Vegetation index in cotton under rates of nitrogen and growth regulator

The increasing cost of nitrogen fertilizer, combined with high losses, demand management practices that result in high efficiency of nitrogen use by crops, considering the reduction of risks to the environment. Our objectives were to evaluate the index of normalized difference vegetation – NDVI – the variation of nitrogen and growth regulator and its relationship to foliar N and chlorophyll in cotton crops. The experiment was conducted on Distroferric Latosol (Oxisol), in Dourados, MS. We adopted a randomized block design in split plot with four replications. The main treatments consisted of doses of growth regulator (0, 0.30 and 0.60 L ha-1), the secondary treatments consisted of five N rates (0, 30, 70, 110 and 150 kg ha-1). The NDVI obtained by an active optical sensor was influenced significantly by the N and the growth regulator application, but on most of the readings the interactions between these two factors were not significant. NDVI values can be used on the diagnostic of N nutritional deficiencies for cotton