陕北毛乌素沙地不同植被类型长期恢复对土壤水力特性的影响OA

To investigate the variation characteristics and influencing factors of soil hydraulic properties under long-term restora-tion(about 40 years)of different vegetation types in the Mu Us Sandy Land of Northern Shaanxi,typical arbor plantations(including Pinus sylvestris var.mongolica,Pinus tabuliformis Carrière,Platycladus orientalis(L.)Franco,and Populus plantations)and shrub plantations(Caragana korshinskii Kom.plantations)were selected as research objects,with waste-land set as the control(CK).By measuring soil hydraulic properties(saturated hydraulic conductivity,field capacity,and saturated water content)in different soil layers(h,0＜h≤10 cm,10 cm＜h≤20 cm,and 20 cm＜h≤30 cm)under various vegetation types,combined with basic soil physical and chemical properties,the response of soil hydraulic properties to long-term restoration of different vegetation types and their influencing factors in this region were revealed.The results showed that the average saturated hydraulic conductivity of different vegetation types in descending order was Populus plan-tation(5.03 cm·h-1),P.orientalis plantation(2.50cm·h-1),P.tabuliformis plantation(1.84 cm·h-1),P.sylvestris var.mongolica plantation(1.79 cm·h-1),C.korshinskii plantation(1.09 cm·h-1),and wasteland(0.64 cm·h-1).The average field capacity in descending order was Populus plantation(23.98％),P.tabuliformis plantation(21.00％),P.orientalis plantation(20.66％),P.sylvestris var.mongolica plantation(19.46％),C.korshinskii plantation(17.24％),and wasteland(15.00％).The average saturated water content in descending order was Populus plantation(26.52％),P.tabuliformis plantation(25.60％),P.orientalis plantation(23.50％),P.sylvestris var.mongolica planta-tion(22.90％),C.korshinskii plantation(21.37％),and wasteland(21.25％).Overall,the soil hydraulic properties of arbor plantations were better than those of shrub plantations,and those of shrub plantations were better than those of waste-land.With the increase of soil depth,the saturated hydraulic conductivity of all plantations decreased significantly(P＜0.05).The variation trends of saturated water content differed among plantations:the saturated water content of P.sylves-tris var.mongolica,P.orientalis,Populus,and C.korshinskii plantations decreased gradually with increasing soil depth(P＜0.05),that of P.tabuliformis plantation increased first and then decreased,while that of wasteland was basically unaffect-ed by soil depth.For field capacity,all plantations and wasteland showed a decreasing trend with increasing soil depth(P＜0.05).Soil bulk density was the main factor affecting soil hydraulic properties in the 0＜h≤30 cm soil layer,and the influ-encing factors of soil hydraulic properties varied among different soil layers.The number of factors affecting soil hydraulic properties decreased gradually with increasing soil depth.