密度与氮肥运筹对陇东旱塬全膜双垄沟播春玉米产量及生理指标的影响

摘要

[Objective] This research aims to determine the optimal planting density, amount of nitrogen utilization, and pattern for nitrogen utilization, so as to develop reasonable measures for cultivation.[Method] In this research, the cultivar “Xianyu335” was applied as research material. Two nitrogen utilization amounts (namely 150 and 225 kg/ha), 2 densities (namely 6×104 and 7.5×104plants/ha), and 5 nitrogen topdressings at different growth stages (namely 100% base manure, 100% topdressing at jointing stage, 50% base manure+50% topdressing at jointing stage, 50% base manure+30% topdressing at jointing stage+20% topdressing at tasseling stage, and 50% base manure+10% topdressing at jointing stage+40% topdressing at tasseling stage) were set under plastic-covered ridge and furrow planting. Through a 3-year field test, the effects of planting density, nitrogen utilization amount, and nitrogen application pattern on arid-field spring maize yield and physiological indexes were investigated.[Result]Within the ranges of nitrogen utilization amount and density used in this research, under the same nitrogen utilization amount, maize yield increased extremely significantly with the enhancement of planting density, while such indexes as Pn,Tr, andGs declined. However, under the same planting density, yield differences among various nitrogen utilization amounts were not significant, despite the fact that yield was greater under high nitrogen utilization amounts than under low ones. Meanwhile, under the same density and the same nitrogen utilization amount, yield differences among various nitrogen utilization patterns were all extremely significant,Pn,Gs andTr were highest in a ratio of base manure to topdressing at the jointing stage reaching 50%:50%, and WUE changed the same as yield did. Compared with a one-step fertilizer application before sowing or at the jointing stage, stage-by-stage topdressing can delay chlorophyll decline in maize leaves at a later-growth period, improve the production and transportation of photosynthetic matters, and optimize yield composition; and such effects are especially salient when the ratio of base manure to topdressing at the jointing stage amounts to 50%:50%. Therefore, the coordinated enhancement of both yield and physiological indexes of spring maize in rain-fed areas of the eastern Gansu Province can be realized through the combined optimization of planting density and a pattern for nitrogen utilization.[Conclusion]Under the experimental conditions of this research, a proposed model represents a high-yield, nitrogen-saving, highly-efficient, and environment-friendly cultivation model suitable for rain-fed agricultural areas of the eastern Gansu Province. Under this model, a planting density of 7.5×104 plants/ha is adopted with a nitrogen utilization amount of 150kg/ha and a 50%: 50% ratio of base manure to topdressing at the jointing stage.%【目的】研究全膜双垄沟播玉米在陇东雨养农业区产量和生育指标同步提高的最佳种植密度、氮肥施用量及运筹方式，制定合理的栽培措施。【方法】本试验以先玉335为试材，在全膜双垄沟播种植条件下设置了2个氮肥用量（150、225kg·hm-2），2个密度（6×104、7.5×104株/hm2）和5个氮肥追施比例及时期（底肥100%；拔节期追施100%；底肥50%、拔节期50%；底肥50%、拔节期30%、抽雄期20%；底肥50%、拔节期10%、抽雄期40%）。通过3年田间试验，研究种植密度、氮肥用量及运筹方式对旱地春玉米产量及生理指标的影响。【结果】在试验氮肥用量及密度范围内，相同施氮量随种植密度增加，玉米产量极显著增加，净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）均减少；相同密度不同氮肥用量间产量差异不显著，但高氮处理玉米产量优于低氮处理；相同密度及氮肥用量条件下，氮肥运筹方式间产量差异均极显著，以基肥﹕拔节肥比例为50%﹕50%的处理 Pn、Gs、Tr均最高，水分利用效率与产量变化一致。与播前或拔节期一次性施肥相比，氮肥分期施用可以延缓玉米生育后期叶片叶绿素相对含量的下降，增加生育后期光合物质生产量和转运量，优化产量构成，基肥和拔节肥施用比例为50%﹕50%时效果尤为显著。因此，通过种植密度和氮肥运筹方式的集成优化，可以实现陇东雨养农业区春玉米产量和生理指标的协同提高。【结论】产量不降低是农业生产的目的，玉米生理指标的提高是保证产量的根本。因此，在本试验条件下，采用密度7.5×104株/hm2、施氮量150 kg·hm-2以及基肥：拔节肥比例为50%﹕50%的氮肥运筹方式，是陇东雨养农业区的一种高产、节氮、增效、环保的栽培模式。