Topsoil Loss—A Continuing Crisis

Author: John W. Head

Soil is life, in many ways. We can plausibly say that soil itself is alive, not only because it contains countless organisms of all types and sizes but also because it constitutes a network of relationships that are regenerative and whose whole is greater than the sum of its parts … and this is surely qualifies it for saying that soil is “alive”. But soil is life in another, more pedestrian sense: it serves as the source of life by providing a rich medium in which food grows to provide nutrition for humans and for all of our fellow creatures.

Given these facts, it seems obvious that we should focus on protecting soil at all costs. And yet the opposite seems to be true: soil degradation of all sorts – erosion, poisoning, organic depletion, and more – occurs in nearly all ecosystems … and nowhere does this occur more egregiously than in the world’s agricultural regions, including such “breadbasket” areas as the Great American Prairies regions of the USA and Canada.

In its Spring 2021 issue of The Land Report, the staff of The Land Institute highlighted the dangers of soil erosion in the USA, focusing on the present situation – that is, on the early 21st century, not on the “dust bowl” days of the 1930s. Most Americans probably think that the single most obvious and offensive form of soil degradation – that is, the simple loss of soil by having it plowed away or washed out of fields during rains – has been arrested by eight decades of soil-conservation efforts, such as terracing, contour farming, no-till farming, and the like. But that’s not the case: soil erosion is still with us, and in a big way. Here are some excerpts from that recent article in The Land Report, printed here with permission:

Roughly 35 percent of plowed land in the [US] Corn Belt has lost all of its topsoil, say University of Massachusetts geoscientists who made their estimate by connecting topography with satellite pictures of soil color. The calculation has a broad margin of error … but far exceeds previous estimates. … The study also attributed most of the loss not to water and wind erosion after tillage, but simply to the plow and gravity.

The finding, in Proceedings of the National Academy of Sciences, said that the loss included 1.4 billion metric tons of carbon, … [some of which] was released to the atmosphere after plowing … . [This study adds to other studies, in which] researchers have estimated global loss of soil erosion under crop agriculture at 35 to 88 million metric tons.

… Other studies have determined that on the convex topography of hilltops and ridges, tillage fluffing up the soil makes for an easy pull by gravity and brings mor3e erosion – soil creep – than do wind or water.

… We can’t restore this denuded farmland by hauling back uphill all of the displaced – and disarranged – topsoil. But [the study’s main authors] conclude by saying that changing how we farm could prevent more soil loss in the [US] Corn Belt, begin regenerating the organic matter than makes soil rich, and turn it into a sink for atmospheric carbon.

Much of our work at the Global RESTORATION Project revolves around soil – its health, its role in food production, and the intrinsic (but underappreciated) connection between it and our own species. And it’s more than just the agroecology element of the GRP that involves soil: a responsible energy policy requires shifting to a post-fossil-carbon world, which will both benefit soil health (by reducing fossil-carbon-based fertilizers, pesticides, and herbicides) and be facilitated by transitioning to a natural-systems agriculture.

In short, soil degradation of all sorts – erosion, poisoning, and the like – still constitutes a crisis of staggering proportion. Restoring the world’s ecosystems requires restoring the world’s soil.