稻草不同还田量对土壤动物群落结构的影响

  目的  研究稻草不同还田量下土壤动物群落结构特征。  方法  在5 m×5 m的样方内，以未进行稻草还田的处理为对照（ck），采用手拣法和干、湿漏斗分离法，调查稻草还田后2个月和稻草还田后5个月，不同还田量0.8（T₂₀）、0.4（T₁₀）、0.2（T₅）和0 kg·m-2（ck）]处理下耕地土壤动物群落特征。  结果  试验共捕获土壤动物1 194只，隶属于3门11纲19目44科，平均密度4.45×105只·m-2；稻草还田处理后的样地土壤动物密度和类群数明显增加（P < 0.05），土壤动物类群数排序为T₂₀（37）> T₁₀（30）> T₅（28）> ck（17）。土壤动物群落垂直分布明显，土壤动物密度随着土层加深而降低，具有明显的表聚性特征。稻草还田2个月后T₂₀处理的土壤动物多样性指数、均匀度指数、丰富度指数均最高，稻草还田后5个月T₁₀处理优势度指数最高。  结论  农业生产上稻草切碎后覆盖还田宜选择0.8 kg·m-2还田量。

Effects of different rice straw returning quantities on soil fauna community structure

  Objective  The aim is to reveal the effects of different straw returning quantities on cropland soil fauna community.  Method  An experiment with four types of straw returning quantities0.8(T₂₀), 0.4(T₁₀), 0.2(T₅) kg·m-2 and no straw returning(ck)], were carried out in 5 m×5 m quadrats. Hand-picking method and dry and wet funnel separation method were used in the experiment.  Result  The total soil animals 1 194 were captured in this survey, belonging to 3 phyla, 11 classes, 19 orders and 44 families. The average density of soil animals was 4.45×105 ind·m-2. The density and variety of soil animals in the sample land increased significantly after straw returning(P < 0.05). The varieties were ranked as follows:T₂₀(37) > T₁₀(30) > T₅(28) > ck(17). The vertical distribution of soil fauna community was obvious, and the density of soil fauna decreased with the deepening of soil layer, which had obvious surface aggregation. Two months after straw returning, T₂₀ had the highest diversity index, evenness index and species richness. Five months after straw returning, T₁₀ had the highest predominant index.  Conclusion  0.8 kg·m-2 straw returning quantity is suggested.