Promoting sustainable smallholder farming via multistakeholder collaboration.

Transforming smallholder farms is critical to global food security and environmental sustainability. The science and technology backyard (STB) platform has proved to be a viable approach in China. However, STB has traditionally focused on empowering smallholder farmers by transferring knowledge, and wide-scale adoption of more sustainable practices and technologies remains a challenge. Here, we report on a long-term project focused on technology scale-up for smallholder farmers by expanding and upgrading the original STB platform (STB 2.0). We created a formalized and standardized process by which to engage and collaborate with farmers, including integrating their feedback via equal dialogues in the process of designing and promoting technologies. Based on 288 site-year of field trials in three regions in the North China Plain over 5 y, we find that technologies cocreated through this process were more easily accepted by farmers and increased their crop yields and nitrogen factor productivity by 7.2% and 28.1% in wheat production and by 11.4% and 27.0% in maize production, respectively. In promoting these technologies more broadly, we created a "one-stop" multistakeholder program involving local government agencies, enterprises, universities, and farmers. The program was shown to be much more effective than the traditional extension methods applied at the STB, yielding substantial environmental and economic benefits. Our study contributes an important case study for technology scale-up for smallholder agriculture. The STB 2.0 platform being explored emphasizes equal dialogue with farmers, multistakeholder collaboration, and long-term investment. These lessons may provide value for the global smallholder research and practitioners.

Uneven agricultural contraction within fast-urbanizing urban agglomeration decreases the nitrogen use efficiency of crop production.

Diverse development paths among cities within an urban agglomeration can lead to uneven changes in their agricultural production scale, which reshape the inter-city food supply patterns and the spatiotemporal characteristics of nitrogen (N) pollution from the food system. Here, using Guangdong-Hong Kong-Macao Greater Bay Area of China as a case, we found a substantial decrease in N use efficiency of crop production from 45.2% to 29.3% during 1989-2007, along with a growing level of concentration of food N production in less-urbanized cities. From 1989 to 2018, 12.3% to 42.2% of total N pollution in food production became embedded in inter-city trade, leading to aggregation of N pollution in peripheral cities with relatively low levels of economic development. We suggest that protection and intensification of cropland from urban encroachment, as well as enhancing the economic and technical synergies among cities, can serve the sustainable transition of the food system with coordinated N pollution mitigation.

Wood ash application for crop production, amelioration of soil acidity and contaminated environments.

Agriculture is vital to human life and economic development even though it may have a detrimental influence on soil quality. Agricultural activities can deteriorate the soil quality, endangers the ecosystem health and functioning, food safety, and human health. To resolve the problem of soil degradation, alternative soil conditioners such as wood ash are being explored for their potential to improve soil-plant systems. This study provides an overview of the production, properties, and effects of wood ash on soil properties, crop productivity, and environmental remediation. A comprehensive search of relevant databases was conducted in order to locate and assess original research publications on the use of wood ash in agricultural and environmental management. According to the findings, wood ash, a byproduct of burning wood, may improve the structure, water-holding capacity, nutrient availability, and buffering capacity of soil as well as other physico-chemical, and biological attributes of soil. Wood ash has also been shown to increase agricultural crop yields and help with the remediation of polluted regions. Wood ash treatment, however, has been linked to several adverse effects, such as increased trace element concentrations and altered microbial activity. The examination found that wood ash could be a promising material to be used as soil conditioner and an alternative supply of nutrients for agricultural soils, while, wood ash contributes to soil improvement and environmental remediation, highlighting its potential as a sustainable solution for addressing soil degradation and promoting environmental sustainability in agricultural systems.

Recycling composted human feces as biofertilizer for crop production: Assessment of soil and lettuce plant tissue contamination by Escherichia coli and human adenovirus.

Using waste from sewage systems, particularly human excreta, could save resources and increase soil fertility, contributing to nutrient management. However, because of the pathogenic content in human feces, this resource can pose health risks to farmers and consumers. Therefore, this work analyzed the behavior of the microorganisms: Escherichia coli ATCC13706 and human adenovirus (HAdV-2) in the soil and the internal part of the plant tissue during the vegetative stage after applying spiked composted human feces as biofertilizer. In a greenhouse, we simulated the application of the biofertilizer in lettuce cultivation by spiking three concentrations of E. coli (6.58, 7.31, and 8.01 log10 CFU.g-1) and HAdV-2 (3.81, 3.97, and 5.92 log10 PFU.g-1). As a result, we achieved faster decay in soil at higher concentrations of E. coli. We estimated linear decay rates of -0.07279, -0.09092, and -0.115 days, corresponding to T90s of 13.7, 11.0, and 8.6 days from higher to smaller concentrations of E. coli, respectively. The estimated periods for the inactivation of 4 logarithmic units of E. coli bacteria in soil are longer than the cultivation period of lettuce for all concentrations studied. Concerning the bacterial contamination in plants, we found E. coli in the internal part of the leaves at the highest concentration tested during the first three weeks of the experiment. Furthermore, HAdV-2 was found in roots at a stable concentration of 2-2.3 log10 PFU.g-1 in five of the six samples analyzed. Therefore, bacterial infection could pose a risk, even if fresh greens are washed before consumption, especially for short-term cultures. Regarding viral infection, a positive result in the roots after disinfection may pose a risk to root and tubercule vegetables. These discoveries highlight the importance of conducting comprehensive evaluations of hygiene practices in incorporating organic amendments in crops, explicitly aiming to minimize the risk of post-contamination.

Managing fragmented croplands for environmental and economic benefits in China.

Cropland fragmentation contributes to low productivity and high abandonment risk. Using spatial statistics on a detailed land use map, we show that 10% of Chinese croplands have no potential to be consolidated for large-scale farming (>10 ha) owing to spatial constraints. These fragmented croplands contribute only 8% of total crop production while using 15% of nitrogen fertilizers, leading to 12% of fertilizer loss in China. Optimizing the cropping structure of fragmented croplands to meet animal food demand in China can increase animal food supply by 19%, equivalent to increasing cropland proportionally. This crop-switching approach would lead to a 10% and 101% reduction in nitrogen and greenhouse gas emissions, respectively, resulting in a net benefit of US$ 7 billion yr-1. If these fragmented croplands were relocated to generate large-scale farming units, livestock, vegetable and fruit production would be increased by 8%, 3% and 14%, respectively, and reactive nitrogen and greenhouse gas emissions would be reduced by 16% and 5%, respectively, resulting in a net benefit of US$ 44 billion yr-1. Both solutions could be used to achieve synergies between food security, economic benefits and environmental protection through increased agricultural productivity, without expanding the overall cropland area.

Narrowing yield gaps does not guarantee a living income from smallholder farming-an empirical study from western Kenya.

Crop yields in sub-Saharan Africa need to increase to keep pace with food demands from the burgeoning population. Smallholder farmers play an important role in national food self-sufficiency, yet many live in poverty. Investing in inputs to increase yields is therefore often not viable for them. To investigate how to unlock this paradox, whole-farm experiments can reveal which incentives could increase farm production while also increasing household income. In this study we investigated the impact of providing farmers with a US$ 100 input voucher each season, for five seasons in a row, on maize yields and overall farm-level production in two contrasting locations in terms of population density, Vihiga and Busia, in western Kenya. We compared the value of farmers' produce with the poverty line and the living income threshold. Crop yields were mainly limited by cash constraints and not by technological constraints as maize yield immediately increased from 16% to 40-50% of the water-limited yield with the provision of the voucher. In Vihiga, at best, one-third of the participating households reached the poverty line. In Busia half of the households reached the poverty line and one-third obtained a living income. This difference between locations was caused by larger farm areas in Busia. Although one third of the households increased the area farmed, mostly by renting land, this was not enough for them to obtain a living income. Our results provide empirical evidence of how a current smallholder farming system could improve its productivity and value of produce upon the introduction of an input voucher. We conclude that increasing yields of the currently most common crops cannot provide a living income for all households and additional institutional changes, such as alternative employment, are required to provide smallholder farmers a way out of poverty.

Crop switching can enhance environmental sustainability and farmer incomes in China.

Achieving food-system sustainability is a multidimensional challenge. In China, a doubling of crop production since 1990 has compromised other dimensions of sustainability1,2. Although the country is promoting various interventions to enhance production efficiency and reduce environmental impacts3, there is little understanding of whether crop switching can achieve more sustainable cropping systems and whether coordinated action is needed to avoid tradeoffs. Here we combine high-resolution data on crop-specific yields, harvested areas, environmental footprints and farmer incomes to first quantify the current state of crop-production sustainability. Under varying levels of inter-ministerial and central coordination, we perform spatial optimizations that redistribute crops to meet a suite of agricultural sustainable development targets. With a siloed approach-in which each government ministry seeks to improve a single sustainability outcome in isolation-crop switching could realize large individual benefits but produce tradeoffs for other dimensions and between regions. In cases of central coordination-in which tradeoffs are prevented-we find marked co-benefits for environmental-impact reductions (blue water (-4.5% to -18.5%), green water (-4.4% to -9.5%), greenhouse gases (GHGs) (-1.7% to -7.7%), fertilizers (-5.2% to -10.9%), pesticides (-4.3% to -10.8%)) and increased farmer incomes (+2.9% to +7.5%). These outcomes of centrally coordinated crop switching can contribute substantially (23-40% across dimensions) towards China's 2030 agricultural sustainable development targets and potentially produce global resource savings. This integrated approach can inform feasible targeted agricultural interventions that achieve sustainability co-benefits across several dimensions.

Cost-effective mitigation of nitrogen pollution from global croplands.

Cropland is a main source of global nitrogen pollution1,2. Mitigating nitrogen pollution from global croplands is a grand challenge because of the nature of non-point-source pollution from millions of farms and the constraints to implementing pollution-reduction measures, such as lack of financial resources and limited nitrogen-management knowledge of farmers3. Here we synthesize 1,521 field observations worldwide and identify 11 key measures that can reduce nitrogen losses from croplands to air and water by 30-70%, while increasing crop yield and nitrogen use efficiency (NUE) by 10-30% and 10-80%, respectively. Overall, adoption of this package of measures on global croplands would allow the production of 17 ± 3 Tg (1012 g) more crop nitrogen (20% increase) with 22 ± 4 Tg less nitrogen fertilizer used (21% reduction) and 26 ± 5 Tg less nitrogen pollution (32% reduction) to the environment for the considered base year of 2015. These changes could gain a global societal benefit of 476 ± 123 billion US dollars (USD) for food supply, human health, ecosystems and climate, with net mitigation costs of only 19 ± 5 billion USD, of which 15 ± 4 billion USD fertilizer saving offsets 44% of the gross mitigation cost. To mitigate nitrogen pollution from croplands in the future, innovative policies such as a nitrogen credit system (NCS) could be implemented to select, incentivize and, where necessary, subsidize the adoption of these measures.

Ionizing Radiation: Effective Physical Agents for Economic Crop Seed Priming and the Underlying Physiological Mechanisms.

To overcome various factors that limit crop production and to meet the growing demand for food by the increasing world population. Seed priming technology has been proposed, and it is considered to be a promising strategy for agricultural sciences and food technology. This technology helps to curtail the germination time, increase the seed vigor, improve the seedling establishment, and enhance the stress tolerance, all of which are conducive to improving the crop yield. Meanwhile, it can be used to reduce seed infection for better physiological or phytosanitary quality. Compared to conventional methods, such as the use of water or chemical-based agents, X-rays, gamma rays, electron beams, proton beams, and heavy ion beams have emerged as promising physics strategies for seed priming as they are time-saving, more effective, environmentally friendly, and there is a greater certainty for yield improvement. Ionizing radiation (IR) has certain biological advantages over other seed priming methods since it generates charged ions while penetrating through the target organisms, and it has enough energy to cause biological effects. However, before the wide utilization of ionizing priming methods in agriculture, extensive research is needed to explore their effects on seed priming and to focus on the underlying mechanism of them. Overall, this review aims to highlight the current understanding of ionizing priming methods and their applicability for promoting agroecological resilience and meeting the challenges of food crises nowadays.

Global trends of cropland phosphorus use and sustainability challenges.

To meet the growing food demand while addressing the multiple challenges of exacerbating phosphorus (P) pollution and depleting P rock reserves1-15, P use efficiency (PUE, the ratio of productive P output to P input in a defined system) in crop production needs to be improved. Although many efforts have been devoted to improving nutrient management practices on farms, few studies have examined the historical trajectories of PUE and their socioeconomic and agronomic drivers on a national scale1,2,6,7,11,16,17. Here we present a database of the P budget (the input and output of the crop production system) and PUE by country and by crop type for 1961-2019, and examine the substantial contribution of several drivers for PUE, such as economic development stages and crop portfolios. To address the P management challenges, we found that global PUE in crop production must increase to 68-81%, and recent trends indicate some meaningful progress towards this goal. However, P management challenges and opportunities in croplands vary widely among countries.

Effect of the seed coating with biomass of Dunaliella salina on early plant growth and in the secondary metabolites content of Coriandrum sativum.

The environmental and health risks associated with the application of synthetic chemical inputs in agriculture increased the demand for technologies that allow higher performance and quality of vegetable crops by implementing synergistic materials with the principles of sustainability. In this work, the seed coating with the biomass of Dunaliella salina incorporated in a bioplastic film of Manihot esculenta (cassava) was evaluated as an initial growth and secondary compounds stimulator of Coriandrum sativum (coriander) plants. The obtained results demonstrated that the coating stimulated an increase in the germination percentage (28.75%) and also in concentration of bioactive compounds, such as the six-fold increment of caffeic acid (13.33 mg 100 g-1). The carbohydrates, lipids, and proteins present in the microalgae biomass seem to be responsible for these increments once they are known for providing energy to the seedling development and coordinating the secondary metabolites synthesis. As conclusion, we consider the coating with biomass of D. salina an alternative for crop improvement that contributes to the development of sustainable agricultural practices.

Trade-offs between economic, environmental and social sustainability on farms using a latent class frontier efficiency model: Evidence for Spanish crop farms.

This article studies trade-offs of farms in terms of economic sustainability (proxied here by technical efficiency), environmental sustainability (proxied here by farmers' commitment towards the environment) and social sustainability (proxied here by farmers' contribution to on farm well-being and communities' well-being). We use the latent class stochastic frontier model and create classes based on three separating variables, representing farms' environmental sustainability and social sustainability. The application to a sample of Spanish crop farms shows that more environmentally sustainable farms are likely to have lower levels of technical efficiency. However, improvements in social concerns, both towards own farm and the larger community, may lead to improved technical efficiency levels. In general, our study provides evidence of trade-offs for farms between economic sustainability and environmental sustainability, but also between environmental sustainability and social sustainability.

Assessment of crop damage by rodent pests from experimental barley crop fields in Farta District, South Gondar, Ethiopia.

This study was conducted in Farta district, south Gondar from 2019 to 2020 cropping years to identify rodent pest species and estimate damage caused on barley crops. Four independent barley crop fields (40 x 40 m each) were sampled randomly to estimate the loss. Two were located near Alemsaga Priority State Forest and the other two were away from the forest. Four (2 x 2 m) rodent exclusion plots were established at 10 m interval as control units in each selected experimental barley fields using fine wire mesh. Rodent pest species were collected using both Sherman and snap traps throughout the different crop growing stages. The damaged and undamaged barley tillers by pest rodents were counted on five 1 x 1 m randomly sampled quadrats for each selected experimental fields. Variations on pest rodent population between cropping years and sites were analyzed using Chi square test. The mean crop damages between cropping years and experimental field sites were analyzed using two way ANOVA. Arvicanthis abyssinicus, Mastomys natalensis, Arvicanthis dembeensis, Mus musculus, Lophuromys simensis, Tachyoryctes splendens and Hystrix cristata were identified as pest rodents in the study area. A total of 968 individual rodents (427 in 2019 and 541 in 2020) were trapped during the study period. There was a statistical variation (χ2 = 13.42, df = 1 and P<0.05) between trapped individuals of the two successive years. The crop fields near the forest were more vulnerable than away from the forest during both cropping years. Statistical variations was observed on mean crop losses between cropping years and experimental barley crop sites. The highest crop damage was seen at maturity stage and the lowest during sowing in all experimental plots and cropping years. The percentage of barley yield loss due to rodent pests was 21.7 kg ha-1. The monetary value of this yield loss was equivalent to 4875 Birr (121.9 US$ h-1). Alemsaga Forest as shelter and conservation strategies like free of farmland from livestock and terracing for soil conservation have great role for the high rodent pest populations in the study area. Field sanitation, trapping and using restricted rodenticides like zinc phosphide are the possible recommendation to local farmers against rodent pests.

Modelling smallholder farmers' preferences for soil fertility management technologies in Benin: A stated preference approach.

The decline of soil fertility is a major constraint which results in lower levels of crop productivity, agricultural development and food security in Sub-Saharan Africa. This study is the first to perform a focalized investigation on the most interesting technological profiles to offer to each category of producers in Benin agricultural development hubs (ADHs) using the stated preference method, more precisely, the improved choice experiment method. The investigation focused on 1047 sampled plots from 962 randomly selected producers in villages of the Smallholder Agricultural Productivity Enhancement Program in Sub-Saharan Africa of the ADHs. An analysis of the experimental choice data with the endogenous attribute attendance and the latent class models was carried out to account for the attribute non-attendance phenomenon and the heterogeneity of the producers' preferences. However, three classes of producer with different socio-economic, demographic, and soil physicochemical characteristics were identified. Thus, the heterogeneity of preferences was correlated with the attributes linked to the cost, sustainability, and frequency of plot maintenance. All producers, regardless of the ADHs, had a strong attachment to accessibility of technologies with short time restoration of soil fertility, and the ability to obtain additional benefits. These latest attributes, added to that relating to cost, tended to have a low probability of rejection in the decision-making process. These results have implications for local decision-makers facing the complex problem of resolving land degradation and local economic development challenges. The generalizability of these findings provides useful insight and direction for future studies in Sub-Saharan Africa.

Nanotechnology and artificial intelligence to enable sustainable and precision agriculture.

Climate change, increasing populations, competing demands on land for production of biofuels and declining soil quality are challenging global food security. Finding sustainable solutions requires bold new approaches and integration of knowledge from diverse fields, such as materials science and informatics. The convergence of precision agriculture, in which farmers respond in real time to changes in crop growth with nanotechnology and artificial intelligence, offers exciting opportunities for sustainable food production. Coupling existing models for nutrient cycling and crop productivity with nanoinformatics approaches to optimize targeting, uptake, delivery, nutrient capture and long-term impacts on soil microbial communities will enable design of nanoscale agrochemicals that combine optimal safety and functionality profiles.

Sucrose Utilization for Improved Crop Yields: A Review Article.

Photosynthetic carbon converted to sucrose is vital for plant growth. Sucrose acts as a signaling molecule and a primary energy source that coordinates the source and sink development. Alteration in source-sink balance halts the physiological and developmental processes of plants, since plant growth is mostly triggered when the primary assimilates in the source leaf balance with the metabolic needs of the heterotrophic sinks. To measure up with the sink organ's metabolic needs, the improvement of photosynthetic carbon to synthesis sucrose, its remobilization, and utilization at the sink level becomes imperative. However, environmental cues that influence sucrose balance within these plant organs, limiting positive yield prospects, have also been a rising issue over the past few decades. Thus, this review discusses strategies to improve photosynthetic carbon assimilation, the pathways actively involved in the transport of sucrose from source to sink organs, and their utilization at the sink organ. We further emphasize the impact of various environmental cues on sucrose transport and utilization, and the strategic yield improvement approaches under such conditions.

Phytomicrobiome for promoting sustainable agriculture and food security: Opportunities, challenges, and solutions.

Ensuring food security in an environmentally sustainable way is a global challenge. To achieve this agriculture productivity requires increasing by 70 % under increasingly harsh climatic conditions without further damaging the environmental quality (e.g. reduced use of agrochemicals). Most governmental and inter-governmental agencies have highlighted the need for alternative approaches that harness natural resource to address this. Use of beneficial phytomicrobiome, (i.e. microbes intimately associated with plant tissues) is considered as one of the viable solutions to meet the twin challenges of food security and environmental sustainability. A diverse number of important microbes are found in various parts of the plant, i.e. root, shoot, leaf, seed, and flower, which play significant roles in plant health, development and productivity, and could contribute directly to improving the quality and quantity of food production. The phytomicrobiome can also increase productivity via increased resource use efficiency and resilience to biotic and abiotic stresses. In this article, we explore the role of phytomicrobiome in plant health and how functional properties of microbiome can be harnessed to increase agricultural productivity in environmental-friendly approaches. However, significant technical and translation challenges remain such as inconsistency in efficacy of microbial products in field conditions and a lack of tools to manipulate microbiome in situ. We propose pathways that require a system-based approach to realize the potential to phytomicrobiome in contributing towards food security. We suggest if these technical and translation constraints could be systematically addressed, phytomicrobiome can significantly contribute towards the sustainable increase in agriculture productivity and food security.

Reduced pests, improved grain quality and greater total income: benefits of intercropping rice with Pontederia cordata.

BACKGROUND: Intercropping, which is growing two or more different crops in the same field simultaneously, is an effective traditional agricultural practice for productivity, resource utilization, and pest control. However, study on intercropping in paddy fields is limited. So in this study, field experiments of 2 years/four seasons (early and late seasons in 2016 and 2017) were conducted to examine the effects of rice-Pontederia cordata intercropping on rice plant growth, pest control, yield, income, and grain quality. RESULTS: We found rice-P. cordata intercropping significantly decreased the occurrence of rice diseases and pests, with a 22.0-45.9% reduction in sheath blight and a 33.8-34.4% reduction in leaf folders. The mean land equivalent ratio (LER) (1.09) result indicates that intercropping rice and P. cordata generated positive yield effects. In addition, due to the economic profit from the replacement stripe of P. cordata in the rice paddy field, intercropping rice with P. cordata could greatly enhance farmer income. The average total income of rice intercropped with P. cordata was 2.5-fold higher than that of rice monoculture. Furthermore, intercropping significantly improved grain quality compared with the rice monoculture. It significantly increased the milled rice rate and whole milled rice rate by 11.2% and 12.8%, respectively, but decreased the chalky rice rate by 30.9-39.8% and chalkiness degree by 32.2%. CONCLUSIONS: We suggest that rice-P. cordata intercropping provides an environmentally effective way to control rice diseases and pests, results in higher overall productivity and total income, and improves grain quality. © 2021 Society of Chemical Industry.

The role of scientists in policy making for more sustainable agriculture.

Dima and Inzé discuss how Europe is lagging behind in embracing the potential of genome editing in crops and highlight how scientists can contribute to advising on effective science-based policies for more sustainable agriculture through genome editing.