performing well in the UK, with grower selection providing the basis for their continuing success. Further, most maintainers swap seed with other growers, indicating that exotic crops are likely to be gradually diversifying in response to different growing conditions—a positive sign for their value for local food security and as national genetic resources with potential for use in crop improvement programs. The research highlights the multitude of benefits that growers obtain through cultivating exotic crops, which are not only related to nutrition and culinary requirements, but also to general health and well-being, culture, and a range of other forms of life enrichment. It is critical that growers are encouraged and supported in continuing to cultivate, save and pass on their exotic crops to younger generations, as well as to protect allotments from development in order to maintain this important diversity adapted to local growing conditions. Importantly, many exotic crops currently grown on a small scale may enter into commerce, and thus expand the diversity of the UK's food crop base. Such a shift may be particularly important in the face of the increasingly detrimental impacts of climate change on crop production. We conclude that exotic crop diversity could be more important for future nutrition, health and food security than we currently appreciate.

Legumes have been shown to enhance bioavailability of phosphorus (P) from sparingly soluble pools, yet this functional trait remains underutilized in agriculture, and is untested at decadal scales. Management and legume presence effects on temporal soil properties were evaluated in a 17-year field crop experiment using soil samples collected in 1992, 2000 and 2006. Management systems compared included: (1) conventional corn–soybean–wheat rotation (C–S–W), (2) organic (C–S–W+red clover), (3) alfalfa and (4) early successional field. To evaluate the effects of long-term management versus recent management (residues and P fertilizer) on P and bio-availability to soybean, subplots of soybean were established with and without P-fertilizer (30 kg P ha−1), and compared to subplots and main plot with the long-term system. We evaluated soil properties (C, total P, Bray extractable inorganic P, particulate organic matter phosphorus) and soybean P uptake, biomass and yield. Recent fertilizer P inputs had no detectable influence on soil P, and total soil P stayed stable at ~350 mg P kg−1, whereas inorganic P (Pi) declined from an initial value of 54 to an average of 35 mg P kg−1. A P balance was constructed and showed a net loss of −96.7 kg P ha−1 yr−1 for the organic system, yet Bray-Pi and soybean P uptake were maintained under organic production at similar levels to the conventional, fertilized system. Particulate organic matter P was 57, 82 and 128% higher in organic, alfalfa and successional treatments, respectively, compared to conventional. A similar pattern was observed for soil C, soybean yield and bioavailable P, which were 20–50% higher in the organic, alfalfa and successional systems relative to conventional. This study provides evidence that long-term management history influences bioavailability of P.

Rapid changes in economic, environmental and social conditions generate both problems and opportunities in agriculture. The cycle from problem identification through discovery of potential solutions is lengthy. The objective of this study was to use collaborative methods to speed the cycle of discovery in sustainable organic strawberry (Fragaria × ananassa) production systems in the southeastern USA. This method, stakeholder-driven adaptive research (SDAR), combines farmers' experiential knowledge with scientists' experimental knowledge to develop rigorous research design collectively. Farmers evaluated our biological research and co-designed research experiments with scientists. Farmers and other stakeholders (1) evaluated on-station experiments individually and then made recommendations as a group, (2) served as advisory council members to direct our goals and objectives, and (3) conducted farmer field trials where they implemented aspects of our on-station experiments under their management regimes. The results eliminated potential solutions that were not feasible, ineffective or too costly for farmers to adopt. Key results included eliminating treatments using high tunnel systems altogether on one field trial on a University of Florida (UF) research facility, adding a leguminous cover crop mix treatment, adding companion planting, and eliminating strawberry cultivars Strawberry Festival and Florida Beauty from our research trials. Our proposed methodology allows farmers and other stakeholders to inform the biological research from design through dissemination to reduce the time needed to create research products in an era of rapid bio-physical, social and economic change. Accelerating the discovery cycle could significantly improve our ability to identify and address threats to the USA and global food and fiber production system.

The weed species Spermacoce densiflora DC. and Spermacoce verticillata L. have shown an increase in their occurrence in cultivated areas in the northeast region of Brazil, and field observations have reported their ineffective control with chemicals. This study aimed to evaluate the germination of S. densiflora and S. verticillata under constant (15, 20, 25, 30 and 35°C) and alternating temperatures (20–30°C) in dark and in constant light; the emergence of seedlings from seven sowing depths (0, 0.5, 1, 2, 4, 6 and 10 cm); the emergence of seedlings under five types of cover crop straw (Crotalaria juncea L., Pennisetum glaucum (L.) R. Br., Sorghum bicolor (L.) Moench, Dolichos lablab L., and Cajanus cajan L.) and four amounts (nil and the average, half and twice the amount of straw produced in the field); and germination at different aqueous cover crop extract concentrations (0, 20, 40, 60 and 100%) to measure allelopathic potential of cover crop straw. The results showed that S. densiflora has positive photoblastic behavior. The alternating temperature provided the highest percentage of germination and germination speed index (GSI) for both species. S. densiflora and S. verticillata seedling emergence decreased with an increase in depth, with no germination at a depth of 10 cm. The presence of straw impaired the emergence of seedlings of S. densiflora and S. verticillata by delaying and even preventing germination from occurring. The gradual increase in the aqueous extract concentrations was accompanied by lower percentages of germination and GSI for S. densiflora and S. verticillata.