不同剖面层次土壤磷素运移研究

以陕西杨凌地区塿土为研究对象,通过饱和稳定流土柱运移试验,测定磷酸盐(H_2PO_4~-)在不同层次土壤中的运移穿透曲线(BTC),应用CDE模型、CXTFIT软件程序对其实测穿透曲线(BTC)进行拟合求其运移参数,研究其运移规律。结果表明,磷酸盐在塿土中的运移受到土壤的强烈阻滞作用,随着CaCO_3含量增加,磷酸盐运移所受的阻滞作用增大。磷酸盐在塿土不同剖面层次中运移所受阻滞作用大小与CaCO_3含量呈极显著的正相关,r=0.9791;而与粘粒含量且成极显著的负相关、r=0.9318。磷酸盐在塿土不同土层运移所受阻滞作用大小顺序为:钙积层>堆垫表层>粘化层,其阻滞因子R值分别为:11.80～13.00,5.20～7.00,3.90～5.00。

Study on phosphorus transport in soil profile layers

Experiments on saturated flow of soil column transport were conducted to determine phosphate breakthrough curve (ETC) in different layer of Lou soils in Shaanxi Province. With CDE model and CXTFIT program, transport parameters were obtained according to BTC measured to study phosphate transport law. The result showed that phosphate transport in Lou soils encountered soil violent retardation. Retardation phosphate transport in Lou soil of different layers encountered enhanced with calcium carbonate increasing. Retardation was positively correlated with the amount of calcium carbonate and the value of r was 0.979 1 **. Retardation was negatively correlated with the amount of clays and the value of r was 0.931 8**. Phosphate can hardly break through the soils rich calcium carbonate completely. Retardation was decreased in the order: Cacic horizon > Cumullic epipedon > Claying horizon. The value of retardation factors ( R ) were 11.80 - 13.00, 5.20 - 7.00, 3.90 - 5.00, respectively.