Use of Winter Annual Cover Crops to Reduce Soil Nitrate Levels
2003
Mays, D.A. | Sistani, K.R. | Malik, Ravi K.
The scientific community and various environmental groups have been concerned about the leaching of nitrate (NO(3)) to ground water from various sources including crop fields where all the applied NO(3) is not utilized by the primary crop. Experiments were conducted on two soil types in Alabama to investigate the use of winter cover crops to capture NO(3) remaining after the harvest of corn, cotton and soybeans. In these experiments, harvest of the primary crops was so late that cover crop growth in the fall was insufficient to immobilize significant amounts of NO(3). Soil testing the following spring showed that most of the soil NO(3) was in the top 30 cm (12 in) of the soil profile. A subsequent cover crop planting date experiment showed that wheat planted after September 18 and rye planted after October 2 made insufficient fall growth to immobilized significant amount of NO(3). Most spring growth occurred after late February when much of the winter rainfall had already occurred. It appears that judicious selection of nitrogen fertilizer rates is a better approach to reducing NO(3) leaching.
显示更多 [+] 显示较少 [-]