四川紫色土坡耕地磷素渗漏迁移初探

Phosphorus Leaching from Slope Cropland of Purple Soil

通过对川中丘陵区冬小麦-夏玉米轮作条件下,玉米季不同施肥试验田渗漏水的观测与分析,研究了紫色土坡耕地在天然降雨时渗漏水的产流规律及土壤磷素的淋溶迁移特征。结果表明,渗漏水量与降雨量呈明显的指数关系,与雨强大小没有直接关系。暴雨下渗漏水中的DTP及PO34--P含量变化过程呈现明显的二次波峰规律。不同的施肥条件显著影响渗漏水的DTP含量,NP处理最高,DTP含量达到了0.047mg·L-1。PO43--P是DTP的主要组成形态,占了DTP的62%～85%。不同施肥处理渗漏水的DTP迁移总量为4.0～7.5g·hm-2。

A field experiment was conducted in hilly area of central Sichuan Basin to study the characteristics of leaching and soll P loss in the leachate from slope cropland of purple soil under natural rainfall during maize growth period. The results showed that there was significantly exponential correlation between the amount of leachate and the precipitation. By contraries, amount of leachatc had nothing with rainfall density. The law of two wave crest had been displayed in the processes of P leaching. Different fertilization had significant effects on the contents of DTP in leachate. The content of DTP from treatment NP is the highest which achieved 0.047 mg· L^-1. 62%-85% of DTP in 3 different treatment plots is PO4^3- -P which is the main form of DTP. DTP transported hy leaching from different treatment plots varied from 4.0 g·hm^-2 to 7.5 g·hm^-2.