Use of a hand-held chlorophyll meter in winter wheat: Evaluation of different measuring positions on the leaves

A portable chlorophyll meter (Minolta SPAD-502) was used to assess the nitrogen status of winter wheat (Triticum aestivum L.) in two fertilizer trials at Apelsvoll Research Centre, located in south-east Norway. The midpoint of the last fully developed leaf was found to be the best position on the winter wheat plant on which to take chlorophyll meter readings. This conclusion was reached after examination of the relationships between soil-plant analyses development (SPAD) readings taken at different positions on the plant and leaf nitrogen concentration, grain yield and grain protein content. Emphasis was also laid on finding a measuring position that was convenient from a practical point of view. The relationships between chlorophyll meter readings and the parameters investigated were better at Zadoks growth stage (GS) 49 than earlier in the season at GS 31.