Nitrogen Fertilization in maize using the Portable Chlorophyll Meter
The cultivation of maize is one of the most important crops for the the Brazilian Agribusiness, representing 6.4% of world production. It should be noted that world production is almost 800 million tons and the United States is responsible for 42% of total production. Nitrogen fertilization is a very important step for the production system of maize, both in the aspect of quantification of doses, and in defining the time of application. The use of portable chlorophyll meter has been widely used, especially in tests of calibration and evaluation of deficiency, on the other hand, there is no literature on using the chlorophyll meter to indicate the amount of N to be applied. The experimental design was the randomized completely blocks with four replications and 6 treatments with nitrogen fertilization by coverage (0, 60,100, 120, 140 and 160 kg N ha-1) using urea. There is verified positive relationship between N rates and nitrogen content and it was affected by increasing doses of this nutrient, until 120 kg N ha-1. The curve of nitrogen fertilization using the Chorophyll meter was possible by the excellent correlations between doses and readings, doses and N content, and doses and grain yield. It was concluded that there was a good correlation between levels of nitrogen applied in coverage, with ICF readings, nitrogen content and and grain yield. Is possible to establish a curve for the nitrogen fertilization by the ICF readings at the time of covering.