用数值反应和实验种群生命表分析胡瓜钝绥螨的控制能力

 在华北平原玉米-潮土系统中,采用原状土柱培养乙炔抑制法研究尿素、硝酸铵、碳酸氢铵和硝酸钙4种氮肥品种的反硝化损失和 N2O 排放量。结果表明,氮肥品种的反硝化损失量为 0.38～1.20　kgN·ha-1,品种间无显著差异;N2O 排放量为 0.05～0.95　kgN·ha-1,品种间差异显著。硝酸铵排放量最高,硝酸钙最低。尿素分 2 次施用比 1 次施用显著或极显著增加反硝化损失量和N2O 排放量,分别增加 4.05 和 1.84　kgN·ha-1。施用氮肥极显著增加玉米产量,增产率达9.7%～19.8%

Denitrification Losses and N2O Emission from Different Nitrogen Fertilizers Applied to Maize-Fluvo-Aquic Soil System

A field experiment was conducted to study the differences of denitrification losses and N2O emission from 4 types of nitrogen fertilizers applied to maize-Fluvo-Aquic soil system in North China Plain by the method of intact soil incubation and acetylene inhibition, and the responses of the nitrogen fertilizers on maize grain yield. Results showed that nitrogen losses from N fertilizer by denitrification ranged from 0.38 to 1.20 kgN.ha-1, N2O emission from 0.05 to 0.95 kgN.ha-1 and a significant difference (P<0.05) existed among the treatments, the highest being from ammonium nitrate, while the lowest from calcium nitrate. The nitrogen fertilizers increased maize grain yield by 9.7%-19.8% compared to control. However, there were no significant differences among nitrogen fertilizer treatments, and urea was the best in yield-increase, while calcium nitrate was the worst. The grain yield increased by 5.7%, but the N loss and N2O emission amounts were also increased by 4.05 and 1.84 kgN.ha-1 for urea was applied in two times and once respectively.