关键词: 秸秆还田, 氮肥利用率, 双氰胺, 减氮

Abstract: In 2008-2009, an investigation was conducted on the community characteristics of soil macro-fauna within and outside the Caragana microphylla and Salix gordejevii in Horqin Sand Land, aimed to understand whether the shrubs in mobile sand land could gather soil macrofauna. As compared with those outside the shrubs, the group number, individual density, and Shannon diversity of soil macrofauna within the shrubs were increased by 125.0%-175.0%, 52.8%-263.9%, and 34.6%-57.1%, respectively, indicating that shrubs had obvious “bug island” effect in mobile sand land. C. microphylla had a greater “bug island” effect than S. gordejevii. Within and outside the shrubs, there were the same dominant groups and a few common groups of soil macro-fauna. However, many soil macro-faunal groups which couldn’t survive outside the shrubs appeared within the shrubs, and the functional group structure of the macro-fauna had obvious change. The “bug island” effect of the shrubs in mobile sand land mainly came from the microclimate effect and “fertile island” effect of shrubs, which reduced wind speed and detained dust, occluded hot sun, improved soil texture and soil moisture, and increased soil nutrient contents, being the main mechanisms of the shrubs in mobile sand land in gathering soil macro-fauna.

Key words: DCD, N use efficiency., straw returning, reducing N fertilizer