滴灌施肥条件下不同种类氮肥在土壤中迁移转化特性的研究

采用室内土柱模拟方法研究了滴灌条件下不同种类氮肥(硝态氮、铵态氮和尿素态氮)在土壤中的迁移、淋溶和转化特征。结果表明,3种氮肥在2种质地土壤中的淋失量均是硝态氮肥>尿素>铵态氮肥,淋失的氮素主要为肥料氮。砂壤土上氮素的淋失量明显高于粘壤土。滴灌施用铵态氮肥,显著增加了土壤中NH4+-N含量,随着硝化作用的进行,NH4+-N的量在培养的第5d左右达高峰,尔后含量逐渐降低。与滴灌施用硝态氮肥相比,施用铵态氮肥和尿素后在培养期间土壤矿质态氮(NO3--N+NH4+-N)的含量有降低的趋势，降低的原因可能与N+NH4+-N在土壤中的固定、挥发等有关。

Leaching and transforming characteristics of different nitrogen fertilizers added by fertigation

Soil column was used to study the characteristics of the movement, transformation, and leaching of different kinds of nitrogen fertilizers in soil added by fertigation. The result shows that the amount of nitrogen leaching was in the decrease order of NO~-_3-N fertilizer>urea>NH~ _4-N fertilizer, and the main form of N leaching was the N-fertilizers added. The amount of nitrogen leaching in sandy loam soil exceeded in clay loam soil. Applying NH~ _4-N fertilizer significantly increased the content of NH~ _4-N in soils, and as the processing of nitrification the content of NH~ _4-N was reduced, and NO~-_3-N was increased gradually. After applying the urea, the content of NH~ _4-N in soils reached up to the peak at the fifth day, and then began to decrease because of the occurring of the nitrification. The content of mineral nitrogen content (NH~ _4-N NO~-_3-N) decreased during the incubation period after applying NH~ _4-N fertilizer and urea. It might be related to the occurrence of NH~ _4-N fixation and volatilization.