秸秆资源收获季节性及其能源供应持续性分析

供应的持续性是能源资源评价的一个重要方面,农作物秸秆收获的季节性制约了其供应的持续性。本研究利用季节指数指标分析秸秆收获季节性,构建持续性系数指标评价供应持续性,并对持续性的影响因素进行深入分析。结果表明：①各地区秸秆收获季节性明显,全国22个省份全年一半以上的秸秆集中于9月、10月份,且地区间季节分布差异显著;②所有地区秸秆不能保证全年持续供应,且地区间供应持续性差异较大,安徽、湖南等南方粮食主产省份持续性较好,可以保证6～8个月充分供应,其余省份除少数月份供应充足外,剩下月份都存在一定程度的供应缺口;③供应持续性与秸秆总量正相关,与季节指数和电力消费量负相关,而地理位置、气候条件、农作制度和经济结构等非可控因素是决定供应持续性的深层次因素;④丰富的总量并不一定带来较好的持续性,因而不能仅靠总量标准评价秸秆资源质量

Analysis of Seasonal Variation in Crop Residue Harvest and Sustainability of Its Energy Supply

Sustainability of energy supply is particularly important for energy resources assessment. Crop residue is important raw material for bioenergy, while the seasonal variance nature of residue harvest may restrain its sustainable supply. In this paper, the authors examined seasonal variations in residue harvest and sustainability of its energy supply in 31 provinces of China by using the seasonal index and building the sustainability coefficient, respectively, based on main crop production data from 2005 to 2009. Subsequently, influencing factors affecting the persistence degree of supply were discussed. Results show that obvious seasonal variation occurred in straw harvest in 31 provinces. Over two thirds of provinces had more than half of their total residue resources distributed in September and October. However, monthly distribution of the residue varied significantly among provinces. All of the provinces could not guarantee continuous residue supply throughout the year in the absence of straw storage. The sustainability of supply varied greatly among provinces. Hunan, Anhui, and other major grain producing provinces located in the lower and middle reaches of the Yantze River had the highest continuity degree of supply with abundant residue which could fulfill the residue demand for 6 to 8 months, whereas other provinces just had enough supply in a few months and suffered from supply shortage to varying degrees during the rest months. The sustainability of supply was positively correlated with total residue production and negatively with the seasonal index and energy consumption, suggesting that abundant residue resources with uneven monthly distribution or huge straw demand measured by electricity consumption might lead to a low continuity degree. Geographic location, climatic condition, cropping system, industrial structure, and agricultural structure were the major causes of supply continuity degree. Diverse and abundant crop residue due to fertile soil across plain areas, temperate climate with plenty of rainfall and sunshine were the primary reasons why southern major grain producing provinces had a higher supply continuity degree than other provinces. Decreases in farmlands and the horticultural crop-oriented agricultural structure due to the advanced secondary industry and tertiary industry might explain why economically developed provinces had the lowest supply continuity. High-cool and rich-wind arid climate in the Qinghai-Tibet Plateau was the chief cause of bad supply persistence degree in Tibet and Qinghai. Henan, Shandong, and Heilongjiang were the largest crop residue producers, while their supply persistence degrees were not the highest ones.