Study on the ecological potential of Chinese straw resources available for bioenergy producing based on soil protection functions

Straw return has positive effect on improving soil ecological environment, and now there are serious ecological problems of arable land in China. Therefore, the concept of basic straw returning amount (BSRA) was put forward based on soil protection functions, and literature review and scenario analysis method were adapted to design BSRA. Based on this, a bottom up dynamic accounting model was built, which considering the changes of sown area, unit crop yield, planting structure and crop straw utilization. Then, the model was applied to assess the potentials of straw resources for bioenergy production. Usable straw resources in low, middle and high BSRA scenario (Table 1) are 265.70, 180.25 and 117.51 Tg respectively in 2030, mainly composed of paddy rice (Oryza sativa L.) stalk, maize (Zea mays L.) stalk and potato (Solanum tuberosum L.) stalk in low and middle scenario, and maize stalk, potato stalk and sugarcane (Saccharum officinarum) stalk in high scenario. Available crop residues mainly distribute in Sichuan, Henan, Heilongjiang and Shandong Province under the three scenarios. There will be interzone spatial transfer of usable straw resources, over time, mainly transferring to Northeast China, North China and Northwest China. The usable straw amount will have shape decrease in August and September as the increase of BSRA.