What’s next in ag drainage?

Using technology and automation to target the use of inputs like fertilizer or irrigation can save costs, boost productivity, and minimize environmental impacts. That's what is offered by precision agriculture, which has permeated nearly all parts of crop production except, until recently, drainage.

"Precision drainage might be the next frontier in precision agriculture strategies for Minnesota farmers and ag professionals," says Tim Gieseke, Extension educator in agricultural water management. He has been developing the MN Drainage Program to convene producers, counties, SWCDs, contractors, engineers and others to build their shared real-world knowledge, which could influence decision-making around adoption and management.

The premise of the technology offers impressive benefits. For example, what if some of the water that is currently drained away during wet periods could instead be "banked" in the soil for future dry spells? This would reduce the movement of nitrates while aligning with a common rhythm of the growing season: wet springs, dry summers.

Yet the proper implementation and management of these systems is crucial. For example, if too much water is in the field for too long, it can negatively affect yield.

Achieving precision

The term "precision drainage" has multiple meanings and tiers.

At its core, "Precision drainage is about maximizing profitability while also minimizing downstream impacts," says Gary Sands, UMN Extension professor focused on water management and quality for agricultural systems. "Knowing your soil is probably the most important thing you can do to make your system more precise." 

Soil type and texture affect the placement of drain tile, such as how deep or close together they are installed. Topography also plays a major role. During MN Drainage Program sessions, participants are introduced to tools, calculators and real-world aerial field plans with arrows describing the flow of water and how soil type and topography may change the layout of the drain tile.

Customizing drain tile installation to a given field's soil and topographic conditions is an example of precision drainage — it's more precise than a one-size-fits-all uniform grid. Producers can add more technology and features such as control structures, edge-of-field bioreactors, saturated buffers and more.

"Just as irrigation relies on soil moisture sensors to manage pivot rigs, drainage can use sensors to inform producers when to raise or lower stop logs in a control structure based on localized rainfall, which can allow water to stay in or flow out," says Gieseke.

A generational decision

Extension's MN Drainage Program provides producers with research-based information to help them make high-stakes drainage decisions. After all, installing drainage is typically a once-in-every-50-years project; it's an investment a farm family may make every few generations.

Today's drainage design decisions create opportunities to implement conservation drainage practices into the future. One recent program participant commented that if it's done right, it can last three to four generations.

Sands emphasizes that both irrigation and drainage are crucial water management practices for agriculture in Minnesota and throughout the world, and it's important that they be practiced with precision. In Minnesota, farmers have installed drainage systems for well over a century.

As new drainage projects are considered, fields can be examined for what Sands calls "optimum drainage capacity" to find just the right amount of drainage that maximizes profitability while minimizing capital costs and environmental impacts.

"The goal is to equip farmers with the right questions to ask their drainage contractor," says Gieseke.

Learn more about  Extension's Minnesota Drainage Program online.

This article originally appeared on Handout: What's next in ag drainage?