Tanzania grass leaf absorption of ammonia volatilized from 15N-urea applied to soil.

摘要

The effect of urea-N rates (40, 80 and 120 kg N/ha) 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 from 2.5 to 16.4% of the volatilized N.