No abstract

Sustainability of winter wheat yield under dryland conditions depends on improvements in crop photosynthetic characteristics and crop yield. Therefore, studying the effects of different sowing methods and nitrogen rates on photosynthetic characteristics of flag leaves, nitrogen translocation, and yield could be an effective strategy to improve the crop yield. In this study, four nitrogen application concentrations and two sowing methods were used. The results showed that the photosynthetic rates were the highest at different stages of wide-space sowing (WSS) after flowering. Nitrogen concentration of 240 kg ha -1 improved the photosynthetic characteristics and significantly increased the net photosynthesis, stomatal conductance, and transpiration rate after flowering and significantly reduced the intercellular CO2 concentration compaired to other nitrogen concentrations. Our overall findings suggested that WSS nitrogen treatment with 240 kg ha -1 enhanced photosynthetic characteristics of flag leaves and nitrogen content of the plants leading to high yield under dryland conditions. Highlights• Nitrogen fertilizer can significantly improve the net photosynthetic rate of winter wheat • Different sowing methods can promote an increase of intercellular CO2 • WSS with nitrogen concentration of 240 kg ha -1 improves wheat yield in Loess Plateau area in the arid regions of North China (Li et al. 2002, Ma et al. 2005. The Loess Plateau in China covers about 0.65 million km 2 area and has the population of 108 millions (Wang et al. 2016). The Loess Plateau has a semiarid climate with low and variable rainfall from 300-700 mm (Li et al. 2010). Nitrogen (N) deposition has dramatically altered terrestrial ecosystem properties and processes, such as plant nutrient cycling, photosynthetic carbon