Effect of Land Use on Soil Properties in Debris Flow Bottomland:A Case Study at Xiaojiang Basin, Yunnan

In order to understand the effect of different land use on soil physics and nutrients properties of the debris flow bottomland, a case study at Daqing gully （in Xiaojiang Basin, Yunnan） was conducted in 2004. Soil samples were taken at depth of 0-10,10-20,20-40,40-60,60-80 cm under three land use patterns crop bottomland （CL）, forest bottomland （FL）, and barren bottomland（BL）. The results showed that the developing bottomland to CL promoted soil toaccumulate total phosphorus （TP） and available phosphorus （AP）, pH value transferred from neutral to alkalescency, and organic matter decreased significantly. Furthermore, the contents of total nitrogen （TN） and available nitrogen （AN） in CL were lower than that of FL and BL because the growth of crops consumed more nutrients in soil. The results also showed that the contents of TP, AP and available potassium （AK） in soil were positively correlated with soil particle.

Peoples’ Perception and Conservation of Dactylorhiza hatagirea (D. Don) Soóin Manaslu Conservation Area, Central Nepal

The present study analyzes the information and perception of the local community of Samagaun VDC, Manaslu Conservation Area Project (MCAP) regarding Dactylorhiza hatagirea (D. Don) Soó (Orchidaceae). We assessed the local peoples’ perception on its population status, its availability, factors causing its decline and management practices of this terrestrial orchids. A pre-designed questionnaire was used to gather information targeting the age group between 25 and 60 years (n = 75, 45 male and 30 female). Most of the informants (76%) believe that the abundance of this orchid is declining. Over grazing of domestic animals, over harvesting and lack of awareness among the local community were determined to be the major causes of decline of D. hatagirea in the study area. Protection measures as prescribed by the informants were control grazing, raising awareness among the individuals and sustainable harvestings for the long-term conservation of the species. Systematic management plans that incorporate the participation of local individuals and prioritization of their views will be applicable for the proper conservation of the species.

An Overview of the Problems and Prospects for Circular Agriculture in Sustainable Food Systems in the Anthropocene

In this overview paper,we outline and explore problems and prospects for circular agriculture’s contributions to transformative change toward sustainable food systems in the Anthropocene.We define circular agriculture(CA)and provide historical context on its development.We then discuss how CA can contribute to food system transformations in four key areas:multi-functional landscapes;sustainable intensification(focusing on nitrogen/crop-livestock management and digital agriculture);smallholder farmers;and dietary change.We find that food systems transitions will be challenging due to the depth,scale,and speed of changes necessary for humans to remain within safe planetary boundaries out to 2050.

Spatiotemporal variation and evaluation of agriculture green development: a case study of Hainan Province, China

The realization of green and sustainable development of agriculture is the common pursuit all over the world. Agriculture green development(AGD)program has been proposed as a sustainable development strategy in China,but insufficient is known about the quantitative evaluation of spatiotemporal variation in AGD at the regional scale. This study aimed to assess spatiotemporal patterns in AGD at the county/city-based regional level. For this purpose, a systematic index evaluation system was developed to assess the performance of socioeconomic, food production and environmental components in a key economic region(Hainan Province) of China. Hainan improved its AGD index(representing the overall performance toward achieving AGD) from 38.8 in 1988 to 40.9 in 2019. The socioeconomic development and agricultural productivity have improved with time;environmental quality declined due to overuse of chemicals from 1988 to 2013, but steadily improved after 2013, indicating positive effects of reducing chemical input. There was a higher AGD index in the coastal vs. central regions and the southern vs. northern regions. Scenarios featuring improved nutrient management or optimized diet structure and reduced waste improved economic benefits and social productivity while concurrently reducing environmental degradation. These results provide new insights for the future development of green and sustainable agriculture and formulation of agricultural policies in Hainan Province of China and even other developing countries that are facing or will soon face similar challenges.

Water Security Problem in North China: Research and Perspective

This paper addresses the emergence of water security problems in North China with the aim of highlighting key waterresources management and water security issues for the long-term development of North China. Three key problemsrelated to water resources and security issues in North China in the 21st century are addressed, namely 1) the watercycle under environmental change, 2) agricultural water saving, and 3) water security. Development of internationalresearch related to these issues is also reviewed. The research plan developed recently by the Chinese Academy of Sciences(CAS) is discussed and suggestions on research and development of water resources science in North China are presented.Thanks to focus on experimental catchments and dedicated research stations, a detailed knowledge of the water cycle onNorth China farmland has been compiled. A range of techniques that include isotope tracers has been used to acquirehydrologic data. Much research has been devoted to developing distributed hydrological models at different scales. In thewell irrigation district, five different water saving irrigation regimes have been investigated, and these regimes have hadwidespread application, and reduced water use 60-150 mm while they increased water use efficiency (WUE) by 20%-30%.Furthermore, preventing water pollution is the most essential step to ensure North China’s water security.

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.

Agriculture green development in China: insights and advances

Reconciling the tasks of producing adequate amounts of nutritious food for the increasing global population while preserving the environment and natural ecosystems simultaneously is an enormous challenge. The concept of agriculture green development(AGD) and the necessary governmental policies were developed to address the aforementioned challenge in China and to help achieve the related global sustainable development goals. Agriculture green development emphasizes the synergy between green and development;current agriculture has to transform from the intensive farming with high inputs, high environmental impacts and low resource-use efficiency to a more sustainable agriculture, in order to ensure an adequate supply of nutritious food while delivering environmental integrity, improved economic profitability,and social equity. A research program on AGD was established by China Agricultural University with four research themes, namely: green crop production, green integrated crop-animal production, green food and industry,and green ecological environment and ecosystem services, to provide a scientific basis for future developments and to facilitate the implementation of AGD in practice. AGD requires a multistakeholder approach, fueled by innovative and interdisciplinary research. Joint actions have to be taken by governments, farmers, supply industries, consumers, educators, extension services and researchers to support AGD. This requires strong coordination and public awareness campaigns. This review presents the progress that has been made over the past 5 years and makes recommendations for more research and development, in order to better deliver agricultural green and sustainable development on national and international scales.

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.

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.

Optimizing nitrogen management in the food system for sustainable development: a case study of Quzhou County

Nitrogen(N) is an essential nutrient for food production. The rapid increase in population requires high inputs of N to meet the growing food demand. If not managed well, the substantial loss of N from the food system has multiple impacts on grain yield, air and water pollution, and the economic benefits of agricultural. Multi-objective(food security, environmental sustainability and economic sustainability) synergistic consideration of N management in the food system is still lacking. This study employed strategies for optimizing N management in the food system, using Quzhou County as a typical example on the North China Plain. Firstly, a food chain approach was adopted to understand drivers and reasons behind N losses from the food system.Secondly, a top-down approach was used to define multi-objective N management, taking into consideration food security, environmental sustainability and economic sustainability. Multi-objective N management aims to reduce N losses to the environment and increase N use efficiencies,while simultaneously increasing yields and economic benefits. Thirdly, 3R(reduce-retain-recycle) N management strategies were identified for specific crops and animals through a bottom-up approach and then analyzed the potential of these strategies to achieve the multi-objectives. Finally, there is a discussion of how to engage different stakeholders to promote the technologies implementation. This study provides new insights into the synergistic achievement of multi-objective N management in the food system and the development of environmentally-friendly agriculture.

Effective removal of antibiotic resistance genes and potential links with archaeal communities during vacuum-type composting and positive-pressure composting

As a major reservoir of antibiotics,animal manure contributes a lot to the augmented environmental pressure of antibiotic resistance genes(ARGs).This might be the first study to explore the effects of different ventilation types on the control of ARGs and to identify the relationships between archaeal communities and ARGs during the composting of dairy manure.Several ARGs were quantified via Real-time qPCR and microbial communities including bacteria and archaea were analyzed by High-throughput sequencing during vacuum-type composting(VTC) and positive-pressure composting(PPC).The total detected ARGs and class I integrase gene(intI1) under VTC were significantly lower than that under PPC during each stage of the composting(p <0.001).The relative abundance of potential human pathogenic bacteria(HPB) which were identified based on sequencing information and correlation analysis decreased by 74.6% and 91.4% at the end of PPC and VTC,respectively.The composition of archaeal communities indicated that methane-producing archaea including Methanobrevibacter,Methanocorpusculum and Methanosphaera were dominant throughout the composting.Redundancy analysis suggested that Methanobrevibacter and Methanocorpusculum were positively correlated with all of the detected ARGs.Network analysis determined that the possible hosts of ARGs were different under VTC and PPC,and provided new sights about potential links between archaea and ARGs.Our results showed better performance of VTC in reducing ARGs and potential HPB and demonstrated that some archaea could also be influential hosts of ARGs,and caution the risks of archaea carrying ARGs.

AOA and AOB communities respond differently to changes of soil pH under long-term fertilization

Archaeal and bacterial ammonia-oxidizers drive the first step of nitrification,ammonia oxidation.Despite their importance,the relative contribution of soil factors influencing the abundance,diversity and community composition of ammonia oxidizing archaea(AOA)and bacteria(AOB)are seldom compared.In this study,the AOA and AOB communities in soils from a long-term fertilization experiment(which formed gradients of pH and nutrients)were measured using 454 pyrosequencing of the amoA gene.Results showed that both AOA and AOB communities were influenced by fertilization practice.Changes of AOA abundance,diversity and community structure were closely correlated with a single factor,soil pH,and the abundance and diversity of AOA were lower under the acidified treatments.By contrast,AOB abundance was higher in the acidified soil than in the control soil while AOB diversity was little impacted by soil acidification,and both the abundance and diversity of AOB were most highly correlated with soil carbon and available phosphorus.These results indicated that AOB diversity seemed more resistant to soil acidification than that of AOA,and also suggested that AOB have greater ecophysiological diversity and broader range of habitats than AOA in this lime concretion black soil,and the potential contribution of AOB to ammonia oxidation in acid environments should not be overlooked.

Effects of logging on the trade-off between seed and sprout regeneration of dominant woody species in secondary forests of the Natural Forest Protection Project of China

Background:Promoting natural regeneration(including seed and sprout regeneration)of dominant woody species is essential for restoring secondary forests.However,such restoration processes have been decelerated by the enclosure under Natural Forest Protection Project of China(NFPP).It remains unclear how to implement appropriate management measures(e.g.,whether to apply logging and the suitable intensity)to facilitate natural regeneration according to the responses of two regeneration modes to management measures.We monitored the early stages of seed regeneration(seed rain,soil seed bank,and 1–3-year-old seedlings)and sprout regeneration(stump sprout rate,stump survival rate,probability of sprouting,and number of sprouts per stump)over the first 3 years(2017–2019)after logging under three intensity regimes(control[0%],25%,and 50%logging intensity)in secondary forests.Results:The seed rain density decreased markedly,seedling density increased insignificantly after logging,and logging promoted seedling survival at an increasing conversion rate of 3-year-old seedlings(37.5%under 0%,100%under 25%,and 80.95%under 50%logging)compared to those of the control.The proportion of 3-year-old seedlings increased with logging intensity and was the highest(16.2%)at 50%logging intensity.Sprout density was not affected by logging intensity,however,under 25%and 50%logging,it decreased by 27%and 6%in 2018,and by 37%and 33%in 2019,respectively.Seedling density was 41.65-and 15.31-fold higher than that of sprouts in the 50%and 25%logging treatments,respectively.Based on the relative contributions of the two regeneration modes after logging,three groups of natural regeneration patterns were classified for dominant woody species in temperate secondary forests,i.e.,seed regeneration preference(Betula dahurica,Carpinus cordata and Fraxinus mandshurica),sprout regeneration preference(Acer mono and Acer pseudosieboldianum)and no preference(Quercus mongolica,Fraxinus rhynchophylla,and Juglans mandshurica).Conclusion:In addition to enclosure,appropriate logging can be applied according to the responses of various natural regeneration patterns of dominant woody species to logging in temperate secondary forests under the NFPP.

Review on drivers,trends and emerging issues of the food wastage in China

China has successfully achieved food selfsufficiency over the past 50 years,however,with large inputs and losses.To meet the challenge of feeding a growing population with limited resources,many studies have explored options for improving productivity and efficiency of the food production.However,there have been few studies into the potential of reducing food loss along the whole food production-consumption chain.Here we review the literature on food waste in China.We briefly analyze(1)the drivers that influence levels of food waste in the food chain,(2)examine trends in the volumes and types of food wasted at different stages in the food chain,(3)assess the environmental and resource consequences of food waste in the food chain,and(4)evaluate the policy and stakeholder responses to the emerging challenges.It is concluded that reducing food loss and meeting food security in China requires a coherent institutional structure that promotes the synergistic outcomes of research,policy and education.Suggested key actions include(1)improving machinery and facility for sowing,harvesting,transportation and storage,which can reduce food loss by up to 50%,and(2)improving food waste recycling management,based on coupled food production and consumption systems.

Innovations of phosphorus sustainability:implications for the whole chain

Phosphorus(P)is a non-renewable resource,therefore ensuring global food and environmental security depends upon sustainable P management.To achieve this goal,sustainable P management in the upstream and downstream sectors of agriculture from mineral extraction to food consumption must be addressed systematically.The innovation and feasibility of P sustainability are highlighted from the perspective of the whole P-based chain,including the mining and processing of P rock,production of P fertilizers,soil and rhizosphere processes involving P,absorption and utilization of P by plants,P in livestock production,as well as flow and management of P at the catchment scale.The paper also emphasizes the importance of recycling P and the current challenges of P recovery.Finally,sustainable solutions of holistic P management are proposed from the perspective of technology improvement with policy support.

GREEN AGRICULTURE AND BLUE WATER IN CHINA:REINTEGRATING CROP AND LIVESTOCK PRODUCTION FOR CLEAN WATER

Crop and livestock production are essential to maintain food security.In China,crop and livestock production were integrated in the past.Today,small backyard systems are still integrated but the larger livestock farms are landless and largely geographically separated from crop production systems.As a result,there is less recycling of animal manures and there are lower nutrient use efficiencies in the Chinese food production systems.This,in turn,results in considerable losses of nutrients,causing water pollution and harmful algal blooms in Chinese lakes,rivers and seas.To turn the tide,there is a need for agricultural“green”development for food production through reintegrating crop and livestock production.An additional wish is to turn the Chinese water systems“blue”to secure clean water for current and future generations.In this paper,current knowledge is summarized to identify promising interventions for reintegrating crop and livestock production toward clean water.Technical,social,economic,policy and environmental interventions are addressed and examples are given.The paper highlights recommended next steps to achieve“green”agriculture and“blue”water in China.

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.

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).