Distribution characteristics, potential contribution, and management strategy of crop straw and livestock-poultry manure in multi-ethnic regions of China: A critical evaluation

This work examined the production of crop straw and livestock-poultry manure (CSLM), both important resources for biogas and soil management, in five multi-ethnic regions of China (i.e., Yunnan, Tibet, Liangshan, Garze, and Aba) from 2007 to 2016, all of which mainly inhabited by Tibetan, Qiang, and Yi people. The CSLM production was evaluated with breakdown from multiple dimensions, based on geography, species source, nutrient composition, etc. The total production of crop straw of the studied regions increased from 18.44 Mt in 2007 to 21.90 Mt in 2016, and that of manure increased from 223.56 Mt to 309.02 Mt. Further analysis aimed to evaluate to what extent the nutrients from CSLM can substitute or supplement chemical fertilizers. In this regard, the content of nutrients in CSLM was quantified in the form of N, P2O5 and K2O, and then compared with the present application of chemical fertilizers in the studied regions. The results suggested that the reuse of waste from agriculture and animal husbandry by returning them to the fields would effectively reduce the use of chemical fertilizers and help combat poverty in the remote and ethnic minority areas, and should be advocated to realize sustainable agricultural development. Introducing practical policies on renewable resources is necessary to financially incentivize farmers, ensure the comprehensive utilization of CSLM, and reduce environmental pollution from CSLM, particularly in the relatively underdeveloped multi-ethnic regions.