平衡施肥及雨强对紫色土养分流失的影响

利用人工降雨装置模拟3种不同强度的降雨,采用模拟径流小区,研究了四川紫色丘陵区玉米净作条件下雨强及平衡施肥对土壤养分损失量及载体的影响.结果表明:雨强是影响地表径流量、径流总量及土壤侵蚀量的最主要因素.在小雨强条件下,无地表径流及土壤侵蚀发生;随着雨强的增大,地表径流量、径流总量及土壤侵蚀量都急剧增加.磷素和钾素流失总量也随雨强的增加而增加,而雨强对氮素流失的影响不大.在3种雨强条件下,3种施肥处理的氮素流失总量表现为:高氮施肥>农户习惯施肥>平衡施肥,平衡施肥能减少氮素流失,而高氮施肥增加氮素的流失.农户习惯施肥处理的磷流失总量和钾流失总量均高于平衡施肥和高氮施肥两种施钾处理,在紫色土坡耕地增施钾肥能减少磷、钾养分的流失.

Effect of balanced fertilization and rain intensity on nutrient losses from a purple soil in Sichuan

By employing an artificial rain device, the effects of three rain intensities and three different fertilizer practices on soil and nutrient losses from sloping corn plots were studied using a complete randomized block experiment. Rain intensity was determined to be the main factor influencing the amount of surface runoff, total runoff, and sediment. No surface runoff or soil erosion occurred at low rain intensity. As rain intensity increased, the amount of surface runoff, total runoff, and sediment increased sharply, causing increased losses of P and K. Rain intensity had little influence on the amount of N lost. The amount of N lost was mainly influenced by fertilizer practices, showing a ranking of N loss from low to high respectively: balanced fertilization