内蒙古地区不同撂荒年限草地与沙棘地的入渗能力比较

Comparison of Infiltration Capacity Between Grassland of Different Time Lengths of Abandonment and Sea Buckthorn Land in Inner Mongolia

[目的]研究内蒙古地区不同植被覆盖对土壤入渗能力的影响,为该区的生态恢复和植被配置提供理论依据。[方法]以该区3种不同年限撂荒草地(13,25,30 a)与13 a沙棘地为研究对象,采用圆盘入渗仪法并结合土壤水分特征曲线比较各样地土壤导水率,土壤大孔隙度及大孔隙连通性的差异。[结果]①土壤入渗能力与撂荒年限正相关,随着撂荒年限的增加而变强,土壤稳定入渗速率表现为30 a撂荒草地>25 a撂荒草地>13 a撂荒草地>13 a沙棘地,分别为1.38,1.29,1.24,1.11 mm/min。相同年限的撂荒草地入渗速率较沙棘地更大。②大孔隙度及大孔隙连通性均依次为:30 a撂荒草地>25 a撂荒草地>13 a撂荒草地>13 a沙棘,占土壤体积0.0004%~0.0034%的土壤大孔隙对土壤饱和入渗速率的贡献高达44.35%~86.92%。③>0.25 mm水稳性团聚体含量是影响土壤入渗速率的主要因素。[结论]撂荒可以改善草地的入渗能力,并且随年限的延长而增强,相同年限下撂荒草地的入渗性能大于种植沙棘地,其主要影响因素为土壤大孔隙数目及连通性、>0.25 mm水稳团聚体。

[Objective]The effect of different vegetation covers on soil infiltration capacity in Inner Mongolia was analyzed in order to provide a theoretical basis for ecological restoration and vegetation allocation of the region.[Methods]Three ages of abandoned grassland(13 years,25 years,and 30 years)and 13 years of sea buckthorn land in this region were used as treatments.The disc infiltration method and soil water characteristic curves were used to compare differences in soil hydraulic conductivity,soil macroporosity,and macropore connectivity.[Results]①Soil infiltration capacity was positively correlated with the length of abandoned years,and became stronger as the number of abandoned years increased.The stable infiltration rate of soil followed the order of 30-year abandoned grassland>25-year abandoned grassland>13-year abandoned grassland>13-year sea buckthorn land.②Macroporosity and macropore connectivity followed the order of 30-year abandoned grassland>25-year abandoned grassland>13-year abandoned grassland>13-year sea buckthorn land.Soil macropores accounted for 0.0004%—0.0034%of the soil volume and accounted for 44.35%—86.92%of the soil saturated infiltration rate.③The content of water stable aggregates>0.25 mm was the main factor affecting soil infiltration rate.[Conclusion]Abandonment improved the infiltration capacity of grassland,and the infiltration capacity increased with increasing number of years of abandonment.The infiltration capacity of abandoned grassland was greater than that of sea buckthorn land having the same number of years of abandonment.The main influencing factors were the number and connectivity of soil macropores,and water stable aggregates>0.25 mm.