Installing a pattern tile system used to amount to installing lines through the field a reasonable distance apart, and tying them into a lateral or main that outlets into a creek. Many systems are still put in that way. The goal is to remove as much water from the field as possible.
The problem, says Jane Frankenberger, with the Ag Engineering Department at Purdue University, is that it also accelerates the loss of nutrients and sediment that leave with the water and go out the tile lines. She has studied a practice that can help reduce the loss of nutrients and sediment leaving through tile lines, and also provide a benefit – moisture in the tile lines during the summer when conditions get dry, if you want to use the system in that way.
Frankenberger is talking about water control structures. Instead of just installing tile and leaving a field, contractors install a water control structure where the water exits the field and heads to an outlet, usually in a ditch. The structure has gates which a farmer can adjust during the year. In the winter once the crop is harvested you can allow water to remain in the lines, keeping fields wet to saturated.
"That's when we lose a lot of nutrients with typical tile systems," she says. "This way the water stays in the soil when you don't need to be on the field anyway, and the sediment and nutrients stay there as well."
Once spring planting season approaches, you adjust the gates so that water exits the field through the tile and flows into the creek. Once the field is planted, you can adjust the gates again if necessary, based upon conditions.
"It doesn't solve every problem, but it is a practice that shows merit," she says. "It's one way to stop loss of sediment and nutrient through tile lines in winter months."