湘西北土壤物理健康对土地利用转换的响应OA北大核心CSTPCD

[Objective]The aims of this study are to reveal the effects of conversion of primary forest to other land use on soil physical health,and to provide scientific basis for rational development and utilization of land resources in the central subtropical mountain region.[Methods]The top soils in typical primary forests and converted plantations,orchards,sloping tillage,and paddies in northwest Hunan Province were selected.The response of major soil physical properties to the primary forest conversion was studied.[Results](1)Following the primary forest conversion to orchard and sloping tillage,the content of sand in soil increased,the soil particle composition showed coarsening trend,and the bulk density and compactness increased by 24％～28％and 27％～76％,respectively,leading to significant topsoil compaction(p＜0.05).(2)Compared to the primary forest,the soil maximum water holding capacity,capillary water holding capacity,and field water holding capacity reduced by 15％～30％,15％～32％and13％～21％,respectively,in orchard,sloping cropland,and paddy.And the content of macroaggregate,mean weight diameter,geometric mean diameter,and aggregate stability index decreased by 34％～59％,27％～52％,36％～73％and 49％～61％,respectively,whereas the fractal dimension increased by 31％～80％(p＜0.05),and the contents of small aggregate,microaggregate,and silt-clay particle tended to increase.[Conclusion]The primary forest conversion resulted in the reduction of water-holding capacity,structural deterioration,and physical health degradation in soil.The response ratios of soil physical properties were lower for the primary forest conversion to plantation than for the primary forest conversion to orchard and sloping cropland.The capacity of soil and water conservation and soil physical health maintenance were higher in plantation than in orchard and sloping cropland.The soil aggregate stability index was sensitive,simply processed,and low-cost,and was recommended for soil health evaluation.