Why One Pond Does Not Runneth Over

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One night last August, Art and Jean Thicke’s hilltop farm in southeast Minnesota was pounded by 15 inches of rain. This was the same storm that dumped record amounts of precipitation on hilly land throughout southeast Minnesota, southwest Wisconsin and northeast Iowa. While driving to the Thicke farm the other day to attend a Farm Beginnings field day, I could still see the results of that downpour in the region: washed out trees and damaged earthen dams, ruined homes, silted-in ditches and, most of all, eroded fields. This storm created great gashes on the land and caused entire hillsides to slump. Soil that took centuries to build was lost in a matter of hours. It set me to wondering: how did a certain little pond on the Thicke farm weather the storm?

The Thickes produce milk with 90 cows on dramatic side-hills near the Mississippi River. Many of the slopes on the Thicke farm are at least a 25 percent grade—so steep that they are quite difficult to walk up without leaning like an Olympic ski-jumper. Despite the challenges of farming in such a fragile environment, the Thicke operation has long been recognized for the positive impacts it’s having on soil, water and even wildlife. The Thickes were part of a group of farmers and researchers called the Monitoring Team, which back in the 1990s developed innovative ways of measuring the environmental impacts of sustainable farming methods.

So perhaps it’s not so surprising that the storm of 2007 wreaked very little damage on the Thicke farm. In fact, that pond I mentioned before didn’t even overflow during the downpour. As you can see from the photo here, the pond is at the bottom juncture of a couple of slopes, and thus very vulnerable to being a catch-all for runoff.

Thicke Pond

The pond, which was built in the 1950s, has become a kind of bellwether of the farm’s hydrological health. Indeed, back in the days when corn was raised on those slopes, the Thickes often grew their crops on 60-foot wide contour strips that in some cases snaked for a mile along these hillsides. At the time, this was considered the height of good conservation farming. In fact, the Thickes’ contoured land was featured in the USDA’s Yearbook of Agriculture twice during the 1950s as a model for how soil conservation should be practiced on steep land.

But even with the contoured tillage, that pond overflowed after just a couple of inches of rain, and the Thickes were often dredging silt out of it to keep it viable.

But even though that 15 inches of rain last August filled the pond to the brim, it didn’t run over. This is impressive, given the fact that numerous dams, manure lagoons and other earthen structures in the area were so swamped by water in the aftermath of the drencher that they simply collapsed. In fact, Art says it’s been so long since that pond overflowed that there are rocks below the dam that have moss on them from lack of being washed over by fast-flowing water.

Obviously, precipitation is infiltrating the Thicke soil, rather than running over the surface as soon as it hits terra firma. Why? During the field day, the Thickes explained how in 1985 they converted their fields to grass and began using managed rotational grazing, a system that moves the cows frequently between pasture paddocks.

Such a system allows livestock farmers to replace row crops with soil-building grass. Instead of the farmer growing and harvesting corn and soybeans for feed in an energy-intensive manner, the animals do their own harvesting for free. Managed rotational grazing also means the animals are hauling their own manure, and since they are moved frequently, the cattle are spreading that manure in a manner that allows the soil to make good use of it as a nutrient and source of organic matter. And organic matter makes that soil a living sponge.

“It’s amazing the holding capacity this land has when there’s life in the soil,” Art told the field day participants while standing upslope of the pond.

As we could see on this spring day, managed rotational grazing’s reliance on perennial plants that cover the land year-round and its ability to put life back into the soil are paying off on the Thicke operation. The steep slopes were covered in a lush, diverse stand of grasses, and the certified organic dairy herd was thriving. Bluebirds, turkeys and other wildlife were making good use of the pastures.

During the field day, Art talked about how rotational grazing has allowed the farm to maintain diversity on the land, and how such a system is good for the soil and the water as well as the Thickes’ bottom line and their quality of life. As Art explains on the Ear to the Ground podcast (episode 50), this is all part of a holistic view of agriculture that connects the health of the land with the health of the farm.

“Nature tends toward diversity, why fight it?” Art said while leading a tour of pastures full of an alphabet soup of grasses and forbs.

The Yearbook of Agriculture ceased publication in 1992. But if the venerable annual compilation of cutting-edge agriculture was still being printed today, an update on the Thickes’ latest conservation farming methods would certainly be in order.

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