小麦秸秆中纤维素与木质素腐解进程的差异

Difference of decay process of cellulose and lignin in wheat straw

通过小麦秸秆添加于土壤的淹水培养试验,测定施氮与不施氮处理下麦秸及其纤维素、木质素含量在培养过程中的变化,并比较两者的腐解进程。结果表明:淹水培养60d时,麦秸纤维素与木质素的累积腐解率分别为61.8%和57.2%;纤维素与木质素的淹水腐解进程均表现为培养前期较快后期较慢,而木质素在培养初期腐解速率高于纤维素,培养中后期木质素的腐解速率很低,而纤维素仍能维持较快的腐解;纤维素完成腐解进度25%、50%及75%所需时间均比木质素长,说明纤维素在淹水土壤中的腐解活跃期比木质素更长;施氮缩短了纤维素的腐解活跃期,但对木质素的影响程度不大;与木质素相比,纤维素腐解进程与秸秆总体腐解进程更为接近。

Wheat straw was incubated under flooded soil condition,and cellulose and ligin in residual straw were extracted and measured at different stages during incubation period.Then dynamic decay processes of cellulose and lignin and response of their decay processes to nitrogen addition were compared and analyzed.Results showed that the cumulative decay rates at 60 dof incubation were 61.8% for cellulose and 57.2% for lignin.Both cellulose and lignin decomposed quickly during early stages of incubation and slowly at late stages.However,compared with cellulose,decay speed of lignin was higher but declined more sharply with the incubation time,which led to a much lower decay speed for lignin at late stages.Days required for cellulose to complete 25%,50%and 75% of whole decay process were longer than those of lignin,which indicated that cellulose can maintain active decay for longer time than lignin.Nitrogen addition delayed active decay of cellulose but had no apparent effect on that of lignin.Compared with lignin,the decay process of cellulose was closer to the overall process of straw.