氮肥基追比和种植模式对棉花氮素代谢和叶片衰老以及产量的影响

Effects of base-topdressing ratio of nitrogen fertilizer on nitrogen metabolism and leaf senescence of cotton under different planting patterns

  • 摘要: 为确定新疆棉区棉花高产高效栽培的合理施肥策略, 研究了氮肥基追比例对不同种植模式棉花氮素利用效率、叶片衰老特性及产量的影响。以‘新陆中84号’棉花品种为研究对象, 于2022—2023年在新疆沙雅县海楼镇进行田间试验。采用裂区设计, 以2种种植模式为主区: 一膜六行(66 cm+10 cm宽窄行距、株距12 cm, M6)、一膜三行(76 cm等行距、株距6 cm, M3); 以4种氮肥基追比例为副区: 0∶0 (CK, 不施氮)、0∶10 (N0)、2∶8 (N2)、4∶6 (N4); 共8个处理。施氮处理总施氮量均为320 kg∙hm−2。本文测定了棉花不同生育期氮代谢酶及叶片衰老相关酶活性、氮素利用效率、产量及产量构成。结果表明, 2022年和2023年M3N4处理的棉花可获得较高籽棉产量, 分别为7342.598085.19 kg∙hm−2, 较M6N2处理(M6最优产处理)提高12.05%和6.18%; M3N4处理表现出更好的结铃性, 单株铃数较M6N2处理增加10.17%, 但单铃重平均减少1.48%。M3N4处理在盛花期—盛铃期棉花功能叶可保持较高的酶活性, 促进棉花氮代谢, 延长叶片功能期; M3模式整体较M6模式的氮素最大积累速率(Vm)有所降低, 氮素最大积累速率出现时间(T)略有推迟, 快速累积持续持续天数(∆t)增加3.85~11.64 d, 氮素快速增长期生长特征值(TG)提高4.23%~27.60%。M3模式下各氮肥处理棉株氮素总积累量均高于M6模式对应氮肥处理, M3N4处理营养器官氮素积累量显著高于其他处理; M3N4处理棉花氮肥农学利用率、氮肥回收率和氮肥偏生产力较于M6N2处理分别增加7.77%、10.56%和8.90%, 但氮肥生理利用率降低3.03%。合理的氮肥基追比和种植模式可调控棉株个体和群体之间的关系, 加快棉花氮代谢水平, 增加棉株各器官氮素积累转运量, 进而提高氮素利用效率, 通过提高生理代谢酶活性延缓棉花叶片衰老, 维持较高棉株单株铃数, 从而充分发挥棉花生产潜力。在本试验条件下, 选择76 cm等行距种植模式, 氮肥基追比控制在4∶6为增产最优组合。

     

    Abstract: This study investigated the effects of different nitrogen fertilizer application ratios of base to topdressing on the nitrogen use efficiency, leaf senescence characteristics, and cotton yield under different planting patterns with the aim of providing a rational fertilization strategy for high-yield and efficient cultivation of cotton in Xinjiang cotton-growing areas. The cotton variety ‘Xinluzhong 84’ was chosen as the research object, and field experiments were conducted in Hailou Town, Shaya County, Xinjiang, in 2022 and 2023. A split-plot design was employed, involving two main planting patterns: one film with six rows with an alternating wide / narrow rows-spacing of 66/10 cm and plants-spacing of 12 cm (M6), and one film with three rows with an equal rows-spacing of 76 cm and plants-spacing of 6 cm (M3); and four nitrogen fertilizer application ratios of base to topdressing of 0∶0 (CK; no nitrogen application), 0∶10 (N0), 2∶8 (N2), and 4∶6 (N4) as subplots. There were totaling eight treatments. The total nitrogen application rate for all nitrogen treatments was 320 kg∙hm−2. The nitrogen metabolism-related enzymes activities, leaf senescence-related enzymes activities, nitrogen use efficiency, yield, and yield components were measured. Results showed that in 2022 and 2023, the yield of seed cotton was higher under the M3N4 treatment, reaching 7 342.59 and 8 085.19 kg∙hm−2, being 12.05% and 6.18% higher than those of the M6N2 treatment (optimal yield treatment of M6 pattern), respectively. Compared with the M6N2 treatment, boll number per plant of the M3N4 treatment increased by 10.17%; however, the boll weight decreased by 1.48% on average. The M3N4 treatment maintained a high activities of enzymes at the full-flowering and full-bolling stages, promoted nitrogen metabolism in cotton, and prolonged the functional period of cotton leaves. Compared with the M6 pattern, the maximum nitrogen accumulation rate (Vm) of the M3 pattern was decreased; however, the occurrence time of the maximum rate of nitrogen accumulation (T) was slightly delayed, duration of rapid nitrogen accumulation (∆t) increased by 3.85–11.64 days, and growth characteristic value of rapid accumulation period of nitrogen (TG) increased by 4.23%–27.60%. The total nitrogen accumulation of cotton plants of each nitrogen fertilizer treatment under the M3 pattern was higher than that of the corresponding nitrogen fertilizer treatment in the M6 pattern, and the nitrogen accumulation in vegetative organs in the M3N4 treatment was significantly higher than that in the other treatments. Compared with the M6N2 treatment, the agronomic nitrogen use efficiency, nitrogen recovery efficiency, and partial factor productivity of cotton in the M3N4 treatment increased by 7.77%, 10.56%, and 8.90%, respectively; however, the physiological nitrogen use efficiency decreased by 3.03%. Reasonable nitrogen base-topdressing ratio and planting pattern can regulate the differences between individual and group cotton plants, increase the nitrogen metabolism levels and nitrogen accumulation and transport in various plant organs to enhance the nitrogen use efficiency, boost the physiological enzyme activity to delay leaf senescence in cotton plants, maintain a higher boll number per plant, and fully exploit the cotton production potential. Under these experimental conditions, a planting pattern with an equal spacing of 76 cm and a nitrogen fertilizer application ratio of 4∶6 was identified as optimal for increasing the yield.

     

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