燕沟流域农田基础肥力分析与培肥途径

黄土丘陵区燕沟流域农田基础肥力水平低下，特别是近几年新修的梯田，土壤有机质、全Ｎ、水解Ｎ，速效Ｐ和阳离子量代换量都处于很低和低等水平，速效Ｋ为中低程度，土壤酶活性也很低。坝地土壤养分和酶生相对梯田较高，但大多也只处于中低水平，是影响农作物产量和限制农业发展的主要因素。土壤肥力水平提高的根本途径在于大量有机肥力的投入、农作物秸秆还田和增加养地作物种植面积来增加土壤有机质的含量。

Primary Fertility and Approaches of Improving Fertility in Yaner Gully Watershed of North Yan an Area

The soil basic fertility is low in the farming land at Yaner Gully watershed, especially in the recently built terrace lands. The soil organic matter, total N, available N and P, and CEC are all relatively low, and also the soil enzymatic activity. The available K is mediate. The soil nutrient and enzymatic activity in the dam land is relatively higher, but still in the low level which limited the crop productivity and agriculture development. The efficient way to improve soil fertility is to input large amount of organic matter, return crop straw into farmland, and plant fertility-improving crops.