Harney Soil Series

The Harney soil series is Kansas's official state soil. It sits on the flat to gently rolling uplands of the High Plains — one of the most level landscapes in North America — where it formed under mixed-grass prairie in a semi-arid climate with cold winters and dry summers.

Harney is a Mollisol, the soil order of the world's great grasslands, but it is a drier and calcareous version. Unlike the wetter Mollisols of Iowa and Illinois, Harney soil has a calcic horizon — a subsoil layer packed with calcium carbonate — because rainfall is low enough that lime stays in the profile rather than washing away.

That combination of a dark, fertile surface and a lime-rich subsoil makes Harney soil almost ideal for winter wheat. The surface holds organic matter and nutrients. The subsoil holds water. The lime keeps the pH near neutral, which wheat prefers.

The Kansas Legislature designated the Harney series as the official state soil in 1990. Soil scientists from Kansas State University and the USDA Natural Resources Conservation Service supported the designation, pointing to the series as the most representative soil of the High Plains landscape that defines western and central Kansas.

The Harney series was first described in Kansas and established by USDA soil scientists working in the central part of the state, where the soil is most extensive. It was named for a geographic feature in the region, following the standard USDA convention of naming series after local landmarks.

Kansas was one of the earlier states to designate an official state soil, joining a movement led by the Soil Science Society of America to give each state a soil symbol the way states have birds and flowers. The Harney series was the clear choice: it is the dominant soil of Kansas's farming heartland and the foundation of the state's wheat economy.

The most distinctive feature of the Harney profile is the calcic horizon — a subsoil layer filled with white calcium carbonate filaments, coatings, and soft masses. If you drip dilute acid on it, it fizzes. This layer forms only in soils where rainfall is low enough that calcium carbonate cannot wash out of the profile. It is the clearest sign that you are looking at a High Plains soil, not a Corn Belt soil.

Above the calcic horizon, the Harney profile looks like many other Mollisols: dark at the surface, getting browner through the argillic subsoil, then lightening toward the parent material. The difference is in the subsoil chemistry, not the structure.

Harney soil covers millions of acres across central and western Kansas, on the flat to gently rolling High Plains uplands. It is the dominant upland soil across a broad east-west band running through the agricultural core of the state.

The greatest concentrations are in the counties around Hays and Dodge City — Ellis, Trego, Ness, Ford, and the surrounding counties where winter wheat fields stretch to the horizon. This is the landscape that defined the Kansas wheat economy and the Kansas identity.

Harney soil is also found in smaller areas of Nebraska, Colorado, and Oklahoma, but Kansas contains the largest and most agriculturally significant concentrations. In western Kansas, it is essentially the default upland soil — the one that fills in everything between the sandy soils of the river valleys and the rocky outcrops of the Smoky Hills.

Winter wheat is the crop that defines Harney soil. Kansas leads the United States in winter wheat production, and the Harney series underlies more of that wheat than any other single soil. Farmers plant winter wheat in September and October, it goes dormant in winter, and it is harvested in June — a cycle perfectly matched to the Harney soil's ability to store water from winter precipitation and release it slowly through the dry spring growing season.

Grain sorghum is the second major crop on Harney soil. Also called milo, it is more drought-tolerant than corn and thrives in the semi-arid conditions of western Kansas where irrigation is limited and summer rains are unreliable. Cattle ranching and hay production occupy the drier or more erodible Harney ground that is not planted to crops.

Before European settlement and farming, the Harney soil landscape was covered by mixed-grass prairie — buffalo grass, blue grama, little bluestem, and sideoats grama. Bison grazed this prairie by the millions. The same soils that fed those bison herds now produce the wheat that supplies flour mills across the central United States.