【摘要】 采用田间小区试验,连续三年研究了太湖地区稻季的氮素径流损失及影响因素,暴雨导致的田面水高度超过土面7 cm后通过管道流入径流收集池。结果表明:稻田氮素径流损失的主要形态是溶解态氮(DN),DN中的NH4+-N浓度基本低于NO3--N浓度,NH4+-N浓度受施氮水平的影响,而NO3--N浓度不受施氮水平的影响。稻田氮素的径流损失量为N 1.0~17.9 kg hm-2,占稻季施氮量的0.3%~5.8%。氮素径流损失量年际差异很大,在同一个稻季损失量随施氮量的增加而增加。氮素径流损失量与径流发生前田面水中氮浓度间的关系可用方程式y=ax+b表示。通过调节施肥与暴雨的间隔时间、控制施氮量以及抬高田埂高度等措施,可以降低稻田氮素的径流损失风险。更多还原

【Abstract】 In order to evaluate nitrogen loss with runoff from paddy field and its affecting factors in the rice season,field experiments were carried out for three years in succession in the Taihu Lake region.When heavy rain shower brought water table of the flooded water 7 cm above the land overflow was piped to a runoff pooling pond.Results of the experiments show that dissolved N(DN) was the main form of N lost with runoff.Among the DN concentration of NH+4-N was lower than that of NO-3-N in general,and the former was correlated with N fertilization rate but the latter was not.Seasonal TN loads in runoff ranged between 1.0 and 17.9 kg hm-2 during the rice seasons,accounting for 0.3%～5.8% of the applied N.N loss with runoff differed greatly between rice seasons and increased with the N rate in the same rice season.The relationship between TN loads in runoff and N concentrations in surface water before runoff could be expressed by equation y=ax+b.The risk of N losses through runoff in the rice season could be minimized by reducing fertilization rate,avoiding fertilization just before heavy rainfall and heightening the ridges of the paddy field.更多还原