Fertilización de maíz con urea de liberación lenta: pérdida por volatilización y eficiencia de uso de nitrógeno

nitrogen (n) loss reduces the efficient use of this nutrient (eun). when added to urea, products such as the maleic-itaconic copolymer nsn and thiophosphoric n-(n-butil) triamide (nbtpt) slow down the rate of release of n and thereby diminish its loss. the aim of this study was to determine n volatilization losses (n-nh3) during two growing seasons, grain yield, grain n content and nue of corn under no-tillage using urea, urea with nsn and with nbtpt in combination with a dose of n (60 and 120 kg ha-1). volatilization losses were extended by 7 and 18 days in the first and second year, respectively. in both years, losses with urea alone were higher than with urea+nsn and with urea+ nbtpt. in first year, n-nh3 losses with urea alone were 3% and 10% for 60 and 120 kg of n ha-1, respectively, whereas with urea+nsn and urea+nbtpt the losses were less than 0.5% in both cases. in the second year, n-nh3 losses with urea alone were 2.3% and 3.8% for 60 and 120 kg of n ha-1, respectively, and with urea+nsn and urea+nbtpt, less than 2%. grain yield did not improve by increasing n or by adding nsn or nbtpt. grain n content increased with higher doses of n and was not affected by the use of nsn or nbtpt. nitrogen use efficiency, physiological efficiency and recovery efficiency were reduced with increasing n but were not affected by the use of nsn and nbtpt. the use of these products was therefore effective in reducing n-nh3 losses but did not significantly affect grain yield, grain n content and nue. this could be due to the fact that under the environmental conditions of the present study, n loss is not a factor of high relevance.