不同玉米秸秆还田量的土壤大型动物夏季群落动态特征

Dynamics of Soil Macrofauna Community in Farmlands Different in Corn Stalk Returning Rate

调查不同玉米秸秆还田量下的农田大型土壤动物群落动态特征,于2016年6-9月玉米生育期内进行,采用手拣法捕获土壤动物。结果表明:共捕获大型土壤动物2681只,隶属于41个类群。方差分析显示,13500 kg·hm^-2还田处理(SR4)显著提高了大型土壤动物个体数,12000kg·hm^-2还田处理(SR3)显著提高了大型土壤动物类群数。多样性表明:多样性指数和丰富度指数随玉米生长季总体呈现出先增加后下降的趋势;均匀度指数随玉米生长季总体呈现出下降的趋势;优势度指数总体与多样性指数变化趋势相反,随玉米生长季呈现出先下降后增加的趋势。垂直分布表明:随玉米的生长时期的推移,表层0~10 cm土层的大型土壤动物有向10~20 cm土层下移的趋势。功能群特征表明:捕食性大型土壤动物个体数随玉米生长季呈现先增加后下降的趋势;植食性和腐食性大型土壤动物个体数随玉米生长季呈现增加的趋势;杂食性大型土壤动物个体数在玉米生长季无明显变化。RDA分析表明:受农田土壤环境因子影响较大的大型土壤动物类群主要是研究区的优势类群,大型土壤动物的个体数与土壤有机质含量和土壤含水量关系紧密。总体上,玉米秸秆还田影响地表土壤的微环境,进而影响了大型土壤动物群落的组成、分布特征和功能群,玉米秸秆还田有益于农田大型土壤动物功能群的发展。

【Objectice】To investigate dynamic characteristics of the soil macrofauna community in farmlands different in corn stalk returning rate,a field survey was carried out.【Method】Soil fauna were captured by hand-sorting during the maize growth period from June to September 2016.【Result】A total of 2681 large soil fauna were captured,belonging to 41 groups.Variance analysis shows that Treatment SR4(13500 kg·hm^-2 in corn stalk returning rate)increased the number of individuals of soil macrofauna significantly(P<0.05),while Treatment SR3(12000 kg·hm^-2 in corn stalk returning rate)increased the number of macrofauna groups significantly(P<0.05).With growth of the corn in the farmland diversity index and richness index of the macrofauna varied,displaying a trend of rising first and then declining,and evenness index a downward trend,while dominance index did reversely,following a trend just opposite to that of the diversity index,that is,declining first and then rising.With growth of the corn,soil macrofuana in the 0~10 cm soil layer tended to migrate downwards to the 10~20 cm soil layer.Analysis of functional groups shows that the group of predacous macrofauna increased first and then decreased in number of individuals with growth of the corn,while.The groups of phytophagous and saprophagous fauna exhibited a trend rising with growth of the corn and in number of individuals with rising corn stalk returning rate too.However,the number of individuals of omnivorous macrofauna did not change significantly with growth of the corn by a certain degree.RDA analysis shows that the groups of soil macrofauna that were affected quite strongly by farmland soil environmental factors were mainly the dominant groups in the research area.The number of macrofauna individuals was closely related to the contents of soil organic matter and soil moisture.【Conclusion】The dominant groups are affected by soil environmental factors.Return of corn stalk alters microenvironment of the surface soil,which in turn affects composition,distribution characteristics and functional groups of the macrofauna community.So return of corn stalk is beneficial to the development of functional groups of the soil macrofauna in farmlands.