【摘要】 强度的耕作管理使土壤生物多样性下降,也使农业可持续发展面临困难,而实行保护性耕作可以缓解这一问题。通过调查小麦季保护性耕作下土壤动物群落结构,分析了耕作方式和秸秆覆盖对土壤动物群落的影响,采用冗余分析(RDA)并设置协变量的方法对土壤动物数量变异进行了研究。结果表明,弹尾目和蜱螨目是土壤动物优势类群,两者数量之和占总数比例约为80%,土壤动物在表层(0～10cm)分布较大,约占总数的75%。土壤动物类群数免耕高于翻耕,覆盖量越大,个体数量越多。免耕在小麦拔节期有更高的多样性指数,但在成熟期土壤动物优势类群明显,多样性指数下降。相似性指数表现为土壤动物类群对环境具有选择性,翻耕和免耕之间类群差异较大。耕作方式、覆盖数量、土壤层次和时间共解释了土壤动物数量变异量的28.7%,其中时间占最大的变异量,为12.2%,其次是秸秆覆盖处理(8.7%)和土壤层次(6.4%)。耕作方式直接解释的变异量较小,但耕作方式显著影响了秸秆覆盖的作用形式,进一步影响了土壤动物的垂直分布状况。更多还原

【Abstract】 Reduced biodiversity in soils is associated with the intensive tillage management which goes against agricultural sustainable development but conservation tillage has been considered one of the effective managements to the problem.No-tillage and straw cover were generally applied under conservation tillage systems.Therefore,a completely randomized 2×3 factorial experiment was set up to investigate the effects of tillage and straw cover on soil fauna in wheat field.Each plot was designed to 4 m×100 m rectangle and each treatment was replicated six times in the experiment.Treatments consisted of:till+total field straw removed(TC0);till+50% of total field straw removed(TC50);till+ total field straw applied(TC100);no-till+total field straw removed(NTC0);no-till+50% of total field straw removed(NTC50);no-till + total field straw applied(NTC100).We investigated abundance and diversity of soil fauna at the jointing stage(March)and the maturity stage(May) under wheat growth season.The results showed that the dominant groups of soil fauna in all treatments were collembola and acari which nearly accounted for 80%.The abundance of soil fauna distributed at 0～10 cm soil depth was as much as 75% of total soil fauna.The numbers of groups of soil fauna was higher under no-tillage than tillage treatment plots,and the individuals of soil fauna were increased with the increase of straw cover.The diversity of soil fauna was higher under the no-tillage plots than that under the tillage plots at the jointing stage,but the result was opposite at the maturity stage.As to similarity index,there was a great difference between tillage and no-till plots,which indicated that many soil animals had their own adaptability to habit in tillage or no-till plots.Redundancy analysis indicated that the factors of tillage method,straw cover,soil layer and time totally explained 28.7% of soil fauna variation,of which,the time was the highest,occupied 12.2%,the straw cover was 8.7% and the soil layer was 6.4%.Tillage method explained the least variation of soil fauna,however,tillage affected the vertical distribution pattern of soil fauna through significantly changed the effects of the straw cover.更多还原