ABSTRACT Nitrogen losses by ammonia (NH3) volatilization can be reduced by appropriate irrigation management or by alternative N sources, replacing urea. The objective of this study was to evaluate the efficiency of irrigation management and N source combinations in decreasing NH3 volatilization from an Argissolo Vermelho Distrófico típico cultivated for 28 years with black oat (Avena strigosa) and maize (Zea mays), under no-tillage in the region of Depressão Central, Rio Grande do Sul, Brazil. The experiment was arranged in a […]

The quantification of ammonia (NH3) losses from sugarcane straw fertilized with urea can be performed with collectors that recover the NH3 in acid-treated absorbers. Thus, the use of an open NH3 collector with a polytetrafluoroethylene (PTFE)-wrapped absorber is an interesting option since its cost is low, handling easy and microclimatic conditions irrelevant. The aim of this study was to evaluate the efficiency of an open collector for quantifying NH3-N volatilized from urea applied over the sugarcane straw. The experiment was […]

Nitrogen (N) is required in large quantities by corn and its supply causes technical concerns related to crop performance and profitability, and environmental concerns in view of the high risk of nitrate leaching. Results of 61 field experiments conducted through 13 years, in a cooperative effort of the Fundação Agrária de Pesquisa Agropecuária (FAPA) and the Universidade Federal do Rio Grande do Sul (UFRGS), were analyzed and interpreted aiming at establishing a N fertilizer indication for high corn yields, adjusted […]

Carbon and nitrogen mineralization rates were determined in samples from a sandy latosolic Red Yellow Podzolic soil, taken at three depths, 0-20, 20-40 and 40-60 cm, during 10 years of sugarcane cultivation, using plots with and without N fertilization (60 kg ha-1 of N, as urea). N mineralization was measured using the incubation – percolation technique and C mineralization by absorbing the C-CO2 in 1 mol L-1 NaOH. Overall, N mineralization was higher (13%) in the treatment with N fertilization than in that without fertilization during the […]