Agricultural Drainage and the Environment

Agricultural drainage often bears the blame for high nitrates in surface water and Gulf Hypoxia issues.  These concerns are at least somewhat legitimate, but farmers are capable of addressing them.  I am an advocate of drainage as a yield boosting production practice.  I am also and advocate of proper nitrogen management.  I recently ran across some estimates that as much as 20 of the nitrogen in surface water is from fall applied nitrogen.  I our area, fall applied nitrogen has not been a great practice, but it is done.  If you must, be careful not to over apply, and be sure that soil temperatures are cool enough.  Use nitrification inhibitors.  Cut rates and sidedress is the best way to go, but it leaves producers with a lot to do in a short time. 

Another nitrogen management technique that is proven, but not widely implemented is the use of Bio-reactors.  Tile lines are designed to release water into a bio-reactor. The bio-reactor consists of a carbon source such as wood chips.  The wood chips help to filter out the excess nitrates before the water is released into the surface drainage system.  For more information check out this link.  Another practice that can remove nitrates from field runoff is filter strips.