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农田土壤的矿质氮残留和淋溶已成为大气和水体氮污染的重要来源。本文通过位于黄土高原南部的田间试验,研究了气温、土壤温度和水分、灌溉和降水等环境条件与夏玉米生长季节土壤残留矿质氮素动态变化的关系。结果表明:①0～200cm土层铵态氮残留量与耕层土壤温度的动态变化趋势一致,但土壤硝态氮残留量与土壤温度变化趋势相反。②大气温度对土壤矿质氮数量的影响趋势和土壤温度的基本相同。③在夏玉米生长季节0～200 cm土层土壤含水量平均值呈波动增加趋势,土壤铵态氮和硝态氮残留量随土壤水分的增减而增减,矿质氮素增减变化与土壤含水量相比有滞后现象。④夏玉米生长季节降水和灌水量达到720.5 mm,大量水分使得土壤硝态氮随着夏玉米生长期的后移而有明显的向下淋移趋势。玉米收获时,土壤硝态氮已被淋失到200 cm以下土层,难以再被下季作物利用。
Mineral nitrogen in agricultural soils remains and leachate has become an important source of nitrogen pollution in the atmosphere and water bodies. In this paper, field experiments in southern Loess Plateau were carried out to study the relationship between temperature, soil temperature and moisture, irrigation and precipitation, and the dynamic changes of residual mineral N in soil during summer corn growing season. The results showed that: ① The dynamic changes of ammonium nitrogen in 0 ~ 200cm soil layer were consistent with that of topsoil temperature. However, the changes of soil nitrate nitrogen residue and soil temperature had the opposite trend. ② The effect of atmospheric temperature on the quantity of mineral N in soil is basically the same as the soil temperature. (3) The mean value of soil water content in 0 ~ 200 cm soil layer showed a trend of increasing during the growing season of summer maize. The content of soil ammonium nitrogen and nitrate nitrogen increased and decreased with the increase or decrease of soil moisture. Water content compared to a lag phenomenon. ④ Summer maize growing season rainfall and irrigation reached 720.5 mm, a large amount of water makes the soil nitrate nitrogen with the summer maize growth stage after the shift and there is a significant leaching trend. When corn is harvested, soil nitrate nitrogen has been leached to soil below 200 cm, making it difficult to be used again by the next crop.