不同农作方式下红壤坡耕地土壤磷素流失特征

研究了6种农作方式红壤坡耕地土壤P素流失特征。结果表明，红壤坡耕地土壤P素的坡面流失主要通过径流和推移质2种方式，顺坡农作处理径流流失P素的比例占土壤全P流失量的55．26％，通过推移质流失的P素和径流流失的P素基本相当，其它处理土壤P素的流失主要以径流方式流失。流失量占土壤全P流失量的67．59％～88．11％。在流失的土壤P素中，泥砂结合态占多数，其比例为57．79％～77．59％，其中有效P的流失基本上通过径流方式，与传统的顺坡耕作的坡耕地利用方式相比。其它5种不同农作措施均有控制和防治土壤P素流失的作用。能减少P流失总量40．73％～84．70％。水平土埂、等高农作措施、休闲措施效果优于水平革带、水平沟农作措施。土壤P素流失时间主要集中在5～8月，占全年土壤P素流失量的89．15％～100％。

Characteristics of phosphorus losses from slope field in red soil area under different cultivated ways

A study on the properties of phosphorus loss under different cultivated ways was conducted in Lanxi Water and Soil Supervision Conservation Station of Zhejiang Province in 2000. The results showed that the phosphorus lost mainly through bed load and runoff. Phosphorus lost through runoff accounted for 55.26% of total lost phosphorus in straight farming field, but in other farming field, phosphorus lost with runoff accounted for 67. 59% ~ 88.11% . Particle phosphorus was the major form of the lost phosphorus, which contributed to 57. 79% ~ 77.59% of total lost phosphorus. The runoff most phosphorus was available phosphorus . Comparing with the traditional cultivated ways in the local area( treatment 5,stright farming field), the alternative different cultivated ways reduced soil phosphorus loss by 40. 73 % ~ 84.70 % , the contour, contour dam and fallow had better effect on controlling loss of phosphorus than the contour ditch and contour grass strip. In a year of 2000 most of the lost phosphorus was occurred during May to August accounting for 89.15% ~ 100% of total lost.