【目的】明确精准条播育秧机插对籼粳杂交稻产量形成的影响及其在减氮条件下降低产量损失的作用。【方法】以甬优538和甬优1540为供试品种,精准条播(precision drill sowing, PS)16条机插,并以相同播种量传统撒播(broadcast sowing, BS)机插为对照,同时设置不施氮肥(0 kg/hm², zero-nitrogen application rate, 0N)、适氮(240 kg/hm², suitable nitrogen application rate, SN)、减氮15%(204 kg/hm²,reduced nitrogen application rate, RN)等3个氮肥施用梯度处理,分析比较产量形成、植株均匀度、干物质积累及氮利用效率。【结果】1)与撒播相比,精准条播通过提高有效穗数使籼粳杂交稻产量平均提高4.3%,减氮条件下精准条播处理的水稻产量降幅小于撒播。2) 精准条播显著降低漏秧率,提高机插苗数均匀度以及有效穗数均匀度。与撒播相比,精准条播处理提高减氮下高峰苗数,两个品种趋势一致。3)与撒播相比,精准条播增加抽穗期叶面积指数,同时增加了抽穗期和抽穗开花后的干物质积累和氮吸收总量,其中减氮处理下表现尤为明显。4) 除0N外,氮素干物质积累量和氮素稻谷生产效率在不同品种方式及氮处理间无显著差异,但精准条播处理显著提高了氮肥吸收利用效率和氮肥农学利用效率,两个品种趋势一致。【结论】精准条播机插能够提高籼粳杂交稻植株均匀度,增加高峰苗数和叶面积指数,促进干物质积累和氮素吸收,进而提高产量,有效减少氮肥减施下籼粳杂交稻的产量损失。

【Objective】 The purpose of the study is to ascertain the effect of precise drill sowing on yield formation of mechanically transplanted rice and its beneficial effect on yield increasing with nitrogen reduction.【Method】 The seeds of Yongyou 538 and Yongyou 1540 were precise drill-sowed (PS) with 16 rows(in horizontal) in standard seedling trays for mechanical transplanting, and the same seed sowing rate was set in traditional broadcast sowing (BS) as the control. And three nitrogen application rate treatments including zero-nitrogen application rate (0 kg/hm², 0N), suitable nitrogen application rate (240 kg/hm², SN), and reduced nitrogen application rate (204 kg/hm², RN) were set to analyze yield formation, plant uniformity, dry matter accumulation and nitrogen use efficiency. 【Results】 1) Compared with BS, PS significantly increased the yield of indica-japonica hybrid rice by 4.3% on average with the increasing productive panicles. Under nitrogen reduction, precise drill sowing led to a lower grain yield drop as compared with BS. 2) PS significantly reduced the unplanted hill percent, improved the uniformity of mechanically transplanted seedlings and productive panicle number. Compared with BS, PS increased the tiller number at peak tillering stage under RN for both cultivars. 3) Compared to BS, PS increased the leaf area index at heading stage, meanwhile increased dry matter accumulation and nitrogen uptake at both heading and post-anthesis stages, particularly under RN treatment. 4) Except 0N, there was no significant difference in N dry matter production efficiency and N grain production efficiency among different cultivars and nitrogen treatments, but PS treatment significantly increased N recovery efficiency and N agronomic use efficiency in both cultivars.【Conclusion】 PS improves plant uniformity of indica-japonica hybrid rice population, increases the tiller number at peak tillering stage and leaf area index, promotes dry matter accumulation and nitrogen absorption, and then increases yield and reduces rice yield losses under nitrogen reduction.