Ammonia and carbon dioxide emissions by stabilized conventional nitrogen fertilizers and controlled release in corn crop

Emissões de amônia e de dióxido de carbono de fertilizantes nitrogenados convencionais, estabilizados e liberação controlada na cultura do milho

ABSTRACT

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 CO₂ 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-NH₃ losses from N fertilizers were: Granular urea (39% of the applied N ) = prilled urea (38%) > urea coated with 16% S⁰ (32%) = blend of urea + 7.9% S⁰ + 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 CO₂   emissions in corn crop. On the other hand, hydrolyzed leather promoted greater C-CO₂ emission, when compared with other nitrogen fertilizers.

Index terms:
CO₂; NH₃ loss; no-tillage; Zea mays L.