The hidden enemy of agriculture is truly a force of nature. Erosion – whether it be wind, water, or tillage – can have a significant impact on soil productivity. At the recent Cavalier County soils workshop held at the NDSU Langdon Research Extension Center, two speakers discussed the impact that erosion can have on fields and ways that producers can protect that invaluable top soil.
By Melissa Anderson
Dr. Larry Cihacek from the soil science department at NDSU reviewed the three biggest causes of erosion in North Dakota which, unsurprisingly, include wind and water but also one type of erosion that producers may not be thinking about when doing field work, tillage erosion.
“We don’t talk about it a lot, because we don’t think about it. We do it every time we till our soil called tillage erosion, and we move soil from one place to another,” Cihacek said.
Wind and tillage are the highest perpetrators of erosion in North Dakota. Cihacek notes that wind erosion events are the worst when the direction of the wind is from south to north. During a wind erosion event where the wind blows at a consistent speed, the soil surface will eventually stabilize, and the erosion process will stop. All it takes to restart the erosion is a high wind or gust from a different direction which will result in further erosion.
Most erosion occurs on the backslope of land, where water flows and wind can easily move soil particles with little resistance. The most common symptom of tillage erosion can be seen in fields where higher areas have lighter colored dirt than the surrounding area.
To offset the loss of productivity of the land, Cihavek says producers need to reduce erosion. The downside to this is that options for doing so take time to become established. When planning, producers must consider a long-term solution. While tillage erosion is unavoidable for most, there is one way to reduce the erosion from the wind – trees. Shelter belts or windbreaks provide random roughness which works to stop wind erosion.
“Where there are shelter belts there is not a lot of soil in the ditches that you can see from this past winter. Where there are no shelter belts, you got a lot of black snow, a lot of ‘snirt’,” Cihacek said. However, trying to stop wind erosion in North Dakota, especially on the high plains of Cavalier County, is no easy feat. Dr. Joe Zeleznik of NDSU discussed what the pros and cons of having shelter belts in fields to try and decrease wind erosion are for the modern farmer.
“Where do windbreaks fit in? Prairie Farm Rehabilitation Administration up in Saskatchewan raised trees and gave them away for shelter belts. In this study, they were looking at perceptions- what people think of shelter belts,” Dr. Zeleznik explained. “Costs were easily identified, especially establishment and maintenance. The benefits were identified, but many were considered non-economic.”
The attitude of producers towards the use of shelter belts varies and is most apparently different when comparing younger generations to the older producers or landowners. When a young farmer is looking at their operation, the cost /benefit ratio is the main decision maker when considering land management options such as shelter belts. Quantifying the economic value of top soil that is not eroded is a challenge according to Zeleznik.
“It’s easy to quantify costs, much more difficult to quantify benefits,” Zeleznik stated.
Older producers and landowners value the windbreaks as a means of protecting the valuable top soil. Younger generation that rent land see the windbreaks as a hindrance and nuisance as it makes fieldwork with the larger equipment more difficult with no visible benefit despite conversations between the generations.
“My greatest struggle when I talk with young producers is that they are so fixated on the time issue. They are so fixated on the herbicide applications that it’s really hard to explain to them the yield increases from a shelter belt. They don’t want to consider that because their time and their hassle issue is greater. It just goes right through them,” one audience member said.
With new producers come new ideas about crops. Over the past few decades, new crops have been introduced and utilized in Cavalier County. While the crops prove to grow well in the soil, they also leave behind less residue that can protect the top soil during the windy winter months. Trees planted in windbreaks can protect the topsoil from getting blown away and increase benefits to the crops planted.
Zeleznik shared that studies have shown that with windbreaks in place, yields within the protected field increase. Anecdotal evidence shared by Zeleznik was that a producer near Grand Forks re-planted their shelter belts after seeing a decrease in yield after the trees were removed.
“They do protect crops; they result in yield increases usually. They can prevent sandblasting. I think they are a part of the solution, and I think they are a part that we can’t forget,” Zeleznik said.
The windbreaks do more than just protect fields from wind erosion, however. When strategically placed, a few rows of trees can become a living snow fence. They also can be used to protect farmyards, livestock, and wildlife. Deer populations tend to flourish in areas where there is protection from the elements. Zeleznik explained from experience and research that when windbreaks are removed, deer populations are affected and show significant decreases.
“With windbreaks, you just need a couple rows to protect the crops. You don’t need four, five, or six row windbreaks to protect crops in fields,” Zeleznik said.