Tile drainage is one of those topics where there are a lot of opinions. A recent update on a 35-year study at Purdue University confirmed that tile drainage enhances the value of cover crops and no-till.
The update, published by Eileen Kladivko with the Purdue Agronomy Department, looked at a 15-acre plot of poorly drained silt loam soil in Indiana. According to Kladivko, installing tile drainage is a good long-term investment, extending the window of fieldwork by as much as 2 weeks, in some cases, and improving corn yields.
The study did not find a significant increase in soybean yields. Part of the yield increase for corn was due to the tile draining areas of the field where water would pool and drown out the crop.
Many of the most popular cover crop species require properly drained soils in order to establish good stands and generate large amounts of biomass. Overwintering varieties like cereal rye grow the most during fallow periods, so tile drainage can allow soil to enable significant growth, improving soil health over time.
Other soil measurements taken during the study found that earthworm populations were higher in plots with no-till and/or cover crops or crop rotations. Physical properties of soil, such as aggregate stability and water infiltration, were also improved by cover crops, even if drainage tile was in place.
One of the most significant findings of the study is that agronomic conservation practices alone can’t make up for inadequate drainage. The shallow water table is a limitation to cover crop and cash crop growth, and proper management allows for better aeration of the soil, which can allow soil biology to flourish.
What do you think? Have you found drainage tile to be helpful to your cover crops?