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通过野外径流小区观测试验,研究了巢湖流域旱地秸秆覆盖与平衡施肥条件下的径流、泥沙和氮素流失特征。结果表明,相对于当地传统耕作区,秸秆覆盖和平衡施肥能分别减少30.47%和21.61%的径流量,减少22.88%和20.59%的泥沙量,表现出显著的水土保持作用。当地传统耕作处理氮向水体迁移的负荷量为3.04 kghm-2,流失系数为1.35,其中溶解态氮是氮迁移的主要形式,其浓度占总氮浓度的60%~88%。秸秆覆盖与平衡施肥均能有效的降低径流氮的流失量,可分别降低27.42%和21.88%的氮流失,但其对径流氮浓度的影响却不明显。作物生长情况显著影响土壤氮素的流失,地上部分生物量与径流总氮的迁移量呈负相关关系。因此秸秆覆盖和平衡施肥可以作为源头控制农田养分流失的较好措施加以推广。
Through field observation experiment, the characteristics of runoff, sediment and nitrogen loss in dry land under the condition of straw mulching and balanced fertilization in Chaohu Lake were studied. The results showed that straw mulching and balanced fertilization could reduce the runoff of 30.47% and 21.61%, decrease the sediment amount of 22.88% and 20.59% respectively, showing significant soil and water conservation compared with the traditional farming areas. The local traditional tillage treatment of nitrogen migration to the water load of 3.04 kghm-2, the loss coefficient of 1.35, of which dissolved nitrogen is the main form of nitrogen migration, the concentration of total nitrogen concentration of 60% to 88%. Both straw mulching and balanced fertilization could effectively reduce runoff nitrogen loss and reduce nitrogen losses by 27.42% and 21.88%, respectively. However, its effect on runoff nitrogen concentration was insignificant. The crop growth significantly affected the soil nitrogen loss, and the aboveground biomass had a negative correlation with the total nitrogen migration. Therefore, straw mulching and balanced fertilization can be used as the better source for controlling farmland nutrient loss and promoting it.