Volatilization Losses of Nitrogen from Surface‐Applied Fertilizers, as Measured by Crop Response

Abstract

Yields and uptake of N by corn forage grown in pot experiments with N fertilizers mixed with and surface‐applied to moist soils a week prior to planting were determined. Losses of N were low with mixed placement. High losses of N, presumably as NH3, occurred from granular urea surface‐applied to Hartsells fine sandy loam limed to pH 6.2 and 7.5 and to Webster silty clay loam (pH 8.2). Losses were reduced by coating urea with S or by including phosphate in the granules as urea ammonium phosphate. Severe losses of N also occurred with surfaceapplied ammonium sulfate and diammonium phosphate, especially from the naturally calcareous Webster soil. Maximum recoveries from soils of pH 6.2 to 8.2 were obtained from monoammonium phosphate, ammonium nitrate, ammonium phosphate nitrate, and ammonium polyphosphate. Differences in losses of N as NH3 among N fertilizers can be explained largely in terms of urea hydrolysis or the reaction of certain acid radicals of ammonium salts with calcium compounds in soil.

Comparison of Ammonium Sulfate With Other Nitrogen and Sulfur Fertilizers in Increasing Crop Production and Minimizing Environmental Impact

“…Incorporation of urea into the soil can significantly reduce NH 3 volatilization (Fenn and Kissel, 1976). Table 1 shows results from an experiment that compared the recovery of N applied as AS and urea by incorporation with the soil and application on the surface with and without liming (Terman and Hunt, 1964). In this study, S was not a limiting factor in plant growth.…”

“…Recovery of N in the Aboveground Parts of Maize Plants From AS and Urea Mixed or Surface Applied to a Fine Sandy Loam Soil at Two pH Values(Terman and Hunt, 1964) …”

Ammonia volatilization from ammonium nitrate, urea and urea phosphate fertilizers applied to alkaline soils

“…Only negligible losses occurred from UP and AN at all rates of application, due to their low volatilization potentials. Urea phosphate gives a low solution pH and AN forms soluble reaction products, thereby preventing the accumulation of (NH 4 )zC0 3 and the resulting ammonia volatilization (Terman & Hunt, 1964;Fenn & Kissel, 1973). Hargrove, Kissel & Fenn (1977) and Hoff,et al (I 981) were able to show that a linear relationship existed between rates of fertilizer applied and the total ammonia loss.…”

“…The objective of such products is to reduce the rate of hydrolysis and dissolution of urea and to maintain a low fertilizer band pH, thereby preventing the formation or accumulation of ammonium carbonate (NH4)2CO) which is most responsible for NH) volatilization (Fenn & Kissel, 1973). Terman & Hunt (1964) and more recently Nelson (1982), Fenn & Hossner (1985) and Haynes & Sherlock (1986) have discussed the mecIianism's of NH3 volatilization. It has been recognized that soil and environmental factors such as temperature, water content, pH, and texture, influence the magnitude of ammonia loss (Jew itt, 1942;Broadbent, Hill & Tyler, 1958;Wagner & Smith, 1958;Volk, 1959;Ernst & Massey, 1960).…”

Fertilização com sulfato de amônio na cultura do milho em um solo de cerrado de Brasília sob pastagem de Brachiaria decumbens.

“…Muito pouco nitrogênio é perdido por volatilização de NH 3 do sulfato de amônio aplicado na superfície em solos ácidos (pH < 6,0). (Anjos & Tedesco 1976 ;Campos 1976 ;Terman, 1964).…”