Fertilizantes nitrogenados convencionais e estabilizados na cafeicultura: análises agronômicas, de qualidade, ambientais e econômica

Abstract

The high demand for nitrogen (N) from coffee crop means that the recommendation and supply of N is the best source to decrease system losses and improve crop yield for better yield and product quality responses. harvested end. The experiment was conducted in Santo Antônio do Amparo, MG. Three sources of N (conventional urea, urea + NBPT and ammonium nitrate) and 4 doses: 150; 275; 400 and 525 kg N ha-1 year-1 and a control treatment without nitrogen fertilization. In article 1, the objective was to evaluate the sources and doses of N applied in a split way in the coffee tree as N losses due to ammonia volatilization (NH3), productivity and attributes related to agronomic efficiency derived from productivity. N volatilization losses were higher with the use of urea, proportional to the applied N rates, in all evaluation years. The lowest N volatilization losses were with the use of ammonium nitrate. In the fourth year, productivity followed the following decreasing order ammonium nitrate = urea + NBPT> common urea> control. After four years of fertilization, ammonium nitrate, urea and urea + NBPT showed no significant differences in the average yield and total accumulated yield, but the control was smaller. In article 2 the objective was to determine the depth distribution in soil of N-mineral (NH4 + and NO3 - ), total N (mineral + organic), total N stocks and leaf and grain N content and their effect. on coffee yield in two crop years. Nitrate concentrations in soil are higher than ammonium from 40 cm depth, where there are not so many effective roots to absorb nutrients. N-total stocks have decreased over the years in all tiers evaluated. Yield is highly correlated with N-total stocks at 400 kg ha-1

nitrogen in multivariate analyzes. In article 3 aimed to evaluate the postharvest characteristics of coffee in relation to coffee quality after three years of management with different nitrogen sources and doses. The sensory analysis presented excellent grades in the three years of evaluation, with very good special description and special classification in the 15/16, 16/17 and 17/18 seasons, and in the 17/18 season the control presented excellent special description and classification. specialty. The number of coffee bean defects was very close with N rates above 150 kg N ha-1 year-1.