黄土高原南部土壤养分流失规律

The Regular Patterns of the Loss of Soil Nutrients on Southern Loess Plateau

本文以定位试验，野外调查和室内分析的方法研究了黄土高原南部坡耕地土壤养分流失机理、数量及时空变化规律。结果表明，泥沙流失是养分流失的主要方式，养分流失总量随地面坡度增大呈幂函数增加，土壤养分衰减氮素较磷素快，肥力高的土壤相对衰减快，坡度增大相对衰减慢，流失土壤的养分在坡度＜１２°时与坡度呈线性相关，在＞１２°时呈幂函数相关。土壤中锰、锌和有效硼微量元素衰减不明显。

The mechanism,quantity and spacial-temporal variation patterns of the loss of soil nu-trients occurring on southern Loess Plateau were studied by the experiment on a fixed position,fieldinvestigation and mathematical analysis.The results showed that soil erosion is the main cause of soilnutrients loss; the total quantity of the loss increased in power function along with the raise ofground gradient;the rate of nitrogen decline is greater than that of phosphorus;the rate of nutrientdecline in fertile soil decreased faster than that in poor soil;the rate of nutrient decline decreased a-long with the raise of ground gradient,and the decline was linearly correlated with the gradient thatwas<l2°,whereas correlated in power function with the gradient that was>12°,No remarkable de-clines of manganese and zinc as well as available Boron were found.