机插密度与氮肥运筹对中嘉早17产量形成及氮肥利用率的影响

针对长江流域双季稻机插秧发展缓慢的问题,以常规早稻品种中嘉早17为材料,在大田条件下研究了栽插密度与氮肥用量对机插双季稻产量的影响。结果表明,机插双季稻产量并未随栽插密度增加而显著增加。以高密(36.4万穴/hm²)+高氮(施纯氮量早稻175.5 kg/hm²,晚稻189 kg/hm²)处理产量最高,其中,早稻为7.80 t/hm²,晚稻为9.05 t/hm²,但与高密+中氮(施纯氮量早稻110 kg/hm²,晚稻140 kg/hm²)处理产量差异不显著,且栽插密度和施氮量间互作效应不显著。氮肥利用率随氮肥用量增加而下降,随栽插密度增加而提高。其中,氮肥吸收利用率中氮比高氮平均增加13.26%,高密度比低密度平均增加17.53%。由此可见,提高栽插密度,减少氮肥用量,既可通过大幅增加有效穗以实现高产,又能显著提高氮肥利用率。少氮密植可作为长江流域机插双季稻高产高效栽培的关键技术。

Effects of Nitrogen Application and Mechanical Transplanting Density on Yield Formation and Nitrogen Use Efficiency of Conventional Rice Zhongjiazao 17

ing at the slow development of rice mechanical transplanting in the Yangtze River Valley, we explored the effects of mechanical transplanting densities and nitrogen application on yield formation and nitrogen use efficiency (NRE) in a field experiment with the conventional variety Zhongjiazao17 as material. The results showed that the grain yield didn’t significantly increase with the increasing levels of transplanting density. At the high density (36.4 hill /m²) and high nitrogen rates (175.5 kg/hm² in early season, 189 kg/hm² in late season) the grain yield maximized, being 7.84 t/hm² in early season and 9.10 t/hm² in late season, while the difference was not significant comparied with high transplanting density plus medium nitrogen rate (110 kg/hm² in early season, 140 kg/hm² in late season). Meanwhile, the interaction between the density and N application was not significant. NRE declined as the N application level increased, while it improved as the density increased. N recovery efficiency at the medium N level was 13.26% higher on the average compared with the high N level. And N recovery efficiency at the high density increased by 17.53% compared with the low density. As a result, at high transplanting density and low nitrogen application level, high yield was achieved by increasing effective panicle number per unit area, and N recovery efficienly was improved. It is a key technology for the high-efficiency and high-yielding cultivation of mechanical-transplanted rice in the Yangtze River Valley.