The market of stabilized, slow and controlled release nitrogen (N) fertilizers represents 1% of the world fertilizer consumption. On the other hand, the increase in availability, innovation and application of these technologies could lead to the improvement of N use efficiency in agroecossystems and to the reduction of environmental impacts. The objective of this study was to quantify agronomic efficiency relative index, ammonia volatilization, and CO 2 emissions from conventional, stabilized and controlled release N fertilizers in corn summer crop. The experiment was carried out in a corn crop area located in Lavras, state of Minas Gerais, Brazil, without irrigation. All treatments were applied in topdressing at rate of 150 kg ha -1 N. N-NH 3 losses from N fertilizers were: Granular urea (39% of the applied N ) = prilled urea (38%) > urea coated with 16% S 0 (32%) = blend of urea + 7.9% S 0 + polymers + conventional urea (32%) > prilled urea incorporated at 0.02 m depth (24%) > urea + 530 mg kg -1 of NBPT (8%) = Hydrolyzed leather (9%) > urea + thermoplastic resin (3%) = ammonium sulfate (1%) = ammonium nitrate (0.7%). Thermoplastic resin coated urea, ammonium nitrate and ammonium sulfate presented low values of cumulative CO 2 emissions in corn crop. On the other hand, hydrolyzed leather promoted greater C-CO 2 emission, when compared with other nitrogen fertilizers.Index terms: CO 2 ; NH 3 loss; no-tillage; Zea mays L. RESUMOO consumo de fertilizantes nitrogenados estabilizados, de liberação lenta e controlada representa 1% do total de fertilizantes utilizados no mundo. Por outro lado, um aumento na disponibilidade, inovação e utilização dessas tecnologias pode levar a maior eficiência no uso do nitrogênio (N) na agricultura com menor impacto ambiental. O objetivo deste trabalho foi quantificar as perdas de amônia (N-NH 3 ) por volatilização e as emissões de CO 2 de fertilizantes nitrogenados convencionais, estabilizados e de liberação controlada na cultura do milho. O experimento foi realizado em condições de campo no município de Lavras (MG) no ano agrícola 2013/2014, sem irrigação. Os tratamentos foram compostos por fertilizantes nitrogenados aplicadas em cobertura na dose de 150 kg ha -1 de N. A perda acumulada de N-NH 3 dos fertilizantes nitrogenados convencionais, estabilizados de liberação controlada em ordem decrescente foi: Ureia granulada (39% do N aplicado) = ureia perolada (38%) > ureia + 16% de S 0 (32%) = mistura física de grânulos (blend) de ureia revestida com S 0 e polímeros e ureia convencional (32%) > ureia perolada incorporada (24%) > ureia + 530 mg kg -1 de NBPT (8%) = hidrolisado de couro bovino (9%) > ureia + resina termoplástica (3%) = sulfato de amônio (1%) = nitrato de amônio (0,7%). O sulfato e nitrato de amônio e a ureia + resina termoplástica promovem a menor emissão de dióxido de carbono (C-CO 2 ) em área de cultivo de milho. Enquanto que, o hidrolisado de couro promoveu a maior emissão total de C-CO 2 para à atmosfera.Termos para indexação: CO 2 ; perdas de NH 3 ; planti...

Information related to phosphate fertilization and coated phosphate fertilizer in onion is scarce. Thus, this study was carried out to evaluate agronomic efficiency, production and nutritional characteristics of triple superphosphate coated with polymers in onion cultivated in contrasting texture soils. Two experiments were carried out under protected conditions in pots containing 5 kg soil. The experimental design was completely randomized with treatments arranged in a 2 x 5 factorial: triple superphosphate (TSP) and polymer-coated triple superphosphate (TSP+P) applied in five phosphorus rates: Dystroferric Red Latosol (LVdf) (clayey) = 0; 100; 200; 400; 800 mg P 2 O 5 kg-1 , and Quartzarenic Neosol (sandy) = 0; 75; 150; 300; 600 mg P 2 O 5 kg-1 , with three replications. Results indicated that polymer-coated TSP showed no difference for bulb mass and agronomic efficiency for phosphorus fertilization. Agronomic efficiency of phosphorus fertilization decreased with the increase in the amount of phosphorus applied. Phosphorus accumulation for onion bulb cultivated in Dystroferric Red Latosol (LVdf) was higher with the use of polymer-coated triple superphosphate. Growth, production and nutritional characteristics in onion were affected by phosphorus. The highest bulbs mass production and phosphorus accumulation occurred at the doses of 783; 629 mg kg-1 P 2 O 5 (Dystroferric Red Latosol-LVdf), and of 406; 600 mg kg-1 P 2 O 5 (Quartzarenic Neosol-RQ).