Open AccessRecommended nitrogen rates and the verification of effects based on leaf SPAD readings of rice
Author(s) -
Wei Hou,
Juan Shen,
Wei Xu,
Muhammad Rizwan Khan,
Yin Wang,
Xue Zhou,
Qiang Gao,
Behzad Murtaza,
Zhongqing Zhang
Publication year - 2021
Publication title -
peerj
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.927
H-Index - 70
ISSN - 2167-8359
DOI - 10.7717/peerj.12107
Subject(s) - grain yield , yield (engineering) , nitrogen , productivity , human fertilization , field experiment , mathematics , agronomy , production efficiency , horticulture , microbiology and biotechnology , biology , statistics , chemistry , engineering , materials science , macroeconomics , organic chemistry , economics , mechanical engineering , metallurgy
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.