Is soil a renewable resource?

My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true. Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives. In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this?

$\begingroup$ "Renewable" is a fairly loose term. It kinda needs to be defined with reference to a specific time-frame, or at least with reference to a usage rate. For instance, forests are a renewable resource only if you used them at around the same rate that they can re-grow. The same could be said of coal (although that would mean we'd only be able to use minuscule amounts every year). $\endgroup$

$\begingroup$ Also, for the purposes of this question, how do you define soil usage rates? Are you talking about destruction via erosion? Or mineral loss by agricultural uptake? Or biota loss due to pesticides or other additives? $\endgroup$

2 Answers 2

Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.

What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.

In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.

I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.

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