Use of chlorophyll meter readings in the management of nitrogen fertilization in bell pepper plants

An adequate nitrogen fertilizing management throughout a crop cycle of bell pepper (Capsicum annuum L.) is problematical for lack of an index of available soil N and because the chemical leaf analysis, on the other hand, is a slow diagnosis method. The experiment was conducted in a plastic tunnel of the Dept. of Natural Resources/Soil Science, of FCA/UNESP, Botucatu, São Paulo State, in pots, with the objective to assess the nitrogen sufficiency index (NSI). Calculations consisted in chlorophyll meter readings as auxiliary tool in the N fertilization management of bell pepper plants. The experiment, in seven replicates, was composed of five N doses (4.9; 9.8; 14.7; 19.6; and 24.5 g of N 50 kg-1 soil - one plant) applied in conventional manner or through (fertirrigation) and one treatment in which plants were treated with other fertilizers beside N. The chlorophyll meter was read fortnightly in five recently matured leaves per plant. The NSI was calculated by the relationship between the readings average of the chlorophyll meter in the treatments plants (LCT) and the readings average of the chlorophyll meter in the plants that had received the largest dose (LCR), in the reference area (NSI = LCT/LCR x 100). The NSI value can be useful to indicate the moment of N application and to help calibrate N rates according to the bell pepper requirements in order to increase the N-efficiency use.

Capsicum annuum L.; SPAD; chlorophyll; nitrogen sufficiency index