长期秸秆还田及休闲处理对土壤肥力的影响

目的]研究秸秆还田对土壤肥力的影响。方法]1984~2004年采用玉米秸秆直接还田与氮磷肥配施种植玉米和小麦,2005年仅施肥和秸秆还田而不种作物为休闲处理。结果]长期秸秆直接还田与单施化肥均可降低土壤容重,两者配施效果更好。土壤孔隙度与秸秆还田量呈显著正相关。长期秸秆直接还田增加土壤有机质、有效氮、有效钾含量的效果均优于单施化肥,而两者配合施用效果更佳。施用磷肥的增磷效果比单施秸秆更有效。休闲处理不仅使土壤容重下降、孔隙度升高、物理属性得到改善,而且还使土壤综合肥力水平得到恢复与提高。结论]长期秸秆还田能改善土壤的通气状况,协调土壤水肥气热等生态条件,为根系生长创造良好的土壤环境。

Effect of Returning Straw to Field in Long Time and Fallowing Treatment on Soil Fertility

Objective] The research aimed to study the effect of returning the straw to field on the soil fertility.Method] In 1984-2004,2 ways of returning the maize straw to field directly and combining N and P fertilizer application were used to plant the maize and wheat.In 2005 the fallow treatment was set up with applying fertilizer and returning the straw to field and without planting crop.Result] Returning the straw to field directly in long term or only using chemical fertilizer could reduce soil bulk density,but the effect of two combined application was better.The soil porosity was significantly correlated with the returned straw volume.The effects of returning the straw to field directly in long term on increasing the soil organic matter,effective N and K content were better than the single application of fertilizer and that of two combined application was better.The effect of increasing P by applying P fertilizer was more effective than that by singly applying the straw.The fallow treatment could not only decrease the soil bulk density,increase the soil porosity and improve the soil physical attributes,but also made the integrated soil fertility levels to be restored and improved.Conclusion] Returning the straw to field directly in long term could improve the soil aeration status and harmonize the soil economic conditions such as water,fertilizer,air and heat and create a good soil environment for root growth.