连续多年秸秆还田对玉米耕层土壤理化性状及微生物量的影响

Effects of Continuous Returning Straw to Maize Tilth Soil on Chemical Character and Microbial Biomass

在甘肃农业大学平凉玉米育种站设计试验,以未进行秸秆还田、连续3年还田(2007-2010年)、连续6年还田(2005-2010年)及连续9年还田(2002-2010年)的玉米田为研究对象,通过测定其耕层土壤理化性状及主要土壤微生物数量的变化,探索连续秸秆还田处理对土壤养分及微生物环境改良效应。结果表明:连续秸秆还田结合土壤浅耕,能够降低耕层深层土壤容重,对土壤高pH值有一定改良降低作用,显著增加0-20cm耕层SOM、TN、TP、AN、AP及AK等含量,且表现H9>H6>H3>CK,但在20-40cm土层中除SOM较CK各处理间差异显著外,其他指标变化处理间差异水平未达显著(P<0.05),连续秸秆还田使0-40cm土层细菌、真菌、放线菌群体数量明显增加,还田9年耕层0-40cm土壤中细菌、真菌增幅最大,较对照的分别增加152%,159%,而放线菌增幅较低为15.1%;0-20cm土层根际土壤微生物量碳值(MBC)亦显著增加,说明连续秸秆还田有效增加土壤微生物C源供给。

The experiment was designed to study the effects of continuous returning straw to maize filed on 0-40 cm soil nutrient and microbe,0-20 cm soil microbial biomass in 3-year returning（2007-2010）,6-year returning（2005-2010）,9-year returning（2002-2010）,and non returning field at Pingliang maize breeding experimental station of Gansu agricultural university from 2002 to 2010.The tilth physical and chemical property and variation of main soil microorganism were tested to probe the effectiveness of continuous straw returning on soil nutrients and microorganism environment.The result indicated that continuous straw returning to the maize field coupling with soil shallow cultivation could reduce deep soil bulk density and pH,significantly increase SOM,TN,TP,AN,AP and AK content in 0-20 cm with the rank of H9H6H3CK;but in but 20-40 cm layer,no significant difference was observed except for SOM.Continuous straw returning also increased soil bacteria,fungi,actinomyces quantity in 0-40 cm,H9 had the highest bacteria and fungi increase（152% and 159%,respectively）,actinomyces increased 15.1%.MBC in 0-20 cm also increased significantly,indicating that continuous straw returning to the field could improve carbon supply of soil microorganism effectively,and help to increase microorganism.