不同施氮量对棉花产量、养分吸收及氮素利用的影响

【目的】覆膜滴灌条件下,研究不同施氮量对棉花产量、养分吸收和氮素利用的影响,为棉花生产合理施氮提供科学依据。【方法】试验于2017～2019年设在新疆阿瓦提县,共5个施氮水平(0、110、220、330、440 kg/hm²),于棉花吐絮期采集植株样品,测定棉花产量、生物量、养分吸收和氮素利用。【结果】当施氮量在0～220 kg/hm²时,棉花产量、生物量和产值随着施氮量的增加显著增加,棉花对氮、磷、钾的吸收也显著增加,当施氮量大于220 kg/hm²时影响不显著。棉花氮素偏生产力和农学效率随施氮量增加显著降低。当施氮量大于220 kg/hm²时,氮素表观利用率显著降低,氮素贡献率差异不显著。【结论】当施氮量在0～220 kg/hm²时,随着施氮量的增加,棉花产量、生物量、产值和氮、磷、钾养分的吸收显著增加,当施氮量大于220 kg/hm²时,氮素表观利用率显著降低。综合棉花产量、经济效益、养分吸收和氮素利用,供试棉田推荐施氮量为220 kg/hm²。当施氮量为220 kg/hm²时,形成100 kg籽棉,需吸收N 4.25 kg、P₂O₅ 1.14 kg、K₂O 3.61kg。

Effects of Different Nitrogen Application Rates on Yield,Nutrient Uptake and Nitrogen Utilization of Cotton in Southern Xinjiang

【Objective】 To study the effects of different nitrogen application rates on yield, nutrient uptake and nitrogen utilization of cotton under the condition of film mulching drip irrigation in the hope of proving scientific evidence for reasonable nitrogen application in cotton production in Awati County, Xinjiang.【Method】 The experiment was conducted in Awati County of Xinjiang from 2017 to 2019 and five different nitrogen application rates were set up under the same amount of phosphorus and potassium. Cotton samples were collected at the boll opening stage, and the yield, biomass, nutrient absorption and nitrogen utilization of cotton were determined.【Result】 The cotton yield, biomass and output value increased significantly with the increase of nitrogen application rate when the rate was 0-220 kg/hm², and the absorption of nitrogen, phosphorus and potassium also increased significantly, but the effect was not significant when the nitrogen application rate was higher than 220 kg/hm². The nitrogen partial productivity and agronomic efficiency of cotton decreased significantly with the increase of nitrogen application rate. Nitrogen apparent utilization decreased significantly when the nitrogen application rate was more than 220 kg/hm², and the difference of nitrogen contribution rate was not significant.【Conclusion】 The cotton yield, biomass and output value increased significantly with the increase of nitrogen application rate when the rate was 0-220 kg/hm², and the absorption of nitrogen, phosphorus and potassium also increased significantly, and nitrogen apparent utilization decreased significantly when the nitrogen application rate was more than 220 kg/hm². Therefore, considering yield, economic benefits, nutrient absorption and nitrogen utilization of cotton, the recommended nitrogen application rate of the selected cotton field is 220 kg/hm², and the amount of N, P₂O₅, K₂O absorbance by 100 kg cotton is 4.25 kg, 1.14 kg and 3.61 kg when nitrogen application rate was 220 kg/hm².