Farm Progress

Ag Water Stewardship: Get ready for the wet months of May and June.

Warren Formo

July 25, 2017

3 Min Read
REDUCE EROSION RISK: Nothing will hold back water during extreme heavy rain events, but there are steps landowners can take to reduce erosion risk.

Weather conditions in recent years have resulted in more frequent reports of wind- and water-driven soil erosion from late winter into the spring.

Despite years of effort to reduce erosion and a long list of tools available to combat erosion, some argue that we are literally losing ground at an unacceptable rate.

I am sure that all of us involved in agriculture would agree that erosion is a bad thing, and that it is sometimes unavoidable. We also generally understand that both wind and water erosion are highly episodic, primarily occurring during weather extremes. We have also learned that tillage and the amount of residue on the soil surface makes a difference, as do structural practices like grass waterways or tree rows.

Data collected in the Discovery Farms programs since 2002 on farms across Minnesota and Wisconsin help highlight the period of greatest risk for water-induced soil erosion. During this period, more than 1,000 surface runoff events have been measured on about 25 farms. On an annual basis, 10% of these runoff events generated 85% of total annual soil loss. In other words, while we refer to erosion on an annual basis, most erosion happens in just a few days each year. As one might expect, these were the often the most intense storms.

These data also show that nearly 70% of soil loss occurs in the months of May and June, prior to crop canopy. Overall soil loss numbers were quite low, with a median value of 134 pounds per year, or about 3 (three) 5-gallon pails per acre. However, several fields produced more than 1,000 pounds per acre. So, while erosion is very low on most fields, there are still areas of potential improvement.

Look for soil loss, sediment accumulation
The first step toward reducing soil erosion is simply looking for signs of soil loss and sediment accumulation. If you see rills or gullies forming on slopes, soil loss is probably well above average. Look also where eroded soil may accumulate, such as low areas below slopes where water is the erosion driver, or in ditches and fence rows where wind is the main concern.

Given that erosion occurs under relatively extreme conditions, I often hear farmers express concern about attempts to regulate soil loss. I agree that a regulatory approach would be extremely difficult. And there are some rains so large that even the best set of waterways one could imagine still result in some erosion.

However, I still challenge farmers to look across their neighborhoods to see what practices can work to reduce erosion.

Take a tour of your neighborhood. Why do some hillslopes show signs of erosion, while similar fields do not? Is it the level of tillage or residue? Is it tillage direction? Are structural practices like grass waterways the key?

Ask similar questions about wind erosion in flatter portions of the state. On those days when dust is blowing in the wind, it is not uniformly coming off all fields. Why are certain fields contributing to the dust storm and others not?

If the answer to these questions points toward a potential tillage change, now is the time to consider any changes to your fall tillage plan — your last chance to address erosion concerns before spring. If you decide a grass waterway, filter strip or windbreak is needed, now is a good time to talk to your local Natural Resources Conservation Service technicians, as these practices are often eligible for cost-share assistance.

While I am quite sure that erosion cannot be eliminated completely, there are steps you can take to reduce erosion risk — and praying for gentle breezes and rains is not a total plan.

Formo is executive director of the Minnesota Agricultural Water Resource Center.

About the Author(s)

Warren Formo

Warren Formo is executive director of the Minnesota Agricultural Water Resource Center.

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