New technologies for farm drainage and tiling are providing more choices for farmers who want more control over soil moisture in their fields.
Decades ago, early drainage systems were used by farmers to remove excess water from fields to improve timeliness of planting and harvest operations, control erosion and improve crops. Many farmers saw the benefits of tiling pay off with increased yields.
Today, with the use of yield monitors, farmers can check their yields intensely across a field and see even the slightest differences between tiled areas vs. areas with insufficient drainage.
Advancements in drainage systems can do more than remove excess soil moisture. Systems can help manage the water table, provide subsurface irrigation or monitor or manage nutrient outflow from a field.
Subsurface irrigation systems are a way producers can use the tile to put water back into a field during dry periods. Those systems can be more expensive and require an irrigation water source.
But, the sophisticated systems could pay off with increased crop yields or better nutrient management.
“I would like every farmer or land owner contemplating a new drainage system to consider one of the conservation options that are available now,” says Gary Sands, Extension engineer with the University of Minnesota. “With the advancements out there, it’s worth looking into a drainage water management or controlled-drainage design.
"And, whether or not the practice is implemented right away, a farmer will have the right design and be able to implement it later on.”
Sands offers some thoughts for farmers, such as considering a shallower system. Rather than the traditional 4-foot-deep tiling, farmers might want to consider a 3-foot-deep system that might conserve more water and nutrients in the water profile.
Landowners might also want to consider a woodchip bioreactor as a method for removing nitrates. Bioreactors have been studied extensively in Illinois and have been shown to effectively reduce nitrate levels in drainage water.
A woodchip bioreactor can be made by digging a trench about 6 feet deep and 2 to 3 feet wide. The length of the trench depends on the amount of water being treated. It's estimated about 10 feet of trench is needed per acre of drained land, based on Illinois data.
The trench is filled nearly full of woodchips, then covered with topsoil. Drainage water is directed to the bottom of the trench with plastic drainage pipe. Water is removed from the downstream end of the bioreactor with another section of perforated plastic tile that directs the water into a drainage main or ditch.
“I challenge producers and landowners to think outside the box a bit and think more about managing water vs. traditional drainage, which was to get rid of water as quickly as possible,” Sands says. “It’s better to think about the advanced options you might want before the drainage system is implemented vs. the cost of retrofitting the system later down the road.”
In addition, GPS positioning systems are allowing farmers and contractors to be more precise with tiling and drainage systems. The new technology has overtaken laser survey and control as the preferred method for design and installation.
The sophisticated navigation system dramatically slashes surveying time.
GPS can help tailor the precise depth of a drainage system, according to high points or dips in a field. Tiling can be installed along contours vs. across contours, which is an important consideration for a controlled-drainage system.
Since tile drainage is a big financial investment, farmers need to assess the economic benefits vs. the costs.
Ohio State University research over 25 years has shown subsurface drainage significantly improved corn and soybean yields on poorly drained soils. Add crop rotation and some sort of conservation-tillage practice, and production improved even more.
For every $1 spent on drainage technology, producers get $3 to $4 back in corn and soybean profits, according to the Ohio State research.
The research was a randomized experiment with three replications. It comprised two drainage treatments — subsurface drainage and no subsurface drainage. Each plot was divided into several crop-rotation treatments: continuous corn, continuous soybeans and a corn-soybean rotation with each crop every year.
The plots were further divided into a series of tillage treatments: plow, ridge-till, no-till, strip-till and deep-tillage or subsoiling.
The average increase in corn yields ranged from 24% to 39% for different tillage systems. Soybean yield increases ranged from 12% to 45%.
Sands encourages producers and landowners to aim for productivity and conservation goals with new drainage systems.