晚播晚栽机插水稻群体生长特征及其调控策略

Population Growth Characteristics and Cultivation Strategies of Mechanically Transplanted Rice in Late Seeding and Planting Conditions

【目的】探究水稻机械化移栽应用中长期存在的晚播晚栽机插稻的特殊应用价值,【方法】在苏南设置大田试验,分析了晚播晚栽机插水稻的产量表现及其群体生产特征,并设置密度和穗肥施用处理,解析栽培措施对晚播晚栽机插水稻群体发育和产量形成的影响。【结果】机插水稻晚播晚栽产量出现一定程度的下降,主要原因是单位面积穗数和每穗粒数降低。晚播晚栽机插稻群体高峰苗出现时间相对前移,茎蘖成穗率则明显下降。同化物质积累和运转均受到一定影响,抽穗期茎鞘中非结构性碳水化合物积累下降,茎鞘物质输出率和转换率也呈下降趋势。可见,晚播晚栽机插水稻存在物质生产和产量形成的必然劣势。增加栽植密度,单位面积穗数显著增加,干物质积累量上升,产量明显提高。在同一密度条件下,随着穗肥施氮量水平的提高,产量表现为先上升后下降的趋势,过多穗肥施用不利于晚播晚栽机插稻结实期的物质积累。较高密度配合适宜水平的穗肥施用,可提高其茎蘖成穗率,并维持结实期叶片活性,保持较高的中后期物质生产能力。【结论】晚播晚栽机插水稻可采用较高移栽密度,促进前期早发提高群体质量,适当减少中后期肥料控制无效分蘖发生,改善结实期生长条件,可获得相对较好的产量和生产效率。

【Objective】It is of great importance to know the long-term special application value of mechanically transplanted rice in late seeding and planting conditions.【Method】An experiment was conducted in southern Jiangsu to analyze the yield performance and population growth characteristics of mechanically transplanted rice in late seeding and planting conditions.Further,the impact of cultivation measures on population development and yield of mechanically transplanted rice in late seeding and planting conditions was analyzed at different planting densities and panicle-promoting fertilizer application level.【Result】Due to the decrease in the number of panicle and grain number per panicle,and slightly-affected seed setting rate and thousand-grain weight,the yield of mechanically transplanted rice in late seeding and planting conditions decreased to some extent.peak seedling number of mechanically transplanted rice in late seeding and planting conditions was relatively advanced,and the productive tiller percentage decreased significantly.The accumulation and translocation of assilimates were affected to some extent.NSC accumulation in the stem and sheath decreased during heading stage,and the export rate and conversion rate in stem and sheath also showed a downward trend.It can be seen that there was an inevitable disadvantage in production and yield formation of the mechanically transplanted rice in late seeding and late planting conditions.By increasing the density,the number of panicle per unit area increased significantly,the performance of above-ground dry matter accumulation increased,and the yield increased significantly.At the same density,with the increase of the nitrogen application level of panicle-promoting fertilizer,the yield first increased and then decreased.However,seed setting,excessive panicle-promoting fertilizer application was not conducive to the dry matter accumulation of mechanically transplanted rice in late seeding and planting conditions.The combination of higher density with the appropriate level of panicle-promoting fertilizer could increase the percentage of productive tillers,and maintain the leaf activity during seed setting and good production capacity in the middle and late phases.【Conclusion】With higher transplanting density,the late seeded and mechanically transplanted rice can gain strong growth momentum at early growth stage and favorable population quality.The unproductive tiller number decreases by reducing fertilizer application in the middle and late growth stages so as to achieve relatively high yield and production efficiency.