Managing Water, Boosting Farmland: An Introduction to Drainage Water Management
By: Tom Collins
In 1938, the invention of in-field tile drainage systems ushered in a new era of productivity for US farmers. Tile works by effectively draining water off agricultural farmland to prevent flooding and oversaturation within the field. Sometimes, though, this drainage can be too effective, amplifying the effects of a dry period and providing a direct route for nutrient runoff to enter our drinking water sources.
Enter drainage water management (DWM). Many times, this consists of a water control structure at a farm’s tile outlet. With this structure, the farmer or landowner can adjust the rate at which water flows off the farm by manipulating the level of retained water throughout their tile system. Controlling a field’s water table can build stronger root networks, reduce nutrient runoff, and increase yields all at once. Additionally, adding DWM practices to a saturated buffer, bioreactor, or other edge of field practice is a great way to stack practices and get the most out of your conservation efforts.
The benefits of DWM start in the spring, and are visible no matter the conditions. In a cold and wet spring, farmers prioritize warming and drying the soil to prepare for planting. While in a warm and dry spring, it is important to retain optimal moisture levels for the planted seeds to flourish. Farmers can adjust gates within a control structure to hold or release stored water as needed.
The same applies throughout the growing season. In wet years, the water can be drained as normal to prevent in-field flooding and oversaturation. In dry summers, the water can be held in the field as long as possible, ensuring the plants have access to moisture when they need it most.
Isaac Ferrie, director of research at Crop Tech Consulting, discussed why it’s so important, saying “we typically get real dry here toward the end of the season,” emphasizing that “there’s a lot of times we get a rain event after being dry, and we have minimal benefit because you lose so much if it out of the tile so quick.
Ferrie states that drainage water management is the solution. “We can hold that water back for 10, 12, 14 hours, and usually we don’t have to let it go. It gets stuck back up into the soil.”
He compared the soil to a stiff sponge, stating that “if you dip [the sponge] in water real quick, it doesn’t pick up anything, but if you dip it in the water and hold it, it soaks up a lot of water.”
Like with many conservation practices, there are a variety of options for drainage water management. The big decision is choosing between manual vs automated drainage systems. Both achieve the same goal, but are differentiated by time commitment and cost. In the words of Josh Shuler, technical product and business development manager of automation at Agri Drain,
“[DWM] really builds on the benefit of the tile drainage system. We all know tile is important. It gets rid of the water, but there’s times when you want to hold it back, and that’s what we’re really trying to do with drainage water management.”
Addressing the difference between the two methods, Shuler described manual DWM as the “cheap and effective” way, highlighting its lower implementation cost along with its ability to make a quick and measurable difference on farmland. However, he cautioned that manually adjusting the water level can be time-consuming.
“The technology works great as long as you’re there in a timely fashion,” said Shuler, “but we all know farmers are busy. So sometimes they don’t get changed appropriately.” In contrast, he emphasized that “with automation, we can either set it and forget it, or set it on a schedule, and that really lets us maximize the benefit.”
Shuler also showcased the ability to control water levels remotely on newer automated DWM systems, giving farmers peace of mind that their water is exactly where it needs to be.
Whether manual or automated, when it comes to managing drainage water, Shuler says “we’ve got lots of options.”
For every farm, there is a unique solution to conservation and water quality. Explore https://www.iaagwater.org/conservation-library/ to find the right practice for your farm, or utilize our Conservation Agronomist network to get help finding the perfect solution for you.