生物炭对混施沼肥秸秆还田腐解特性的影响

为提高秸秆与沼肥同步翻埋还田的腐解效果,在室温条件下,秸秆中混施沼肥,采用网袋法模拟翻埋还田,在105 d的试验周期内,探讨在土壤中配施生物炭对秸秆与沼肥同步翻埋还田腐解的影响规律。结果表明,在土壤中配施生物炭能显著提高秸秆各指标的降解速度,且不同土壤之间玉米秸秆的降解率表现为砂土组大于壤土组,添加生物炭组大于未添加生物炭组,试验结束时,壤土组、壤土+生物炭组、砂土组、砂土+生物炭组的降解率分别为69.96%、74.63%、78.19%和79.14%;腐解前49 d为秸秆各组分的快速腐解期,后期腐解速率逐渐变慢;秸秆的降解率与纤维素降解率具有显著的相关性,添加生物炭对木质素的降解具有显著的促进作用,且木质素的降解与有机碳的降解呈正相关性。

Effect of Biochar on Decomposition Characteristics of Corn Stover Presoaked with Digestate in Soil

A great number of crop straws are produced each year in China. Among all the comprehensive utilizations of crop straw, the method of returning straw to soil has been paied attention and accepted as a recycle technology featuring with increasing the porosity of soil, improving the aggregate structure of soil and increasing the production of crops. The most important indicator to evaluate the effect of straw returning is the decomposition condition of straw. Biochar and digestate were combined as accelerants to expedite the decay of corn stover. The corn stover presoaked with digestate was buried into the soil added with biochar by mesh bag method at room temperature. The experimental process lasted 105d. The decomposition ratio of corn stover and the characteristics of cellulose, hemicellulose, lignin, organic carbon and total cumulative nitrogen were investigated systematically to achieve the effect of biochar on the decomposition characteristics of corn stover presoaked with digestate in soil. The results indicated that the biochar increased the decomposition rate of corn stover significantly. The decomposition condition of corn stover in sandy loam was better than that in loamy soil. The decomposition ratios of comparison samples were 69.96% for the corn stover in loamy soil, 74.63% for the corn stover in loamy soil added with biochar, 78.19% for the corn stover in sandy loam and 79.14% for the corn stover in sandy loam added with biochar, respectively. Furthermore, the decomposition ratio of corn stover was increased as the increase of time. The decomposition rate was fast before 49d and decreased gradually after 49d. The decomposition ratios of cellulose, hemicellulose and total cumulative nitrogen were different significantly (P<0.05). In addition, the decomposition ratio of corn stover was significantly correlated with the decomposition ratio of cellulose (P<0.05). The research result can lay a theoretical foundation for the technology development of returning straw to soil and the comprehensive utilization of biochar.