高密度直播油菜氮磷钾肥推荐用量及影响因素

针对我国目前油菜生产上施肥过量与不足并存，肥料利用率低的问题，运用“3414”试验方案进行一年多点田间试验，研究了高密度(375 000株/hm2)直播油菜氮磷钾肥的适宜用量。结果表明，氮磷钾肥不同用量显著影响油菜籽粒产量，通过建立施肥与产量间的效应函数方程，得出供试条件下油菜氮磷钾肥推荐施用量，桂林试验点油菜产量2 416.3kg/hm2，施用量为N 118.5 kg/hm2、P2O5 36.5kg/hm2、K2O 60.6 kg/hm2；枝江试验点油菜产量3 095.1kg/hm2，施用量为N 176.3 kg/hm2、P2O5 73.0kg/hm2、K2O 100.6 kg/hm2；玉龙试验点油菜产量4 474.3kg/hm2，施用量为N 256.7 kg/hm2、P2O5 88.1kg/hm2、K2O 137.7 kg/hm2。结论认为不同地理区域和不同油菜品种在该区域生长发育的生态学特征，以及肥料的边际利润率、肥料和产品价格是油菜推荐施肥的重要依据，不能简单依据供试土壤基础肥力进行油菜推荐施肥。

Optimum application rates and influence of nitrogen,phosphorus and potassium on yield of high density and direct seeding oilseed rape

To improve the fertilizer efficiency in oilseed rape under direct seeding and high density planting (as 375 000 plant per hectare), a “3414” design were used to study the optimum rates of nitrogen (N), phosphorus (P) and potassium (K) fertilizers in oilseed rape (Brassica napus L.) in field. Experiments were carried out in three sites in Guilin of Guangxi Province, Zhijiang of Hubei Province and Yulong of Yunnan Province. Results showed that rates of NPK fertilizers significantly affected rapeseed yield. By establishing the fertilizer response equations, the optimum fertilizer rates in oilseed rape were as following, N 118.5kg per hectare, P2O5 36.5kg per hectare, K2O 60.6 kg per hectare for the yield of 2 416.3kg per hectare at Guilin; N 176.3 kg per hectare, P2O5 73.0kg per hectare, K2O100.6kg per hectare for the yield of 3 095.1kg per hectare at Zhijiang, N 256.7 kg per hectare, P2O5 88.1kg per hectare, K2O 137.7kg per hectare for the yield of 4 474.3kg/hm2 at Yulong. It could be concluded that the most important influence factors on optimum rates of fertilizer applied to rapeseed included agro-ecology condition, genotype of cultivar, marginal profit ratio, prices of seeds and fertilizers. It was inaccurate to get the optimum fertilizer rates if they were only based on basic available nutrients of soil.