Tecnologias de fertilizantes nitrogenados para lavouras cafeeiras: fertilizantes convencionais blend e organomineral

Abstract

An important way to increase productivity in coffee farming is to improve fertilizer efficiency through the adoption of innovations and technologies. In this sense, the objective of this work was to evaluate the efficiency of using nitrogen fertilizer technologies for coffee plants in production. The experiment was carried out in Coffeaarabica L. crops, located in the municipality of Santo Antônio do Amparo - MG, Brazil. A randomized block design was followed, with three replications with the following fertilizers: 1) conventional urea; 2) ammonium nitrate and 3) organomineral, divided into three applications (3x); 4) physical mixture of controlled-release urea + urea with NBPT (1x) and 5) organomineral in installments (1x) at N doses: 0, 200, 280 and 400 kg ha-1year-1. The following evaluations were carried out: N release curves from fertilizers in the field and laboratory; leaf N levels; N-mineral dynamics in the soil; ammonia (NH3) losses; productivity, income and yield. In the nutrient release test in the field, the physical mixture of controlled-release urea + urea with NBPT promoted the release of 86% of N after 252 days. The organomineral released 100% of the N in the 1st week. Increases in leaf N levels occurred up to a dose of 240 kg ha-1 year-1 in the 1st leaf sampling carried out in December and at a dose of 216 kg ha-1 year-1 in the 2nd collection in March with values of 3.32 dag kg-1 and 3.01 dag kg-1. The accumulated losses of N-NH3 followed the decreasing order: organomineral (3x) (87.45 kg N ha-1) > urea (76.97 kg N ha-1) >organomineral (1x) (64.10 kg N ha-1) > blend (47.37 kg N ha-1) > ammonium nitrate (6.95 kg N ha-1). Coffee productivity increased depending on the N doses, reaching a maximum value of 3,360 kg ha-1 at a dose of 400 kg N ha-1 year-1, a value 31% higher compared to the control. Nitrogen fertilizer technologies are an important option to mitigate N-NH3 losses, compared to conventional urea, and promote better use of nitrogen fertilizers in coffee farming.