移栽和直播油菜的氮肥施用效果及适宜施氮量

 【目的】研究氮肥施用对移栽油菜和直播油菜生长发育状况和籽粒产量的影响，探寻直播油菜的氮素营养特点，比较和明确两种种植方式下油菜氮肥施用效果和适宜施氮量的差异，为油菜科学施肥提供依据。【方法】2009—2010年度在湖北省沙洋县布置移栽油菜和直播油菜氮肥用量田间试验，开展田间调查和产量分析，根据肥效模型确定适宜施氮量。【结果】由于种植方式的不同，移栽油菜和直播油菜生育期内植株形态和生长发育特点存在较大差异。移栽油菜单株优势明显，植株各方面发育均好于直播油菜，而直播油菜具有群体优势，籽粒产量水平与移栽油菜接近。施氮有效促进移栽油菜和直播油菜的生长发育，显著提高油菜籽粒产量。同时，两种种植方式下油菜氮肥施用效果存在差异，移栽油菜各项生长发育指标及产量形成受氮素影响更为明显。直播油菜拥有庞大的根群结构，吸收土壤氮素的能力强，对外源氮肥需求量少于移栽油菜。本试验条件下，移栽油菜和直播油菜的适宜施氮量分别为228.4 kg?hm-2和130.3 kg?hm-2。【结论】移栽油菜和直播油菜的植株形态、生长发育及施氮效果存在明显差异，产量水平相近的情况下直播油菜氮肥适宜用量明显低于移栽种植。因此直播油菜的经济效益较高，具有较好的发展前景。

Study on Nitrogen Fertilizer Effect and Optimum Fertilizer Rate for Transplanting and Direct-Seeding Rapeseed

【Objective】In order to provide a scientific basis for rapeseed fertilization, the effects of nitrogen fertilization on growth and yield of transplanting and direct-seeding rapeseed were studied to seek the characteristics of nitrogen nutrition for direct-seeding rapeseed, and to compare and understand the difference of nitrogen fertilizer effect and optimum fertilizer rate between the transplanting and direct-seeding planting patterns.【Method】A field experiment of nitrogen fertilization on transplanting and direct-seeding rapeseed was conducted in Shayang of Hubei during 2009-2010, field surveys and yield analysis were taken, and the optimum nitrogen fertilizer rate was determined based on the fertilizer effect model. 【Result】 Due to the different planting patterns, the plant morphology and growth characteristics were quite various for transplanting and direct-seeding rapeseed. Transplanting rapeseed developed better in all aspects than direct-seeding rapeseed, the advantage of individual plant was obvious, but the direct-seeding rapeseed had group advantage, and the yield level was similar to that of transplanting rapeseed. Nitrogen fertilizer promoted effectively growth and increased significantly yield of both transplanting and direct-seeding rapeseed. Meanwhile, effects of nitrogen fertilizer on rapeseed were different in two planting patterns, and the growth and yield formation of transplanting rapeseed were more significantly influenced by nitrogen fertilizer. Direct-seeding rapeseed had a large root group, could uptake more nitrogen from soil, and the requirement to exogenous nitrogen was lower than that of transplanting rapeseed. The optimum fertilizer rates of transplanting and direct-seeding rapeseed in this experiment were 228.4 kg?hm-2 and 130.3 kg?hm-2, respectively.【Conclusion】 The plant morphology, growth and nitrogen effect of transplanting and direct-seeding rapeseed are obviously different. Compared to transplanting rapeseed, direct-seeding rapeseed requires less nitrogen fertilizer, and has high economic benefit when their yield are similar. Therefore, the direct-seeding rapeseed has better prospects for rapeseed production.