Abstract:

The paper aims to explore the interaction effects of nitrogen application rate and planting density on yield and nitrogen use efficiency of winter wheat. Under the condition of field positioning experiment in 2017 and 2018, ‘Aikang 58’ was used as experimental material to study the effects of planting density and nitrogen application rate on dry matter accumulation and transport, yield and nitrogen use efficiency of wheat, with three sowing densities of 112.5, 150 and 187.5 kg/hm² and four nitrogen application levels of 0, 180, 240 and 300 kg/hm². The results showed that under the same sowing density, the transport amount of dry matter stored after anthesis and its contribution rate to grain yield increased first and then decreased with the increase of nitrogen application level, while the trend before anthesis was opposite; the population tiller number, spike number, grain number per spike and yield of winter wheat increased with the increase of nitrogen application level, but the thousand seed weight and nitrogen use efficiency decreased with the increase of nitrogen application level. In addition, the negative effects of reducing nitrogen application rate on wheat yield and nitrogen use efficiency could be offset by increasing planting density. Therefore, the reasonable combination of nitrogen application rate and planting density can improve wheat yield and nitrogen use efficiency. The recommended nitrogen application rate for winter wheat is 240 kg/hm² and the planting density is 150 kg/hm².

Key words: nitrogen fertilizer, planting density, nitrogen use efficiency, dry matter transport, grain yield, winter wheat