不同农作制对四川紫色丘陵区地表径流氮、磷流失的影响

以小麦(Triticum aestivum)-玉米(Zea mays)轮作制为基础,通过在仁寿县建立18个径流小区监测试验,对4种不同农作制与4种施肥水平下各小区径流水样中的氮、磷含量进行了分析.探讨了四川紫色丘陵区坡耕地氮、磷流失系数及其影响因素.结果表明,氮流失总量随施氮量而增加,在增量施肥+横坡种植方式下最大,为0.326 kg·hm~(-2);氮流失总量和流失系数在优化施肥+横坡种植+秸秆覆盖+植物篱方式下最小,其流失总量为0.270kg·hm~(-2),流失系数为0.009%0磷流失总量和流失系数在不同处理方式下总体上虽较为接近,但增量施肥+横坡种植方式下磷的流失总量最大,为0.020kg·hm~(-2);而优化施肥+横坡种植+秸秆覆盖+植物篱最小,为0.015kg·hm~(-2).研究表明,优化施肥、横坡种植、秸秆覆盖和植物篱拦蓄地表径流作用明显,是遏制耕地氮、磷流失的有效途径.

Effects of different farming systems on nitrogen and phosphorus loss from surface runoff in purple hilly region in Sichuan

Based on the wheat(Triticum aestivum) maize(Zea mays) rotation pattern, we studied the nitrogen and phosphorus loss coefficient and its influencing factors in Shichuan purple hilly region through the monitoring test in eighteen runoff plots located in Renshou County. We analyzed nitrogen and phosphorus content in different water samples collected in different runoff plots from regions where four different cultivation patterns and four different fertilization standard were applied. The results showed that it produced the maximal total amount of nitrogen loss under the condition of incremental fertilization plus cross-slope cultivation; the total loss is 0.326 kg per ha. It produced the minimal total amount of nitrogen loss and the loss coefficient under the condition of optimal fertilization plus cross-slope cultivation plus straw mulch plus economic hedgerow; the total loss is 0.270 kg per ha and the loss coefficient is 0.009%. Although the total amount of phosphorus loss and the loss coefficient are closer in different treatments, it produced the maximal total amount of phosphorus loss 0.020 kg per ha under the condition of incremental fertilization plus cross-slope cultivation and the minimal total amount of phosphorus loss under the condition of optimal fertilization plus cross-slope cultivation plus straw mulch plus economic hedgerow; the total loss is 0.015 kg per ha. This study indicated that optimal fertilization, cross-slope cultivation, straw mulch and economic hedgerow showed evident effect on reducing surface runoff. These measures are effective to decrease the nitrogen and phosphorus loss.