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Climate ChangeDisasters & Extreme WeatherDroughtFoodNature

Topsoil Fertility Decline & Soil Erosion — A Few Musings

The processes by which fertile topsoil is created are slow ones, to put it in mild terms. Generally speaking, the timespans necessary to turn glacial rock dust into something that agricultural crops can possibly grow in aren’t relevant when considered from the perspective of what’s needed to plant this year’s crops. The processes by which highly degraded land can be made capable of sustaining intensive agriculture aging aren’t much faster.

The famous quote by one of the fathers of modern geology, noting that when looking at geologic history “we find no vestige of a beginning, no prospect of an end” is an apt one when considering the subject.

While the rapid loss and degradation of much of the world’s topsoil over just the last few centuries isn’t something that will trouble, or even be noted by, whatever forms of life may be living on the Earth a million years from now, they are highly relevant to those living in the world now. What’s happened over recent centuries in this regard will have effects that impact outwardly in unpredictable ways for many tens of thousands to hundreds of thousands of years.

At the every least, agricultural capacities and yields will decline precipitously — with a high water mark likely already having been hit (or nearly so) when it comes to crop yields. The reality here, one that is often avoided by those discussing the subject, is that while crop yields have largely been kept somewhat level there has been a vast hollowing-out of the foundations on which agriculture rests over the last century.

While yields-by-weight rose for a while during the “green revolution” there has been at the same time an accompanying and vast loss of soil fertility and nutrient content, a vast erosion of topsoil itself, a loss of atmospheric moisture in many agricultural regions due to desertification, and a great loss of genetic diversity amongst crops.

That last bit is something that should be explained here first, before moving onto the crux of the article. When someone is talking about using genetic engineering or crop-breeding programs to maximize yields, and thus “solve” hunger problems in the poorer parts of the world, what they are largely talking about is taking an agricultural system whereby there’s a large amount of genetic diversity within the crops (seeds) being grown and replacing it with one with far less genetic variability that’s been engineered (or selected for) to show higher yields in specific highly controlled conditions.

In the real world, highly specified and completely controlled conditions don’t exist outside of a laboratory. By taking a crop/seed base that has great variability built into it simply due to the process of not over-selecting for the conditions of a specific year (but rather for performance of longer periods of time and varied climate patterns), and replacing it with seeds shown to have slightly higher yields in the conditions provided for in the controlled setting where they were developed, what you are doing is taking the leeway out of the system.

This practice overspecializes it, which makes it more prone to catastrophic failure. The fact that this either isn’t obvious to those trumpeting such an approach, or that they just don’t care about on-the-ground reality and blowback is somewhat hard to believe. From where does such a vast blindspot come?

In the biological world, you can’t have it all. There’s always a trade-off occurring, even if it isn’t immediately obvious. Issues of immunity, resiliency in the face of drought, growth-rates, nutrient-content, et cetera, are tied together in a myriad of ways that aren’t easily comprehended in a reductionist sort of way.

Anyway, back to the subject at hand … as it stands, the global average rates at which soil erosion occurs have been increased by an average of 30-40 times over by human activity in recent centuries. In North America, figure the rate of which soil erosion occurs actually increased more than 100-fold following European colonization. More than half of the Great Plains’ topsoil has been lost since just the 1890s or so.

Much of this erosion has been due to the use of agricultural approaches in the Mississippi valley, in New England, and in the Great Plains, all of which are ill-suited to the regions in question (imported approaches). Considering that the Mississippi River region supported some of the highest population densities in the world previous to the introduction of smallpox, measles, leptospirosis, and other diseases, this is notable.

A similar (but lesser) situation is also true of the parts of South America held by the Incan Empire at the time of contact with the Spanish — a highly developed and varied agricultural system that minimized soil erosion and nutrient depletion, while still allowing for large yields, easy harvesting, and increased growing seasons (partly due to systems utilizing large amounts of thermal mass).

What’s the common element here? Topsoil sustainability is rooted in the practice of using agricultural systems that were well adapted to (and indeed borne from) the regions where they were used…rather than the overuse of overspecialized and oversold (gimmicky) “solutions.” Good agricultural practices were borne from practical knowledge of local conditions, and a development of relation with those conditions and the variability that they contained.

What point am I making here (you might be asking yourself)?

That as topsoil continues to be lost at very high rates, that as local waterways become increasingly dirty due to this erosion (which carries with it agricultural chemicals), that as nutrient levels in crops continue declining, that as some of the best farmland in the world continues to be paved over and polluted due to urban and roadway expansion, that it becomes more and more clear that current agricultural systems are a dead man walking.

If there’s a way forward from here that doesn’t involve the return of large-scale famines over just the next 50 or so years, I haven’t seen it. Accompanying this loss of agricultural productivity due to soil erosion and nutrient depletion, will be a loss of agricultural productivity due directly to climate weirding and warming. Further exacerbating all of this will be increasing geopolitical and social strife as water scarcity, mass migrations, and a slew of other factors, continue to intensify.

My primary reason for writing this, with all of the aforementioned in mind, is that it certainly is possible to practice agriculture in such ways that it doesn’t undermine the world in which you live. Such approaches have been used at various different points in time in various different parts of the world.

The barrier to such approaches nowadays is largely cultural, and due to the inertia inherent in large populations. Entrenched interests (of those with wealth) is one factor, but not the most important factor. A much more important factor is simply that people have grown accustomed to not considering the “where froms” and “hows” of what they consume. Of not considering the true costs, that is. Something to keep in mind, when making the everyday decisions of your life.

(As an endnote here — altogether, over 75 billion tons of topsoil is known to be lost every year; that is, eroded and washed into the sea, into lakes, blown away with the wind, etc. In addition, well over 40% of the world’s agricultural land is now known to be “seriously degraded” owing to the approaches used over the last few centuries in many parts of the world. To put that a different way, the world loses an area of fertile land roughly equivalent to the size of Ukraine every year — due to erosion, desertification, and urbanization.)




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