EVALUATION OF NITROGEN DEFICIENCY IN THE BEAN PLANT USING A PORTABLE CHLOROHYLL METER

Abstract

Nitrogen is one of the main nutrients for the bean plant, and its deficiency is very common. Because nitrogen also participates in construction of chlorophyll molecules, evaluation of n deficiency in the plant may be determined by indirect measurement of the chlorophyll content. The objective of this study was to use a chlorophyll meter for the detection of nitrogen deficiency. The study included 5 treatments (0, 50, 100, 150 and 200 kg ha-1 of N), with 10 repetitions, summing 50 pots with 8 dm3 of soil material. Ten readings were performed per pot at 30, 40 and 50 dae (days after emergency). The simple linear regression coefficients and those of second order were significant for all the study periods of this work, however the lack-of-fit was also significant, except for the behavior of the values obtained at 50 dae. In general, the values obtained with the chlorophyll meter trended to increase with elevation of N and with the advance of the plant development stages, indicating the potential for using this equipment to differentiate the various doses of nitrogen applied. It was verified that the different nitrogen doses applied influenced the values measured by the chlorophyll meter.