Ammonia volatilization from nitrogen fertilizers in no-till wheat and maize in southern Brazil

Abstract

SUMMARYCrop residues on the soil surface of no-till systems can intensify ammonia volatilization from N fertilizers applied to cereal crops. This study assessed the magnitude of N losses through ammonia volatilization from urea applied to no-till winter (wheat) and summer crops (maize) on a Typic Hapludox in the south-central region of Paraná, southern Brazil. In addition, the potential of alternative N sources (urea with urease inhibitor, liquid fertilizer, ammonium nitrate and ammonium sulfate) and different urea managements (fertilizer applied in the morning or afternoon) were evaluated. Two experiments with maize and wheat were carried out for two years, arranged in a randomized block design with four replications. Nitrogen volatilization losses were assessed with a semi-open static collector until 21 days after fertilization. In winter, the losses were low (<5.5 % of applied N) for all N sources, which were not distinguishable, due to the low temperatures. In the summer, volatilization rates from urea were higher than in the winter, but did not exceed 15 % of applied N. The main factor decreasing N losses in the summer was the occurrence of rainfall in the first five days after fertilization. Urea with urease inhibitor, nitrate and ammonium sulfate were efficient to decrease ammonia volatilization in maize, whereas the application time (morning or afternoon) had no influence.Index terms: nitrogen fertilization, efficiency, yield. RESUMO: VOLATILIZAÇÃO DE AMÔNIA DE FERTILIZANTES NITROGENADOS APLICADOS NAS CULTURAS DO TRIGO E DO MILHO EM PLANTIO DIRETO, NO SUL DO BRASILOs resíduos culturais na superfície de solos em plantio direto (PD) podem intensificar a volatilização de amônia, quando da aplicação dos fertilizantes nitrogenados em sistemas de produção de cereais. Este estudo visou avaliar a magnitude das perdas de N por volatilização, quando da aplicação superficial de ureia nas culturas do trigo e do milho, em Latossolo Bruno em PD, no centro-sul do Paraná. Adicionalmente, avaliou-se o potencial de fontes alternativas de N (ureia com inibidor de urease, fertilizante líquido, nitrato de amônio e sulfato de amônio) e de variantes no manejo da ureia (fertilizante aplicado pela manhã ou à tarde) em reduzir as perdas de amônia por volatilização. Dois experimentos foram conduzidos, por dois anos, com as culturas do trigo (Triticum aestivum L.) e milho (Zea mays L.), seguindo um delineamento de blocos casualizados, com quatro repetições. As perdas de N por volatilização de amônia foram avaliadas utilizando-se um coletor semiaberto estático, no período de até 21 dias após a aplicação dos fertilizantes. No inverno, as perdas foram baixas para todas as fontes nitrogenadas (<5,5 % N aplicado) em razão das baixas temperaturas e independentes do regime de chuvas. No verão, as taxas de volatilização de amônia, quando da aplicação superficial de ureia, mantiveram-se inferiores a 15 % do N aplicado e foram dependentes da ocorrência de chuvas nos primeiros cinco dias após a aplicação do fertilizante. A utilização de ure...

Addition of Urease Inhibitor Has No Effect on Ammonia Volatilization Following Soil Application of Poultry Litter or Organomineral Fertilizer, Unlike Urea

“…The amount of ammonia volatilized from the addition of urea to the soil surface in our experiment is in the range found by most studies, which varies from 5 to 25 % (Cantarella et al, 2008;Viero et al, 2014). In extreme conditions, however, these losses may be higher than 40 % (Oliveira et al, 2014).…”

“…Tasca et al (2011) found that ammonia volatilization following urea application was 30 % higher at a temperature of 35 °C than at 18 °C. Viero et al (2014) observed ammonia losses following urea application of approximately 5 and 15 % of the N applied for winter and summer crops, respectively. O' Connor and Hendrickson (1987) observed that hydrolysis of urea was completed after 1, 4, 6, 7, and 8 days after soil application Unlike the pattern that occurred with urea, the highest losses of ammonia from treatments with OMF or PL were on the days immediately following soil application, regardless of the presence or absence of urease inhibitor.…”

“…In extreme conditions, however, these losses may be higher than 40 % (Oliveira et al, 2014). Addition of NBPT to urea has usually been effective in decreasing ammonia losses (Cantarella et al, 2008;Viero et al, 2014), but not always (Tasca et al, 2011;Oliveira et al, 2014).…”

“…Sharpe et al (2004) measured ammonia volatilization after addition of poultry litter to the soil and found losses up to 3.3 and 24 % of the total N applied in the winter and summer, respectively, where the highest values occurred in periods of high temperatures, drought, and high wind. Following urea application, ammonia volatilization may range from negligible values (Viero et al, 2014) up to more than 40 % of the total N applied (Oliveira et al, 2014).…”

Urease Inhibitor and Irrigation Management to Mitigate Ammonia Volatilization from Urea in No-Till Corn

“…Ammonia volatilization has been extensively studied in different regions of Brazil, where reported NH 3 -N losses range from 5 to 78 % of N applied as urea depending on the particular environmental conditions (Lara Cabezas et al, 1997;Cantarella et al, 2008;Rojas et al, 2012;Soares et al, 2012;Viero et al, 2014;Viero et al, 2015). The addition of a urease inhibitor such as N-(n-butyl) thiophosphoric triamide (NBPT) to urea has proved to be an effective, technically feasible method to reduce NH 3 -N losses from common urea and increase the efficiency of topdressed N fertilization in corn (Cantarella et al, 2008;Soares et al, 2012;Viero et al, 2015).…”