Soil loss: 1/3 of our most fertile land has vanished in the past 40 years
I wish the news was always good, but sadly, it isn't. A new study conducted by the University of Sheffield’s Grantham Centre for Sustainable Futures reports some rather alarming fact about how much arable soil we're losing to bad farming practices, erosion, and pollution, just as global demand for food is growing rapidly. The researchers have found that over the past four decades, nearly 33% of the world's arable land has been lost, and the scientists "urge that a sustainable model for intensive agriculture is crucial to cope with the increase in global food production needed to feed the world’s growing population."
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Duncan Cameron, Professor of Plant and Soil Biology at the University of Sheffield, said: “Soil is lost rapidly but replaced over millennia and this represents one of the greatest global threats for agriculture. Erosion rates from ploughed fields average 10-100 times greater than rates of soil formation and nearly 33 per cent of the world’s arable land has been lost to erosion or pollution in the last 40 years." He adds: “This is catastrophic when you think that it takes about 500 years to form 2.5 cm of topsoil under normal agricultural conditions. A sustainable model for intensive agriculture could combine the lessons of history with the benefits of modern biotechnology.”
So what can be done?
Professor Cameron and his team believe that a sustainable model for intensive agriculture is founded on three principles:
-Managing soil by direct manure application, rotating annual and cover crops, and practising no-till agriculture (not cultivating and preparing the land). These practices connected to ‘conservation agriculture’ restore soil organic matter, structure, water-holding capacity and nutrients, averting soli loss while benefiting crops.
-Using biotechnology to wean crops off the artificial world we have created for them, enabling plants to initiate and sustain symbioses (close interactions) with soil microbes. These symbioses allow crops to exploit microbial biology to tap into soil organic nutrient reserves, and prime plants to better defend themselves against pests and diseases.
-Recycling nutrients from sewage in a modern example of the circular economy. Inorganic fertilizers could be manufactured from human sewage in biorefineries operating at industrial or local scales. A number of technical challenges impede the immediate adoption of this idea, but these can readily be addressed through research.
Of course, that's just the kind of things that we can do directly. Indirect solutions are to deal with our climate and pollution problems, which directly affect agriculture.
We have a lot of work ahead of us, but this isn't optional. Burying our heads in the sand and hoping that problems will go away isn't a viable strategy!
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