秸秆还田对宁南旱作农田土壤活性有机碳及酶活性的影响

Effects of Straw Returning on Soil Labile Organic Carbon and Enzyme Activity in Semi-arid Areas of Southern Ningxia,China

在宁南旱区通过研究秸秆还田对土壤活性有机碳及酶活性的影响,旨在为该区作物生产及土壤培肥制度的建立提供参考。在为期3a秸秆还田定位试验中,设置了不同秸秆还田量处理,谷子秸秆按3000kg·hm-(2低L)、6000kg·hm-(2中M)、9000kg·hm-2(高H)粉碎还田;玉米秸秆按4500kg·hm-(2低L)、9000kg·hm-(2中M)、13500kg·hm-(2高H)粉碎还田,对照为秸秆不还田,对不同处理条件下的土壤有机碳、土壤酶活性及其相关性进行了分析。结果表明,土壤总有机碳、活性有机碳含量和土壤酶活性均随土层的加深而减少;各处理0～60cm土层土壤有机碳含量和酶活性大小为中、高量秸秆还田>低量秸秆还田>秸秆不还田;秸秆还田不仅增加了土壤活性有机碳含量,同时提高了活性有机碳占总有机碳含量的比重。相关性分析表明,运用土壤活性有机碳和碳库管理指数表征土壤酶活性及土壤肥力变化,比土壤有机碳更具灵敏性。在宁南半旱区采用秸秆还田能有效提高土壤活性有机碳含量和土壤酶活性。

The effects of straw returning treatments on soil labile organic carbon and enzyme activities was studied in semi-arid areas of Southern Ningxia for providing a scientific basis of crop production and soil fertilizing system.The different straw returning treatments were 3 000 kg·hm-2（L）,6 000 kg·hm-2（M） and 9 000 kg·hm-2（H） of millet straw and 4 500 kg·hm-2（L）,9 000 kg·hm-2（M） and 13 500 kg·hm-2（H） of corn straw,the CK had no straw returning.The results of three years field experiment showed that in the third experiment year（2009）,soil total organic carbon,labile organic carbon and soil enzyme activities decreased with deeper layer;different straw returning treatments had different effects on the contents of soil organic carbon and enzyme activities of 0～60 cm soil layer,follow the order from high to low：middle and high straw returning treatmentslow straw returning treatmentsCK;straw returning treatment was not only increased the content of soil labile organic carbon,but also improved the proportion of the labile organic carbon accounting for the total organic carbon content.Correlation analysis revealed that soil labile organic carbon and carbon management index may be a better indicator than soil organic matter used to reflect the changes of soil enzyme activities and soil nutrients.In semi-arid areas of Southern Ningxia,the content of soil labile organic carbon and enzyme activities could be improved efficiently by using of straw returning technology.