烟稻轮作模式下烤烟增密减氮的主要化学成分效应分析

Effect of density-increasing and nitrogen-saving on chemical components of flue-cured tobacco under tobacco-rice rotation system

目的】增密减氮是一项绿色增产增效技术,明确我国南方烟稻轮作模式下烤烟增密和减氮的可行性,对指导特色优质烟叶开发具有重要意义。【方法】在湖南邵阳烟区烟稻轮作田块进行了密度和施氮量双因素三水平完全随机田间试验。三个种植密度分别为16667(习惯种植密度)、18182和20000株/hm^2,三个施氮量分别为N 105、120和135 kg/hm^2。测定了烤后烟叶主要化学成分,采用隶属函数对化学成分数据进行标准化,用主成分分析计算每个成分权重,构建了烟叶化学成分可用性指数,采用η_p^2分析了烤烟种植密度和施氮量及其互作对烟叶化学成分的效应。【结果】烤烟化学成分可用性指数以种植密度18182株/hm^2和施氮量120 kg/hm^2组合处理最高,其次是密度18182株/hm^2和施氮量135 kg/hm^2组合处理。施氮量对烟叶化学成分可用性的效应约为46.3%,种植密度对烟叶化学成分可用性的效应约为30.1%,种植密度和施氮量互作对烟叶化学成分可用性的效应约为23.6%。【结论】采用η_p^2更能客观地定量分析种植密度和施氮量及其互作对烟叶化学成分的影响。种植密度、施氮量及二者互作对烟叶化学成分可用性的效应不同,以施氮量为主,其次是种植密度。与邵阳当地和我国南方类似地区现行的种植密度(16675株/hm^2)和施氮量(N 135 kg/hm^2)相比,邵阳地区烤烟适当增加种植密度和减施氮肥是可行的,烟稻轮作模式下烤烟推荐种植密度和施氮量分别为18182株/hm^2、120 kg/hm^2。

[ Objectives ] Density-increasing and nitrogen-saving are main techniques for high yield and high quality. The feasibility of the density-increasing and nitrogen-saving in flue-cured tobacco production was studied in this paper in South China tobacco-rice rotation field. [ Methods ] A field experiment with two factor and three levels was conducted using tobacco cultivar of K326 as materials in Shaoyang tobacco-rice rotation area in Hunan Province. The three density levels were 16667 plant/hm： （currently used）, 18182 plant/hmz and 20000 plant/hm2, and the three nitrogen application levels were 105, 120 and 135 kg/hm2. The contents of important chemical components in flue-cured tobacco leaves were measured and standardized by the membership function and the principal component analysis method, their weight to construct the chemical composition of tobacco leaf usability index of chemical composition were calculated. The effects of planting density, nitrogen level and their interaction on chemical components of flue-cured tobacco were analyzed by establishing chemical components usability index （CCUI） and adopting partial eta-squared （ηp^2） value. [ Results ] The highest chemical availability index was in density treatment of 18182 plant/hm2, in nitrogen treatment of N 120 kg/hm2, and in the combination of density 18182 plant/hm2 with nitrogen 120 kg/hm2 among the respective treatment groups. The combination of density 18182 plant/hm2 and N 135 kg/hm2 showed the second highest chemical availability index. The contribution of nitrogen fertilizer on tobacco chemical components usability was about 46.3%, and that of planting density was about 30.1%, and that of the interaction of planting density and N rate was about 23.6%. [ Conclusions ] Nitrogen application rate plays major role in contents of chemical components in tobacco leaves and planting density does the secondary role. Compared with the currently planting density of 16675 plant/hm2 and nitrogen application rate of 135 kg/hm^2 in southern China tobacco production areas, it is feasible to increase planting density to 18182 plant/hm2 and reduce nitrogen application rate to 120 kg/hmL