The year 1862 marked a pivotal point in Nebraska history — it was the year the first Homestead Act was enacted. As a result, thousands of settlers laid their claim across the Great Plains, tilling up the native prairie and replacing the big bluestem, little bluestem, indiangrass and switchgrass with annual crops.
Most farmers and landowners are familiar with the rest of this history: The fertile prairie soil turned out to be an ideal location to raise row crops like corn, beans and wheat. Nebraska has since risen to become the third-largest producer of corn for grain in the country and fourth in soybean production, producing 1.693 billion bushels of corn and 305.67 million bushels of soybeans last year, according to statistics from the Nebraska Department of Agriculture, USDA National Agricultural Statistics Service and the Nebraska Bankers Association.
However, since that sod was first overturned 154 years ago, Nebraska has lost roughly 7 inches of topsoil per acre, according to Natural Resources Conservation Service calculations.
National Resource Inventory erosion figures collected in 1982 by the Nebraska NRCS office in Lincoln show a state average of 4.65 tons of topsoil per acre per year lost to water erosion, and 1.75 tons per acre per year lost to wind erosion. That's 985.6 tons per acre lost through the years. Considering an inch of topsoil weighs about 150 tons per acre, that's almost 7 inches of soil lost since 1862 — a conservative estimate, considering there was essentially no conservation farming in the 75 years between 1862 and 1937, before the Soil Erosion Service and Soil Conservation Service were established.
What does that mean? Research at Iowa State University suggests corn yields drop 2.2 bushels per acre per inch of topsoil loss and soybean yields about 0.8 bushels an acre in Iowa, and that's not accounting for cumulative effects of loss over time. That's not only attributed to a loss of topsoil, aggregate stability and organic matter, but a loss of nutrients like nitrogen and phosphorus as well. Those who have been around long enough know that this loss was instigated by the overuse of conventional tillage, and has been exacerbated by the increase in weather extremes in recent years.
However, it's important to note that farmers, especially in Plains and Midwest states like Nebraska, have made a lot of headway in how they take care of the soil. Since 1862, and since the "dirty 1930s," when many High Plains farmers realized the devastation caused by year after year of intensive tillage, Nebraska has become one of the most prominent states for no-till agriculture.
According to USDA NASS Census of Agriculture data, Nebraska ranked second in the number of no-till acres in 2012, with 9.4 million acres under no-till — behind Kansas, with 10.4 million acres, and ahead of North Dakota and South Dakota, with 7.8 million and 7.2 million, respectively.
Enter cover crops — the latest conservation farming practice that's been making headlines in national news outlets — although many no-tillers have been using them for at least 20-plus years. According to last year's Sustainable Agriculture Research and Education Cover Crop Survey Analysis, cover-crop acres in the U.S. continue to expand every year, the biggest users being Corn Belt states like Iowa and Illinois, followed by Plains states like Kansas, Nebraska and the Dakotas. The 2014 SARE cover-crop survey reports that from 2010 to 2013, there was a 30% increase in cover-crop acreage per year among survey respondents.
The benefits of long-term no-till, especially when cover crops are thrown into the mix, are often touted: improved aggregate stability and infiltration; higher organic matter and greater nutrient cycling; increased microbial activity; and faster, more uniform residue breakdown. The challenge, for many, is translating that into a uniform description and a quantified benefit.
No-till advocates like Dwayne Beck, manager of Dakota Lakes Research Farm in Pierre, S.D., describe a kind of "soil health highway" — that is, it's not about taking a giant leap of faith and going broke trying to make your soil the healthiest it can be. It's about starting down the path to healthier soils, and continuously working to improve them.
The ultimate goal is an agricultural landscape that's resilient in its ability to produce crops in the increasingly dynamic weather and climatic conditions we're familiar with in the Great Plains and the Midwest — one with the water-holding capacity and infiltration to store soil moisture for use during drought, and the residue and aggregate stability to hold the soil and nutrients during flooding. What it comes down to is an ag landscape that protects the grower's investment over the long term.
This article is the first in a series of articles on resilient agricultural landscapes.