长沙地区稻稻油三熟制机插双季稻适宜播期初探

Study on Suitable Sowing Date of Machine-transplanted Seedling of Double-season Rice under Rice-rice-oilseed Rape Triple-cropping System in Changsha

优化油稻稻三熟制机插秧条件下双季稻适宜的播种期可为三熟制全程机械化生产技术的推广提供指导。选用8个早晚稻品种,在湖南浏阳研究了播种期对机插双季稻产量、生育期、干物质积累、冗余生长和辐射利用率(RUE)的影响。结果表明,随播种期的推迟,早稻全生育期缩短、晚稻全生育期延长,水稻群体干物质积累呈先增后减变化趋势,同时,冗余度增加、RUE变小。水稻产量随播期的推迟呈先增后降的变化趋势,后期物质转化利用率降低影响结实率可能是推迟播种后产量下降的原因之一。本试验条件下,长沙地区机插双季早稻播种期可推迟至4月7~12日,机插双季晚稻播种期可推迟至7月5日,既能解决三熟制的季节矛盾,又能保证稳产和高产。

To optimize the suitable sowing date of machine-transplanted seedling in the double-season rice under the rice-rice-oilseed rape triple-cropping system can provide technical support for popularizing of the mechanized transplanting techniques in triple-cropping system.In this paper,eight early and late rice varieties were used to study the differences in yield,growth period,DMA(dry matter accumulation),redundant growth and RUE(radiation use efficiency)under different sowing date.The results were shown as follows:the growth duration of early rice was shortened and that of late rice was extended as the sowing date delayed;moreover,DMA was increased first and then decreased.In additional,redundancy was increased and RUE was decreased with the sowing date delayed.Rice yield was increased first and then decreased with the sowing date delayed,and its possible reason was the seed setting rate affected by decrease of utilization rate of dry matter after the full-heading stage.Therefore,the sowing date of machine-transplanted seedling in the early rice could be postponed until 7th April–12th April,and that of late rice could be postponed till 5th July,which was relieved the seasonal contradictions between double season rice and oilseed rape season,and also to ensure stable and high yield.