大田条件下稻田土壤氮素淋失研究

在大田条件下研究了稻田土壤渗漏水中氮素淋失规律.结果表明，稻田土壤渗漏水中的氮素(N)淋失形态以硝态氮(NO^-₃-N)为主，土壤中高硝态氮含量和施氮肥是造成种稻田前期氮淋失的主要原因.种稻期间的淹水作用，增强了土壤的还原性并抑制了土壤的硝化反应，可减少硝态氮的淋失.稻田土壤氮素淋失数量与渗漏水中氮素的浓度和水的渗漏速率有关，而水的渗漏速率主要受土壤犁底层的透水性和水文条件的控制和影响.试验以施用氮肥250 kg/hm²和渗漏水量214 mm估算出单季稻田氮素淋失总量为6.44 kg/hm²，占当季施肥量的2.58%.

Study on Nitrogen Leaching of Paddy Soil in the Field Experiments(Chinese)

A field case study was conducted to elucidate the dynamic characteristics of N leaching in paddy fields during the rice-cropping season.The results showed that,nitrate(NO_3~--N)is the dominant species in natural leaching water of paddy soil.High NO_3~--N concentration in paddy field and fertilizer application are the main reasons of the heavy N leaching loss at the first few days of immerging.However,the leaching loss amount is weak in later paddy planting because the soil nitrification is inhibited under the condition of immerging.The leaching amount of N is affected by the concentration of N and leaching rate,while the leaching rate is controlled by per- viousness of the plough pan and the hydrographic conditions.Under the conditions of an applica- tion rate of 250 kg/hm~2 and a percolation of 200 mm,the N leaching load of 6.44 kg/hm~2 and are 2.58% of total fertilizer application amount are estimated for the single-rice cropping paddy.