The story of South Dakota since the 1862 Homestead Act has been in large part the story of converting grassland into cropland. It’s nothing new to sow wheat or corn where there once was grass. Drive along any East River highway and you’ll spot rocks plucked from beds of prairie grass or water draining from rich, dark soil.

But scientists studying satellite images of the western edge of the Corn Belt say something different is happening now – grasslands are being turned over to make cropland at a frightening pace. That includes fragile Conservation Reserve Program lands that the federal government in past decades paid farmers to seed to conservation crops for set periods of time. But in parts of South Dakota it also includes some prairie that has never before felt the bite of a plow.

High corn and soybean prices, in particular, have some ranchers growing more crops while some farmers opt for more row crops.

Over the past seven years, 1.3 million acres of native grasslands have been lost in the Prairie Pothole Region, and more than 451,000 of those acres lie within South Dakota’s borders. If conversion rates continue at the same pace, nearly half of South Dakota’s remaining native prairie grassland will vanish over the next 35 years.

It’s disconcerting news to those aware of how important the grassland ecosystem is to the state’s livestock, tourism and hunting industries.

In the past, research has attempted to quantify exactly how much and at what rate the region’s grassland is being converted. But it was the work of South Dakota State University professor Michael Wimberly and post-graduate fellow Chris Wright that provided a comprehensive, updated look at the western Corn Belt’s changing landscape between 2006 and 2011.

In January 2013, Wright and Wimberly released their study, “Recent land use change in the Western Corn Belt threatens grasslands and wetlands.” The paper was a product of the duo’s original research, which focused on determining the best places to grow perennial biofuel crops.

Wright and Wimberly decided to first examine contemporary land cover change via satellite imagery and geospatial analysis. The result was an examination of areas converted from native grassland and pastures to corn or soybeans between 2006 and 2011.

The study reported that grassland conversion between 2006 and 2011 was mostly concentrated in North Dakota and South Dakota, east of the Missouri River. South Dakota alone experienced a net loss of 451,000 acres of native grassland, and research shows that up to 5 percent of the state’s grassland and pasture is being converted every year.

Wright said he and Wimberly were initially surprised by the high rates of conversion in areas such as the Dakotas.

“In retrospect, it isn’t surprising,” Wright said. “It’s on the periphery of the Corn Belt, and there’s still quite a bit of grassland and pasture remaining.”

Driving factors

But what’s left of South Dakota’s native grassland is at risk due to several factors driving conversion – high commodity prices, crop insurance programs and unintended consequences of federal farm policy.

These factors have motivated landowners across the western Corn Belt to expand corn and soybean production onto marginal lands highly vulnerable to drought and erosion. Farming in this way is financially feasible compared to ranching native pasture or putting grassland into the Conservation Reserve Program.

“The best lands were converted to corn and soybeans a long time ago, and this is what’s left over,” Wright said. “It appears to us that this land was in cattle production, but as crop prices rise, you can get a higher return from corn and soybeans than you can from cattle.”

That higher return has convinced some ranchers to downsize cattle herds, or sell them off entirely. The beef industry has a $2.8 billion economic impact on South Dakota, but the state has lost about 200,000 beef cows since 2001 – at least in part a response to the growing appeal of corn and soybeans.

A lot more like Iowa?

Wright said the study is not meant to be pro-ranching or anti-farming; it’s meant to explore some of the implications of such expansive grassland to farmland conversion.

“It’s hard to speculate, but as my co-author said to me, (South Dakota) is going to look a lot more like Iowa,” Wright said. “That’s kind of an inescapable conclusion with all of the corn and soybeans. I think it’s important that we discuss this now rather than 10 years down the road.”

Wright said he feels most people know this conversion is happening, but noticing a converted pasture down the road may be different from piecing the whole puzzle together.

“Driving around, you see grassland converted to corn and soybeans. You hear anecdotal stories – say, from hunters – that there is grassland conversion occurring,” Wright said. “But you don’t really put it all together until you look at the big picture. We have a lot of small land cover change events occurring, and they’re starting to add up.”

To the degree that grassland conversion takes away wildlife habitat, it affects South Dakota’s hunting and outdoor recreation industries. Last year alone, pheasant hunters contributed nearly $226 million to South Dakota’s economy.

The financial incentive to put more land into crops may also put more prairie wetlands under the plow. Unlike western Minnesota, where farmers decades ago drained most of their wetlands, farmers in the Dakotas had left many of theirs intact. That’s why the Prairie Pothole Region in the eastern part of the Dakotas and extending north into Canada is called the “duck factory” of North America.

And the impact on the region hasn’t gone unnoticed.

Tim Kizer, an Arkansas-based private lands field representative of the Theodore Roosevelt Conservation Partnership, said the TRCP and other organizations are concerned about the conversion of less-than-ideal lands into cropland on the northern Great Plains because the impact extends to other states. People who hunt the ducks that grow up in the Dakotas’ Prairie Pothole Region are affected; and so are hunters who come to the Dakotas to hunt upland game birds such as pheasants.

Kizer said conversion will be an issue in upcoming farm bill negotiations in Washington later this fall.

Closer to home, Wright hopes to see more discussion in South Dakota about balancing the state’s interests – agriculture, tourism, hunting and environmental stewardship. He said South Dakotans seem to understand both sides of the issue and should be able to work together to come up with a reasonable solution.

“If I was a farmer, I might be tempted to put my CRP land back into corn and soybeans – with prices being so high, and the fact that CRP payments haven’t kept up with those increases,” Wright said. “But that brings up the issue – how can we make it more sustainable for farmers to keep these lands in grassland?”


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