油菜秸秆腐解进程及碳氮释放规律研究

为推进农村作物秸秆的资源化利用，减少秸秆焚烧对环境的影响，培养与提高土壤肥力，采用尼龙网袋法设置了油菜秸秆归还到水稻田的田间试验，研究了油菜秸秆的腐解进程及碳氮元素释放情况。结果表明，油菜秸秆的腐解率、碳、氮释放率均随时间延长而逐渐增大，秸秆的碳氮比总体呈现波动下降趋势；秸秆还田量与腐解率呈反相关关系，表现为全量还田〈2／3量还田〈1／2量还田〈1／3量还田；油菜秸秆还田深度在10cm时腐解最慢，在表层腐解最快，20cm深时腐解速度居中。该研究对调控还田秸秆腐解速度，利用秸秆释放养分培肥地力具有重要的意义。

Study on Decomposition Course and Release Characteristics of C and N in Rapeseed Straw

Promoting decomposition of agricultural straw and resources utilization of rural crop straw can reduce the negative impact of straw burning on the environment and improve soil fertility. Different treatments of straw returned to field were conducted by using the method of nylon net bag in field trials. The decomposition course and release characteristics of C and N in rapeseed straw returned to soil were studied. The results showed that the ratio of straw decomposition and C or N release all increased with time, while C/N ratio decreased volatility. Straw decomposition ratio was negatively interrelated with the amounts of rapeseed straw-returning. The decomposition rate of rapeseed straw returned to field on the soil surface was faster than that returned to field 20cm below the soil surface, which is also faster than that 10cm below the soil surface. The study provided the basis parameters for controlling straw decomposition rate, which promoted nutrient release in straw to improved soil fertility.