不同界面玉米秸秆腐解特征及其碳释放量动态变化

Decomposition Characteristics of Maize Straw at Different Interfaces and Dynamic Changes of Carbon Release

[目的]探究不同界面玉米秸秆腐解规律。[方法]从秸秆腐解的3个界面-避光厌氧的近土层(SC)、避光厌氧的中层(ZC)、见光好氧的上层(XC)的腐解特征进行对比探讨。[结果]随腐解时间的增加玉米秸秆的质量残留量呈先快速降低后缓慢降低的变化趋势。其中前期2个月为快速腐解期,第3个月为缓慢腐解期,而在第3个月以后则进入了稳定腐解期。根据玉米秸秆腐解过程中的质量残留量计算腐解率,XC的玉米秸秆腐解率明显优于SC和ZC,不同界面玉米秸秆中碳的释放量呈先快速增加后逐渐减缓最后趋于稳定的趋势。在玉米秸秆腐解的各个时间节点,XC中碳的释放量显著高于其他界面。此外,一级动力学方程表明XC中的玉米秸秆有较高的碳矿化能力。[结论]玉米秸秆在避光厌氧的近土层的腐解效果优于避光厌氧的中层以及见光好氧的上层,更有利于玉米秸秆中碳的释放,向土壤归还碳元素。

[Objective]The research aimed to explore the decomposition rule of maize straw at different interfaces.[Method]The decomposing characteristics of the three interfaces of straw degradation:dark anaerobic nearly soil(SC),middle(ZC)dark anaerobic,see the light of the aerobic decomposing and characteristics of the upper(XC)exposed to light aerobic are compared and discussed.[Result]With the increase of the decay time for the quality of maize straw residue have been rapidly reduced down slowly.The first 2 months were rapid decay,the third month was slow decay,and the third month was stable decay.According to the calculation of decomposition rate based on the mass residue in the decomposition process of maize straw,the decomposition rate of XC maize straw was significantly better than that of SC and ZC.The carbon emission of maize straw at different interfaces increased rapidly at first,then slowed down gradually,and finally became stable.At each time point of maize stalk decomposition,carbon release in XC was significantly higher than that at other interfaces.In addition,the first-order kinetic equation indicated that corn straw in XC had higher carbon mineralization capacity.[Conclusion]The decomposition effect of corn straw in the near soil layer that avoids light and anaerobic is better than that in the middle layer that avoids light and anaerobic and that in the upper layer that sees light and aerobic,which is more conducive to the release of carbon in corn straw and the return of carbon elements to the soil.