我国农作物秸秆综合利用现状及焚烧碳排放估算

目的]为加快推进秸秆资源化利用工作,有效缓解因秸秆焚烧带来的环境问题。方法]将全国划分为黄淮海区、西北区、东北区、东南区、西南区五大区域,对各类农作物秸秆进行了统计分析,研究了秸秆产生量、秸秆资源密度、秸秆利用结构、秸秆焚烧碳排放量。结果]全国秸秆理论资源量达到10.4亿t,可收集量达到9.0亿t,玉米、水稻和小麦3类农作物秸秆占总量的79.19%,黄淮海区秸秆产量最高,占总量的33.41%。秸秆已利用量为7.21亿t,综合利用率达到80.11%,其中肥料化、饲料化、基料化、燃料化、原料化利用量占已利用量的比例分别为53.93%、23.42%、4.98%、14.27%、3.40%,形成了农用为主的利用格局,但不同秸秆种类综合利用率和利用结构存在显著差异。全国秸秆资源密度和人均占有量分别为523.57kg/667m~2和1.75 t,东北区显著高于全国平均水平,西南区和东南区则显著低于全国平均水平。根据环保部卫星遥感监测的露天焚烧火点数比例估算,2015年我国秸秆露天焚烧量约为8 110万t,总碳排放量约为3 450万t,其中东北地区约占74.1%。结论]我国秸秆综合利用的重点和难点在东北地区,进一步推动区域秸秆实现全量利用,对于促进低碳农业发展,应对气候变化有着十分重要的意义。

COMPREHENSIVE UTILIZATION STATUS OF CROP STRAW AND ESTIMATION OF CARBON FROM BURNING IN CHINA

In order to promote the comprehensive utilization of crop straw in China, and alleviate the environmental problems effectivelly caused by straw burning, the statistical analysis of various crop straws in Huanghuaihai region, Northwest region, Northeast region, Southeast region and Southwest region were carried out to study the straw yield, straw resource density, straw utilization structure and carbon emission from straw burning. The results showed that the amount of straw resources reached 1.04 billion t, and the collected amount reached 0.9 billion t. Maize, rice and wheat straw yield accounted for the proportion of the total 79.19%, and the yield of straw in Huanghuaihai region was the highest, accounting for 33.41%. The utilization amount of straw was 0.721 billion t, and the comprehensive utilization ratio was 80.11%. The proportion of fertilizer, fodder, stroma, energy and fuel, feed stock was 53.93%, 23.42%, 4.98%, 14.27% and 3.40%, respectively. There was a significant difference in the comprehensive utilization ratio and utilization structure among different straw species. The density and per capita hold of straw resources were 523.57 kg/667m2 and 1.75 t respectively, and the Northeast region was significantly higher than the national average, but the southwest and southeast regions were significantly lower than the national average. According to the proportion of open burning in 2015, straw burning amount was 81.1 millin t in China, the total carbon emissions was about 34.5 millin t, and the northeastern region accounted for about 74.1%. The above results showed that the focus and difficulty of straw comprehensive utilization was in Northeast region. Promoting the full use of straw had a very important significance to the development of low-carbon agriculture and response for climate change.