控释尿素对夏玉米产量、氮肥利用效率及土壤硝态氮的影响

Effects of applying controlled-release urea on the yield,nitrogen use efficiency and soil NO-3-N of summer maize

以夏玉米为研究对象,通过田间试验,比较分析不同氮水平下控释尿素与普通尿素的夏玉米产量、氮肥利用效率及土壤硝态氮间的差异。结果表明:控释尿素能显著提高玉米产量,相同氮水平下,控释尿素处理的籽粒产量较普通尿素的均有所增加,其中氮水平为75%处理的增产幅度最大,100%的处理次之,50%的最小,其增产达5.7%～28.9%。控释尿素与普通尿素的氮素表观损失量均随施肥量增加而升高,与对照不施氮处理差异显著。N肥利用率与N肥农学效率则表现为75%>50%>100%,且控释尿素处理有高于普通尿素处理的趋势,其中75%控释尿素处理的N肥利用率及N肥农学效率分别高达24.1%和17.4kg/kg。土壤剖面NO3--N含量随施氮量的增加而增加,控释尿素在夏玉米的2个氮素利用关键期(大喇叭口和抽雄)的土壤硝态氮含量均高于普通尿素,说明控释尿素在夏玉米氮素关键期能维持较高的水平以满足作物对于N素的需求,其中以75%控释尿素处理表现最好。本试验条件下,控释尿素75%的施氮水平是提高夏玉米产量、降低土壤硝态氮淋失的合理施氮量。

Effects of the application of controlled-release urea and urea on the summer maize yield, N use efficiency and so showed that, applying contro 1 nitrate were examined through field experiment in this study. It led-release urea significantly increased the maize yield by 5.7%- 28.9% in contrast to urea at the same N level, where the greatest yield increase occurred in 75% treatment followed by 100% and then 50%. Meanwhile, apparent N losses of controlled- release urea and urea application both increased with the respective N fertilization rate, which were significantly greater than CK. N use efficiency and agronomic efficiency of different treat- ments was inthe order of 75〉50〉100%, the trend was controlled-release urea greaterthan the respective urea treatment at a given N level, the N use efficiency and agronomic effi- ciency of 75% of control-released urea reached 24.1% and 17.4 kg/kg. Moreover, the increase of soil nitrate with N application rate was also obtained~ greater soil nitrate content in the con- trol-released urea treatments than the respective urea treatments in the critical periods of large bell and tasseling demonstrated their stronger N supply to meet the crop requirement, 75% of control-released urea has the best performance. Through this study, N fertilization rate of 75% of control-released urea was identified reasonable for summer maize production and reducing ni- trate leaching in soil.