蚯蚓活动对宝鸡地区农田土壤水分入渗过程的影响

The effects of earthworm activity on soil water infiltration process in farmland soil in Baoji area

目的研究蚯蚓活动对土壤水分入渗过程的影响。方法通过土柱模拟实验,设置3种土壤容重(ρ1,ρ2,ρ3分别为1.28,1.32和1.36 g/cm 3)条件,分析接种蚯蚓和对照处理(无蚯蚓)下土壤水分入渗速率(又称入渗率)、出水速率和累积入渗量变化规律及土壤孔隙特征。结果接种蚯蚓后,土壤水分入渗率随时间推移呈“降低-增加-降低”的曲线变化,蚯蚓活动改变了土壤水分入渗过程。接种蚯蚓后土壤水分初始入渗率提高了0.3%~66.7%,稳定入渗率提高了1.67~2.08倍,土壤出水量提高了1.0~1.3倍。蚯蚓活动使得土壤容重降低了9.4%~12.5%。容重越小,蚯蚓活动越强烈,土壤孔隙越发育,土壤水分入渗能力越强。与对照组相比,土壤容重对土壤水分入渗过程的影响远小于蚯蚓活动产生的影响。土壤水分累积入渗量和出水量均随土壤孔隙度的增加而增加,二者之间呈极好的线性关系。结论蚯蚓活动通过改变土壤孔隙,可促进极端强降雨条件下的土壤水分入渗,减少土壤表面侵蚀,提高深层土壤含水量,进而对植被生长产生重要影响。

Purposes—To study the effect of earthworm activity on soil water infiltration.Methods—Three soil bulk densities(ρ1=1.28 g/cm 3,ρ2=1.32 g/cm 3,ρ3=1.36 g/cm 3)were set up to simulate the effects on soil infiltration rate,effluent rate and cumulative infiltration amount by earthworm inoculation(10 ind)and control(CK,0 ind)in this study.Results—Soil water infiltration rate showed a"decrease-increase-decrease"curve over time,which changed the soil water infiltration process under earthworm inoculation.Comparing the CK,the initial infiltration rate of soil water increased by 0.3%~66.7%and the steady infiltration rate increased by 1.67~2.08 times in earthworm inoculation treatment.Soil effluent water of earthworm inoculation was 1.0~1.3 as large as CK.The soil bulk density was reduced by 9.4%~12.5%under earthworm activity.The more developed the soil pores,the stronger soil water infiltration capacity in the smaller soil bulk density.The effect of soil bulk density on soil water infiltration was much less than that of earthworm activity.The cumulative infiltration and water output of soil water increase with the increase of soil porosity,and there is an excellent linear relationship between them.Conclusions—Earthworm was not only conducive to the infiltration of water into the soil under extreme heavy rainfall conditions rapidly by increasing soil porosity,but also reduced soil surface erosion and increased soil water content on deep soil,thus having an important impact on vegetation growth.