Stability Characteristics of Soil Water-stable Aggregates under Different Land-use Patterns on the Loess Plateau
The stabilities of soil aggregates of different land-use patterns in the Loess Plateau were studied,and the distributions of water-stable aggregates were obtained by fractionafing the aggregates with a wet-sieving procedure.Geometric mean diameter (GMD),mean weight diameter (MWD),fractal dimension (D),destruction rate (PAD),peak convex coefficient (CE) and bias coefficient (Cs) were used to analyze and compare soil aggregates stability (＞0.25 mm).The study aimed to explore the stability of soil aggregates under different land use patterns,obtain the best indexes to represent soil aggregates stability and reveal the influences of land use transformation on soil structure.The content of soil water-stable aggregates,GMD and MWD under different land use patterns were all in the same order as farmland ＜ arborshrub mixed forestland ＜ arbor forestland ＜ natural grassland ＜ shrub forestland.Forest and grass were conducive to form larger-particle aggregates,in which the weight of soil aggregates with 1-5 mm particles accounted for 53.90％-80.20％ of the weight of soil aggregates with particles greater than 0.25 mm and this structure was obviously inhomogeneous in forestland (especially shrub forestland) and grassland.For farmland,the weight of soil aggregates with 0.25-1 mm particles accounted for 81％ of the weight of soil aggregates with particles greater than 0.25 mm and the structure was homogeneous.The size of dominant particles in the aggregation gradually became smaller from top layer to deep layer in soil profiles of forestland and grassland so that the differences of structure became less.This trend was sharp in arbor forestland,but it was slow in shrub forestland and natural grassland.There were significant positive correlation among GMD,MWD,CE and Cs,while these indexes had negative correlation with D and PAD.The aggregate stability features in the whole profile could be described felicitously by GMD and Cs,while the soil at 0-20 cm depth could be described by PAD properly.
the Loess Plateauland-useswater-stable aggregatesthe stability indexes
NETL
NSTL
万方数据
维普
