Soil moisture characteristics of different vegetation measures in loess hilly region of southern Ningxia

In order to illustrate the relation between artificial vegetation and soil moisture characteristics in loess hilly region of Ningxia,the centrifugation method and invariable water height method were used for measuring the curve of soil moisture characteristics and saturated hydraulic conductivity of soil,and the soil moisture characteristics of sloping land in loess hilly region of southern Ningxia were studied.The results showed that there was high power function correlation between the soil moisture and the potential of soil water.The mathematical model was θ=aS^b.The value a and different sloping land were ranged in order from higher ones to lower ones as follow: Medicago lupulina,Hippophae rhamnoides,Natural Grassland,Prunus armeniaca,Caragana korshinskii,farmland.Grassland,Shrubbery,Arbor Forest,cropland.Saturated hydraulic conductivity of Natural Grassland and Medicago lupulina were the highest than the others,and cropland was the lowest,and Grassland,Hippophae rhamnoides and Caragana korshinskii were middle.At the same soil water potential range,soil water content of Medicago lupulina was highest,Hippophae rhamnoides took second place,cropland was the lowest and others' were around the same.At the low potential range,the average soil water content,from high to low,was Medicago lupulina,Natural Grassland,Cropland,Natural Grassland,Prunus armeniaca,Caragana korshinskii.At the middling soil potential range,the order of average soil water content was Medicago lupulina > Natural Grassland > Prunus armeniaca,and with the soil suction increasing,soil water content changed little.Languishing soil water content of vegetations except Medicago lupulina was still highest,and cropland kept was lowest.