Preliminary Field Denitrification Studies of Nitrate-Fertilized and Nitrogen-Fixing Crops
Soil cores were sampled and treated by the acetylene inhibition technique to follow denitrification rates in fields with barley (0 and 120 kg N ha−1), meadow fescue grass ley (200 kg N ha−1) and lucerne. The acetylene inhibition method was also used in studies of denitrification potential.
Denitrification rates, elevated over a baseline rate, were obtained when the soil was wetted by rain. This was noted especially in the fertilized crops. Higher rates were obtained with samples taken in plant rows as compared with those between plant rows.The rates seemed to be highest during the autumn. A large variation between the cores may be due to an uneven distribution of denitrification potential in the soil. Potential denitrification rates were highest in the plough layers (down to about 30 cm), compared with the sand and clay layer underneath. The potential was also higher in the fertilized treatments than in those receiving no fertilizer nitrate. These results probably reflect energy availability and nitrate abundance, respectively.
KeywordsClay Layer Denitrification Rate Potential Denitrification Anaerobic Incubation Plough Layer
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