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In mountainous and hilly areas, cultivated land resources are scarce, and the phenomenon of cultivated land fragmentation is serious. The long and narrow arable land plots are complex in structure, which makes it difficult to obtain the information of cultivated land at the land level quickly and accurately, and hinders the application of precise digital agricultural services based on high resolution remote sensing images in mountainous and hilly areas. Parcle-level cultivated land information can intuitively show the spatial distribution, boundary details of farmland, and is of great significance for precision agriculture management, distribution of planting subsidies, and agricultural resource survey. Existing edge detection/semantic segmentation networks-based farmland extraction methods ignore the structural features of the parcel, thus have limit performance for handling narrow and small plots, and there is also a blurring boundary problem. To address these issues, we proposed an accurate extraction method of cropland in mountainous area based on geographic parcels. This method combines the advantages of semantic segmentation and edge detection, and effectively extracts and integrates the linear features of the boundary and the internal texture features of the parcel, so as to improve the recognition accuracy of the cultivated land. The main features of the model in this paper are as follows: 1) The edge of cultivated land is regarded as a new class independent of cultivated land parcels, so that the semantic segmentation network can better distinguish the edge and internal area of cultivated land parcels; 2) A cascaded semantic segmentation and edge detection network is introduced to correlate the prediction of cultivated land surface and line, realize the fusion of boundary and texture features of cultivated land parcels and strengthen the edge features of cultivated land, so as to improving the accuracy of cultivated land block edge detection; 3) A focus training technique is proposed to address the problem that the edge pixels of cultivated land are far fewer than non-edge pixels, by enforcing the model pay more attention to the important but underrepresented edge pixels in high resolution remote sensing images in the training process, so as to improve the edge detection accuracy. We conduct experiments in Shaodong County, Hunan Province in the southwest mountainous area, using the Google Earth high-resolution remote sensing images as the data source, with a spatial resolution of 0.53 m. After manual selection, a total of 1000 512×512 image patches are obtained. Among them, 600 pieces are used as the training set, 200 pieces are used as the verification set, and 200 pieces are used as the test set. Experimental results show that the presented model achieves satisfying results with an overall accuracy of 92.91% and IoU (Intersection-Over-Union) of 82.84% on the test set, which was 4.28% and 8.01% higher than the baseline method respectively. Compared with the existing methods, the cultivated land extracted in this study is more consistent with the actual distribution pattern of cultivated land, which provides a practical method for accurate extraction of cultivated land information at the plot scale in mountainous and hilly regions. [ABSTRACT FROM AUTHOR]

Crop straw is a valuable biomass energy resource and raw material for livestock forage, organic fertilizer and industrial use. However, the comprehensive utilization level of straw resources in China is not high due to various reasons including agricultural intensification, capital shortage and farmers’ cognition. Regional, seasonal and structural surplus of crop straw is common in China and a lot of straw is discarded and burned casually, especially in rural areas. It is not only a huge waste of resources, but also leads to serious atmosphere and soil environment pollutions. Thus, it is of great importance to improve the straw utilization rate. That take regional planning as a whole and realize full utilization of the regional total straw resources is a good strategy. Assessment of regional straw resources’ quantity, type, and distribution pattern is the prerequisite to achieve regional straw resources full utilization. In addition, the utilization modes and levels of straw resources are also restricted by many other factors including the social and economic development status. Thus, to make better use of straw resources and optimize utilization structure, it is necessary to take all the above factors into comprehensive consideration, carrying out scientific layout and rational planning. Hunan province is an important agricultural province and also a main producing area of double cropping rice in China. The present study estimated the straw quantity and amount per capita of the main crops in Hunan province. The spatial distribution patterns of straw resources in Hunan province were also analyzed. In addition, the paper also analyzed the potential of full utilization of the total straw resources in the province through comparing the current straw utilization structure and quantities with their corresponding competitive straw demands. The results showed that the theoretical and collectable amount of the main crop straw resources in Hunan province in 2018 were 4 021.7× 104 t and 3 039.1×104 t, respectively. The mean amount per capita of straw resource is only 0.68 t, which is much lower than the national average level. The straw of rice, rape, maize and vegetables accounted for 64.7%, 16.0%, 6.1% and 7.5% of the total straw resources of the Province, respectively. The various types of crop straws exhibited different spatial distribution patterns. The amount of rice, rape and vegetable straw increased from west to east and south to north in the province, whereas corn straw displayed an opposite distribution trend. Through estimating the potential utilization ways of straw resources, the competitive demand of straw in Hunan province included 887.3×104 t for fertilizer, 885.1×104 t for fodder, 65.7×104 t for raw material and 83.2×104 t for stroma material. The remaining amount of straw for potential energy utilization was 1 117.9×104 t. Considering the current straw utilization structure and the results as above, the overall trend of realizing full utilization in the province should be to improve the ratio of fodder and energy utilization and slightly reduce fertilizer utilization on the basis of maintaining the amount for stroma and raw material utilization. [ABSTRACT FROM AUTHOR]

Anhua, located in Hunan province, is a state poverty county, whose types of terrain are divided into high mountainous, reservoir and low-mountain hilly area. Considering different terrain areas and poor rural households, analyzing the poverty characteristics and influencing factors under the regional type is conducive to take targeted poverty alleviation measures. Based on the data sources of 578 questionnaires of poor rural households and combined with the actual situation of three types of terrain area, this paper analyzes poverty characteristics, influencing factors and interaction of two-factor under different terrain area using spatial autocorrelation and geo-detector in Anhua county. The results show that: 1) The poverty degrees of different terrain area are different. Specifically, the order of the absolute value of mean poverty level is that the is reservoir area (0.214), high mountain area (0.187) and low-mountain hilly area (0.115). The per capita net income of the reservoir area is low, and the source of economic income is only relying on the reservoir aquaculture industry. The per capita net income of high mountainous area is low, and the source of economic income is mostly self-sufficient planting and poultry farming. The per capita net income is higher, the source of economic income is diversified, such as going out to work and developing family planting. 2) Poverty influencing factors in different terrain types are different: the reservoir area is mainly affected by infrastructure construction, policy implementation degree and terrain slope. Among the main influencing element, the impact values of factors are policy, nature, economy, human capital; the high mountainous area is mainly affected by the terrain slope, labor population and family business income factors, the influence value of natural factors is the highest, followed by human capital, economic factors, and policy factors; the low-mountain hilly area is mainly affected by the labor population, policy implementation and wage income factor, the human capital has the highest influence value, followed by policy, economic, natural element. 3) The intensity of the interaction between the influence factors of different terrain area are that the interaction intensity of economic element and natural element is higher than the interaction intensity between policy element and other element. The high mountainous and reservoir area are mainly family-run incomes for planting and breeding. The low-mountain hilly area is mainly based on wages income, non-agricultural employment has been selected as their main livelihood strategy choice, giving play to the external role of policy elements, taking into account the economic factor forms of each district. 4) The significant impact factors of poverty degree in different terrain area are different. The reservoir area is significantly affected by policy element, the high mountainous area is significantly affected by natural element, the low-mountain hilly area is mainly affected by human capital. To implement differentiated policies for different terrain areas, so as to ensure the precise implementation of policies in poverty alleviation. Different terrain area should combine regional internal and external, policy element and economic element, financial capital and human capital in the work of poverty alleviation and work to achieve stable poverty alleviation. [ABSTRACT FROM AUTHOR]

The pig-biogas project-fruit circular economy development model is characterized by the “waste farming-biogas project-fruit tree fertilization” waste recycling route, which is to solve the current non-point source pollution of pig farms in the agricultural field and provide an effective means of application for the energy and fertilizer industries. In this waste recycling, the integrated analysis of material flow and value flow is the main method to measure its engineering technology and economic benefits. At present, compared with the relatively mature material flow analysis methods, the value flow method reflecting economic input and output is relatively rare in the agricultural field. Based on this, this paper proposed a pig-biogas project-fruit” circular economy value stream analysis model, revealed its material flow balance mechanism, and constructed “material flow (technology)-value flow (economic)-environmental damage cost assessment (environment)” . Through the two-dimensional mechanism analysis of the material flow-value flow of its resource recycling, the material flow balance map was determined around the goal of “recycling waste”, and the different production centers with gradual carry-over relationship in the circulation were divided to collect the input cost, calculate the effective use of resources, waste loss costs, and make an objective assessment of the external environmental damage costs (governance opportunity costs) of waste. The integrated calculation and evaluation method system was applied to the verification and demonstration of a large-scale farm in Hongshilin Town, Guzhang County, Western Hunan. The application results showed that: 1 755 pigs were slaughtered in the pig farm, and the biogas project was built, and the grassland was 4.67 hm² and the organic orchard was 4 hm². Through the observation and analysis of the production material process, four interrelated material circulation cost calculation and evaluation centers for pig production, pig fattening, biogas engineering and organic orchard were established, and according to production input, intermediate conversion, recycling, and product output. In the five major parts of landfill treatment, the panoramic view of value circulation was calculated, and the distribution of the whole material flow and value flow at a glance was investigated. According to the calculation data and the changes of pig farm waste discharge before and after the development of circular economy, the costs of pig farm labor, depreciation, energy, etc (internal resource cost loss), and the recovery and control of pig farm waste discharge environment were compared and analyzed. The opportunity cost (cost of external environmental damage) was reduced, and the production efficiency (product increase efficiency) of prolific pigs, energy and fruits was obtained, and the evaluation results were obtained. In this case, the result of the analysis was that the internal resources were reduced by about 1 400 yuan, the external environmental damage was reduced by about 19 300 yuan, and the product added benefit was about 36 600 yuan. The research results could provide decision-making basis for enterprises to improve resource recycling efficiency and government implementation of agricultural policy subsidies. [ABSTRACT FROM AUTHOR]

The pig-biogas project-fruit circular economy development model is characterized by the “waste farming-biogas project-fruit tree fertilization” waste recycling route, which is to solve the current non-point source pollution of pig farms in the agricultural field and provide an effective means of application for the energy and fertilizer industries. In this waste recycling, the integrated analysis of material flow and value flow is the main method to measure its engineering technology and economic benefits. At present, compared with the relatively mature material flow analysis methods, the value flow method reflecting economic input and output is relatively rare in the agricultural field. Based on this, this paper proposed a pig-biogas project-fruit” circular economy value stream analysis model, revealed its material flow balance mechanism, and constructed “material flow (technology)-value flow (economic)-environmental damage cost assessment (environment)” . Through the two-dimensional mechanism analysis of the material flow-value flow of its resource recycling, the material flow balance map was determined around the goal of “recycling waste”, and the different production centers with gradual carry-over relationship in the circulation were divided to collect the input cost, calculate the effective use of resources, waste loss costs, and make an objective assessment of the external environmental damage costs (governance opportunity costs) of waste. The integrated calculation and evaluation method system was applied to the verification and demonstration of a large-scale farm in Hongshilin Town, Guzhang County, Western Hunan. The application results showed that: 1 755 pigs were slaughtered in the pig farm, and the biogas project was built, and the grassland was 4.67 hm2 and the organic orchard was 4 hm2. Through the observation and analysis of the production material process, four interrelated material circulation cost calculation and evaluation centers for pig production, pig fattening, biogas engineering and organic orchard were established, and according to production input, intermediate conversion, recycling, and product output. In the five major parts of landfill treatment, the panoramic view of value circulation was calculated, and the distribution of the whole material flow and value flow at a glance was investigated. According to the calculation data and the changes of pig farm waste discharge before and after the development of circular economy, the costs of pig farm labor, depreciation, energy, etc (internal resource cost loss), and the recovery and control of pig farm waste discharge environment were compared and analyzed. The opportunity cost (cost of external environmental damage) was reduced, and the production efficiency (product increase efficiency) of prolific pigs, energy and fruits was obtained, and the evaluation results were obtained. In this case, the result of the analysis was that the internal resources were reduced by about 0.14 million yuan, the external environmental damage was reduced by about 19 300 yuan, and the product added benefit was about 36 600 yuan. The research results could provide decision-making basis for enterprises to improve resource recycling efficiency and government implementation of agricultural policy subsidies. [ABSTRACT FROM AUTHOR]

Warming climate has been a global concern. Methane is an important greenhouse gas. Double rice cropping system in Hunan province contributes a large proportion of the national rice production. In this study, we studied the effect of agricultural managements of rice on methane emissions from double cropping paddy fields in Hunan Province, China based on Meta-analysis method. Only studies designed as side-by-side paired field experiments were included in this study. Field management practices, treatments, and controls were described in detail in each study, and the location of the experiment was provided. If seasonal accumulative CH4 emission fluxes were not directly provided, these values were calculated by multiplying time and mean CH4 emissions by the measurement period. A total of 53 published peer-reviewed papers published before 2018were obtained by reference retrieval. From them, 840 groups of data were drawn. The management measures included crop rotation, symbiosis ecosystem, tillage, nitrogen fertilizer input, organic manure and residue retention. The control and treatment groups were fallow versus winter crops, paddy-rice system versus rice-duck and rice-fish systems, conventional versus no tillage, no fertilizer-N input versus fertilizer-N input, no manure input versus fertilizer-N and manure input, and fertilizer-N input versus residue retention. Natural log of response ratio was used as the effect size in the random effect meta-analysis. Results showed that CH4 emissions from both early and late rice accounted for 97.9% of annual CH4 emissions, and more CH4 emissions from late rice was observed than that for early rice. In the double rice cropping system, adding winter crops could significantly increase CH4 emissions from double rice season by 43.88% (P < 0.05) compared to winter fallow. Moreover, the increase in methane emissions from early rice was significantly higher than that from late rice. Symbiosis ecosystem of rice (i.e., with ducks or fishes) and adopting no-till significantly decreased CH4 emissions by 37.02% and 26.84% (P < 0.05), respectively. The decrease in the emission from early rice field was much higher than that from late rice field. As for yield-scaled emission, application of N fertilizer decreased yield-scaled CH4 emissions by 40.01% (P < 0.05) mainly due to the yields increased by 73.87% (P < 0.05). Additionally, organic fertilizer application and residue retention increased 68.11% and 71.80% (P < 0.05) of yield-scaled CH4 emissions without impacting the rice yield. The results suggested adopting symbiosis ecosystem rice production or no-till along with optimized N input is conducive to balancing rice yield and CH4 emissions from fields with double rice cropping system in Hunan province. [ABSTRACT FROM AUTHOR]