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 […]

Ammonia volatilization and nitrification/denitrification are the two major N loss mechanisms in rice production. If N fertilizer is not managed appropriately, N recovery by rice plants can be low. The purpose of this study was to quantify ammonia volatilization in flooded soils influenced by the urea application method. A greenhouse study was conducted to quantify the potential of N loss via ammonia volatilization in flooded soils influenced by the urea application method. Two experiments were carried out, one in Mississippi, […]

The effect of urea-N rates (40, 80 and 120 kg ha-1 N) and the distance (0, 27 and 35 cm) from sink (leaf) to source (urea applied to soil) on leaf absorption of ammonia by the pasture species Panicum maximum cv. Tanzania was evaluated. A randomized design was used in a split-plot arrangement with four replicates. The distance had no effect on leaf ammonia absorption (p < 0.05), but the absorption decreased exponentially (p < 0.05) with increasing N-rates or ammonia volatilization rates. Leaf ammonia absorption varied […]