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

Abstract

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.