Contour Farming: A Smart Approach to Soil Conservation

Written by Rachel Sim, with expertise provided by Nate Couillard, Sound Agronomist.

Contour farming is the practice of planting crops in rows that follow the natural curves of the landscape rather than straight lines. This method is designed to manage water runoff and reduce soil erosion.

“Contour farming is a water management tactic,” says Nate. ​“Water will always choose the path of least resistance, so the goal of contour farming is to slow down that water as it travels downhill by farming in strips across the hill instead of up and down the hill,” says Nate Couillard, Sound Agronomist.

When rows are perpendicular to the slope, the water encounters more resistance as it moves down hill. When it hits plant structures like stems, leaves, and roots, the water is further slowed, giving the soil and crops a chance to absorb more moisture.

The Benefits of Contour Farming
While the primary benefits of contour farming is erosion reduction and improved water management, there are several other associated benefits that growers can take advantage of. When water moves too quickly over a field, not only does it not get the chance to infiltrate into the soil, it also carries away nutrients and topsoil. By creating natural barriers that slow water movement, contour farming disrupts this process and helps growers keep nutrients in the soil.

“We’re not having our nutrients and fertilizers run out of the field, maybe even into the local waterways,” says Nate. ​“We’re keeping them in the field where the plants can access and utilize them. It only hurts your business and the local environment if they’re leaving the field with the soil.”

For nutrients like phosphorus and potassium that may bond to particles in the soil, erosion is a major concern when it comes to nutrient loss. If soil particles leave the field, so do the nutrients.

“Keeping your nutrients in your field is closely tied to keeping your soil in your field,” says Nate.

Erosion can also affect microbial populations in the soil. A 2020 study found that erosion had a significant negative impact on both the diversity and functionality of soil microbes in agricultural soils.

Despite these advantages, there are fewer acres being contour farmed in the U.S. today than there were 20 or 30 years ago. Today, advancements in technology, the rise of no-till farming and increased cover cropping have provided alternative methods for erosion control, reducing reliance on contour farming in some areas.

“No-till technology has improved a lot in recent decades, including no-till planters,” he says. ​“Less tillage means the erosion potential is lower in a no-till soil compared to a tilled soil.”

Increases in Machinery Size
Equipment has also gotten a lot bigger, making it harder to maneuver and to get across a contour farmed slope. The 15 foot wide, six row planter of previous decades is dwarfed by modern machinery.

“That used to be an average size planter,” Nate says, ​“But they doubled in size and then doubled again and again. Now, we’re looking at 60 foot planters that are 24 rows or even 90 foot planters that are 36 rows. I even know of a few 48 foot planters that are 120 feet.”

But it isn’t just the planters that are bigger — so are the sprayers and combines. As a result, many farmers are opting for wider strips or transitioning away from contour farming altogether.

Changes in Farming Practices
Contour farming is just one of a variety of water management techniques available to growers, and the growth of other practices has reduced the need for contour farming. For example, one common way Nate says contour farming has been done is by planting alternating rows of annual and perennial crops.

“When we think about water’s behavior in a field and on a landscape, remember that water will always choose the path of least resistance,” says Nate. ​“Different types of plant and root structures and densities will influence how water flows downhill and that slows down water and helps minimize erosion.”

After the annual crop was harvested, the perennial was left in the ground to provide continued protection. But as cover cropping has increased in popularity, it’s offered another way to keep roots in the soil over the winter, anchoring it in place. Operations that use no- or reduced-tillage practices also see reduced erosion and improved water retention, making contour farming less of a necessity.

Rather than viewing contour farming as an all-or-nothing approach, Nate says it can be considered part of a continuum of soil conservation practices. Historically, growers had fewer options for erosion control, making contour farming a good water management technique. Today, growers have more strategies available to them, including no-till farming and cover cropping, providing increased flexibility in soil and water conservation approaches.

“Common sense will always apply,” says Nate. ​“On hillier or more sloped ground, growers will still think about what direction to plant their rows. It may not exactly qualify as contour farming, but farming across a slope is still often seen as a best practice.”

Some farms may still benefit from contour farming, particularly those with severe slopes or where erosion has been a problem. Others may find that modern conservation practices provide similar benefits. The key is understanding the specific landscape and selecting the best combination of techniques to achieve long-term soil health and water management.

Contour farming is just one of many input management tools growers have at their disposal, but the thread that ties many of these practices together is soil health. Healthy soils improve water infiltration and retention, reduce erosion, support a diverse soil microbiome and provide crops with the nutrition they need to flourish.

Emerging technologies like SOURCEⓇ and BLUEPRINT^TM from Sound Agriculture are offering new ways to improve soil health and nutrient efficiency. BLUEPRINT is an arbuscular mycorrhizal fungi (AMF) inoculant that works with plants to improve soil health through access to macronutrients, micronutrients and water. SOURCE mimics the plant-to-microbe signal that activates microbes in the soil, including nitrogen-fixing and phosphorus-solubilizing microbes and AMF. When applied together, SOURCE + BLUEPRINT work synergistically to ensure the crop gets plant-available forms of the nutrients it needs when it needs them.

“SOURCE provides the signal to the spores to wake up and connect, and then BLUEPRINT helps extend the plant’s root mass,” says Nate. ​“A bigger root footprint increases the uptake of nutrients and water, improving the grower’s water and nutrient use efficiency,”

Products like these that enhance root development and microbial activity can play a role in increasing soil stability and nutrient availability. Living roots hold soil in place and microbes improve soil texture, making soil less prone to erosion and improving water infiltration.

“The reason that SOURCE and BLUEPRINT work really well together for managing soil and water inputs is because we’re making better use of those inputs,” says Nate. ​“We’re getting water and nutrients into the crop more efficiently.”

Contour farming is just one piece of the soil conservation puzzle. For enhanced nutrient efficiency and improved soil health, discover how SOURCEⓇ and BLUEPRINT™ from Sound Agriculture can support your operation.