A joint use of emergy evaluation,carbon footprint and economic analysis for sustainability assessment of grain system in China during 2000–2015

The rapid growth of grain yield in China accelerates a discussion on whether the grain system in China is sustainable. To answer the question, a comprehensive assessment from economic and environmental points is necessary. This study jointly used economic analysis(ECA), emergy evaluation(EME) and carbon footprint(CF) to analyze the environmental and economic sustainability of the grain production system in China based on the national statistical data during 2000–2015. Results showed that the costs of maize, wheat, rice and soybean had increased by 252-346% from 2000 to 2015, causing the lower profit of grain system in recent years. The situation resulted in a serious problem on economic sustainability of grain system in China. Meanwhile, the emergy sustainability index(ESI) of maize, wheat, rice and soybean systems were increasing during 2000–2015, and the CF on unit yield of the crops had been reduced by 10-30% in the study period. The results reflected the improved environmental sustainability of grain system in China during 2000–2015. Nevertheless, the emergy flow of industrial inputs for the crops were increased by 4-22% in the study period, and the CF from the inputs presented a growth rate of 16-23% as well during the same period. The results implied that the grain system in China was relying more on fossil-based inputs. Finally, according to the key points of cost, emergy and CF, we suggest that improving labor efficiency, advanced agricultural practices and optimizing cropping pattern will be effective ways to further improve the economic and environmental sustainability of grain system in China.     

The causes and impacts for heat stress in spring maize during grain filling in the North China Plain——A review

High-temperature stress(HTS) at the grain-filling stage in spring maize(Zea mays L.) is the main obstacle to increasing productivity in the North China Plain(NCP). To solve this problem, the physiological mechanisms of HTS, and its causes and impacts, must be understood. The HTS threshold of the duration and rate in grain filling, photosynthetic characteristics(e.g., the thermal stability of thylakoid membrane, chlorophyll and electron transfer, photosynthetic carbon assimilation), water status(e.g., leaf water potential, turgor and leaf relative water content) and signal transduction in maize are reviewed. The HTS threshold for spring maize is highly desirable to be appraised to prevent damages by unfavorable temperatures during grain filling in this region. HTS has negative impacts on maize photosynthesis by damaging the stability of the thylakoid membrane structure and degrading chlorophyll, which reduces light energy absorption, transfer and photosynthetic carbon assimilation. In addition, photosynthesis can be deleteriously affected due to inhibited root growth under HTS in which plants decrease their water-absorbing capacity, leaf water potential, turgor, leaf relative water content, and stomatal conductance. Inhibited photosynthesis decrease the supply of photosynthates to the grain, leading to falling of kernel weight and even grain yield. However, maize does not respond passively to HTS. The plant transduces the abscisic acid(ABA) signal to express heat shock proteins(HSPs), which are molecular chaperones that participate in protein refolding and degradation caused by HTS. HSPs stabilize target protein configurations and indirectly improve thylakoid membrane structure stability, light energy absorption and passing, electron transport, and fixed carbon assimilation, leading to improved photosynthesis. ABA also induces stomatal closure to maintain a good water status for photosynthesis. Based on understanding of such mechanisms, strategies for alleviating HTS at the grain-filling stage in spring maize are summarized. Eight strategies have the potential to improve the ability of spring maize to avoid or tolerate HTS in this study, e.g., adjusting sowing date to avoidHTS, breeding heat-tolerance varieties, and tillage methods, optimizing irrigation, heat acclimation, regulating chemicals, nutritional management, and planting geometric design to tolerate HTS. Based on the single technology breakthrough, a comprehensive integrated technical system is needed to improve heat tolerance and increase the spring maize yield in the NCP.     

Development and evaluation of the carbon–nitrogen cycle module for the GPFARM-Range model

Rangelands cover approximately 50% of the terrestrial surface of the earth. Consequently, the soil carbon and nitrogen storage and turnover in rangeland systems are becoming increasingly important for sustainable grazing management and climate change. In this study, a carbon–nitrogen (C–N) cycle module from the N Leaching and Environmental Analysis Package (NLEAP) was added into the GPFARM-Range model. This linkage was tested against a 14-year forage dataset (1993–2006) with measurements of C and N in 1993, 2003, and 2006 near Cheyenne, WY. The results showed that the peak standing crop (PSC), and changes in soil organic carbon (SOC) and total soil organic nitrogen (TON) in the rangeland were reasonably simulated by the new GPFARM-Range model. The indices of agreement (d) were >0.85 and the mean bias errors (MBE) were <130 kg ha⁻¹ for the PSC simulation. The SOC and TON in the soil profile were simulated with relative root mean squared error (RRMSE) <5% for the calibration treatment without grazing and <20% for the validation treatments with grazing, both showing no significant bias or error from the observed values. A sensitivity analysis showed that the model responded reasonably to changes in temperature and precipitation. A long-term dataset with more soil C and N measurement events on the rangeland is needed to further test the model, but it is not available at this time. Additional investigation is needed into the adequacy of root-to-shoot ratio approaches to simulate root growth for forage groups in these systems.     

Determinants of cooperative pig farmers' safe production behaviour in China——Evidences from perspective of cooperatives' services

Farmers' production behaviour is a key to ensuring the safety and quality of their final products, and cooperatives play an important role in shaping that behaviour. This paper aims to explore the determinants of pig farmers' safe production behaviour, giving special focus from the perspective of cooperatives' services. This study adopted cross sectional survey data from 27 pig cooperatives and their 540 farmers in China to test the influence of cooperatives' services on farmers' safe production behaviour. The hypotheses were tested using a logit regression model. The findings indicated that although the number of services is not a key determinant of farmers' safe production behaviour, service quality matters. When a cooperative is strongly capable of involving more farmers in certain services, and provides certain services in more frequency, member farmers behave more safely. The results also show that veterinarian and pig-selling services play an important role in ensuring farmers' safe production behaviour. For this study, the quality of cooperatives' services is implied to have a positive impact on farmers' safe production behaviour. Leaders/managers of cooperatives must try to improve the quality of their services instead of merely attempting to provide a large number of services. For government officials and policy makers, designing policies that encourage cooperatives to improve their service quality is important. This research contributes to the scant literature on how cooperative services could help farmers engage in safer production behaviour, which would improve the safety of pork products in the future.     

Yield gap and resource utilization efficiency of three major food crops in the world——A review

Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha~(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha~(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.     

Technical and environmental efficiency of hog production in China—A stochastic frontier production function analysis

This article analyses the technical and environmental efficiency of hog production in China using data from the China Agricultural Product Cost-Benefit Compilation(NDRC 2005–2013) and the First National Census of Pollution: Manual of Discharge Coefficient of Livestock and Poultry Industry(IEDA and NIES 2009). The empirical results show a great variation in environmental efficiency, ranging from 0.344 to 0.973 with a mean value of 0.672 that declines over time. Southwest China is found to be the most environmentally efficient region, while the Northeast and the Northwest are the least efficient. Another finding is that technical and environmental efficiencies are highly correlated in hog production; the most environmentally efficient regions are usually found to have high technical efficiency, and vice versa. In addition, we computed the output elasticities with respect to each factor input. The results show that feed is the most efficient input, with an output elasticity of approximately 0.551, which is much higher than the elasticity of the nitrogen surplus, other capital or labour. The output elasticity with respect to the nitrogen surplus is 0.287 on average. Finally, the scale elasticity in hog production is slightly higher than 1.     

Optimal design of culling compensation policy under the African swine fever — Based on simulations of typical pig farms in China

This paper aims to optimize the culling compensation policy from a micro perspective through scenario simulation. Based on an investigation of 273 pig farms in eight regions, four typical pig farms were constructed according to farm size and breeding mode, representing the swine producers in China. Besides, a decision objective function of pig farms facing suspected African swine fever (ASF) outbreaks was constructed. This study used a mathematical programming model to design and simulate scenarios based on compensation standards and local implementation levels, aiming to incentivize pig farms to report epidemics. The results show that the optimal decisions on epidemic reports differed among typical farms and by herd daily age. The results suggest the following adjustments for optimizing culling compensation policies: (1) to set culling compensation standards based on the market value and (2) to maintain a high level of epidemic surveillance capability in the animal husbandry and veterinary sector.     

Significance of β-glucan in barley grain during breeding for brewing and nutritional properties

A method is given for determining the content of ??-glucan in grain of barley varieties, and polymorphism of the species in this trait, including collection and breeding accessions, is shown. Within the breeding nurseries of Kazakhstan, the ??-glucan content varies from 2.6 to 6.2% in spring and from 2.2 to 5.7% in winter barley grain, increasing under dry-farming conditions. For brewing purposes, accessions with a value of this index lower than 4%, some of which displayed relative stability across reseedings, are singled out. The need for purposeful breeding for the given trait, for which it is necessary to introduce it into the selection scheme, and use of identification methods are substantiated.     

Spatial and temporal changes of paddy rice ecosystem services in China during the period 1980–2014

The ecological systems services or multi-functionality of paddy rice cultivation are critical to the functioning of the Earth's life-support system. We estimated the ecosystem services value (ESV) of paddy rice during 1980–2014 across China. The results indicated that the ESV of the paddy field in China showed an upward trend during this period. The share of ESV on CO₂ sequestration was the highest, followed by ESV on temperature cooling and greenhouse gas (GHG) emission. The yield-scaled ESVs of Zones II (southern rice–upland crops rotation regions) and III (southern double rice production regions) were similar and significantly higher than the ESVs of Zones I (northeastern single rice production regions) and IV (Southwest rice–upland crops rotation regions). Between 1980 and 2014, the ESV of each region increased to varying degrees, except for the ESVs of Guangxi, Zhejiang, Fujian, and Guangdong. Such effects suggest the existence of a significant spatial–temporal variation in the total amount, structure, and density of ESV of paddy fields in China, which can further guide the development of future options for the adaptation of healthy rice production in China.     

Comparison of energy consumption and economic performance of organic and conventional soybean production——A case study from Jilin Province,China

Modern agriculture heavily depends on energy consumption, especially fossil energy, but intensive energy input increases the production cost for producers and results in environmental pollution.Organic agricultural production is considered a more sustainable system, but there is lack of scientific research on the energy consumption between organic and conventional systems in China.The analysis and comparison of energy use between the two systems would help decision-makers to establish economic, effective and efficient agricultural production.Thus, the objectives of the present study are to analyze energy inputs, outputs, energy efficiency, and economic benefits between organic and conventional soybean(Glycine max(L.) Merrill) production.A total of 24 organic farmers and 24 conventional farmers in Jilin Province, China, were chosen for investigation in 2010 production year.Total energy input was 71.55 GJ ha–1 and total energy output was 96.18 GJ ha–1 in the organic system, resulting in an energy efficiency(output/input) of 1.34.Total energy input was 9.37 GJ ha–1 and total energy output was 113.4 GJ ha–1 in the conventional system, resulting in the energy efficiency of 12.1.The huge discrepancy in energy inputs and respective efficiencies lies in the several times higher nutrient inputs in the organic compared to the conventional production system.Finally, the production costs ha–1 were 33% higher, and the net income ha–1 25% lower in the organic compared to the conventional soybean production system.It is recommended to improve fertilizer management in organic production to improve its energetic and economic performance.     

Genetic diversity center of cultivated soybean(Glycine max) in China——New insight and evidence for the diversity center of Chinese cultivated soybean

Information on the center of genetic diversity of soybean(Glycine max) will be helpful not only for designing efficient strategies for breeding programs, but also for understanding the domestication and origin of this species. Here, we describe an analysis of genetic diversity based on simple-sequence repeat(SSR) variations within a core collection of 2 111 accessions of Chinese soybean landraces. Prior to the diversity assessment, the geographic origin of each accession was mapped. The map was then divided into grids each 2.5° in latitude and 5° in longitude. We found two regions that had higher number of alleles(NA) and greater polymorphic information content(PIC) values than the others. These regions are adjacently located within grid position of 30°–35°N×105°–110°E, which includes the valley of the middle and lower reaches of the Wei River, and the valley of the upper reaches of the Hanjiang River. It was also observed that in many regions, genetic diversity decreased with the increase in distance from the center. Another region, in northern Hebei Province(115°–120°E×40°–42.5°N), was observed having higher diversity than any surrounding regions, indicating that this is a sub-center of soybean diversity. Based on the presented results, the domestication and origin of soybean are also discussed.     

Can food security and low carbon be achieved simultaneously? —An empirical analysis of the mechanisms influencing the carbon footprint of potato and corn cultivation in irrigation areas

Irrigated agriculture has tripled since 1950, accounting for 20% of the global arable land and 40% of food production.  Irrigated agriculture increases food security yet has controversial implications for global climate change.  Most previous studies have calculated carbon emissions and their composition in irrigated areas using the engineering approach to life-cycle assessment.  By combining life cycle assessment (LCA)-based carbon emissions accounting with econometric models such as multiple linear regression and structural equation modeling (SEM), we conducted an interdisciplinary study to identify the influencing factors and internal mechanisms of the carbon footprint (CFP) of smallholder crop cultivation on irrigation reform pilot areas.  To this end, we investigated corn and potato production data in the 2019–2020 crop years for 852 plots of 345 rural households in six villages (two irrigation agriculture pilot villages and four surrounding villages as controls) in Southwest China.  The crop CFP in the irrigation agriculture pilot areas was significantly lower than in non-reform areas.  Irrigation reforms mainly impacted the crop CFP through four intermediary effects: the project (implementation of field irrigation channels), technology (improving adoption of new irrigation technologies), management (proper irrigation operation and maintenance), and yield effects.  All effects inhibited the CFP, except for the project effect that promotes carbon emissions.  Among them, yield increase has the greatest impact on reducing CFP, followed by management and technology effects.  Furthermore, planting practices, individual characteristics, and plot quality significantly impacted the crop CFP.  This study has policy implications for understanding the food security–climate nexus in the food production industry.     

What determines irrigation efficiency when farmers face extreme weather events? A field survey of the major wheat producing regions in China

Water availability is a major constraint on grain production in China, therefore, improving irrigation efficiency is particularly important when agriculture faces extreme weather events. This paper first calculates irrigation efficiency with a translog stochastic frontier production function and then investigates what happens when extreme weather events occur via a Tobit model. The estimated results reveal several important features of irrigation practices: i) irrigation efficiency is lower when extreme weather events occur; ii) large variations in irrigation efficiency occur across irrigation facilities; iii) the farm plots exhibit an extreme distribution across efficiency levels; and iv) water-saving techniques, technology adoption, and the maintenance of farmers’ economic resilience are major determinants of irrigation efficiency. Based on these results we propose the following recommendations: i) farmers should balance crop yield and water use; undertake relevant training programs and adopt water-saving techniques; ii) local governments and researchers should help farmers to find the optimal level of irrigation water use based on their own circumstances and provide better water-saving techniques and training programs rather than simply encouraging farmers to invest in irrigation facilities in the most extreme weather years; and iii) the income level of farm households should be increased so as to improve their resilience to natural disasters.     

Identification of Behavior of Voluntary Traceability and Analysis of Its Determinants： A Case Study of Hog Slaughtering and Processing Firms in Zhejiang Province, China

In recent years, the Chinese government has highlighted the importance of adopting hog safety/quality traceability, and a growing amount of research continues to entice firms to adopt traceability systems. In this study, a survey was conducted on a sample of pig slaughtering and processing firms in Zhejiang, China through personal interviews and emails. The aim of this study was to examine the determinants of firm behavior on the implementation of voluntary traceability systems with more stringent standards and controls than those of the mandatory system in China. The results revealed that motivation based on product quality improvement, capital ability and role perception (business type) had significantly positive relationships with a firm’s voluntary traceability. Other incentives, such as operation improvement, recall risk reduction, reduced occurrence of safety issues, and technical strength were not found to be supportive in our study. This study provides an opportunity to better understand the determinants of firm behavior on voluntary traceability, particularly in light of the fact that some Chinese firms are facing the threat of criminal action for the use of illegal additives and the abuse of Clenbuterol. Policy recommendations on encouraging the implementation of pork safety voluntary traceability by hog slaughtering and processing firms are also discussed.     

Genetic bases of improved soybean cultivars released from 1923 to 2005 in China—A historical review

Improved soybean cultivars are cultivars released from a scientific breeding program in China in contrast to the historical landraces kept by farmers from their own seed lots. The pedigree data of 1300 soybean cultivars [Glycine max (L.) Merr.] released in China from 1923 to 2005 were collected, checked, and corrected. These cultivars traced back to 670 nuclear and 344 cytoplasmic ancestors; 45% (50%) of the nuclear (cytoplasmic) germplasms were from Eco-region I, 23% (26%) from II, 7% (10%) from III, 4% (5%) from IV, 1% (1%) from V, 1% (1%) from VI, 18% (7%) from foreign countries, and 0% (1%) from geographically unknown sources. Both nuclear and cytoplasmic germplasm from Eco-regions I, II, and III, and foreign countries accounted for most of the ancestry of the released cultivars. In each of the eco-regions, with the exception of region VI, but especially in region I, the local nuclear and cytoplasmic germplasm was dominant in the released cultivars. Exotic germplasm accounted for an increasing portion of the nuclear and cytoplasmic germplasm, especially in Ecoregions I and II. The genetic base of the released cultivars is relatively narrow but has been gradually broadened, especially in Eco-regions I and II; and the average number of ancestors per cultivar released between 1996 and 2005 in various eco-regions was approximately double the period between 1986 and 1995. Seventy-eight ancestors accounted for 12% of the total ancestors but explained that 64% of the nuclear contribution and 70% of the cytoplasmic contribution to the 1300 released cultivars. For broadening the genetic base of future cultivars, the utilization of germplasm from outside regions is emphasized.     

Index Identification of Suitable Temperature at the Booting Stage and Accumulated Temperature over 10℃ during the Whole Growth Period in Rice in the South of China

According to phenological observation data of fourteen stations in Hunan,Hubei and Jiangxi provinces from 1994 to 2006,indices of suitable temperature at the booting stage and accumulated temperature(≥10 ℃)during the whole growth period in early or late rice in the south of China were analyzed by statistics and biological relationship between factors.Indices of the optimum daily mean temperature and the minimum temperature at the booting stage were as follows:Early convention rice variety was 25.7 ℃ and 22.3 ℃ respectively,hybrid variety was 26.5 ℃ and 23.3℃ respectively;while late convention rice variety was 25.6 ℃ and 22.3 ℃ respectively,hybrid variety was 25.8 ℃ and 22.6 ℃ respectively.Indexes of accumulated temperature during the whole growth period were as follows:The early-maturing variety,the middle-maturing variety and the late-maturing variety of early rice was 2 512.1 ℃,2 528.4 ℃ and 2 651.3 ℃ respectively,while the early-maturing variety,the middle-maturing variety and the late-maturing variety of late rice was 3 126.2 ℃,3 031.5 ℃ and 3 335.2 ℃ respectively.The above indexes all met the requirements of identification,which could provide reference for formulating the meteorological standard of rice in the south of China.     

A Friendly Bridge between Hunan and the World——Opening Speech for the Official Publication of HASTN

At the time when the new millennium comes, I am very delighted at the news that Hunan Agricultural Science & Technology Newsletter(HASTN) in English edition officially starts publicatiou. We think it will certainly establish another more friendly bridge between our Hunan Province and foreign countries in scientific and economic exchange and cooperation during the mportant days when our People's Republic of China is ready to enter the WTO.     

Towards sustainable intensification of apple production in China—Yield gaps and nutrient use effi ciency in apple farming systems

China is in a dominant position in apple production globally with both the largest apple growing area and the largest export of fresh apple fruits.However,the annual productivity of China’s apple is significantly lower than that of other dominant apple producing countries.In addition,apple production is based on excessive application of chemical fertilizers and the nutrient use efficiency(especially nitrogen)is therefore low and the nutrient emissions to the environment are high.Apple production in China is considerably contributes to farmers’incomes and is important as export product.There is an urgent need to enhance apple productivity and improve nutrient use efficiencies in intensive apple production systems in the country.These can be attained by improved understanding of production potential,yield gaps,nutrient use and best management in apple orchards.To the end,priorities in research on apple production systems and required political support are described which may lead to more sustainable and environmental-friendly intensification of apple production in China.