[Effects of nitrogen application on yield and nitrogen use efficiency of rapeseed (Brassica napus)].

A greenhouse pot experiment was conducted to study the effects of nitrogen application on the yield and nitrogen use efficiency of rapeseed under post anthesis waterlogging condition. Two high nitrogen use efficiency rapeseed genotypes 'Monty' and 'Xiangyou 15' and two low nitrogen use efficiency rapeseed genotypes 'R210' and 'Bin270' were treated with 3 nitrogen levels (0.05, 0.2, 0.3 g N·kg-1soil) under waterlogging or normal water condition. The results showed that compared with the normal water condition, rapeseed pods per plant, 1000-seed mass, seed number per pod and seed yield decreased significantly under post anthesis waterlogging condition. Under the normal water condition, yield increased significantly along with the increment of nitrogen fertilizer, while under waterlogging condition the contribution of increment of nitrogen fertilizer was not significant. Compared with the low nitrogen use efficiency rapeseed genotypes, the high nitrogen use efficiency rapeseed genotypes stimulated seed filling under post anthesis waterlogging condition. Under the same water treatment, nitrogen use efficiency, nitrogen partial factor productivity, agronomic nitrogen use efficiency, nitrogen uptake efficiency and N harvest index of nitrogen fertilizer decreased significantly as the results of post anthesis waterlogging, nitrogen uptake and utilization capability of different rapeseed genotypes were affected significantly by waterlogging. Compared with the low nitrogen use efficiency rapeseed genotypes, the high nitrogen use efficiency rapeseed genotypes were more conducive to nitrogen translocation and redistribution of nitrogen to the pods under waterlogging condition, thus improving the seed production efficiency. Significant water and nitrogen interaction effects existed in rapeseed yield performance parameters, and the effects of water, nitrogen fertilizer and their interaction on rapeseed yield and yield performance parameters varied among diffe-rent genotypes.温室盆栽试验条件下,设置渍水和对照2个水分处理,每个水分处理下设置3个施氮水平(0.05、0.2、0.3 g N·kg-1土),研究了花后渍水逆境下氮素营养对两个氮高效基因型‘Monty’、‘湘油15’和两个氮低效基因型‘R210’、‘Bin270’油菜产量、产量性能及氮肥利用效率的影响.结果表明:与对照相比,花后渍水处理显著降低了油菜的单株角果数、千粒重、每角粒数和籽粒产量.在适宜水分条件下,增施氮肥显著增加了油菜籽粒产量,而在渍水逆境处理下,增施氮肥对油菜籽粒产量的形成贡献不大.氮高效基因型较氮低效基因型对花后渍水逆境下的籽粒灌浆充实具有一定的促进作用.在同一水分处理下,花后渍水明显降低了油菜氮肥利用率、氮肥偏生产力、氮肥农学利用率、氮素吸收效率和氮收获指数,渍水显著影响了不同基因型油菜的氮素吸收利用能力,而氮高效基因型在渍水逆境下较氮低效基因型更有利于将氮素转运、再分配到角果中,提高籽粒生产效率.油菜产量性能参数存在显著的水氮互作效应,水分、氮肥及水氮互作对油菜籽粒产量和产量性能参数的影响因基因型的不同而异.