氮肥用量对迟直播早熟油菜产量及氮素利用效率的影响

Effects of nitrogen application rate on yield and nitrogen use efficiency of early- mature rapeseed under delayed sowing condition

为了探讨江西省双季稻区冬闲稻田早熟油菜高效生产及合理高效的氮肥调控模式,以早熟杂交油菜丰油730和早熟常规油菜1358为试验材料,于2012^(-2)013年在江西省油菜主产县(市)设置10个田间试验和7个施氮处理(N0、N90、N120、N150、N180、N210和N240,数字表示纯氮用量,单位为kg·hm^(-2))。通过大田试验,研究不同氮肥用量对江西双季稻区冬闲稻田早熟油菜干物质积累、产量构成因素、产(油)量、效益及氮素吸收和利用等影响。结果表明:早熟油菜单产比较低,早熟杂交品种丰油730单产比早熟常规品系1358高,合理氮肥施用(N180)条件下各试验点平均增产显著,产量分别达1 700kg·hm^(-2)和1 500kg·hm^(-2)左右;与对照(不施氮)相比,施氮显著提高了油菜产(油)量、干物质累积量和效益,两个早熟品种平均产(油)量增幅均在75%以上,效益增幅达80%以上;但当施氮量高于180kg·hm^(-2)(即N210和N240),氮肥的增产效应不显著,产油量和经济效益则明显降低。采用线性加平台回归模型对产量和施氮量关系进行拟合,结果发现,丰油730和1358各试验点肥效模型的拟合均达到显著水平。在各个试验点的推荐用氮量上,丰油730为157~224kg·hm^(-2),1358为159~199kg·hm^(-2)。两个早熟品种施氮150kg·hm^(-2)处理和180kg·hm^(-2)处理间氮肥农学利用率(ANUE)差异未达到显著水平,与其他处理间氮肥农学利用率(ANUE)差异均达到显著水平,且显著高于其他处理。因此,利用双季稻区冬闲稻田种植早熟油菜来扩大种植面积可迅速增加油菜籽总产,江西双季稻区冬闲稻田早熟迟直播油菜施纯氮150~180kg·hm^(-2)能较好地协调油菜高效生产与氮肥合理利用的统一。

For efficient nitrogen（ N） management and high yield of early- mature（ with shorter growth period） rapeseed for winter fallow paddy in 10 sites of Jiangxi Province,field experiments were carried out to study the effects of N application on dry matter accumulation,yield and components,profits and oil production under delayed sowing condition during 2012hm^-2013. 7 levels of N treatments were N0,N90,N120,N150,N180,N210 and N240（ numbers indicate pure nitrogen amount in kg per hectare）. Results showed that yield of short- growth- period rapeseed was lower than that of moderate- growth- period rapeseed and long- growth- period rapeseed. Hybrid rapeseed cultivars had higher yields than bred lines. Their significantly high yield were under N180,at the peaks about 1 700kg·hm^-2and 1 500kg·hm^-2respectively. N application significantly improved dry matter accumulation,yield,profits and oil production of rapeseed compared to N0. The average yield increase and oil production of 2 rapeseed were more than 75%. The average increase of profits were improved more than 80%,but when nitrogen application rate was higher than N180,oil production and profit were significantly reduced. By linear and platform regression model,Fengyou 730 and 1358 recommended N applications were 157hm^-224kg·hm^-2and159- 199kg·hm^-2respectively. ANUE（ agronomic nitrogen use efficiency） of the two rapeseeds showed no significant difference at 0. 05 level between N150 and N180 treatments. But ANUE under N150 was significantly higher than those under N210 and N240. Therefore,planting early- mature rapeseed,the optimum N fertilizer application rate was 150- 180kg·hm^-2under delayed sowing condition in winter fallow paddy of Jiangxi Province.