Ag runoff impacts people, environment

posted Aug. 7, 2017 9:06 a.m. (CDT)
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by / Gaylord E. Olson II | Jackson County Land Conservation Department

In the past few weeks, as you drive around Jackson County, you may have seen cropland erosion occurring.

There are various factors that determine what impacts cropland erosion: Soil type, rotation of the crops grown, length of field slope and steepness, precipitation, tillage and the way the field is planted. Some of these factors can be controlled by the farmer.

In my observations, one of the common factors that appears in excessively eroded fields is excessive tillage where the soil structure appears to be broken down. It may be from multiple tillage passes in a single year or from continuous tillage year after year. Some tillage equipment can break down the soil structure after one pass. It is unreasonable to expect the soil to withstand precipitation events and stay in place once its structure has been compromised.

A layer of soil only the thickness of a dime across an acre of ground equates to seven to 10 tons of soil. Excessive tillage and intense rainfall have caused tremendous amounts of erosion. In some cases, hundreds of tons of valuable soil have moved down the slope and off the field.

Unfortunately for those down slope, the soil runoff continues to have negative impacts as a pollutant. Runoff sediment can damage neighbors’ fields, road ditches, and wetlands, and appears as discolored water in our streams. The soil runoff carries fertilizer, chemicals and soil, which causes negative impacts to all of those that use the water.

As a farmer or a landowner, did you take time to review what your fields looked like after recent rainfall events? There are many conservation practices that have been used for decades that can minimize and prevent excessive erosion, like no-till planting, grassed waterways, cover crops, contour planting, contour buffer strips, crop rotation and crop residue management.

Manure runoff is a threat to the environment. When manure is managed properly, it is a very valuable fertilizer and helps build soil structure. When it reaches surface water or groundwater, it becomes a pollutant. Manure runoff contains phosphorus, nitrogen, pathogens and bacteria that are harmful to humans, animals and fish and can cause beach closures, drinking water advisories and fish die-offs.

Manure runoff comes from improper manure spreading or discharge from animal and livestock facilities. Generally, facilities closer to surface water or wetlands have greater potential to contribute manure and sediment runoff. Sites without buildings but where a feedlot situation develops can be a source of runoff as well.

Livestock can generate a significant amount of manure. Twenty adult dairy cows produce the equivalent solid waste of 1,000 humans. A 1,000-pound horse produces 9 tons of manure annually, and a 1,100-pound steer produces about 16.8 tons of manure a year. Proper location and management of livestock and animal facilities is critical to preventing manure pollutants from harming the environment.

Since Jackson County is at the headwaters of several streams and rivers, such as the Trempealeau, Buffalo, Black and Beaver, most of our polluted water flows into adjacent counties and causes problems for our neighbors. On streams where lakes or ponds are formed by dams, some of the pollutants settle out where the water slows. Sediment also negatively affects man-made lakes.

Sedimentation fills in lakes and leaves nutrients that feed aquatic plant growth, possibly blue-green algae that robs oxygen from the water. The water continues beyond Wisconsin contributing to sedimentation and other pollutants in the Mississippi River and eventually into the Gulf of Mexico where a hypoxia zone — also called a dead zone — the size of Connecticut exists.

It is important that Jackson County landowners and farmers strive to prevent and protect our natural resources, because we impact not just Jackson County but many others outside the county. As a landowner, you should be aware of what is happening on your property and are responsible for what is happening there as well. Following state and county environmental standards for agriculture is the responsible way to prevent pollution from occurring.

Olson can be contacted at An unedited version of this article can be found in the July 5 Banner Journal, Black River Falls.

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