Drainage Control to Diminish Nitrate Loss from Agricultural Fields1
- J. W. Gilliam,
- R. W. Skaggs and
- S. B. Weed2
In an attempt to reduce NO3−-N movement to drainage waters, flashboard riser-type water level control structures were installed in tile mains or outlet ditches at two locations to raise the water table to increase denitrification during the winter. A large reduction in NO3−-N movement through tile lines occurred (from 25–40 to 1–7 kg/ha) in moderately well-drained soils because of reduction in effluent volume. In the moderately well-drained soils, there was no indication of increased denitrification in the field. In poorly drained soils, drainage control had no influence upon soil profile oxidation-reduction potentials but resulted in approximately.a 50% reduction in NO3− movement through drainage ditches. This reduction was due to increased water movement into and through deeper soil horizons (below 1 m). The NO3−-N concentrations and low Eh values in all profiles below 1 m indicate that the NO3− which moved to this depth underwent denitrification.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .