秸秆还田深度对黄棕壤养分及物理性质的影响

Effects of Straw Returning Depth on Nutrients and Physical Properties of Yellow Brown Soil

[目的]通过改变秸秆还田深度来探讨其对黄棕壤养分和物理性状的影响,探索最适秸秆还田深度,为提高秸秆利用率和改善土壤理化性质提供科学依据。[方法]以黄棕壤为研究对象,设置5个处理:无秸秆还田(CK)、表面覆盖(T_0)、10cm还田(T_(10))、20cm还田(T_(20))和30cm还田(T_(30)),分析了小麦收获后土壤0—40cm土层物理性质和土壤养分状况。[结果](1)秸秆还田能显著降低土壤容重,增加土壤总孔隙度、饱和含水量、田间持水量和有效水含量,使土壤有机质、有效磷和全氮含量分别增加6.56%~9.96%,2.81%~7.32%和1.67%~10.00%;(2)秸秆还田减少了土壤铵态氮和硝态氮含量,降幅为1.48%~15.04%和14.90%~53.42%,其中土壤硝态氮含量与秸秆还田深度呈显著负相关关系;(3)由主成分分析可知,各处理下的土壤综合得分次序为:T_(20)>T_(30)>T_(10)>T_0>CK,说明秸秆还田处理能改善土壤养分和物理状况,其中秸秆还田深度为20cm时效果最为显著。[结论]综合黄棕壤物理性状和养分含量,秸秆还田深度20cm处理最为适宜。

[Objective]The effects of different straw returning depths on nutrients and physical characters of yellow brown soil were studied in order to explore the optimal straw returning depth and to provide a scientific basis for improving straw utilization,and soil physical and chemical properties as well.[Methods]This research studied on yellow brown soil,and five treatments of straw returning were set：no straw turning（CK）,straw covering surface（T0）,10 cm-straw turning（T10）,20 cm-straw turning（T20）and 30 cm-straw turning（T30）,to analyze soil physical indexes and nutrient contents of 0—40 cm soil layer after wheat harvest.[Results]（1） Straw returning decreased the soil bulk density and increased the soil total porosity,saturated water content,field water holding capacity and effective water content.These treatments improved the contents of SOM,AP and total-N in soil by 6.56%-9.96% ,2.81%-7.32% and 1.67%-10.00% ,respectively;（2） Straw returning treatments decreased the contents of NO-3-N and NH＋4-N by 14.90%-53.42% and 1.48%-15.04% ,respectively.There was a significantly negative correlation between NO-3-N content and the depth of straw returning.（3） The principal component analysis showed that comprehensive score indifferent straw returning depth treatments decreased in the following order：T20〉T30〉T10〉T0〉CK,which elucidated that straw returning improved nutrients and physical properties of yellow brown soil,and it showed the most significant depth of straw returning was 20 cm.[Conclusions]If physical properties and nutrient contents were considered,the best depth of straw returning was 20 cm.