Pathways of nitrogen loss as affected by soil surface management of an ultisol
1993
Deare, F.M.
Four studies were conducted to assess N losses as a result of overland and downward movement on an Aquoxic Tropudults and to evaluate management practices that would minimize losses. Soil loss ranged from 0.8 to 7.9 t/ha for individual runoff events accompanied by total N losses ranging from 0.5 to 22.1 kg/ha. Liquid N application increased total N loss while plants fertilized with solid (NH4)2 SO4 produced the highest number and fresh weight of okra pods. Four management practices: bare, ridge-tilled; mulched, ridge-tilled; bare, flat-tilled; and mulched, flat-tilled were tested under bare-fallowed and cropped conditions. The lowest soil and N losses were obtained from the mulched flat-tilled soil and highest from the bare, ridged soil. Urea increased ammonium - N levels in the soil. Ridging and mulch application increased water transmission and downward movement of N. nitrate -N movement occurred about 4 weeks after fertilizing in bare-fallowed plots and at 1-3 weeks in the cropped plots. Although ridging increased N losses from the soil, this was necessary for high crop yields, however the use of a bagasse mulch can reduce losses.
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