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Maize Response to Time of Nitrogen Application as Affected by Level of Nitrogen Deficiency
Author(s) -
Binder Darren L.,
Sander Donald H.,
Walters Daniel T.
Publication year - 2000
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2000.9261228x
Subject(s) - nitrogen , zea mays , fertilizer , nitrogen deficiency , yield (engineering) , grain yield , agronomy , zoology , chlorophyll , mathematics , chemistry , biology , horticulture , materials science , organic chemistry , metallurgy
Fine tuning current best nitrogen management practices, such as delayed N application to maize ( Zea mays L.), is needed to improve fertilizer recommendations. This study was conducted to determine the relationship between relative maize N deficiency and time of N application. Levels of N deficiency were established by applying different rates of N fertilizer. Additional N was applied to each level of N deficiency at eight growth stages ranging from early vegetative growth to late reproductive growth. Chlorophyll meter readings were taken before each N application as a measure of maize N deficiency. A N sufficiency index (SI) was calculated based on the relationship between N‐deficient and non‐N‐deficient maize. Delaying N application to the six‐leaf stage resulted in nearly a 12% decrease from maximum grain yield when the SI was below 0.90, indicating N deficiency can be severe enough to prevent full recovery when N is side dressed. The greater the N deficiency, the earlier N had to be applied to obtain maximum grain production. Grain yield was increased from N application as late as R3 stage for extremely N‐deficient maize, but maximum yield was not obtained. Grain yield was depressed when N was applied at R3 for slightly N‐deficient maize. The potential benefit of late season N application depends on the degree of N deficiency. A predictive function was developed in order to determine if N fertilizer application would be warranted given the SI and time of N application.