South Dakota is one of the most productive agricultural states in the northern Great Plains, and its crop portfolio is dominated by corn and soybeans. Those two row crops account for the vast majority of planted acreage, followed by wheat, sunflowers, hay, and a handful of smaller but economically meaningful crops like oats, sorghum, and flaxseed. The mix reflects the state’s geography, with fertile river valleys in the east supporting intensive grain farming and drier rangeland in the west favoring different strategies entirely.
Corn Leads by a Wide Margin
Corn is South Dakota’s most valuable crop and its largest by acreage. The state consistently ranks among the top corn-producing states in the country, with millions of acres planted each year, mostly concentrated in the eastern third of the state where rainfall is more reliable and soils are deep and rich. Most of this corn is field corn, grown for livestock feed, ethanol production, and export rather than for eating fresh off the cob. South Dakota’s ethanol industry, which includes multiple large-scale plants, creates massive local demand for corn grain and has been a significant driver of expanded corn acreage over the past two decades.
Corn yields in South Dakota vary considerably depending on location and weather. The eastern counties near the Big Sioux and James River valleys routinely post yields competitive with Iowa and Minnesota, while fields farther west face lower and less predictable rainfall that can cut production sharply in dry years. Weed pressure is also a persistent challenge. Research conducted at sites in South Dakota found that velvetleaf, a common broadleaf weed in corn, could reduce yields by as much as about 37% at high densities, with losses of roughly 4% for each additional weed plant per square meter.1Cambridge University Press. Velvetleaf (Abutilon theophrasti) Effect on Corn (Zea mays) Growth and Yield in South Dakota That kind of finding illustrates why weed management in corn is taken seriously and why herbicide-tolerant varieties have been widely adopted across the state.
Soybeans as the Other Half of the Rotation
Soybeans are South Dakota’s second-largest crop and the natural rotation partner for corn. Most farmers in eastern South Dakota alternate corn and soybeans on the same fields from year to year, a practice that helps break pest and disease cycles, manages soil nitrogen, and spreads economic risk across two commodity markets. Soybean acreage in South Dakota has expanded dramatically since the 1990s, and the state now regularly plants several million acres annually.
The crop thrives in the same eastern counties where corn does well, though soybeans are somewhat more tolerant of marginal soils and can be planted a bit farther west than corn with reasonable results. South Dakota soybeans are largely exported or crushed domestically for soybean meal and soybean oil. The meal goes primarily into animal feed, while the oil enters food manufacturing and, increasingly, renewable diesel production.
The expansion of both corn and soybeans in South Dakota has come partly at the expense of grassland. Research tracking land-use change in the western Corn Belt found that rising commodity prices created strong incentives for landowners to convert grassland into corn and soybean production, and the region was rapidly moving along that trajectory.2PubMed Central. Recent land use change in the Western Corn Belt threatens grasslands and wetlands That shift has implications for wildlife habitat and soil carbon that continue to generate debate among conservationists and agricultural groups.
Wheat Across Several Classes
Wheat is South Dakota’s third most important crop and has historically been even more central to the state’s agricultural identity. South Dakota grows multiple classes of wheat, including spring wheat and winter wheat. Spring wheat is planted in April or May and harvested in late summer, while winter wheat goes into the ground in the fall, overwinters as a low-growing plant, and is harvested the following July. The western part of the state, where the climate is too dry for consistent corn and soybean production, relies more heavily on wheat as a cash crop.
Winter wheat acreage has fluctuated over the decades, partly in response to commodity price swings and partly because corn and soybeans have become more profitable in many eastern counties. When corn prices are high, some land that might otherwise grow wheat gets rotated into corn instead. Still, wheat remains a core crop in central and western South Dakota, and the state produces enough to contribute meaningfully to domestic flour milling and export markets. Hard red spring wheat, valued for its high protein content and strong gluten characteristics, is particularly prized by bread bakers.
Sunflowers on the Western Plains
South Dakota is one of the leading sunflower-producing states, alongside North Dakota and Kansas. Sunflowers are grown in two main types: oilseed sunflowers, which are crushed for cooking oil, and confection sunflowers, the large-seeded variety that ends up as snack seeds or in bird feed mixes. Oilseed sunflowers make up the larger share of production. The crop is well suited to the semi-arid conditions of western South Dakota because sunflowers are relatively drought-tolerant and can produce reasonable yields on less water than corn demands.
Sunflower production has expanded into hotter and drier portions of the state in recent decades, which has introduced new disease pressures. Charcoal rot, caused by a soil-borne fungus, was first identified on oilseed sunflower plants in western North and South Dakota in the late 1990s. Researchers noted that the expansion of sunflower acreage into these hotter, drier areas could lead to increased incidence of the disease.3APS Publications. First Report of Charcoal Rot (Macrophomina phaseolina) on Sunflower in North and South Dakota That concern has played out to some degree, making disease-resistant varieties and crop rotation important management tools for sunflower growers in the region.
Hay, Alfalfa, and Forage Crops
South Dakota’s large livestock sector, particularly its beef cattle industry, creates substantial demand for hay and forage crops. Alfalfa is the most valuable forage crop in the state, grown both for on-farm use and for sale to dairies and feedlots. Alfalfa hay is prized for its high protein content and digestibility. Other hay types, including grass hay and mixed grass-legume hay, are also produced across the state, especially in areas where alfalfa does not establish well or where native grass hayfields are maintained.
The western two-thirds of South Dakota is dominated by rangeland rather than cropland, and much of the forage in that region comes from native grass pastures that are grazed directly rather than harvested as hay. When those pastures are cut for hay, it tends to be a lower-protein grass hay compared to alfalfa. The state’s total hay production, in terms of both acreage and tonnage, is significant enough to make South Dakota a consistent presence in national hay markets. Drought years can tighten hay supplies dramatically, forcing ranchers to either buy feed from out of state or reduce herd sizes.
Oats, Sorghum, and Flaxseed
Several smaller crops round out South Dakota’s agricultural picture. Oats have a long history in the state, originally grown as horse feed in the homesteading era and now used mainly for livestock feed and, to a lesser extent, food-grade oat products. South Dakota remains one of the top oat-producing states, though total acreage is modest compared to corn or soybeans. Oats also serve a practical role in crop rotations as a nurse crop, providing cover for newly seeded alfalfa or grass stands.
Grain sorghum, sometimes called milo, is grown primarily in the south-central part of the state. It handles heat and drought better than corn, making it a logical choice for fields where water is the limiting factor. Sorghum acreage in South Dakota tends to fluctuate from year to year depending on spring planting conditions and price expectations relative to corn. When it is too dry to plant corn with confidence, some farmers shift acres into sorghum as a lower-risk alternative.
Flaxseed occupies a small but noteworthy niche. South Dakota is one of the few states where flax is still grown commercially, though acreage has declined substantially from its peak decades ago. Flaxseed is used for linseed oil in industrial applications and increasingly for food products rich in omega-3 fatty acids. The crop grows well in the northern Great Plains climate but faces stiff economic competition from more profitable alternatives.
Pulse Crops and Specialty Grains
In recent years, South Dakota has seen growing interest in pulse crops like field peas, lentils, and chickpeas. These crops fix atmospheric nitrogen in the soil through their root systems, reducing the need for synthetic fertilizer in subsequent years, and they have expanding markets in plant-based protein products and international exports. Seed producers in South Dakota propagate certified seed for field peas, lentils, and chickpeas alongside traditional cereal grains. The fit is natural for the state’s climate, particularly in the drier central and western regions where pulse crops can produce acceptable yields without irrigation.
That said, pulse crop acreage in South Dakota is still a small fraction of what corn and soybeans occupy. North Dakota and Montana are the clear leaders in U.S. pulse production. South Dakota’s potential lies in the rotation benefits these crops offer: a farmer who grows lentils or field peas every few years can reduce fertilizer costs and break up disease cycles that build in continuous small-grain rotations. Whether pulse acreage grows significantly will depend on market development and whether processing infrastructure expands into the region.
The East-West Divide
Understanding South Dakota’s crop mix requires understanding its geography. The state is split roughly down the middle by the Missouri River, and the agricultural character of the land changes dramatically from east to west. Eastern South Dakota sits at the edge of the Corn Belt, with deep, dark prairie soils, 20 to 25 inches of annual rainfall, and flat to gently rolling terrain that supports intensive row cropping. This is where the vast majority of the state’s corn and soybeans are grown, along with much of its alfalfa and oats.
West of the Missouri, rainfall drops to 15 inches or less in some areas, and the landscape transitions to mixed-grass prairie and rangeland. Crops here are more likely to be wheat, sunflowers, or sorghum, and many operations are primarily cattle ranches that grow some crops as supplemental feed. The Black Hills region in the far west is mostly forested and not significant for crop production, though hay and small grains are grown in surrounding valleys.
This divide means that statewide crop statistics can be misleading. When South Dakota reports millions of acres of corn, nearly all of that acreage is east of the Missouri. A farmer in Brookings County and a rancher in Haakon County are operating in fundamentally different agricultural worlds despite being in the same state.
How the Crop Landscape Has Shifted
South Dakota’s crop mix today looks quite different from what it was a generation ago. The most dramatic change has been the expansion of corn and soybeans into areas that were previously grassland or planted to small grains like wheat and oats. High commodity prices in the late 2000s and early 2010s were a powerful incentive. Research documented this trend across the western Corn Belt, finding that the region was converting grassland and wetland into row crops at a pace that drew comparisons to deforestation in the Amazon.2PubMed Central. Recent land use change in the Western Corn Belt threatens grasslands and wetlands South Dakota, sitting right at the western edge of the Corn Belt, was a focal point of that conversion.
The shift was enabled by several factors beyond commodity prices. Improved corn and soybean varieties bred for shorter growing seasons and better drought tolerance made it feasible to grow these crops farther north and west than in previous decades. Crop insurance programs also reduced the financial risk of planting row crops in marginal areas, since farmers could collect insurance payments in bad years. The result has been a steady march of corn and soybean fields westward across the state, though that expansion slows and eventually stops where rainfall simply cannot support the crops even in good years.
Meanwhile, wheat acreage has declined, and crops like oats and flax that were once staples of the northern plains rotation have been pushed to the margins. Whether this trend continues depends on commodity markets, climate patterns, and federal farm policy. A sustained period of low corn prices could reverse some of the grassland-to-cropland conversion, though once sod is broken, it rarely returns to native prairie.
Cover Crops and Soil Health Practices
One emerging piece of South Dakota’s cropping landscape is the adoption of cover crops, plants grown between cash crop seasons primarily to protect soil, improve soil health, and reduce erosion. Cover crops are not harvested for sale in most cases; instead, they are terminated before the next cash crop is planted. Common cover crop species in South Dakota include cereal rye, radishes, turnips, and various legumes.
Adoption has been growing but remains limited. A machine-learning analysis of satellite imagery found that only about 4% of corn and soybean fields in eastern South Dakota had a cover crop during the fall of 2022 or spring of 2023.4PubMed Central. Monitoring the Spatial Distribution of Cover Crops and Tillage Practices Using Machine Learning and Environmental Drivers across Eastern South Dakota That figure underscores how early the state still is in cover crop adoption, despite enthusiasm from soil health advocates and some financial incentives through conservation programs. The short growing season in South Dakota is a practical barrier: after corn harvest in October, there is often little time for a cover crop to establish before winter sets in. Planting cover crops after soybeans, which are typically harvested a bit earlier, is somewhat more practical.
Integrated crop-livestock systems, where cattle graze cover crops during the fall or early spring, have attracted attention in South Dakota as a way to add economic value to cover crops that would otherwise generate no direct revenue. Some ranchers are experimenting with grazing cattle on cover crop fields between cash crop seasons, turning what would be a cost into a modest income stream while still capturing the soil health benefits.
Ethanol, Livestock Feed, and Where the Crops Go
A large share of South Dakota’s crop production never leaves the state as raw grain. The state’s ethanol plants consume hundreds of millions of bushels of corn annually, converting it into fuel ethanol and distillers grains, a protein-rich byproduct that goes right back into livestock feed. South Dakota is a top ethanol-producing state, and the industry’s appetite for corn is a major reason corn acreage has been so resilient even when export markets soften.
The livestock sector absorbs much of the remaining grain. South Dakota has a large cattle feeding industry, a growing dairy sector, and significant hog and poultry operations. These animals eat corn, soybean meal, distillers grains, hay, and oats produced within the state, creating a closed loop where crops feed animals and animal manure fertilizes the fields that grow the next round of crops. Soybeans that are not exported are typically crushed at processing facilities to produce meal and oil, with the meal sold domestically for animal feed.
For sunflowers, the market splits between oilseed varieties processed at crushing plants in the region and confection varieties sold through snack food channels. Wheat is mostly shipped to flour mills in the Upper Midwest or exported through rail to Pacific Northwest ports. The diversity of end markets for South Dakota’s crops helps buffer farmers against downturns in any single sector, though corn and soybeans are so dominant that their prices still set the economic tone for the state’s agriculture in any given year.