Developed land is on the increase, while cropland, pastureland, and rangeland are on the decrease, according to the 2012 Natural Resources Inventory. The U.S. Department of Agriculture has conducted the inventory every 5 years since 1982, but it takes several years to put the report together, so the inventory for 2017 is not yet available.
Figure 1 graphs the surface area of the contiguous 48 states by land cover/land use in 2012. The top 3 uses were forest land, rangeland, and federal land, each of which accounted for 21% of the total. When the USA was first settled, forest land and rangeland were much more extensive, but they have been converted into cropland and developed land. In addition, we think of our country as having huge freshwater lakes, but only about 3% of the surface area is water. Freshwater is very precious and special.
Of course, federal land could also be categorized into forest land, rangeland, cropland, and the other categories, but the Natural Resources Inventory does not do so.
Figure 2 shows the change in land cover/land use since 1982. Over that time, cropland decreased and developed land increased by more acres than did any other category. “CRP Land” is land placed in the Conservation Resource Program.
The Natural Resources Inventory grew out of the National Erosion Reconnaissance Survey, conducted in 1934 because of severe dust storms and erosion during the Dust Bowl. Thus, since its inception, the report has been concerned with erosion. Figure 3 shows the estimated erosion rate on cropland in 1982, and Figure 4 shows the same data for 2012. You can see that in 1982, erosion was most severe in a region centered on Iowa’s borders with Illinois, Missouri, and Nebraska, but also extending along the Mississippi River into western Tennessee. In 2012, that region remained the one with the most severe erosion, but the rate had been significantly reduced. Across northern Missouri in 1982, more than 10 tons of soil eroded from each acre of cropland each year! In 2012 that had been reduced by 50% or so.
Figure 5 shows land use in Missouri from 1982 – 2012 in a few broad categories. The green areas of the columns represent federal land, which is not broken-out according to use. The red areas represent water. The two blue areas represent non-federal land, and they are broken into two categories: developed (light blue) and rural (dark blue). You can see that rural land represents by far the largest use of land in Missouri. In 2012, it represented 86.8% of Missouri’s surface area, while federal land, water areas, and developed land represented 4.5%, 2.0%, and 6.7%, respectively. Over the 30-year period, federal land increased slightly, water areas increased slightly, and developed areas increased by a whopping 38%, all being converted from rural land.
Figure 6 looks at Missouri’s non-federal rural land more closely. In 2012, more land was used for crops than for any other purpose (36% of rural land), followed by forest land (32%) and pastureland (27%). Over the 30-year period, the amount used for cropland decreased slightly, pastureland has decreased 17%, and rangeland, which was already such a small portion of the land that you can barely see it on the chart, declined 62%. Forest land and other rural land have increased. The Conservation Reserve Program (CRP Land) began after 1982, peaking in 1997, and declining since then.
This report is compiled and published by the U.S. Department of Agriculture, and from an environmental perspective it may be a bit misleading. Figure 5 shows that developed land represents only 6.7% of all Missouri land. However, Figure 6 shows that almost 1/3 of rural land is cropland, and another 27% of it is pastureland. It is not as if these lands are undeveloped. While they may not be covered in asphalt or highly populated, they are intensively used. They may be subject to high levels of erosion, as shown in Figure 3, or they may be disturbed by tilling and the application of agricultural chemicals. Pig farms and feed lots, for instance, are located in rural areas, but they are highly developed operations, in many cases resembling factories.
Thus, the Natural Resources Inventory probably provides the most comprehensive look at land cover/land use in the USA. It does not, however, provide an in depth review of the ecological status of the land.
Missouri Department of Natural Resources. 2018. Soil and Water Conservation Program. Viewed online 4/18/2018 at https://dnr.mo.gov/env/swcp.
U.S. Department of Agriculture. 2015. Summary Report: 2012 National Resources Inventory, Natural Resources Conservation Service, Washington, DC, and Center for Survey Statistics and Methodology, Iowa State University, Ames, Iowa. http://www.nrcs.usda.gov/technical/nri/12summary.