节水灌溉条件下氮密互作对双季晚稻丰源优299物质生产特性的影响

Effects of Nitrogen Application and Planting Density on Late Rice Fengyuanyou 299 Material Production Characteristics under the Condition of Water Saving Irrigation

为明确湖南双季稻区节水灌溉条件下水稻生产适宜的施氮水平和栽植密度,采用裂区试验设计,以施氮量为主区,栽植密度为副区,研究不同氮密处理对晚稻丰源优299物质生产特性的影响。结果表明:水稻产量随生物量的增加而增加,在水稻生育后期二者呈极显著相关关系;而施氮量对生物量的增加有一定促进作用,密度增加对生物量也有显著提高作用,总体上以低氮高密处理生物量最高。光合势对水稻产量的建成有正向促进作用,而光合势随施氮量和栽植密度的增加呈上升趋势,净同化率对水稻产量的作用不明显。在物质转运方面,水稻产量与穗后干物质积累量呈显著正相关,与茎叶表观输出量、茎叶表观输出率、茎鞘物质转换率及茎鞘物质输出率相关性不大,穗后干物质积累量总体随着施氮量和栽植密度的增加而增加,以施低氮高密处理的穗后干物质积累量最大。水稻产量随叶面积指数的增加呈上升趋势,同时施氮量、栽植密度对叶面积指数呈极显著正相关。水稻产量与叶绿素含量无直接相关性,叶绿素含量随施氮增加有所上升,栽植密度对叶绿素含量无直接影响。水稻产量与根系活力呈正相关关系,施氮量增加明显提高前期根系活力,但后期无明显作用,栽植密度有利于提高根系活力。所以,构建适宜的水稻群体对水稻高产十分重要,研究表明适宜降低施氮量和增加栽植密度能够有效形成水稻高产高效的群体结构,进而促进产量的增加。

To explore suitable nitrogen fertilizer and planting density of rice under water saving irrigation in the double cropping rice area of Hunan, a split-plot experimental with the nitrogen treatment as amount area and planting density as subplot was designed, to explore the effects of different nitrogen and density to the matter production characteristics of double cropping late rice cultivar Fengyuanyou 299.The results showed that：Rice yield increased with the increase of biomass, they were extremely significantly correlated in the late growth stage of rice;while the application of nitrogen promoted the biomass to some extent, high planting density also significantly enhance the biomass, generally low density nitrogen treatment got the highest biomass.Photosynthetic potential played a positive role in the formation of rice economic product, and photosynthetic potential increased with the planting density and nitrogen application rate on the rise, the effects of net assimilation rate to rice yield was not obvious.In terms of assimilation transport, economic yield of rice and dry matter accumulation after heading were significantly positively related, with the export amount of the matter in stem and leaves, export percentage of the matter in stem and leaves, transformation percentage of the matter in stem and sheaths, export percentage of the matter in stem and sheaths correlation were not correlated, the overall amount of dry matter accumulation after heading increased with the rising of nitrogen and planting density,the dry matter accumulation was most abundant under the treatment of low nitrogen and high density.Rice yield increased with the rising of leaf area index, while the level of nitrogen fertilizer, planting density showed a significant positive impact to leaf area index.Rice yield and chlorophyll content had no direct correlation, chlorophyll content increased with the increase of nitrogen fertilizer, planting density had no direct influence on chlorophyll content.Rice yield and root activity were positively correlated, the application of nitrogen significantly increased pre-root activity, but later no significant effect, high planting density helped improve root activity.So, it was very important to build appropriate rice population for high-yield rice, our study demonstrated that the optimum low nitrogen level and high planting density could help to form an efficient high-yield rice population structure, thus contributing to the increase of production.