Nitrogen concentration and dry-matter accumulation in maize crop: assessing maize nitrogen status with an allometric function and a chlorophyll meter.

摘要

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.