Toward to agricultural green development by multi-objective zoning and nitrogen nutrient management:a case study in the Baiyangdian Basin,China

Although China has achieved great advancements toward national food security,the country is still confronted with a range of challenges,including natural resource stress,imbalanced diets and environmental pollution.Optimized management of crop–livestock systems is the key measure to realize agricultural green transformation.However,optimized management of crop–livestock systems that use multi-objective zoning is lacking.This study employed a multi-objective zoning management approach to comprehensively analyze four indicators:ammonia volatilization,nitrogen surplus,soil carrying capacity and ecological red line area.With its significant ecological integrity and a strong emphasis on sustainability,the Baiyangdian Basin serves as a unique and suitable test case for conducting analyses on multi-objective nutrient optimization management,with the aim to facilitate the agricultural green transformation.This study finds that less than 8%of the area in the Baiyangdian Basin meet the acceptable environmental indicator standard,whereas around 50%of the area that had both nitrogen surplus and ammonia volatilization exceeded the threshold.Implementation of unified management,that is,the same management technique across the study areas,could result in an increase of areas meeting environmental indicator thresholds to 21.1%.This project developed a novel multi-indicator partition optimization method,in which distinct measures are tailored for different areas to satisfy multiple environmental indicators.Implementation of this method,could potentially bring more than 50%area below the threshold,and areas with ammonia emissions and nitrogen surplus could be reduced to 15.8%.The multi-indicators partition optimization method represents a more advanced and efficiency-oriented management approach when compared to unified management.This approach could be regarded as the best available option to help China achieve agricultural transformation to improve efficient production and reduce environmental pollution.It is recommended that current policies aimed at nutrient management toward sustainable agricultural development should shift toward the application of multi-indicators partition optimization.

Goal-oriented insect farming and processing can alleviate the dilemma faced by the industrialization of insect resources

Insects are the most widely distributed and most abundant biological resources on earth,and are as precious a biological resource as plants and microorganisms.With the increasing population pressure and the serious shortage of food resources,insects as an ideal food substitute have gradually been paid more attention by scientists.In addition to being used as food and feed,the application value of insects in waste treatment,medicine and other aspects(such as ornamental and pollination)has also been widely recognized around the world.However,industrialization of insect resources still faces many challenges in terms of acceptability,safety,nutrition and productivity.We argue that insect mass production should be purpose-oriented and targeted cultivation.For example,insects used for food and feeding should be safe,tasty and nutritious.Insects used for waste disposal should maximize their survival rate and their conversion rate of the waste.For insects with medicinal significance,it is necessary to clarify their medicinal active ingredients and related pharmacological mechanism,and to cultivate insect strains with high content of active ingredients by proper induction.A goal-driven development strategy will help to avoid the risk of the insect industry technically and managerially.

Effects of different pretreatments on the physiochemical properties of pig manure and its potential in promoting the growth and nutrient accumulation of black soldier fly larvae(BSFL)

An economic and feasible way to use black soldier fly larvae consists of treating livestock manure to convert it into high value-added protein feed.This study was aimed to investigate the effects of different pretreatments on the physiochemical properties of pig manure and its potential in promoting the growth and nutrient accumulation of black soldier fly larvae(BSFL).Fresh pig manure was pretreated by aerobic fermentation(AE),anaerobic fermentation(AN)and high temperature anaerobic fermentation(HAN)for 2 or 5 d,and then inoculated with BSFL.Results indicate that EC value,DOC,DON,TN,NH_(4)^(+)-N and protein content were the highest in HAN pretreated manure.The individual body weight and protein content of BSFL fed with HAN pretreated manure increased by 20%and 30%,respectively,compared with those fed with AE pretreated manure.In terms of performance,BSFL fed with HAN pretreated manure showed the highest waste reduction,bioconversion rate,waste conversion efficiency and protein conversion efficiency.The conclusion of the present study may be helpful for further research on the conversion of organic waste by BSFL.

China requires region-specific manure treatment and recycling technologies

Heterogenous distribution of crops,feed and livestock across China has halted the circulation of nutrients within the agricultural system and is responsible for massive nutrient losses[1,2].Generated livestock manure exceeded optimal crop requirements in 30%and 50%of over 2300 studied counties when there was improved recycling of nitrogen(N)and phosphorus(P)in the food chain,repectively[2].Most of these counties are located in southern and coastal areas,whereas there is a deficit of livestock manure in northern and western China.Such heterogenous distribution of crop-livestock production led to 4.0 Tg manure N and 0.9 Tg manure P[2],which are economically impossible to recycle and will end up in the surrounding environment.In addition,about 40%of feed protein consumed by domestic livestock production relied on importation,putting China’s livestock production supply at high risk in the post pandemic world[3].Hence,China is facing the twin issues of too many manure nutrients but too little feed nutrients simultaneously.

Multiple pollutants from crop and livestock production in the Yangtze River: status and challenges

The rapid increase in the proportion of cash crops and livestock production in the Yangtze River Basin has led to commensurate increases in fertilizer and pesticide inputs. Excessive application of chemical fertilizer, organophosphorus pesticides and inappropriate disposal of agricultural waste induced water pollution and potentially threaten Agriculture Green Development(AGD). To ensure food security and the food supply capacity of the Yangtze River Basin, it is important to balance green and development, while ensuring the quality of water bodies. Multiple pollutants affect the transfer, adsorption, photolysis and degradation of each other throughout the soil-plant-water system. This paper considers the impact of multi-pollutants on the nitrogen and phosphorus cycles especially for crops, which are related to achieving food security and AGD. It presents prospective on theory, modeling and multi-pollutant control in the Yangtze River Basin for AGD that are of potential value for other developing regions.

Comparison of indicators for agricultural green development and the Sustainable Development Goals,and mapping the way forward

While agricultural green development(AGD)is highly recognized and has become a national strategy in China,it is imperative to bridge the knowledge gaps between AGD and the UN Sustainable Development Goals(SDGs),and to evaluate the contribution of AGD to meeting the SDGs.The first aim of this study was to compare the AGD goals and indicators with those of the SDGs so as to identify their relationship.The next aim was to examine the historical evolution of AGD indicators and analyze the gaps between the current status of various indicators and their benchmarks.Limiting factors were identified in China's transition toward AGD.These findings reveal that the indicators of AGD align with those of the SDGs,but have greater specificity to the context in China and are more quantifiable.There has been a significant increase per capita calorie and protein intakes in China,as well as a notable rise in agricultural output per unit of arable land and rural incomes from 1980 to the 2010s.However,these achievements have been accompanied by a high resource use and environmental pollution,highlighting the need for a more sustainable,environmentally responsible agriculture in China.

Toward sustainable food systems: global initiatives and innovations

A recent UN Sustainable Development Goals(SDGs) analysis indicated a significant regression in the global SDG goal scores, particularly in SDG 2—Zero Hunger. The emissions of environmental pollution caused by meeting food demands have prompted some countries to intensify their climate change mitigation efforts. These circumstances have introduced significant uncertainty to the future global sustainable food development. Additionally, a notable global challenge is the persistence of hidden hunger, primarily characterized by the insufficient consumption of high-quality animal protein. Addressing this issue would necessitate increased environmental costs to attain high-quality food security. The future food system presents a significant challenge in coordinating food security, food quality and environmental quality. This article presents a comprehensive review and proposes a three-step strategy for future agricultural development based on food security, quality, and environmental aspects. This is a novel food system transfer strategy, as it concurrently addresses both global food security and environmental thresholds. It involves the construction of an efficient food system that operates within the constraints of environmental limits. The objective is to align with global SDG indicators and to maintain natural resource consumption and pollutant emissions within planetary boundaries.

STRATEGIES FOR A LOW-CARBON FOOD SYSTEM IN CHINA

In China,there has been insufficient study of whole food system greenhouse gas(GHG)accounting,which limits the development of mitigation strategies and may preclude the achievement of carbon peak and carbon neutrality goals.The paper presents the development of a carbon extension of NUFER(NUtrient flows in Food chain,Environment and Resources use model),a food system GHG emission accounting model that covers land use and land-use change,agricultural production,and post-production subsectors.The spatiotemporal characteristics of GHG emissions were investigated for the Chinese food system(CFS)from 1992 to 2017,with a focus on GHG emissions from the entire system.The potential to achieve a low-carbon food system in China was explored.The net GHG emissions from the CFS increased from 785Tg CO_(2)equivalent(CO_(2)-eq)in 1992 to 1080 Tg CO_(2)-eq in 2017.Agricultural activities accounted for more than half of the total emissions during the study period,while agricultural energy was the largest contributor to the GHG increase.In 2017,highest emitting regions were located in central and southern China(Guangdong and Hunan),the North China Plain(Shandong,Henan and Jiangsu)and Northeast China(Heilongjiang and Inner Mongolia)and contributed to over half of the total GHG emissions.Meanwhile,Xinjiang,Qinghai and Tibet are shown as carbon sink areas.It was found that foodsystem GHG emissions could be reduced to 355 Tg CO_(2)-eq,where enhancing endpoint mitigation technologies,transforming social-economic and diet conditions,and increasing agricultural productivities can contribute to 60%,25%and 15%,respectively.Synergistic mitigation effects were found to exist in agricultural activities.

China needs long-term solutions for African Swine Fever

African Swine Fever(ASF)has received a lot of public concerns in and outside of China(1)Currently,more than 1 million head of pigs have been culled,and the stocking number of fattening pigs and sows has been reported reduced by more than 20%(Fig.1a,b),and the price of pork has been increased by around 30%compared with the same period in 2018(Fig.1c).ASF in China has also had a significant impact on the world meat market,due to its huge contribution to global pig production.

Strategies to reduce nutrient pollution from manure management in China

As the demand for livestock products continues to increase in China,so too does the challenge of managing increasing quantities of manure.Urgent action is needed to control point source(housing,storage and processing)and diffuse(field application)pollution and improve the utilization of manure nutrients and organic matter.Here,we review strategies to improve management at each stage of the manure management chain and at different scales.Many strategies require infrastructure investment,e.g.,for containment of all manure fractions.Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies.At the field-scale,there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types,cropping systems,soils and climates throughout China.At the regional scale,coordinated planning is necessary to promote recoupling of livestock and cropping systems,and reduce nutrient accumulation in regions with little available landbank,while minimizing the risk of pollution swapping from one region to another.A range of stakeholders are needed to support the step change and innovation required to improve manure management,reduce reliance on inorganic fertilizers,and generate new business opportunities.

NUTRIENT USE EFFICIENCY AND LOSSES OF INDUSTRIAL FARMS AND MIXED SMALLHOLDINGS:LESSONS FROM THE NORTH CHINA PLAIN

The proportion of industrial livestock in China has increased over the past 30 years,which increases animal performance but causes the decoupling of crop and livestock production.Here,we aimed to quantify nutrient flows,nutrient use efficiency,and nutrient losses in different livestock systems in the North China Plain based on the NUFER-farm model.Activity data were collected by face-to-face surveys on pig and dairy(41 livestock farms)during 2016-2018.The two systems included industrial farms and mixed smallholdings.In mixed smallholdings,4.0%and 9.6%of pig and dairy feed dry matter(DM)were derived from household farmland,but 4.8%and 9.3%of manure DM recycled to household farmland.Nutrient use efficiency in industrial farms was higher than in mixed smallholdings at animal level,herd level,and system level.To produce 1 kg N and P in animal products,nutrient losses in industrial pig farms(2.0 kg N and 1.3 kg P)were lower than in mixed pig smallholdings,nutrient losses in industrial dairy farms(2.7 kg N and 2.2 kg P)were slightly higher than in mixed dairy smallholdings.Liquid manure discharge in industrial farms was the main losses pathway in contrast to mixed smallholdings.This study suggests that feed localization can reduce nutrient surpluses at the district level.It is necessary to improve manure management and increase the degree of integrated crop-livestock in smallholdings.In industrial farms,it is desirable to increase the liquid manure recycling ratio through cooperating livestock and crop production at the district level.

China’s low-emission pathways toward climate-neutral livestock production for animal-derived foods

Animal-derived food production accounts for 19%of global anthropogenic greenhouse gas(GHG)emissions.Diet followed in China is ranked as lowcarbon emitting(i.e.,0.21 t CO_(2-)eq per capita in 2018,ranking at 145^(th) of 168 countries)due to the low average animal-derived food consumption rate,and preferential consumption of animal-derived foods with lower GHG emissions(i.e.,pork and eggs versus beef and milk).

PROGRESS ON IMPROVING AGRICULTURAL NITROGEN USE EFFICIENCY: UK−CHINA VIRTUAL JOINT CENTERS ON NITROGEN AGRONOMY

Two virtual joint centers for nitrogen agronomy were established between the UK and China to facilitate collaborative research aimed at improving nitrogen use efficiency(NUE)in agricultural production systems and reducing losses of reactive N to the environment.Major focus areas were improving fertilizer NUE,use of livestock manures,soil health,and policy development and knowledge exchange.Improvements to fertilizer NUE included attention to application rate in the context of yield potential and economic considerations and the potential of improved practices including enhanced efficiency fertilizers,plastic film mulching and cropping design.Improved utilization of livestock manures requires knowledge of the available nutrient content,appropriate manure processing technologies and integrated nutrient management practices.Soil carbon,acidification and biodiversity were considered as important aspects of soil health.Both centers identified a range of potential actions that could be taken to improve N management,and the research conducted has highlighted the importance of developing a systemslevel approach to assessing improvement in the overall efficiency of N management and avoiding unintended secondary effects from individual interventions.Within this context,the management of fertilizer emissions and livestock manure at the farm and regional scales appear to be particularly important targets for mitigation.

Dairy farming in China at a crossroad

The self-sufficiency of China's milk declined rapidly from 100% in 2008 to 60% in 2017,and may decline to 33% in 2050 according to a recent research [1].China's domestic milk production increased by 10 times between 1988 and 2008,but has remained unchanged since the well-known melamine scandal in 2008.This was due to a great variety of reasons,such as market malfunction, insufficient scientific and technological innovation system,as well as high cost of dairy production itself.