Many Iowa farmers are discovering that their old tiling systems aren't doing the job any more. Heavy cropping has caused the soil to pack, so that more of the water runs off. It collects in low spots instead of seeping down into the tile. For the long-time solution, we need better soil management-more legumes, more organic matter.
Barnes, Kenneth K.
"Draining Field Ponds,"
Iowa Farm Science: Vol. 2
, Article 3.
Available at: https://lib.dr.iastate.edu/farmscience/vol2/iss11/3