湘南红壤丘陵区不同生态种植模式下土壤磷素流失特征

以湖南省祁阳县红壤坡地大型标准径流场为例,研究了湘南红壤丘陵区8种不同生态种植模式下土壤磷素的地表流失特征.结果表明: 总磷流失量以撂荒处理(T₁)最严重,顺坡种植模式处理(T₂、T₃)其次,5种梯田模式处理(T₄～T₈)均能有效减少土壤磷的流失,磷流失量分别是T₁处理的9.9%、37%、0.7%、2.3%和1.9%.生态种植模式直接影响红壤坡地土壤磷素的地表流失形态,研究区流失的磷素以颗粒磷为主.暴雨(日降雨量＞50 mm)情况下,降雨量对不同生态种植模式下磷流失量影响差异不大,但磷流失量随降雨强度增大而增加.红壤坡地土壤磷素地表流失主要集中在6-9月,降雨量和降雨强度是影响湘南红壤丘陵区土壤磷素地表流失时间分布的直接因素.

Characteristics of soil phosphorous loss under different ecological planting patterns in hilly red soil regions of southern Hunan Province,China.

Taking a large  standard runoff plot on a red soil slope in Qiyang County, southern Hunan Province as a case, this paper studied the surface soil phosphorus loss characteristics in the hilly red soil regions of southern Hunan under eight ecological planting patterns. The phosphorus loss from wasteland (T1) was most serious, followed by that from natural sloped cropping patterns (T2 and T3), while the phosphorus loss amount from terrace cropping patterns (T4-T8) was the least, only occupying 9.9%, 37%, 0.7%, 2.3%, and 1.9% of T1, respectively. The ecological planting patterns directly affected the forms of surface lost soil phosphorus, with the particulate phosphorus (PP) as the main lost form. Under the condition of rainstorm (daily rainfall >50 mm), rainfall had lesser effects on the phosphorus loss among different planting patterns. However, the phosphorus loss increased with increasing rain intensity. The surface soil phosphorus loss mainly occurred from June to September. Both the rainfall and the rain intensity were the factors directly affected the time distribution of surface soil phosphorus loss in hilly red soil regions of southern Hunan.