不同栽培模式对氮磷钾养分径流流失的影响

为了寻求提高肥料利用率、降低养分流失、减少环境污染的最佳种植模式，在广西丘陵坡耕地进行定位观测，研究广西主要经济作物、农民常规施肥和主要种植模式下的坡耕地养分径流流失特征，结果表明，木薯+玉米模式径流水中的总磷、总钾、硝态氮流失量最大，其次为总氮、铵态氮；木薯+花生模式径流水中的养分流失量除总磷（245.1 g/hm²）最多外，其他养分流失量均较少，氮素流失以硝态氮为主，占总氮的50%以上。产生径流量最多的模式是木薯+花生为60 974 L/hm²，其次是甘蔗模式为58 583 L/hm²，最少的模式是木薯+玉米为52 676 L/hm²；木薯+玉米种植模式下作物吸收氮、磷、钾的量最多（7月13日），甘蔗吸收氮、磷、钾的量均是最多的（11月13日）。三种种植模式中施肥量最大的是木薯+玉米，其次是木薯+花生，甘蔗是最少的。养分氮、磷径流率最大的均为甘蔗单种模式，养分钾径流率最大的为木薯+玉米种植模式。

Effect of Different Cultivation Methods on Nitrogen and Phosphorus Losses along with Runoff

In order to optimize cropping pattern of increasing fertilizer use efficiency, decrease nutrient loss and reduce environmental pollution, the field experiment was conducted to study the characteristics of slope farmland nutrient losses along with runoff in the main cash crop fields under the conventional fertilization practiced by farmers and major cropping patterns in Guangxi hilly sloping land. The results showed that loss amount of total phosphorus, total potassium and nitrate were maximum in cassava+maize mode, followed by loss amount of total nitrogen, ammonium nitrogen. The loss amount of the remaining nutrients was less except for the total phosphorus (245.1 g/hm), and the loss of nitrate nitrogen was the main loss form of nitrogen, which accounted for more than 50% of the total lost nitrogen. The maximum runoff was 60 974 L/hm² in the cassava+peanut model, the next was 58 583 L/hm² in sugarcane mode, and the least was 52 676 L/hm² in cassava+maize model. The amounts of the crop absorbing nitrogen, phosphorus and potassium were the most in cassava+maize model on July 13, Also the amounts of the nitrogen, phosphorus and potassium uptake by sugar cane were the most in sugar cane model on November 13. The amount of applying fertilizer of 3 cropping models was the highest in cassava+maize mode, higher in cassava+nut mode, but the least in sugar cane model. The runoff rate of nitrogen and phosphorus of 3 planting models was the highest in sugar cane model. The runoff rate of potassium of 3 planting models was the highest in cassava+maize model.