Spatial And Temporal Distribution Of Crop Residue Resource In The East, Central-South, And Southwest Regions Of China

Crop residue resource has been recognized as an important potential lignocellulosic biomass feedstock. The exploitation and utilization of residue resources involves efficient material transformation and energy circulation in the agricultural production system which has become an important way for realizing circulatory economy, and it also relates to the systainable development problems of soil fertility, soil and water conservation, environment security, and highly-effective utilization of renewable resources in the agro-ecosystem. It has turned an inevitable demand for the sustainable development of agriculture and rural society and economy. This study was performed to evaluate the spatial and temporal variation in residue quantities of field crops in seven provinces of East China (EC), six provinces of Central-South China (CSC), and five provinces of Southwest China (SWC). The availability of crop residue was derived from statistical data on the provincial level. The key factors affecting biofuel feedstock availability were:storage capacity, irrigation acreage and fertilizer input. Main research conclusion is as follows:1. Residue factor (RF) is an important parameter which can exactly estimate field residue resource. According to different kinds of field crops in China Statistical Yearbook in this research, residue factor was determined in31provinces (excluding Hong Kong, Macao, and Taiwan) through mathematical modeling valuing method, same or similar region valuing method, and congener crop synthetically valuing method. Results indicated that the RF of rice varied between0.74and1.33, the average of rice was1.04. RF of wheat varied between1.05and1.41, the average was1.28. Maize had RF with the range of0.93and1.30and the average with1.07.2. Process residue (PR) is a constituent of crop residue resources. The annual quantity of field crops PR produced is evaluated based on provinces of China in this article, after the PR conception and PR factor and calculation are clarified. Among different provinces, Rice husk factor varied between0.16and0.20and averaged0.18. Corn cob factor varied between0.12and0.22and averaged0.16. Peanut hull ranged between0.25and0.30and averaged0.27. The factors of cotton seed hull, sugarcane bagasse and sugarbeet bagasse are0.47,0.16and0.05respectively.3. The average quantity of total crop residue in EC was199.5Mt annually comprised of180.9Mt field residues and18.6Mt process residues. The richest amount of crop residue was rice residue estimated as83.9Mt, which was composed of72.1Mt field residues and11.8Mt rice hull. The harvested date was from June to December among the seven provinces in EC.The average amount of total biomass residue in CSC of213.9Mt annually comprised of179.7Mt field residues and34.2Mt process residues. In CSC, the richest amount of crop residue was rice residue estimated as82.5Mt, which was composed of69.5Mt field residues and13.0Mt rice hull. In July to September, the amount of field residue (58.9Mt) was harvested. In SWC, the average amount of total residue of93.3Mt annually comprised of80.3Mt field residues (86.0%) and13.0Mt process residues (14.0%). The amount of field residue was harvested all the year excluding November.4. The temporal distribution of crop residues depends on the crops maturity or harvest dates, which affects greatly on sustainable residue utilization. After maturity dates of crop residues (MDCR) was defined in this article, we identified maturity dates of field crops in different regions of China according to data collected from original papers published mainly between2006and2011. The MDCR early stage of wheat and maize was from May to June. The period from July to November was the predominated MDCR for rice, wheat and maize.