水氮互作下直播稻群体质量与氮素利用特征的关系

探讨水氮耦合下直播稻群体质量和氮素利用特征可为直播水稻丰产高效生产提供理论基础和实践依据。以杂交稻‘F优498’为试验材料,设置淹水灌溉(W₁)、干湿交替灌溉(W₂)、旱种(W₃)3种灌水方式和基肥∶蘖肥∶穗肥分别为5∶3∶2(N₁)、3∶3∶4(N₂)、3∶1∶6(N₃)3种氮肥运筹模式,以不施氮处理(N₀)为对照,研究水氮互作对直播稻群体质量和氮素利用特征的影响,并探讨水氮互作下直播稻群体质量构建与氮素利用特征和产量的关系。结果表明:灌溉方式和氮肥运筹对直播稻各生育时期干物质积累、稻谷收获指数、抽穗及抽穗20 d高效叶(上3叶)干重、结实期群体透光率、氮素积累总量、氮肥表观利用率、氮肥偏生产力、氮肥生理利用率和产量均存在显著的互作效应。综合直播稻群体质量、产量和氮肥利用特征,各灌溉方式下,氮肥后移比例均以占总量的20%～40%(N₁～N₂)为宜,氮肥后移比例达到总量的60%(N₃)和W₃处理均会显著降低直播稻群体质量、产量、氮肥农学利用率和氮肥偏生产力。相关分析表明,水氮互作下直播稻产量和氮素利用特征与最终有效分蘖数、结实期干物质积累、其余叶(除上三叶以外叶片)干重减少量、总叶片干重减少量,以及群体中部和基部受光率均呈显著或极显著正相关。干湿交替灌溉(W₂)可以提高直播稻茎蘖成穗率、各时期干物质积累、稻谷收获指数、氮肥吸收总量、氮肥农学利用率和最终产量,配合N₂的氮肥运筹模式可优化调控直播稻群体质量,实现高产与氮肥高效利用的协调统一,为本试验最优组合。

Relationship of population quality and nitrogen fertilizer utilization characteristics of direct seeding rice under water-nitrogen interaction

Understanding population quality and nitrogen utilization characteristics of direct seeding rice under water-nitrogen interaction could provide theoretical and practical basis for high yield and ample production of direct seeding rice. Hybrid rice F You 498 was used as the material. Three irrigation methods were set in this study: flooding irrigation (W₁), dry-wet alternate irrigation (W₂) and drying irrigation (W₃), with different ratio of base fertilizer: tiller fertilizer: panicle fertilizer at 5:3:2 (N₁), 3:3:4 (N₂), 3:1:6 (N₃), respectively. No nitrogen application (N₀) was set as the control. We investigated the effects of water-nitrogen interaction on population quality and nitrogen utilization characteristics of direct seeding rice, with the aim to clarify the relationship between population quality construction, nitrogen utilization characteristics and yield of direct seeding rice. The results showed that irrigation and N rate significantly interacted to affect dry matter accumulation, rice harvest index, heading high-efficiency leaf (the upper three leaves) dry weight, light transmittance rate at maturity stage, total nitrogen accumulation (TNA), apparent nitrogen use efficiency (ANE), nitrogen partial factor productivity (NPFP), nitrogen physiology efficiency, and rice yield. Taking population quality, yield and N fertilizer utilization characteristics into consideration, suitable panicle N-fertilizer under each irrigation mode was 20%-40% (N₁-N₂). Panicle N-fertilizer reached 60% (N₃) and W₃ treatment would significantly reduce population quality, yield, nitrogen agronomy efficiency (NAE), NPFP of direct seeding rice. Yield and nitrogen utilization characteristics of direct seeding rice were significantly correlated with effective panicles, dry matter accumulation at maturity stage, other leaf (except the upper three leaves) dry weight reduction, total leaf dry weight reduction, and middle part and basel part light-receiving rate under water-nitrogen interaction. The dry-wet alternative (W₂) treatment could increase the rate of production til-lers, dry matter accumulation, rice harvest index, TNA, NAE and rice yield. W₂ combined with N₂ could improve population quality of direct seeding rice and realized the coordination and unification of high yield and efficient utilization of nitrogen, which is the best combination in this experiment.