Capacity of a terrestrial optical sensor as a tool to detect nitrogen deficiency in cotton crop por cultivation

The objective of the present investigation was to evaluate the effect of the nitrogen dose variation (N) on the reflectance properties of the cotton por culture, through an optical sensor. The research was conducted in the experimental field of the FCA/UNA. Subsidiary Santa Rosa, Misiones. The cotton cultivars evaluated were IAN-425 and IPTA-212. The doses of N used were 0, 50, 100, 150, 200 and 250 kg ha, in the form of urea, with an experimental design of random blocks in divided plots, where the main plots were the cultivars and the subplots by the dose of N. The results were subjected to a comparison of means (Tukey p<0.05). The NDVI values obtained by the sensor were significantly influenced (p<0.05) as a function of the N doses applied to the plant, based on the evaluations made at 76 DDE, regardless of the type of cultivar, where they were recorded. the highest spectral values (0.85 and 0.84) with the N dose of 250 kg ha. In spite of not detecting significant differences between the cultivars, neither in the doses of nitrogen applied to the plants, as well as in the interaction of the studied factors (Cultivar x Dosage) in the yield of fiber in branch, we can emphasize that the average yield of the cultivar IAN-425 was 3,143.17 kg ha and in turn, the cultivar IPTA-212 obtained an average yield of 3,036.91 kg ha, results that far exceed the national average yield of 1,180 kg ha for the harvest 2015/2016.