Nitrogen loss by volatilization of nitrogen fertilizers applied to coffee orchard

Perdas de nitrogênio por volatilização de fertilizantes nitrogenados em cultivo de café

ABSTRACT

Ammonia volatilization (N-NH₃) is one of the main pathways of Nitrogen loss reducing nitrogen use efficiency in coffee orchard. This work aimed at quantifying ammonia volatilization (N-NH₃) losses from N-sources to be used in coffee plantations fertilization in Brazil. The experiment was conducted in the field on a dystrophic red latosol (Ferralsol in FAO's classification) at the Coffee Research Sector, University of Lavras, MG, Brazil. The experimental design was of complete randomized blocks with three repetitions of the following treatments: conventional urea, ammonium nitrate and urea + 0.15% Cu and 0.4% B, urea + anionic polymers, urea + elementary sulfur (S⁰⁾ + polymers, and urea + plastic resin. These N sources were split into three doses of 150 kg ha^-1 and band applied. The N-NH₃ losses by volatilization and variations of pH (H₂O) were measured, before and after N application. The N-sources contributed to reduce the soil pH, measured after the third nitrogen fertilization. The N-NH₃ losses by volatilization (average from three applications) was as follows: urea + anionic polymers (35.8%) > conventional urea (31.2%) = urea + S⁰ + polymers (31.0%) > urea + 0.15% Cu + 0.4 % B (25.6%) > urea + plastic resin (8.6%) = ammonium nitrate (1.0%).

Index terms:
Coffee arabica; slow and controlled release and stabilized fertilizers; ammonium nitrate; urea