Regional Suitability Evaluation And Development Strategy Research Of Rural Biogas Industry

China’s agricultural production has grown rapidly in recent years.As the scale of the planting and breeding sector has grown,and intense development has increased,the separation of planting and breeding,agriculture,and husbandry has become increasingly apparent.The surplus of agricultural waste in local areas directly pollutes the environment and indirectly contributes to using chemical fertilizers and pesticides in resource-scarce places.Developing circular agriculture,which combines planting and breeding,is a key step toward mitigating this issue.Developing circular agriculture can effectively reduce the environmental burden of agricultural production,protect the ecological environment,improve production efficiency,reduce production costs,increase farmers’income,and contribute to national food security and sustainable agricultural development capability.Using Shaanxi Province as an example,this study assessed the environmental carrying capacity of livestock and poultry manure-polluted soil in various cities throughout Shaanxi Province using the nitrogen and phosphorus nutrient balancing concept.Developing circular agriculture can effectively reduce the environmental burden of agricultural production,protect the ecological environment,improve production efficiency,reduce production costs,increase farmers’income,and contribute to national food security and sustainable agricultural development capability.Using Shaanxi Province as an example,this study assessed the environmental carrying capacity of livestock and poultry manure-polluted soil in various cities throughout Shaanxi Province using the nitrogen and phosphorus nutrient balancing concept:（1）According to an analysis of the existing carrying capacity of livestock and poultry manure land for"fruit,vegetable,and tea"in Shaanxi province,the overall fecal pollution supply in Shaanxi province is insufficient to meet the demand for the fruit and vegetable manure business.The land environmental carrying capacity index of Shangluo City,Ankang City,Hanzhong City,Baoji City,and Yulin City is larger than 1,and livestock and poultry agricultural theoretical carrying capacity have been exceeded.The amount of livestock and poultry breeding in Xi’an,Tongchuan,Xianyang,Weinan,and Yan’an cannot meet the local demand for manure,and the manure required by economic orchards and vegetable greenhouses must be deployed from nearby cities in order to achieve regional planting and breeding balance.（2）The total energy input of the monoculture mode is 8.32×10¹⁷ sej/yr,according to an examination of the energy composition and economic revenue and expenditure ratio of the typical monoculture and monoculture system in Shaanxi province.7.08×10¹⁷sej/yr was the energy input used to acquire resources,making up 85.1%of the total energy,with labor and fertilizer accounting for 41%and 31%of the total energy purchase.Labor costs the most economically in the planting phase,at 67.2%of the overall investment.2.70×10¹⁸sej/yr was the overall energy value input for breeding,of which 99.99%came from purchased resources,followed by investments in feed,machinery,and calf investments of44.1%,22.8%,and 22%.The agricultural model’s biggest economic expense is the procurement of calves,which represents 47.4%of the entire investment.（3）The economic and emergency benefits of several cycle models were examined based on the two situations.Compared to scenario 1,scenario 2 had higher emergency yield rates,renewability ratios,sustainability indices,emergency self-sufficiency rates,and emergency feedback rates.Both the energy investment rate and environmental burden rate are lower than in scenario 2.In comparison to scenario 2 with isolated units,scenario 1with integrated planting and cultivation has a larger capacity for waste use,a higher capacity for self-sufficiency,a lower environmental impact,better economic development,and a greater potential for vitality and development.The optimization direction of numerous inputs in several agricultural models is simultaneously suggested.（4）This study offers some recommendations for the establishment of a circular agriculture model in the Shaanxi Province and suggests an approach for its development that maximizes efficiency.