灌溉方式和施氮量对直播稻氮素和水分利用的影响

Effect of irrigation management and nitrogen rate on nitrogen and water utilization of direct-seeded rice

  • 摘要: 为研究不同灌溉方式和施氮量对直播稻的光合生产、干物质积累、氮素利用、水分利用和稻谷产量的影响,采用裂区试验设计,主区因素为品种:‘德香4103’和‘金农丝苗’,副区因素为3种灌溉方式:浅水灌溉、轻干湿交替灌溉和重干湿交替灌溉,副副区因素为4个施氮量:0 kg(N)·hm-2、120 kg(N)·hm-2、180 kg(N)·hm-2、240 kg(N)·hm-2,分析测定直播稻的干物质积累量、氮素积累量和利用率、水分利用率和产量等指标。结果表明:灌溉方式和施氮量对直播稻氮素利用和产量形成的影响存在显著的互作效应。与浅水灌溉相比,轻干湿交替灌溉处理下‘德香4103’和‘金农丝苗’抽穗期剑叶净光合速率、拔节-抽穗期干物质积累量、结实期茎叶氮素转运量、成熟期籽粒中氮素积累量、氮素农艺效率和氮肥回收效率显著增加;抽穗期叶面积指数、拔节前干物质积累量、成熟期茎叶氮素积累量显著降低。施氮量对‘德香4103’和‘金农丝苗’氮素积累量、氮素利用效率、产量的影响存在差异。浅水灌溉处理中,与无氮相比,‘德香4103’和‘金农丝苗’施氮后产量分别提高31.79%~48.77%和29.72%~45.36%;施氮量超过180 kg·hm-2后,‘德香4103’的产量显著下降,而‘金农丝苗’相应指标却无显著变化。轻干湿交替灌溉处理中,与无氮相比,‘德香4103’和‘金农丝苗’施氮后产量分别提高32.58%~61.10%和36.49%~48.45%;施氮量超过180 kg·hm-2后‘德香4103’的产量无显著变化,氮肥回收效率、氮素农艺效率均显著下降,‘金农丝苗’的产量和干物质积累量无显著变化,成熟期氮素积累量显著提高。重干湿交替灌溉处理中,与无氮相比,‘德香4103’和‘金农丝苗’施氮后产量分别提高37.01%~42.88%和30.11%~42.63%;施氮量超过180 kg·hm-2后,‘德香4103’和‘金农丝苗’的产量无显著变化;但‘德香4103’成熟期氮素积累量显著增加,‘金农丝苗’氮素积累量却无显著增加,两个品种氮素农艺效率均显著降低。综上所述,轻干湿交替灌溉更适合于直播稻高产、节水、高效栽培,其中‘德香4103’产量在轻干湿交替灌溉下施纯氮240 kg·hm-2处理最高,‘金农丝苗’产量在轻干湿交替灌溉下施纯氮180 kg·hm-2处理最高。

     

    Abstract: Direct-seeded rice has advantages of less labor, lower labor strength and cost. But it meantime has different development characteristics from the transplanted rice. It is necessary to investigate the cultivation and growth of direct-seeded rice. In this study, a field experiment was conducted to investigate the effects of irrigation managements and nitrogen application rates on nitrogen and water utilization and yield of direct-seeded rice. In the experiment, a split-split plot design was set with rice varieties ('Dexiang 4103' and 'Jinnongsimiao') as the main factor, irrigation managements (shallow water irrigation, alternate irrigation with wetting and moderate drying, alternate irrigation with wetting and severe drying) as the sub-plot factor, and N rate (0 kg·hm-2, 120 kg·hm-2, 180 kg·hm-2 and 240 kg·hm-2) as the split-split plot factor. The photosynthetic rate, dry matter accumulation, nitrogen utilization, water utilization and yield of direct-seeded rice were measured at different growth stages. There was a significant interaction between irrigation management and N rate on nitrogen utilization, water utilization and yield of direct-seeded rice. Compared with the shallow water irrigation, the net photosynthetic rate at jointing stage, dry matter accumulation at jointing-heading stage, nitrogen transport amounts of stems and leaves at mature stage, nitrogen accumulation of grains at maturity stage, nitrogen agronomic efficiency and nitrogen fertilizer recovery efficiency were significantly increased in the alternate irrigation with wetting and moderate drying; however, the leaf area index at heading stage, dry matter accumulation before jointing and nitrogen accumulation in stems and leaves at mature stage were significantly decreased. The effect of N rates on nitrogen accumulation, nitrogen utilization efficiency and yield of 'Dexiang 4103' and 'Jinnongsimiao' were different. Under the shallow water irrigation, compared with nitrogen free treatment, the yields of 'Dexiang 4103' and 'Jinnongsimiao' increased by 31.79%-48.77%, 29.72%-45.36%, respectively, under treatments of applying nitrogen fertilizer. But with the N rate increase (higher than 180 kg·hm-2), the yield of 'Dexiang 4103' was significantly decreased, and the corresponding indicators of 'Jinnongsimiao' were not significantly changed. Under the alternate irrigation with wetting and moderate drying, compared with nitrogen free treatment, the yields of 'Dexiang 4103' and 'Jinnongsimiao' increased by 32.58%-61.10%, 36.49%-48.45%, respectively, under treatments of applying nitrogen fertilizer. When N rate was more than 180 kg·hm-2, for 'Dexiang 4103', the yield was not significantly changed, nitrogen fertilizer recovery efficiency, the nitrogen agronomic efficiency decreased with the increase of N rate. For 'Jinnongsimiao', the yield, dry matter accumulation not changed significantly, and the nitrogen accumulation at maturity stages increased significantly. Under the alternate irrigation with wetting and severe drying, compared with nitrogen free treatment, the yields of 'Dexiang 4103' and 'Jinnongsimiao' increased by 37.01%-42.88%, 30.11%-42.63%, respectively, under the treatments of applying nitrogen fertilizer. When N rate was more than 180 kg·hm-2, the yield of two cultivars was not changed significantly, their nitrogen agronomic efficiency decreased with the N rate increaseing. The nitrogen accumulation of 'Dexiang 4103' at maturity stage increased significantly and that of 'Jinnongsimiao' was not changed significantly with N rate increasing. In summary, alternate irrigation with wetting and moderate drying was more suitable for high yield, water saving and high efficiency cultivation of direct-seeded rice. Furthermore, the highest yields of 'Dexiang 4103' and 'Jinnongsimiao' were observed under N rates of 240 kg·hm-2 and 180 kg·hm-2, respectively.

     

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