Billions of tons of northern Plains topsoil has blown away -- far away
Soil loss doesn’t just affect the fields that lost it or ditches where it piles up. That soil eventually reaches the oceans.
GRAND FORKS, N.D. — When early farmers broke up the prairies of the northern Plains they found soil that was vastly different than it is today, according to Dave Franzen, North Dakota State University Extension soil specialist.
Soil surveys from the early 1900s described “very black” soil that was 2- to 3-feet deep and was made up of 65% to 70% organic matter. The soil contained high levels of plant-available nitrogen, potassium and phosphorus levels, Franzen said. Meanwhile, the soil was rich with calcium, magnesium and micro-nutrient levels.
The soil of eastern North Dakota produced early wheat yields of 40 bushels per acre near the Sheyenne River in Kindred, North Dakota and as much as 30 bushels per acre in Jamestown, North Dakota, in 1890, according to Franzen, who cited information from the late Hiram Drache, a Minnesota historian.
“Without any fertilizer, with antique equipment, they were getting yields that were similar to today,” Franzen said. “This would have only been possible if over 100 pounds of nitrogen per acre and substantial phosphorus and other nutrients were released from soil organic matter mineralization that season."
The farmers, who had moved to the prairies from forested areas further east, weren’t aware that winds would sweep across the prairies, carrying with it topsoil.
“Some of the letters people wrote home, they would comment that they couldn’t believe how windy it was,” Franzen said. “As soon as the plow came into the area, it started to blow.”
Then came the Dust Bowl years, an entire decade when the northern Plains sky was filled with dust.
“It was pretty horrible. They lost feet of soil in some events,” Franzen said. “It was at least as bad here as it was in Texas.”
Between the decades when the prairie was plowed and the late 1930s, the northern Plains lost about a foot of soil from hilltops and 8 inches from slopes, he said. Overall, topsoil loss averaged 6 inches from about 30 million acres, which totaled a weight of 30 billion tons.
Soil loss doesn’t just affect the fields that lost it or ditches where it piles up. It eventually reaches the oceans.
“Only a small part goes into the ditches. It just goes a long, a long way,” Franzen said.
The loss of the topsoil began to result in decreased crops yields in the 1920s, and they didn’t rebound until the 1950s when farmers began to apply fertilizer to their fields, he said.
Topsoil continues to blow today, but many farmers and landowners don’t appear to be overly concerned because the effects are masked with tillage, they have no frame of reference, or are ignoring the obvious, Franzen said.
Steps farmers can take to reduce erosion include planting cover crops after short-season crops are harvested, combining corn and sunflowers at a level that leaves high stalks and allowing volunteer grain to grow after harvest.
“No-tillers say your next spring’s work should always start on the combine” during the previous harvest, Franzen said.
Individual farmers have to devise soil health plans that work for their acreages, he said.
“Everyone wants a recipe. There are no recipes. Every farm is different, every soil type is different,” Franzen said.