HYDRUS-1D模型对河套灌区不同灌施情景下氮素迁移的模拟

选取河套灌区五原建丰的典型土壤,应用HYDBUS-1D 模型对不同灌溉强度、不同表施浓度以及将表施改为灌施3类情景下土壤氮元素的迁移进行了动态模拟,研究了灌溉和施肥对河套灌区典型区域土壤氮元素迁移的影响.结果表明,灌水强度小于0.10 cm·h-1时,铵态氮与硝态氨累积流出通量变化极为缓慢;强度大于 0.14 cm·h-1时,累积流出通量急剧攀升,表明氮元素大量向土层深层流失.铵态氮表施浓度的变化对氮素的迁移几乎没有影响.保持相同的施肥量,灌施情景对铵态氮迁移几乎无影响,但表施换为灌施后硝态氮下渗浓度增加47%,更易于向深层渗漏.

Simulation of N transfer under different irrigation and fertilization scenarios in the Hetao irrigation area using HYDRUS-1D model

The effects of irrigation and fertilization on nitrate transfer from typical soil in Wuyuan Jianfeng of the Hetao irrigation area were determined. Three scenarios of different irrigation intensity, different surface fertilizer concentration and application of fertilizer solution instead of surface fertilization were configured in a validated Hydrus-1D model. The results showed that: the cumulative bottom nitrogen fluxes change slowly when the irrigation intensity is lower than 0.10 cm·h-1. When irrigation intensity is up to 0.14 cm·h-1, the cumulative bottom nitrogen flux rises sharply which indicates that a large amount of nitrogen leaches to the deeper layer. The concentration of surface fertilizer does not affect the amount of fertilizer losses. The bottom concentration and cumulative bottom flux of nitrogen calculated by the model are the same, which indicates that surface fertilization concentration has almost no influence on nitrogen transport. Under the fertilizer solution scenario, when the same amount of fertilizer is applied, the different ammonium nitrogen concentrations has almost no influence on transport and transformation of ammonium nitrogen. Meanwhile, the concentration of nitrate nitrogen leaching increases by 47%, the nitrate nitrogen leaches to the deeper layer and is not retained for a long time in the soil.