Study on straw multi-use potential in China

Abstract: Straw is both a by-product of agriculture and a valuable resource for biomass. Turning straw wastes into resource will increase industrial efficiency, promote the cycle of planting and breeding, and meet the needs of people's livelihood such as clean heating in villages and towns. In China, the zoning layout of straw utilization is still not perfect, resulting in structural excess of straw in different regions and in certain season. The problems of straw resource waste and environmental pollution are outstanding. Based on the theory of comprehensive utilization of straw, we proposed a comprehensive utilization path of straw, which was "agricultural priority, agricultural production, rural energy utilization, and diversified utilization of fertilizers, feed, fuel, base materials and raw materials". The goal was "market user demand orientation, continuous supply of raw materials, comprehensive utilization for agriculture and industry, and significant improvement in comprehensive benefits". The comprehensive utilization potential of straw in China was 876 million tons, an increase was 156 million tons from 2015, Fertilizer utilization potential of straw was 476 million tons; Feed utilization potential of straw was 220 million tons; Energy utilization potential of straw was 120 million tons; Base material and raw material utilization potential of straw was 60 million. Among them, fertilizer, feed and energy utilization increased by 87.224 million tons, 51.232 million tons and 17.20 million tons from 2015. The straw resources in the six regions of Northeast China, North China, East China, South China, Northwest China and Southwest China could be fully utilized. The demand for forage in Central China was still unsatisfactory. Through fertilizer and feed utilization, the directly and indirectly substitution potential of chemical fertilizers was: nitrogen fertilizer (N) 14.816 million tons, phosphate fertilizer (P2O5) 4.19 million tons, potash fertilizer (K2O) 18.851 million tons, saving cost of fertilizers about 6 859 million yuan, equivalent to saving costs for unit straw replacement of fertilizer by 98.5 yuan per ton of straw. Through energy utilization, it could replace 59.824 million tons of fossil energy such as coal, reduce 150 million tons of carbon dioxide emissions, 4.487 million tons of sulfur dioxide, 2.243 million tons of nitrogen oxides, and 40.68 million tons of soot. The economic benefits of carbon emissions trading could reach 2 025 million yuan, equivalent to the increase in straw carbon emissions by16.9 yuan per unit ton of straw. Therefore, environmental and economic benefits were significant. The results of the study provide a reference for improving the comprehensive utilization level of straw, and the government decision-making and industrial development.