Deep placement of nitrogen fertilizer increases rice yield and nitrogen use efficiency with fewer greenhouse gas emissions in a mechanical direct-seeded cropping system
Lin Li,
Hua Tian,
Minghua Zhang,
Pingshan Fan,
Umair Ashraf,
Haidong Liu,
Xiongfei Chen,
Meiyang Duan,
Xiangru Tang,
Zaiman Wang,
Zheng Zhang,
Shenggang Pan
Affiliations
Lin Li
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture, Guangzhou 510642, Guangdong, China; Guangzhou Key Laboratory for Science and Technology of Fragrant Rice, Guangzhou 510642, Guangdong, China
Hua Tian
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture, Guangzhou 510642, Guangdong, China; Guangzhou Key Laboratory for Science and Technology of Fragrant Rice, Guangzhou 510642, Guangdong, China
Minghua Zhang
Key Laboratory of Key Technology for South Agricultural Machine and Equipment, Ministry of Education, Guangzhou 510642, Guangdong, China
Pingshan Fan
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; College of Tropical Crops, Hainan University, Haikou 570228, Hainan, China
Umair Ashraf
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; Department of Botany, Division of Science and Technology, University of Education, Lahore 54770, Punjab, Pakistan
Haidong Liu
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; Hezhou Academy of Agricultural Sciences, Hezhou 542800, Guangxi, China
Xiongfei Chen
School of Engineering, Jiangxi Agricultural University, Nanchang 330045, Jiangxi, China
Meiyang Duan
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture, Guangzhou 510642, Guangdong, China; Guangzhou Key Laboratory for Science and Technology of Fragrant Rice, Guangzhou 510642, Guangdong, China
Xiangru Tang
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture, Guangzhou 510642, Guangdong, China; Guangzhou Key Laboratory for Science and Technology of Fragrant Rice, Guangzhou 510642, Guangdong, China
Zaiman Wang
Guangzhou Key Laboratory for Science and Technology of Fragrant Rice, Guangzhou 510642, Guangdong, China
Zheng Zhang
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture, Guangzhou 510642, Guangdong, China; Guangzhou Key Laboratory for Science and Technology of Fragrant Rice, Guangzhou 510642, Guangdong, China
Shenggang Pan
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, Guangdong, China; Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture, Guangzhou 510642, Guangdong, China; Guangzhou Key Laboratory for Science and Technology of Fragrant Rice, Guangzhou 510642, Guangdong, China; Corresponding author.
Deep placement of nitrogen fertilizer is a key strategy for improving nitrogen use efficiency. A two-year field experiment was conducted during the early rice growing seasons (March–July) of 2016 and 2017. The experimental treatments comprised two rice cultivars: Wufengyou 615 (WFY 615) and Yuxiangyouzhan (YXYZ), and three N treatments: mechanical deep placement of all fertilizers as basal dose at 10 cm soil depth (one-time deep-placement fertilization, namely OTDP fertilization); manual surface broadcast (the common farmer practice) of 40% N fertilizer at one day before sowing (basal fertilizer) followed by broadcast application of 30% each at tillering and panicle initiation stages; and no fertilizer application at any growth stage as a control. One-time deep-placement fertilization increased grain yield of both rice cultivars by 11.8%–19.6%, total nitrogen accumulation by 10.3%–13.1%, nitrogen grain production efficiency by 29.7%–31.5%, nitrogen harvest index by 27.8%–30.0%, nitrogen agronomic efficiency by 71.3%–77.2%, and nitrogen recovery efficiency by 42.4%–56.7% for both rice cultivars, compared with the multiple-broadcast treatment. One-time deep-placement fertilization reduced CH4-induced global warming potential (GWP) by 20.7%–25.3%, N2O-induced GWP by 7.2%–12.3%, and total GWP by 14.7%–22.9% for both rice cultivars relative to the multiple-broadcast treatment. The activities of glutamine synthetase and nitrate reductase were increased at both panicle-initiation and heading stages in both rice cultivars following one-time deep-placement fertilization treatment. Larger leaf area index at heading stage and more favorable root morphological traits expressed as larger total root length, mean root diameter, and total root volume per hill were also observed. One-time deep-placement fertilization could be an effective strategy for increasing grain yield and nitrogen use efficiency and lowering greenhouse-gas emissions under mechanical direct-seeded cropping systems.
