Subsurface tile drains are installed more closely together, but shallower than conventional tile drainage installation in Iowa - 2.5 feet compared to 4 feet.
Corn yields and nitrate-N concentrations are not affected significantly, but tile drainage volume is reduced by an average of 32%, thus reducing nitrate load. A benefit of shallow drainage over drainage water management is that there is no need for annual or biannual management.
As we left the last field, Gary looked over, chuckled and said, “So that’s part of my story. I just wish I was 20 years younger so I could stick around and enjoy all this stuff.”