洱海流域不同轮作与施肥方式对农田氮磷径流损失的影响

为了探讨洱海流域不同轮作与施肥方式对农田土壤径流氮磷损失的影响，在洱海地区利用田间小区试验，研究了7种轮作模式（大蒜-玉米、大麦-水稻、油菜-水稻、蚕豆-烤烟、大蒜-烤烟、蚕豆-水稻、大蒜-水稻）和3种施肥方式（速效肥、缓释掺混肥、不施肥）下的作物产量以及地表径流氮磷损失特征。与习惯施肥处理（CF）相比，施用缓释掺混肥（BB）能够减少肥料使用量，氮、磷肥减少量分别为9.85%~47.49%和10.81%~63.33%；同时部分作物产量有明显提高，大麦-水稻轮作下水稻产量提高19.69%，蚕豆-水稻轮作下蚕豆产量提高16.99%，大蒜-水稻轮作下大蒜产量提高24.32%，油菜-水稻轮作下油菜产量提高35.79%。7种轮作模式下施用BB肥均能降低土壤径流中氮磷损失，BB处理较CF处理土壤径流总氮和总磷流失量分别降低10.72%~28.80%和17.13%~47.87%。种植烤烟施肥量偏高，易造成土壤径流氮磷流失，总氮和总磷流失量分别达到5 907.00g·hm^-2和821.25 g·hm^-2；油菜-水稻轮作易造成土壤径流磷损失，总磷损失量达到1 045.77 g·hm^-2。研究表明，在洱海地区，施用相应作物专用BB肥能够有效降低土壤径流氮磷损失，蚕豆-水稻轮作是一种较好的减少氮磷面源污染的种植模式。

Influence of different crop rotations and fertilization methods on nitrogen and phosphorus runoff losses in Erhai Lake basin,China

This study explored the influence of different crop rotations and fertilization methods on the nitrogen and phosphorus runoff losses in Erhai Lake basin. Field plot experiments were conducted to investigate the crop yields and characteristics of nitrogen and phosphorus runoff losses under seven different rotation systems:Garlic-corn, barley-rice, oilseed rape-rice, broad bean-tobacco, garlic-tobacco, broad bean-rice, and garlic-rice, combined with three fertilization methods:Fast-release fertilizer (CF), slow-release bulk blending fertilizer (BB), and no fertilizer (CK). Compared with CF, application of BB reduced the amount of nitrogen and phosphorus fertilizer by 9.85%~47.49% and 10.81%~63.33%, respectively, and there were obvious yield increases:19.69% for rice in the barley-rice rotation, 16.99% for broad beans in the broad bean-rice rotation, 24.32% for garlic in the garlic-rice rotation, and 35.79% for oilseed rape in the oilseed raperice rotation. Under the seven rotation systems, the total amounts of nitrogen and phosphorus runoff losses in BB treatments were lower by 10.72%~28.80% and 17.13%~47.87%, respectively, than those in the CF treatments. Higher amounts of fertilizer applied to flue-cured tobacco resulted in increased runoff losses of nitrogen and phosphorus of 5 907.00 g·hm^-2 and 821.25 g·hm^-2, respectively. The oilseed raperice rotation resulted in high runoff loss of phosphorus (1 045.77 g·hm^-2). Our results indicated that BB fertilizers specifically tailored for targeted crops and soils could effectively reduce the nitrogen and phosphorus runoff losses. Broad bean-rice is a good rotation system for decreasing non-point pollution from nitrogen and phosphorus in Erhai Lake basin.