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模拟降雨条件下农田径流中氮的流失过程
Nitrogen losses from farm runoff under simulated rainfall conditions
【摘要】 在室内降雨模拟试验条件下,研究暴雨径流中农田氮素养分流失及施肥处理的影响。结果表明,农田暴雨径流氮养分的流失量与累积径流量成正相关;施用NH4HCO3显著地增大了农田径流中溶解态氮浓度及流失量(P=0.01),而对颗粒态氮浓度及流失量没有显著影响(P=0.1);在大暴雨和裸露地试验条件下,颗粒态氮是农田暴雨径流氮养分流失的主要形态;在44 min降雨径流中,以颗粒态流失的氮达476.3~488.7 mg/m2;侵蚀泥沙有富集氮养分的特点,其富集系数与侵蚀泥沙累积量存在对数线性关系:LOG(ER)=0.770-0.300LOG(SED);减少地表径流和土壤侵蚀,降低表土中速效氮养分含量是减少农田地表径流氮流失的关键。
【Abstract】 Rainfall simulation experiment was performed to evaluate nitrogen losses from farmland and show the effect of fertilizer application on nitrogen concentration and losses of runoff. As expected, cumulative N loss of runoff is directly correlated with cumulative runoff; dissolve nitrogen concentration and the dissolve nitrogen lost significantly increase (P=0.01), but particulate nitrogen concentration and particulate nitrogen lost do not significantly increase (P=0.1) in farmland runoff of fertilizer application of NH4HCO3. Particulate nitrogen lost account for 476.3~488.7 mg/m2, and particulate nitrogen is the main form of N losses. Nutrient of N is enriched in eroded sediment, the logarithm of N enrichment ratio (ER) is negatively correlated with the logarithm of accumulated sediment discharge: log(ER)=0.770-0.300 log(SED).
【Key words】 simulated rainfall; farm runoff; nitrogen loss; enrichment ratio (ER);
- 【文献出处】 土壤与环境 ,Soil and Environmental Sciences , 编辑部邮箱 ,2001年01期
- 【分类号】X14
- 【被引频次】309
- 【下载频次】1072