All farmers know that rain is a good thing – in moderation. But what do we do when it rains too much?
Many of us use tiling to protect our roads and properties from excessive rain and flooding. We use tiling just as cities use storm sewers, except tiling has the added benefit of filtering rainwater along the way. In my watershed at our farm in Minnesota, we don’t have nitrate issues, and less phosphorous comes out of tiling compared to above ground.
Tiling is an old technology, yet it remains a practical and efficient way to protect our roads and property from excessive rain, along with providing an important environmental benefit. I’ve found that agriculture drainage and water quality can be misunderstood and wanted to talk about some of these misperceptions.
- Tiling is one of the most highly regulated activities affecting farmers. It’s common for as many as five regulators to review a proposed drainage project to ensure compliance with all rules.
- Tiling does not speed water movement off the land. Compared to surface runoff, tiling moves water quite slowly.
- Tiling does not contribute to water quality issues. This is a matter of trade-offs. Tile water does contain nutrients and sediment. Research shows that tile drainage reduces surface runoff, resulting in less sediment being transported. There is a corresponding reduction in phosphorus losses, though not quite as large due to the presence of a very small amount of dissolved phosphorus contained in tile water. Tile drainage also contains nitrates. The key to determining the net effect of tiling lies in understanding how much sediment and phosphorus are reduced relative to the increase in nitrates. In my experience, the tradeoff is positive, as farmers are becoming increasingly aware of this concern and are constantly working harder to improve our nitrogen application practices.
- Tiling is good for soil health. Healthy soils contain both water and oxygen, but some of the most productive soils are not able to drain naturally, starving the microorganisms in the soil of oxygen. This, in turn, affects nutrient cycling in the soil and can reduce crop productivity, which is important in returning organic matter to the soil to continue the cycle. Improved drainage contributes to improved soil health.
- Tiling is an important conservation practice and is key to the successful implementation of many other conservation practices. Sometimes conservation simply means that land is left undisturbed as habitat. But once the decision is made to farm a tract of land, farming it with efficiency results in fewer acres required for crop production and more acres available for other uses, including habitat. The technology available today allows drainage to be accomplished with less environmental impact and greater improvements in productivity than 50 to 100 years ago. Well-designed tile systems that follow field contours and provide uniform drainage are the norm today. This allows more options for farmers to move to reduced tillage systems, improves nutrient uptake, and extends the growing season.