施肥量对膜孔灌土壤氮素动态变化影响

为了研究施肥量对膜孔灌玉米整个生育期土壤硝态氮动态变化和收获后累积影响以及对硝态氮的环境影响进行评价,在测坑中进行了膜孔灌不同肥量施尿素试验,分析测定了膜孔灌玉米不同生育时期的土壤硝态氮质量分数。研究表明,不同施肥量处理距膜孔中心距离越大,垂直剖面上的硝态氮质量分数越小,施肥量越大,垂直剖面上的硝态氮质量分数越大;不同施肥量处理距膜孔中心3cm和8cm的垂直剖面上出现硝态氮累积峰,增大施肥量推迟了玉米吸收硝态氮最大时期;施肥量越大,玉米产量越高,累积的硝态氮质量分数越大,硝态氮累积量与施肥量之间存在对数函数关系;在拔节期和抽穗期,中肥量和高肥量处理下层的土壤硝态氮质量分数高于本底值,是硝态氮淋失的危险时期。

Effect of Fertilizer Amount on Dynamic Change Characteristic of Soil Nitrogen under Film Hole Irrigation

Though the different urea amount experiment made under film hole irrigation in the testing-hole,the soil nitric nitrogen amount of maize field under different growth period was determined in order to study the dynamical change of soil nitric nitrogen and evaluate the environment effect of soil nitric nitrogen.The result showed: the nitric nitrogen amount on the profile is little as the distance from film hole center is increase and large as the fertilizer amount increase;there is nitric nitrogen accumulation peak on the profiles being 3 cm and 8 cm away from film hole center under different fertilizer.To increase fertilizer postponed the max nitric nitrogen absorption period.The corn yield and nitric nitrogen accumulation amount is large with fertilizer increasing and there is logarithm function relationship between nitric nitrogen accumulation amount and fertilizer amount;shooting stage and heading stage is the dangerous period of nitrogen leaching because the nitrogen amount is large in the lower soil.The result provided the proof for reasonable fertilizer and evaluating effect of nitrogen on environment.