Abstract

TORIBIO, Mirta et al. DETERMINANTS OF AMMONIA VOLATILIZATION LOSSES AND THEIR EFFECT ON MAIZE YIELD. Cienc. suelo [online]. 2023, vol.41, n.2, pp.193-205. ISSN 1850-2067.

Volatilization is a process by which nitrogen (N) is lost. Identifying the main factors determining this process is essential for a more economically and environmentally sustainable agriculture. The objectives of this work were to: a) integrate existing information about volatilization losses and their effect on maize yield (Zea mays L.), b) identify the main factors that control such losses in Argentina, and c) evaluate the effect of urease inhibitor on ammonia volatilization, yield and nitrogen agronomic efficiency (NAE). A systematic review, including a total of 21 experiments carried out between 1997 and 2021, was performed. A path analysis was used to examine the causal pathway of the factors that determine N volatilization rates, and a meta-analysis was carried out to evaluate the magnitude of the effect of management and edaphoclimatic variables on N volatilization. The main variable presenting a direct effect on ammonia losses was the N rate (r= 0.66), while clay content (r= -0.59) was the most relevant edaphoclimatic variable. An indirect and negative effect of organic matter (OM) was determined through the clay percentage (r= -0.39), while the direct effect of OM presented a low magnitude (r= -0.01). The highest N losses by volatilization occurred with N rates ≥100 kg N ha-1, OM <20 g kg-1 and clay content <200 g kg-1, temperature >20°C and <10 days of precipitations greater than 10 mm. The use of urease inhibitors reduced losses by 73%, without increasing yield or EAN. These results bring a solid foundation on which are the main determinants of volatilization losses.

Keywords : ammonium; nitrogen agronomic efficiency; urease inhibitor.

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