Reducing N Application by Increasing Plant Density Based on Evaluation of Root, Photosynthesis, N Accumulation and Yield of Wheat

Agronomy

Shizhou Du¹  Xiangqian Zhang¹  Chengfu Cao¹  Huan Chen¹  Yunji Xu² 

[1] Crops Research Institute, Anhui Academy of Agricultural Sciences, Office 621, Crop Building, No. 40, Nongke South Road, Luyang District, Hefei 230031, China;Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China;

关键词: root traits;    photosynthetic rate;    canopy photosynthetically active radiation;    N accumulation;   

DOI  :  10.3390/agronomy11061080

来源: DOAJ

【 摘 要 】

(Aims) To clarify the mechanisms though which dense planting could alleviate the negative effect of the reducing N rate on yield, (Methods) an experiment with four nitrogen levels—0 (N0), 120 (N1), 180 (N2) and 240 (N3) kg N ha⁻¹—and three plant densities—180 (D1), 240 (D2) and 300 (D3) × 10⁴ basic seedlings ha⁻¹—was conducted. (Results) Increasing plant density decreased the root length, root volume, root surface area and root tips of individual plant while it enhanced the aforementioned root traits in population. The chlorophyll content, photosynthetic rate, stomatal conductance and transpiration rate of the individual plants were decreased with the increase in plant density and enhanced with the increase in N level. The increasing density and N application rate enhanced the leaf area index, photosynthetic high-efficiency leaf area and canopy photosynthetically active radiation of population. N accumulation per plant was decreased with increasing density and was enhanced with an increasing N application level. Within the same N level, the N accumulation in the population, N production efficiency and N recovery efficiency were consistently D3 > D2 > D1. A high N application rate with high density was not conducive to improving the NR (nitrate reductase), GS (glutamine synthetase) and GOGAT (glutamate synthase) activities. The yield could be maintained as stable or improved if decreasing by 60 kg N ha⁻¹ with increasing 60 × 10⁴ basic seedlings ha⁻¹ within the range of N application in this experiment. (Conclusions) These results indicated that the yield of wheat could be improved with less N application by adjusting the compensatory effects from the plant density in populations.

【 授权许可】

Unknown