Nitrogen loss by volatilization of nitrogen fertilizers applied to coffee orchard

Abstract

Ammonia volatilization (N-NH 3 ) is one of the main pathways of Nitrogen loss reducing nitrogen use efficiency in coffee orchard. This work aimed at quantifying ammonia volatilization (N-NH 3 ) 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 (S 0 ) + polymers, and urea + plastic resin. These N sources were split into three doses of 150 kg ha -1 and band applied. The N-NH 3 losses by volatilization and variations of pH (H 2 O) were measured, before and after N application. The N-sources contributed to reduce the soil pH, measured after the third nitrogen fertilization. The N-NH 3 losses by volatilization (average from three applications) was as follows: urea + anionic polymers (35.8%) > conventional urea (31.2%) = urea + S 0 + 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. RESUMOA volatilização de amônia é uma das principais causas da redução da eficiência no uso de fertilizantes nitrogenados em lavouras cafeeiras. Neste trabalho, objetivou-se quantificar as perdas de nitrogênio por volatilização de fertilizantes nitrogenados aplicados em lavoura cafeeira. O experimento foi realizado em condições de campo, em um Latossolo Vermelho distrófico, cultivado com café, localizado no Setor de Cafeicultura/Departamento de Agricultura/UFLA, Lavras -MG. O delineamento experimental foi em blocos casualizados e os tratamentos foram: ureia; nitrato de amônio; ureia + 0,15% de Cu + 0,4% de B; ureia + polímeros; ureia + enxofre elementar (S 0 ) + polímeros e; ureia + resina plástica; distribuídos em três parcelamentos com doses iguais de 150 kg ha -1 . Foram quantificadas as perdas de nitrogênio por volatilização (N-NH 3 ) e as variações no pH em água, da camada de 0-5 cm de solo, antes e depois dos parcelamentos das adubações nitrogenadas. Os fertilizantes nitrogenados reduziram os valores do pH do solo após as três adubações de manutenção. A perda de nitrogênio por volatilização dos fertilizantes nitrogenados (média das três adubações) foi: ureia + polímeros (35,8% do total do N aplicado) > ureia (31,2%) = ureia + S 0 + polímeros (31,0%) > ureia + Cu + B (25,6%) > ureia + resina plástica (8,6%) = nitrato de amônio (1,0%).Termos para indexação: Coffee arabica; fertilizantes estabilizados e de liberação controlada; nitrato de amônio; ureia.

Ammonia volatilization from blends with stabilized and controlled-released urea in the coffee system

“…These factors contributed to the peak of N volatilization of urea (5.6% of the applied N -8.4 kg N ha -1 ) occurring on day three after application ( Figure 1b). N-NH 3 loss peaks in coffee crops occurred between the 1 st and 3 rd days after the application of urea in amounts equivalent to 5.0%, 8.4%, and 9.1% of the total N applied (450 kg N ha -1 ) in each of the three fertilizations (150 kg N ha -1 ) (Dominghetti et al, 2016). The urea blends with NBPT and polymer sulfur-coated urea (Polyblen Extend ® -100%, Polyblen Extend ® -70%, Polyblen Montanha ® -100% and Polyblen Montanha ® -70%) had the maximum possible daily losses of N-NH 3 equal to 6.5 kg N ha -1 (2% of the applied N); 4.6 kg N ha -1 (2.1% of the applied N); 6.5 kg N ha -1 (1.4% of N applied) and 2.7 kg N ha -1 (0.9% of the applied N) 3, 9, 11 and 42 days after the 1 st fertilization, respectively.…”

“…Thus, N is less susceptible to losses in the first few days after application. However, conventional urea, because it is highly soluble in water, hydrolyzes faster (Azeem et al, 2014;Dominghetti et al, 2016).…”

“…The use of coated urea can provide a synchronized release of the nutrient by the fertilizer with the crop demand throughout the entire cycle (Dominghetti et al, 2016). This synchronism may allow for a reduction of costs regarding staff during fertilization because the fertilizer will supply the nutrient throughout the entire cycle of coffee crop fertilization, thus avoiding the requirement of three splittings, as recommended by Guimarães et al (1999).…”

“…The volume extracted from the foams was measured; aliquots were transferred to test tubes and distilled in a semi-micro Kjeldahl apparatus (Dominghetti et al, 2016).…”

“…However, in relation to its agronomic aspects, when urea is applied to the soil surface without any incorporation, significant losses by volatilization may occur, reaching average values of 30% of the total applied N (Dominghetti et al, 2016) and thus changing the availability of N to the coffee plants (Fenilli et al, 2007).…”