Spatial Distribution and Influencing Factors of Soil Hydraulic Parameters and Related Physiochemical Properties in River-nearby Plain
To study the spatial distribution characteristics of soil hydraulic parameters and their influencing factors,the typical agricultural area near the Yangtze River in Jianghan Plain was taken as the study unit,the undisturbed and disturbed soil samples were collected from shallow layers(0-40 cm)of different farmland types,and the hydraulic parameters and related physiochemical properties were determined,then the spatial distribution characteristics of hydraulic parameters and their relation with physiochemical properties were studied and compared.The results showed that the basic physicochemical properties of soil(soil mechanical composition,organic matter content,bulk density,diameter＞0.1 mm and＞0.3 mm large pore content)and hydraulic parameters(saturated water content(θs),residual water content(θr),water characteristic curve fitting parameters α and n,field water holding capacity(θf),wilting soil water content(θw)and maximum effective water content(θAW)in the study area had apparent spatial heterogeneity.The physical and chemical properties of soil mechanical composition,organic matter content,and bulk density were strongly correlated with the distance from the river.The spatial distribution characteristics of diameter＞0.1 mm and＞0.3 mm large pore content,θs and θr,θf and θAW were similar.Organic matter content,bulk density and macroporosity with a diameter＞0.3 mm significantly differed among the different land types.Differences in soil physiochemical properties significantly affected Ks and moisture profile parameters(especially θs and n).The paddy and dry fields had better infiltration performance with the highest median Ks(18.7 cm/h),and the Ks of other fields had little difference(9.2-10.5 cm/h).The vegetable field had the strongest water-holding capacity with higher θf(0.46 cm3/cm3),θW(0.07 cm3/cm3)and θAW(0.39 cm3/cm3),and soil hydraulic parameters of other plots had little difference.The distribution of alluvial deposits significantly affected soil mechanical composition and had some influences on the distribution of bulk density and organic matter.Human farming activities significantly changed soil organic matter content,macropore porosity and bulk density,but little influenced soil mechanical composition.The distribution characteristics of hydraulic parameters were affected by the combination of natural factors and human activities.In conclusion,the distribution characteristics of alluvial deposits need to be considered for soil surveys and agricultural production planning in agricultural areas near the river.
万方数据
维普
