Reducing nitrogen application with dense planting increases nitrogen use efficiency by maintaining root growth in a double-rice cropping system
Jin Chen,
Xiangcheng Zhu,
Jiang Xie,
Guoqiang Deng,
Tianhua Tu,
Xianjiao Guan,
Zhen Yang,
Shan Huang,
Xianmao Chen,
Caifei Qiu,
Yinfei Qian,
Caihong Shao,
Minggang Xu,
Chunrui Peng
Affiliations
Jin Chen
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China; Jiangxi Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Jiangxi Agricultural University, Nanchang 330045, Jiangxi, China
Xiangcheng Zhu
College of Life Science and Environmental Resources, Yichun University, Yichun 336000, Jiangxi, China
Jiang Xie
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China
Guoqiang Deng
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China
Tianhua Tu
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China
Xianjiao Guan
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China
Zhen Yang
Agricultural Technology Extension Center in Yifeng County of Jiangxi Province, Yichun 343100, Jiangxi, China
Shan Huang
Jiangxi Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Jiangxi Agricultural University, Nanchang 330045, Jiangxi, China
Xianmao Chen
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China
Caifei Qiu
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China
Yinfei Qian
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China
Caihong Shao
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China
Minggang Xu
Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, National Engineering Laboratory for Improving Quality of Arable Land, Beijing 100081, China; Corresponding authors.
Chunrui Peng
Jiangxi Academy of Agricultural Sciences, Key Laboratory of Crop Ecophysiology and Farming System for the Middle and Lower Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, National Engineering and Technology Research Center for Red Soil Improvement, Nanchang 330200, Jiangxi, China; Corresponding authors.
Rational nitrogen (N) application can greatly increase rice (Oryza sativa L.) yield. However, excessive N input can lead not only to low N use efficiency (NUE) but also to severe environmental pollution. Reducing N application rate with a higher planting density (RNHD) is recommended to maintain rice yield and improve NUE. The effects of RNHD on fertilizer N fate and rice root growth traits remain unclear. We accordingly conducted a two-year field experiment to investigate the influence of RNHD on rice yield, fertilizer 15N fate, and root growth in a double-rice cropping system in China. In comparison with the conventional practice of high N application with sparse planting, RNHD resulted in similar yield and biomass production as well as plant N uptake. RNHD increased agronomic NUEs by 23.3%–31.9% (P < 0.05) and N recovery efficiency by 17.4%–24.1% (P < 0.05). RNHD increased fertilizer 15N recovery rate by 14.5%–34.7% (P < 0.05), but reduced 15N retention rate by 9.2%–12.0% (P < 0.05). Although a reduced N rate led to significantly reduced root length, surface area, volume, and biomass, these root traits were significantly increased by higher planting density. RNHD did not affect these root morphological traits and reduced activities of nitrate reductase (NR) and glutamine synthetase (GS) only at tillering stage. Plant N uptake was significantly positively correlated with these root traits, but not correlated with NR and GS activities. Together, these findings show that reducing N application with dense planting can lead to high plant N uptake by maintaining rice root growth and thus increase NUE.
