Recommended nitrogen rates and the verification of effects based on leaf SPAD readings of rice
Wenfeng Hou,
Juan Shen,
Weitao Xu,
Muhammad Rizwan Khan,
Yin Wang,
Xue Zhou,
Qiang Gao,
Behzad Murtaza,
Zhongqing Zhang
Affiliations
Wenfeng Hou
Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases/College of Resources and Environmental Science, Jilin Agricultural University, Changchun, Jilin, Changchun, China
Juan Shen
Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases/College of Resources and Environmental Science, Jilin Agricultural University, Changchun, Jilin, Changchun, China
Weitao Xu
Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases/College of Resources and Environmental Science, Jilin Agricultural University, Changchun, Jilin, Changchun, China
Muhammad Rizwan Khan
Soil and Environmental Sciences Division, Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan
Yin Wang
Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases/College of Resources and Environmental Science, Jilin Agricultural University, Changchun, Jilin, Changchun, China
Xue Zhou
Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases/College of Resources and Environmental Science, Jilin Agricultural University, Changchun, Jilin, Changchun, China
Qiang Gao
Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases/College of Resources and Environmental Science, Jilin Agricultural University, Changchun, Jilin, Changchun, China
Behzad Murtaza
Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, Vehari, Pakistan
Zhongqing Zhang
Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases/College of Resources and Environmental Science, Jilin Agricultural University, Changchun, Jilin, Changchun, China
Modern rice production systems need a reliable, easy-to-use, efficient, and environmentally-friendly method to determine plant nitrogen (N) status , predict grain yield, and optimize N management. We conducted field experiments to determine the influence of different N rates on Soil Plant Analysis Development (SPAD) readings of rice leaves. We also performed field validations to evaluate the grain yield and N use efficiency under recommended N rates. Our results showed that leaf SPAD readings increased as N rates increased. We applied the recommended N based on the relationships between the N rates and leaf SPAD readings at the tillering and booting stages. The recommended N decreased N rates and improved N use efficiency without sacrificing grain yield. When compared to farmer practices (FP), the recommended N rates of optimization (OPT) decreased by 5.8% and 10.0%, respectively. In comparison with FP, the N agronomic efficiency of OPT increased by 5.8 and 10.0% while the partial factor productivity of N increased by 6.0 and 14.2%, respectively. The SPAD meter may be a reliable tool to analyze the N in rice, estimate real-time N fertilization, and improve N use efficiency.
