| Abstract: | The ability to determine the optimal nitrogen (N) content in maize plants needed to obtain maximum growth is important to the management of the crop. It has been shown that N content declines as a function of aboveground biomass accumulation (W): [N] = 3.4W–0.37. The goal of this study is to evaluate the applicability of relating chlorophyll meter readings with the optimal N content relationship to provide a tool for whole-plant N-status diagnosis in maize without the necessity of measuring N content. Biomass of shoot and specific organs, N concentration, and chlorophyll meter measurement of specific leaves were measured over several sites and years. Nitrogen-concentration measurements indicated that whole-plant N status can be represented by the N concentration of the topmost fully expanded leaf. A quantitative relationship between N concentration and chlorophyll meter measurement on the uppermost expanded leaf was established and validated. |
