AGRI-ENVIRONMENTAL ASSESSMENT OF CONVENTIONAL AND ALTERNATIVE BIOENERGY CROPPING SYSTEMS PROMOTING BIOMASS PRODUCTIVITY

● Agri-environmental assessment of food, feed and/or biogas cropping systems (CS). ● Four-year experiment for the agri-environmental assessment of two innovative CS. ● Biogas CS has equal soil returned biomass than food CS but higher exported biomass. ● Feed and biogas CS present higher biomass productivity, but higher CO₂ emissions. ● CO₂ emissions related to produced biomass are 26% (±5%) lower in biogas CS. Bioenergy, currently the largest renewable energy source in the EU (64% of the total renewable energy consumption), has sparked great interest to meet the 32% renewable resources for the 2030 bioeconomy goal. The design of innovative cropping systems informed by bioeconomy imperatives requires the evaluate of the effects of introducing crops for bioenergy into conventional crop rotations. This study aimed to assess the impacts of changes in conventional cropping systems in mixed dairy cattle farms redesigned to introduce bioenergy crops either by increasing the biomass production through an increase of cover crops, while keeping main feed/food crops, or by substituting food crops with an increase of the crop rotation length. The assessment is based on the comparison between conventional and innovative systems oriented to feed and biogas production, with and without tillage, to evaluate their agri-environmental performances (biomass production, nitrogen fertilization autonomy, greenhouse gas emissions and biogas production). The result showed higher values in the biogas cropping system than in the conventional and feed ones for all indicators, biomass productivity (27% and 20% higher, respectively), nitrogen fertilization autonomy (26% and 73% higher, respectively), methanogenic potential (77% and 41% higher, respectively) and greenhouse gas emissions (15% and 3% higher, respectively). There were no negative impacts of no-till compared to the tillage practice, for all tested variables. The biogas cropping system showed a better potential in terms of agri-environmental performance, although its greenhouse gas emissions were higher. Consequently, it would be appropriate to undertake a multicriteria assessment integrating agri-environmental, economic and social performances.     

HIGH QUALITY DEVELOPMENTAL APPROACH FOR SOIL AND WATER CONSERVATION AND ECOLOGICAL PROTECTION ON THE LOESS PLATEAU

● Analyse the effects of ecological management measures undertaken so far. ● Point out the main problems that confront effective ecological management. ● Suggest some measures to guide ecological management and high-quality development. ● Develop some models to improve the quality of clear waters and green mountains. ● Provide scientific and technological support for green and eco-friendly development. The Loess Plateau is the core area in the Yellow River basin for implementing environmental protection and high-quality development strategies. A series of ecological projects has implemented aimed at soil and water conservation and ecological management on the Loess Plateau over the past 70 years. The effects of the ecological projects are apparent mainly through a marked increase in vegetation cover, controlled soil erosion and reduced flow of sediment into the Yellow River, continual optimization of the industrial structure and increased production from arable land, poverty alleviation and greater prosperity, and optimal allocation of space for biological organisms. Major problems have also been analyzed in ecological management including the fragile ecosystem of the region, maintaining the stability of vegetation, lower agricultural productivity and continued risk from natural disasters. Some suitable schemes and models have been developed for the coordinated development of the region through research and demonstration, striking the optimum balance between rural industry and ecology, and increased regional capacity to supply high-quality ecological products. Countermeasures to address the problems are suggested to guide ecological management and high-quality development in the future.     

A NEW APPROACH TO HOLISTIC NITROGEN MANAGEMENT IN CHINA

● Progress on nitrogen management in agriculture is overviewed in China. ● 4R principles are key to high N use efficiency and low N losses in soil-crop systems. ● A new framework of food-chain-N-management is proposed. ● China’s success in N management provides models for other countries. Since the 1980s, the widespread use of N fertilizer has not only resulted in a strong increase in agricultural productivity but also caused a number of environmental problems, induced by excess reactive N emissions. A range of approaches to improve N management for increased agricultural production together with reduced environmental impacts has been proposed. The 4R principles (right product, right amount, right time and right place) for N fertilizer application have been essential for improving crop productivity and N use efficiency while reducing N losses. For example, site-specific N management (as part of 4R practice) reduced N fertilizer use by 32% and increased yield by 5% in China. However, it has not been enough to overcome the challenge of producing more food with reduced impact on the environment and health. This paper proposes a new framework of food-chain-nitrogen-management (FCNM). This involves good N management including the recycling of organic manures, optimized crop and animal production and improved human diets, with the aim of maximizing resource use efficiency and minimizing environmental emissions. FCNM could meet future challenges for food demand, resource sustainability and environmental safety, key issues for green agricultural transformation in China and other countries.     

SUSTAINABLE SUGARCANE CROPPING IN CHINA

● Cost escalation and declining profits evident in sugarcane production in China. ● Monoculture and fertilizer overuse causes poor soil health, crop productivity plateau. ● Matching crop nutrient demand and supply key to recovery of sugarcane soils. ● Inorganic inputs need to be replaced with organic sources to restore soil health and sustainability. ● Integrated multidisciplinary solution for sustainable sugarcane cropping system needed. Demand for sugar is projected to grow in China for the foreseeable future. However, sugarcane production is unlikely to increase due to increasing production cost and decreasing profit margin. The persisting sugarcane yield plateau and the current cropping system with fertilizer overuse, soil acidification and pests and diseases remain the major productivity constraints. Sugarcane agriculture supports the livelihood of about 28 million farmers in South China; hence, sustaining it is a socioeconomic imperative. More compellingly, to meet the ever-increasing Chinese market demand, annual sugar production must be increased from the current 10 Mt to 16 Mt by 2030 of which 80% to 90% comes from sugarcane. Therefore, increasing sugar yield and crop productivity in an environmentally sustainable way must be a priority. This review examines the current Chinese sugarcane production system and discuss options for its transition to a green, sustainable cropping system, which is vital for the long-term viability of the industry. This analysis shows that reducing chemical inputs, preventing soil degradation, improving soil health, managing water deficit, provision of clean planting material, and consolidation of small farm holdings are critical requirements to transform the current farming practices into an economically and environmentally sustainable sugarcane cropping system.     

SOIL NITROGEN CYCLING AND ENVIRONMENTAL IMPACTS IN THE SUBTROPICAL HILLY REGION OF CHINA: EVIDENCE FROM MEASUREMENTS AND MODELING

● Soil nitrogen fluxes and influencing factors were reviewed in the subtropical hilly regions. ● Fertilizer application and atmospheric deposition contributed largely to soil nitrogen input. ● High gaseous, runoff and leaching losses of soil nitrogen were measured. ● Soil nitrogen cycles are well modelled with the Catchment Nutrients Management Model. The subtropical hilly region of China is a region with intensive crop and livestock production, which has resulted in serious N pollution in soil, water and air. This review summarizes the major soil N cycling processes and their influencing factors in rice paddies and uplands in the subtropical hilly region of China. The major N cycling processes include the N fertilizer application in croplands, atmospheric N deposition, biological N fixation, crop N uptake, ammonia volatilization, N₂O/NO emissions, nitrogen runoff and leaching losses. The catchment nutrients management model for N cycle modeling and its case studies in the subtropical hilly region were also introduced. Finally, N management practices for improving N use efficiency in cropland, as well as catchment scales are summarized.     

TRADE-OFFS IN THE DESIGN OF SUSTAINABLE CROPPING SYSTEMS AT A REGIONAL LEVEL: A CASE STUDY ON THE NORTH CHINA PLAIN

● Impacts of 30 cropping systems practiced on the North China Plain were evaluated. ● Trade-offs were assessed among productive, economic and environmental indicators. ● An evolutionary algorithm was used for multi-objective optimization. ● Conflict exists between productivity and profitability versus lower ground water decline. ● Six strategies were identified to jointly mitigate the trade-offs between objectives. Since the Green Revolution cropping systems have been progressively homogenized and intensified with increasing rates of inputs such as fertilizers, pesticides and water. This has resulted in higher crop productivity but also a high environmental burden due to increased pollution and water depletion. To identify opportunities for increasing the productivity and reducing the environmental impact of cropping systems, it is crucial to assess the associated trade-offs. The paper presents a model-based analysis of how 30 different crop rotations practiced in the North China Plain could be combined at the regional level to overcome trade-offs between indicators of economic, food security, and environmental performance. The model uses evolutionary multi-objective optimization to maximize revenues, livestock products, dietary and vitamin C yield, and to minimize the decline of the groundwater table. The modeling revealed substantial trade-offs between objectives of maximizing productivity and profitability versus minimizing ground water decline, and between production of livestock products and vitamin C yield. Six strategies each defining a specific combination of cropping systems and contributing to different extents to the various objectives were identified. Implementation of these six strategies could be used to find opportunities to mitigate the trade-offs between objectives. It was concluded that a holistic analysis of the potential of a diversity cropping systems at a regional level is needed to find integrative solutions for challenges due to conflicting objectives for food production, economic viability and environmental protection.     

SUSTAINABLE NITROGEN MANAGEMENT FOR VEGETABLE PRODUCTION IN CHINA

● Sustainable nitrogen management strategies for Chinese vegetable production are summarized. ● Research on reactive N (Nr) losses in Chinese vegetable systems is limited compared to cereal crop systems. ● Knowledge-based optimization of N fertilizer rate strategy maintains soil N supply to meet the dynamic vegetable demand in time, space and quantity. ● Innovative products and technology strategy regulates the soil N forms and promotes the vegetable root growth to further control the Nr loss. ● Integrated knowledge and products strategy is needed to produce more vegetables with lower Nr losses. Inappropriate nitrogen fertilizer management for the intensive Chinese vegetable production has caused low N use efficiency (NUE), high reactive nitrogen (Nr) losses and serious environmental risks with limited yield increase. Innovative N management strategy is an urgent need to achieve sustainable vegetable production. This paper summarizes recent studies on Nr losses and identifies the limitations from Chinese vegetable production systems and proposes three steps for sustainable N management in Chinese vegetable production. The three N management steps include, but are not limited to, (1) knowledge-based optimization of N fertilizer rate strategy, which maintains soil N supply to meet the dynamic vegetable demand in time, space and quantity; (2) innovative products and technology, which regulates the soil N forms and promotes the vegetable root growth to reduce the Nr loss; (3) integrated knowledge and products strategy (IKPS). The knowledge-based optimization of N fertilizer rate strategy and innovative products and technology, can maintain or increase vegetable yield, significantly improve NUE, and mitigate the region-specific and crop-specific Nr losses. More importantly, IKPS, based on combination of in-season root-zone N management strategy, innovative products and technology, and best crop cultivation management, is needed to produce more vegetables with lower Nr losses.     

SUSTAINABLE NITROGEN MANAGEMENT IN AUSTRALIAN AGROECOSYSTEMS: CHALLENGES AND OPPORTUNITIES

● There is huge potential for improvement of nitrogen management in Australia. ● N management should incorporate environmental, social and economic sustainability. ● Agronomic, ecological and socioeconomic approaches and efforts are needed. Nitrogen is an essential nutrient that supports life, but excess N in the human-environment system causes multiple adverse effects from the local to the global scale. Sustainable N management in agroecosystems, therefore, has become more and more critical to address the increasing concern over food security, environmental quality and climate change. Australia is facing a serious challenge for sustainable N management due to its emission-intensive lifestyle (high level of animal-source foods and fossil fuels consumption) and its diversity of agricultural production systems, from extensive rainfed grain systems with mining of soil N to intensive crop and animal production systems with excessive use of N. This paper reviews the major challenges and future opportunities for making Australian agrifood systems more sustainable, less polluting and more profitable.     

BUILDING CLIMATE-RESILIENT FOOD SYSTEMS IN EAST AND SOUTHEAST ASIA: VULNERABILITIES,RESPONSES AND FINANCING

● Food systems in East and Southeast Asia are vulnerable to global warming. ● Regional governments strive for adaption, mitigation and financing for climate resilience. ● Vulnerabilities of food system actors and activities exacerbate the challenges faced. ● Agriculture-specific goals, climate-smart agriculture and market integration are key to building climate resilience. Food system resilience to climate change is uniquely imperative for bringing Sustainable Development Goals within reach and leaving no one behind. Food systems in East and Southeast Asia are interacting with planetary boundaries and are adversely affected by extreme weather-related events. A practical question for East and Southeast Asian stakeholders is how to foster climate-resilient food systems in the face of lingering food system vulnerabilities and policy gaps. This paper reviews food system vulnerabilities and policy responses to climate change. In the policy-based review, this paper compares the economy-wide and agriculture-specific targets of low-carbon development across East and Southeast Asia. With China and member states of the Association of Southeast Asia Nations as case studies, multilevel policies in building and financing climate-resilient food systems are further synthesized. The findings confirm significant differences in agriculture-specific emission goals and public financing supports across East and Southeast Asian nations. With an objective to break practical barriers and finance climate-resilient food systems for the future, this paper recommends defining agriculture-specific greenhouse gas emission goals, reorienting the public finance scheme and enhancing mechanisms for the synergy of public and private resources.     

RESEARCH AND APPLICATION OF CROP PEST MONITORING AND EARLY WARNING TECHNOLOGY IN CHINA

● Crop pests are a major factor restricting agricultural production in China. ● The National Monitoring and Early Warning System (NMEWS) was established > 40 years ago. ● Application of NMEWS has increased national capability to tackle pests. The importance of food security, especially in combating the problem of acute hunger, has been underscored as a key component of sustainable development. Considering the major challenge of rapidly increasing demands for both food security and safety, the management and control of major pests is urged to secure supplies of major agricultural products. However, owing to global climate change, biological invasion (e.g., fall armyworm), decreasing agricultural biodiversity, and other factors, a wide range of crop pest outbreaks are becoming more frequent and serious, making China, one of the world’s largest country in terms of agricultural production, one of the primary victims of crop yield loss and the largest pesticide consumer in the world. Nevertheless, the use of science and technology in monitoring and early warning of major crop pests provides better pest management and acts as a fundamental part of an integrated plant protection strategy to achieve the goal of sustainable development of agriculture. This review summarizes the most fundamental information on pest monitoring and early warning in China by documenting the developmental history of research and application, Chinese laws and regulations related to plant protection, and the National Monitoring and Early Warning System, with the purpose of presenting the Chinese model as an example of how to promote regional management of crop pests, especially of cross border pests such as fall armyworm and locust, by international cooperation across pest-related countries.     

IMPROVING FERTILIZATION METHODS AND CROPPING SYSTEMS FOR SUSTAINABLE PRODUCTION OF PEARL MILLET (PENNISETUM GLAUCUM) IN WEST AFRICA: A REVIEW

● Constraints in cultivation and production of pearl millet in West Africa are summarized. ● Production systems and fertilization methods in pearl millet production are highlighted. ● Sustainable production needs integrated cropping systems and fertilizer use efficiency. ● A holistic approach is required to establish a strong collaboration among rural actors. West African countries are among the larger global millet producers but have low yields mainly due to the low quality of their marginal soils. The objectives of this work were to analyze the benefits and constraints of pearl millet production, to summarize the impact of different cropping systems and fertilization modes while proposing a holistic approach for sustainable production. The major constraints on millet yields are low rates or absence of fertilizers, unsuitable cropping systems, and the proliferation of pests and diseases. Intercropping with cowpea is a widely used cropping system in addition to crop rotation, monocropping and agroforestry systems. Microdosing is the best fertilization mode for West African smallholders. It is concluded that integrated systems (breeding new cultivars, intercropping and microdosing) in tied ridges or infiltration pit practices, sustained by the implementation of innovative approaches such as the ‘Science and Technology Backyards’ from China are a promising approach for increasing pearl millet production. In addition, policies such as land protection of the farmers and subsidies of inputs from the government and the effective involvement of farmers and extension officers are necessary in sustaining millet production in West Africa.     

AGRONOMIC AND ENVIRONMENTAL BENEFITS OF REINTRODUCING HERB- AND LEGUME-RICH MULTISPECIES LEYS INTO ARABLE ROTATIONS: A REVIEW

● Arable-ley rotations can alleviate soil degradation and erosion. ● Multispecies leys can improve livestock health and reduce greenhouse gas emissions. ● Ley botanical composition is crucial for determining benefits. ● Lack of livestock infrastructure in arable areas may prevent arable-ley uptake. ● Long-term (10–25 years) research is needed to facilitate evidence-based decisions. Agricultural intensification and the subsequent decline of mixed farming systems has led to an increase in continuous cropping with only a few fallow or break years, undermining global soil health. Arable-ley rotations incorporating temporary pastures (leys) lasting 1–4 years may alleviate soil degradation by building soil fertility and improving soil structure. However, the majority of previous research on arable-ley rotations has utilized either grass or grass-clover leys within ungrazed systems. Multispecies leys, containing a mix of grasses, legumes, and herbs, are rapidly gaining popularity due to their promotion in agri-environment schemes and potential to deliver greater ecosystem services than conventional grass or grass-clover leys. Livestock grazing in arable-ley rotations may increase the economic resilience of these systems, despite limited research of the effects of multispecies leys on ruminant health and greenhouse gas emissions. This review aims to evaluate previous research on multispecies leys, highlighting areas for future research and the potential benefits and disbenefits on soil quality and livestock productivity. The botanical composition of multispecies leys is crucial, as legumes, deep rooted perennial plants (e.g., Onobrychis viciifolia and Cichorium intybus) and herbs (e.g., Plantago lanceolata) can increase soil carbon, improve soil structure, reduce nitrogen fertilizer requirements, and promote the recovery of soil fauna (e.g., earthworms) in degraded arable soils while delivering additional environmental benefits (e.g., biological nitrification inhibition and enteric methane reduction). Multispecies leys have the potential to deliver biologically driven regenerative agriculture, but more long-term research is needed to underpin evidence-based policy and farmer guidance.     

SUSTAINABLE NITROGEN MANAGEMENT INDEX: DEFINITION,GLOBAL ASSESSMENT AND POTENTIAL IMPROVEMENTS

● A composite N management index is proposed to measure agriculture sustainability. ● Nitrogen management has been moving towards sustainability targets globally. ● The improvement was achieved mainly by yield increase, while Nitrogen Use Efficiency (NUE) stagnated. ● No country achieved both yield and NUE targets and spatial variation is large. ● Region-specific yield targets can be used to supplement the standard Sustainable Nitrogen Management Index (SNMI). To represent the sustainability of nitrogen management in the Sustainable Development Goals indicator framework, this paper proposes a sustainable nitrogen management index (SNMI). This index combines the performance in N crop yield and N use efficiency (NUE), thereby accounting for the need for both food production and environmental protection. Applying SNMI to countries around the world, the results showed improvement in the overall sustainability of crop N management over the past four decades, but this improvement has been mainly achieved by crop yield increase, while global NUE has improved only slightly. SNMI values vary largely among countries, and this variation has increased since the 1970s, implying different levels of success, even failure, in improving N management for countries around the world. In the standard SNMI assessment, the reference NUE was defined as 1.0 (considered an ideal NUE) and the reference yield was defined as 90 kg·ha⁻¹·yr⁻¹ N (considering a globally averaged yield target for meeting food demand in 2050). A sensitivity test that replaced the reference NUE of 1.0 with more realistic NUE targets of 0.8 or 0.9 showed overall reduction in SNMI values (i.e., improved performance), but little change in the ranking among countries. In another test that replaced the universal reference yield with region-specific attainable yield, SNMI values declined (i.e., improved performance) for most countries in Africa and West Asia, whereas they increased for many countries in Europe and South America. The index can be improved by further investigation of approaches for setting region-specific yield targets and high-quality data on crop yield potentials. Overall, SNMI offers promise for a simple and transparent approach to assess progress of countries toward sustainable N management with a single indicator.     

HARNESSING ECOLOGICAL PRINCIPLES AND PHYSIOLOGIC MECHANISMS IN DIVERSIFYING AGRICULTURAL SYSTEMS FOR SUSTAINABILITY: EXPERIENCE FROM STUDIES DEPLOYING NATURE-BASED SOLUTIONS IN SCOTLAND

● Diversification enhances nature-based contributions to cropping system functions. ● Soil management to improve production and ecosystem function has variable outcomes. ● Management of the production-system to use legacy nutrients will reduce inputs. ● Intercrops, companion crops and cover crops improve ecological sustainability. ● Sustainable interventions within value chains are essential to future-proof agriculture. To achieve the triple challenge of food security, reversing biodiversity declines plus mitigating and adapting to climate change, there is a drive to embed ecological principles into agricultural, value-chain practices and decision-making. By diversifying cropping systems at several scales there is potential to decrease reliance on inputs, provide resilience to abiotic and biotic stress, enhance plant, microbe and animal biodiversity, and mitigate against climate change. In this review we highlight the research performed in Scotland over the past 5 years into the impact of the use of ecological principles in agriculture on sustainability, resilience and provision of ecosystem functions. We demonstrate that diversification of the system can enhance ecosystem functions. Soil and plant management interventions, including nature-based solutions, can also enhance soil quality and utilization of legacy nutrients. Additionally, this is facilitated by greater reliance on soil biological processes and trophic interactions. We highlight the example of intercropping with legumes to deliver sustainability through ecological principles and use legumes as an exemplar of the innovation. We conclude that there are many effective interventions that can be made to deliver resilient, sustainable, and diverse agroecosystems for crop and food production, and these may be applicable in any agroecosystem.     

OPPORTUNITIES AND APPROACHES FOR MANIPULATING SOIL-PLANT MICROBIOMES FOR EFFECTIVE CROP NITROGEN USE IN AGROECOSYSTEMS

● Matching nitrification inhibitors with soil properties and nitrifiers is vital to achieve a higher NUE. ● Enhancing BNF, DNRA and microbial N immobilization processes via soil amendments can greatly contribute to less chemical N fertilizer input. ● Plant-associated microbiomes are critical for plant nutrient uptake, growth and fitness. ● Coevolutionary trophic relationships among soil biota need to be considered for improving crop NUE. Soil microbiomes drive the biogeochemical cycling of nitrogen and regulate soil N supply and loss, thus, pivotal nitrogen use efficiency (NUE). Meanwhile, there is an increasing awareness that plant associated microbiomes and soil food web interactions is vital for modulating crop productivity and N uptake. The rapid advances in modern omics-based techniques and biotechnologies make it possible to manipulate soil-plant microbiomes for improving NUE and reducing N environmental impacts. This paper summarizes current progress in research on regulating soil microbial N cycle processes for NUE improvement, plant-microbe interactions benefiting plant N uptake, and the importance of soil microbiomes in promoting soil health and crop productivity. We also proposes a potential holistic (rhizosphere-root-phyllosphere) microbe-based approach to improve NUE and reduce dependence on mineral N fertilizer in agroecosystems, toward nature-based solution for nutrient management in intensive cropping systems.     

DISCIPLINE SYSTEM OF ALFALFA BIOLOGY: FROM MULTIOMICS TO BIOLOGICAL BREEDING

● This review systematically raises the subject concept of alfalfa biology. ● The discipline of alfalfa biology has been divided into six major sections. ● The recent advances from the perspective of discipline system have been reviewed. Alfalfa (Medicago sativa) is the main leguminous forage crop with great ecologic and economic value. The research of alfalfa in various fields has exploded, but has not been included in a systematic framework. This paper summarizes the status of global alfalfa research over the past 10 years, raise the subject concept of alfalfa biology, and review the recent advances from the perspective of discipline system as germplasm resources, multiomics and biotechnology, environmental biology, symbiotic nitrogen fixation, biological breeding and cultivation. This paper proposes the key unsolved scientific and technical issues in alfalfa biology, and hope to appeal the research interest of more plant scientists and to promote the development of alfalfa industry.     

IMPACTS OF CLIMATE CHANGE ON CROP PRODUCTION,PESTS AND PATHOGENS OF WHEAT AND RICE

● An overview of impacts of climate change on wheat and rice crops. ● A review on impacts of climate change on insect pests and fungal pathogens of wheat and rice. ● A selection of adaptation strategies to mitigate impacts of climate change on crop production and pest and disease management. Ongoing climate change is expected to have impacts on crops, insect pests, and plant pathogens and poses considerable threats to sustainable food security. Existing reviews have summarized impacts of a changing climate on agriculture, but the majority of these are presented from an ecological point of view, and scant information is available on specific species in agricultural applications. This paper provides an overview of impacts of climate change on two staple crops, wheat and rice. First, the direct effects of climate change on crop growth, yield formation, and geographic distribution of wheat and rice are reviewed. Then, the effects of climate change on pests and pathogens related with wheat and rice, and their interactions with the crops are summarized. Finally, potential management strategies to mitigate the direct impacts of climate change on crops, and the indirect impacts on crops through pests and pathogens are outlined. The present overview aims to aid agriculture practitioners and researchers who are interested in wheat and rice to better understand climate change related impacts on the target species.     

SMALLHOLDER ADOPTION OF GREEN PRODUCTION TECHNOLOGIES ON THE NORTH CHINA PLAIN: EVIDENCE FROM SCIENCE AND TECHNOLOGY BACKYARDS

● A systematical technology diffusion mode that can simultaneously achieve smallholders’ technology adoption to different scales was discovered. ● Collaborative, tree-shaped and jump-start modes are the main forms to promote technology diffusion. ● The combination of three modes above facilitates technology diffusion to different scales. ● The STB-based technology diffusion empowered smallholders through technology adoption. ● Trust is the key to promoting technology dependence and adoption among smallholders. Understanding the impact of agricultural socialized services on smallholder adoption of green production technologies and their mechanisms of action is of great importance for sustainability of farming systems. Currently, there were numerous related studies, but it is still unclear how to gradually achieve the diffusion of technological innovations on pilot sites to a regional level. To answer this question, this paper presents the pathways and mechanisms of green production technologies diffusion by comparing international typical service organizations or modes such as agricultural technology extension service centers (ATESC), farmer field schools (FFS), participatory technology innovation (PTI) and integrated colearning approach (ICLA), while taking Wangzhuang Science and Technology Backyard (WZ STB) in Quzhou, Hebei Province, China as an example. This research had three key outcomes. (1) The combination of collaborative, tree-shaped and jump-start diffusion modes promotes the diffusion of participatory technology innovation to different scales, such as farmers, villages and counties. (2) The three diffusion modes combine and expand the advantages of existing international modes. The collaborative diffusion mode not only provides full scope for the advantages of PTI, but also provides smallholders with service supply for the whole production period. The tree-shaped diffusion mode combines the advantages of FFS from point technology innovation to village diffusion, while achieving a full range of technical service support. The jump-start diffusion mode cannot only achieve large-scale technology diffusion like ATESC and ICLA, but also empower smallholders through adaptive technology innovation. (3) Trust is the key to promoting smallholder reliance on the science and technology provided by STB and to promote their adoption of green production technologies. Accordingly, the following policy recommendations were proposed: strengthen the combination of top-down and bottom-up technology innovation and diffusion models, establish an effective service communication platform and evaluation mechanism, and strengthen the linkage mechanism between socialized services providers and smallholders, which will provide a realistic basis for the national policy of targeted socialized services provision and promote smallholder adoption of green production technologies.     

ROLE OF NITROGEN SENSING AND ITS INTEGRATIVE SIGNALING PATHWAYS IN SHAPING ROOT SYSTEM ARCHITECTURE

● The Green Revolution broadened the trade-off between yield and nitrogen-use efficiency. ● Root developmental and metabolic adaptations to nitrogen availability. ● Mechanisms of nitrogen uptake and assimilation have been extensively studied. ● Modulating plant growth-metabolic coordination improves nitrogen-use efficiency in crops. The Green Revolution of the 1960s boosted crop yields in part through widespread production of semidwarf plant cultivars and extensive use of mineral fertilizers. The beneficial semidwarfism of cereal Green Revolution cultivars is due to the accumulation of plant growth-repressing DELLA proteins, which increases lodging resistance but requires a high-nitrogen fertilizer to obtain high yield. Given that environmentally degrading fertilizer use underpins current worldwide crop production, future agricultural sustainability needs a sustainable Green Revolution through reducing N fertilizer use while boosting grain yield above what is currently achievable. Despite a great deal of research efforts, only a few genes have been demonstrated to improve N-use efficiency in crops. The molecular mechanisms underlying the coordination between plant growth and N metabolism is still not fully understood, thus preventing significant improvement. Recent advances of how plants sense, capture and respond to varying N supply in model plants have shed light on how to improve sustainable productivity in agriculture. This review focuses on the current understanding of root developmental and metabolic adaptations to N availability, and discuss the potential approaches to improve N-use efficiency in high-yielding cereal crops.     

A WAY TO SUSTAINABLE CROP PRODUCTION THROUGH SCIENTIST−FARMER ENGAGEMENT

● Farmer–scientist collaboration for improved farming was achieved. ● Wheat and maize yields of STB farmers improved by 13%. ● NUE increased 20% for wheat and maize production. ● GHG emissions and EEF decreased by 23% and 52%, respectively. Feeding a large and growing population with scientifically sustainable food production is a major challenge globally, especially in smallholder-based agricultural production. Scientists have conducted a considerable theoretical research and technological innovation to synergistically achieve increased food production and reduced environmental impact. However, the potential and feasibility of synergistic smallholder-led agricultural production to achieve increased food production and environmental friendliness is not yet clear. Exploring the potential and feasibility of smallholders to synergistically achieve these two goals, this research collected survey data from 162 farmers implementing standard farming practices and 112 farmers engaged in Science and Technology Backyard (STB) in Quzhou County, Hebei Province, China. Grain yield, nitrogen use efficiency (NUE), greenhouse gas emissions (GHG), and emergy ecological footprint (EEF) of the wheat-maize cropping system dominated by smallholders were analyzed. The results showed smallholders in the STB group improved wheat and maize yields by about 13% and NUE by 20%, respectively. Also, a reduction of 23% in GHG emissions and 52% in EEF were simultaneously achieved in the wheat-maize cropping system. Compared with standard farming practices, 75 kg·ha⁻¹ nitrogen-based fertilizer was saved in the STB farmers. In summary, this study shifts the main perspective of research from scientists to smallholder, and uses a combination of greenhouse gas emission calculations, EEF and material flow analyses to demonstrate from multiple perspectives that agricultural systems under the leadership of smallholders can synergistically achieve high crop yields and low resource use and environmental impacts. The results of this study also show that the smallholder-led scientist-farmer collaborative model established by STB can fully exploit the initiative and potential, and that this collaborative model can be a successful strategy for smallholders as operators to achieve food security at low environmental impacts. The results of this study can provide useful evidence for a sustainable shift toward more sustainable agricultural production systems.