Critical Nitrogen Dilution Curve for Optimizing Nitrogen Management of Winter Wheat Production in the North China Plain
- Shanchao Yuea,
- Qingfeng Menga,
- Rongfang Zhaob,
- Fei Lic,
- Xinping Chena,
- Fusuo Zhanga and
- Zhenling Cui *a
- a Dep. of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
b Dep. of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, and College of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
c Dep. of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, and College of Ecology and Environmental Science, Inner Mongolia Agricultural University, Hohhot 010019, China
Investigating critical N concentration, that is, the minimum N concentration necessary to achieve maximum growth, provides insights into N nutrition and can serve as a guide to improving agricultural practices and regulations. Our objectives were to evaluate N dilution curves for deficient, optimal, and excess added N and to determine the critical N dilution curve for winter wheat (Triticum aestivum L.) in the North China Plain (NCP) based on 15 N fertilization experiments with three to six N fertilization rates. The N supplements significantly affected the N dilution curve, and increased N supply generally resulted in a greater N concentration. The critical N dilution curve for winter wheat was described by the equation nitrogen concentration (Nc) = 4.15 W–0.38 when aboveground biomass was between 1 and 10 Mg dry matter (DM) ha−1. When aboveground biomass was <1 Mg DM ha−1, the constant critical value Nc = 4.15% DM, which was independent of aboveground biomass. This curve was lower than that of winter wheat in France. This critical N dilution curve was validated through the nitrogen nutrition index (NNI) defined as the ratio between measured N concentration and critical Nc. The critical N dilution curve holds promise as an efficient tool for guiding N-fertilization practices and regulations for winter wheat production in the NCP.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2012. . Copyright © 2012 by the American Society of Agronomy, Inc.