You might think that there’s no shortage of ‘dirt’ in the world, but you’d be wrong.
I don’t really mean ‘dirt’ of course, but soil – that complex mixture of minerals, organic materials and organisms, that is necessary for the growth of all land plants.
Now that we’re no longer hunter-gatherers, and rely on the cultivation of soil based crops for our survival, the health of the world’s soil is a critical concern, but something we all too often take for granted.
It might seem like soil is an endless and replenishing substance, but it’s not. It takes hundreds of years to build-up a few centimeters of fertile, humus rich soil, essentially making soil a non-renewable resource in any meaningful time frame.
This is a problem because many modern farming methods have resulted in rates of soil erosion and degradation well in excess of rates of replacement, as Professor David Montgomery points out in his book Dirt, if we spent our money up to ten times faster than we earned it, we’d go broke pretty quickly – so it is with soil.
Overgrazing or slash and burn agriculture leaves soil bare and exposed to erosion. Sustained compaction by heavy machinery causes increased rainfall run-off, removing sediments, and leaving soil dryer. Removing hedges and trees, whether to aid mechanised monoculture or to gather firewood, increases erosion by wind. All removes fertile topsoil, making land less productive and requiring greater fertilizer inputs in order to maintain yields.
Ultimately the soil can become too thin to sustain large plants, and without their supporting root structures, may simply be washed or blown away, resulting in duststorms and desertification - a significant and growing problem in many parts of the world.
History gives us several traumatic examples of agricultural collapse and societal disruption following the loss of fertile soils – from the American dustbowl of the 1930s, to the collapse of mechanised collective farmland in soviet Kazakhstan in the 1950s and 60s. Those of us living in cooler climes shouldn’t think we’re immune either, as Iceland’s catastrophic soil loss of the 1800s shows. Even as you read this blog Chinese engineers are battling against the continued growth of the Gobi desert, which is threatening water resources and food production for millions of Chinese.
Maintaining our soils is a complex problem, and the solutions will need to be equally complex – but better land management techniques will be key, with greater emphasis on sustaining the quality of the soil over a period of time.
Land reform is also going to be a critical issue across much of the developing word, where unsustainable farming practices are often the consequence of poor subsistence farmers having no long term security on the land.
Granting them longer-term rights to farm the land, and providing access to affordable initial capital, would allow them to remain in place, develop more sustainable farming methods, enhancing their ability to feed themselves and their family, without constantly destroying more natural habitat and giving rise to soil erosion in the process.
Sustainable fertile soils are the basis of human civilization. If we don’t respond successfully to the challenges of Peak Soil, we’re going to struggle to continue to produce enough food for the 7 billion of us now living on the planet – not to mention the additional 219,000 new mouths the world has to feed every day !
“A nation that destroys its soil destroys itself.”
- President Roosevelt (in 1937 – after the Mid-West dust bowl)
Photo by Wikimedia Commons
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