低碳背景下四位一体循环农业模式研究——以新疆南疆棉花秸秆资源循环利用为例

Under the Background of Low Carbon Four in One Cycle of Agricultural Model Research——Take the Recycling of Cotton Straw Resources in Southern Xinjiang as an Example

农业废弃物作为可"变废为宝"的资源,其循环利用成效对于农民增产增收、改善农村环境、推进"两型农业"快速发展及生态文明建设进程具有重要意义。文章通过构建农业废弃物的碳排放量核算指标体系,在科学估算2007～2016年南疆棉区棉花秸秆资源不同利用方式碳排放量的基础上,结合棉区实际,设计出在低碳背景下实现以棉花秸秆发酵沼气为核心的"四位一体"循环模式,即"秸秆—沼气—有机肥还田—低碳农业"。结果表明:(1)新疆南疆棉区棉花秸秆资源的利用潜力巨大,2016年可收集棉花秸秆资源量为898. 646万t,年均可收集量达670万t。(2)2007～2016年南疆棉区棉秆不同处理方式的年平均碳排放总量为266. 664万t,年平均碳排放强度为3. 12 t/hm^2,不同利用方式碳排放量由大到小排序依次为:秸秆薪柴燃料>秸秆焚烧>秸秆肥料化>秸秆饲料化>秸秆发酵沼气。(3)以棉花秸秆发酵沼气为中心"四位一体"循环模式的基本实现路径为"棉花秸秆—沼气池—沼气发电—提供农户生产生活用能"、"棉花秸秆—沼气池—沼渣、沼液—肥料化—有机肥还田—果蔬种植"、"棉花秸秆—沼气池—沼渣、沼液—饲料化—畜禽粪便—有机肥还田—棉花、果蔬种植"。

As a resource that can "turn waste into treasure", agricultural waste recycling effect is of great significance for farmers to increase production and income, improve rural environment, promote the rapid development of "two-oriented agriculture" and the construction of ecological civilization. Based on the scientific estimation of carbon emissions of different utilization modes of cotton straw resources in Southern Xinjiang cotton region from 2007 to 2016 and the actual situation of cotton region, this paper designs a "four-in-one" cycle mode with the core of the biogas fermentation from cotton straw under the background of low carbon,namely "straw--biogas--organic fertilizer returning to the field--low-carbon agriculture". The results showed are:(1) the cotton straw resources in the Southern Xinjiang cotton region have great potential for utilization. In 2016, the amount of cotton straw resources that can be collected was 8. 986 646 million tons, with an average annual amount of 6. 7 million tons.(2) From 2007 to 2016, the annual average carbon emission of cotton straw under different treatment methods in Southern Xinjiang cotton region was 2. 666 64 million tons, and the annual average carbon emission intensity was 3. 12 t/hm^2. The carbon emission under different utilization methods was in descending order: straw firewood fuel > straw burning > straw fertilizer > straw forage > straw fermentation methane.(3) The basic realization path of the "four-in-one" circulation mode centered on the biogas fermentation from cotton straw is as follows:"cotton straw--biogas pond--biogas power generation--providing household production and living energy";"cotton straw--biogas pond--biogas residue, biogas slurry--fertilizer--returning organic fertilizer to the field--planting of fruits and vegetables";"cotton straw--biogas pond--returning organic fertilizer to the field--planting of cotton and fruits and vegetables".