不同施氮方式对玉米田土壤无机氮动态变化的影响

Effects of Different Nitrogen Application Methods on Dynamic Changes of Soil Inorganic Nitrogen in Corn Field

研究不同施氮方式对玉米田土壤水分动态变化和土壤无机氮变化特征的影响。结果表明，玉米生育期不同施氮方式下，0-100cm土壤水分变化趋势相似，非雨季0-20cm土壤含水量施肥处理比不施肥（CK）低2-4个百分点，雨季由于降雨的补给各处理各层土壤水分无明显变化。施氮显著增加了0-100cm土层无机氮含量。习惯施肥处理土壤硝态氮含量受降雨影响较大，表现出向土壤深层迁移的趋势；缓控释肥、优化施肥和优化施肥＋秸秆还田处理可降低土壤硝态氮的残留。0-40cm土壤铵态氮含量受基肥和追肥影响较大，41-100cm土壤铵态氮含量为3-5mg／kg，变化幅度较小，趋于稳定。合理的氮肥用量及施氮方式，可有效减少土壤硝态氮的残留，减轻浅层地下水硝态氮污染的风险。

To investigate the effect of different nitrogen application methods on the dynamic changes of soil water content and soil inorganic nitrogen. The results of the experiment showed that a similar trend of soil moisture at 0-100 cm during the growing season of maize. The soil moisture of fertilizer treatments was 2%-4% lower than CK in 0-20 cm soil during the rainy season. All treatments had no significant impact on soil moisture in each layers of soil due to the frequent precipitation. The amounts of nitrogen fertilizer significantly increase soil inorganic nitrogen content in 0-100 em soil. Farmer fertilizer treatment was influenced by rainfall amount and showed a trend to mi- grate to deeper soil. Controlled-release fertilizer, optimum fertilization and straw treatments could decrease the ni- trate residue in the soil. It has a more significant impact on the ammonium nitrogen content by the basal and top dressing nitrogen fertilizer application in 0-40 cm soil, ammonium nitrogen content in 41-100 cm soil was at a low level a 3-5 mg/kg. In summary, reasonable use of nitrogen fertilizer rate and manner can effectively reduce the amount of soil nitrate content, and it also decreased the risk of nitrate pollution in shallow groundwater.