Today, Monday December 5th 2016, is World Soil Day.
Who knew? Who cares?
There are more than two reasons to care. First is that nearly all of our food production requires soil to grow in. Second is that we have only 60 years of food harvests left at current rates of soil degradation.
The 60-year estimate comes from the UN Food and Agriculture Organisation (FAO) in their first Status of the World’s Soil Resources report published last year.
The FAO argue that “Without soils we cannot sustain life on earth and where soil is lost it cannot be renewed on a human timeline. The current escalating rate of soil degradation threatens the capacity of future generations to meet their needs.”
Let’s be clear what soil is. Soil is one of our three major natural resources, alongside air and water. It is so much more than the dirt that covers much of the earth’s land. Soil is made up of three main components: the minerals that come from rocks; organic matter from the residues of plants and animals; and the living micro-organisms that live in soil.
It takes nature 200 – 400 years to make a layer of soil one centimetre deep. To make it fertile, may take 3,000 years.
The FAO estimate that between 25 and 40 billion tonnes of topsoil are eroded by wind or rain every year.
Not only does this loss lower farm profitability, it is also a major driver of climate change.
Soil organic matter is exposed when forests are clear-felled and when agricultural lands are tilled. The exposure of soil organic matter to oxygen means that previously sequestered carbon joins the carbon cycle and is added to the atmosphere as a new source of carbon dioxide.
To avoid catastrophic climate change, the world needs us to stop putting new carbon in to the atmosphere. The longer it takes us to act on that need, the harder it is to avoid catastrophe.
As well as driving climate change, the loss of soil organic carbon reduces the availability of nutrients and minerals to plants and so affects the quality and safety of our food. It also leads to increased pests and diseases which, in a downward spiral, further reduces food availability.
For the sake of our climate and our food supply, the health of our soils needs to be assured. This can best be done through regenerative farming and gardening practices.
One regenerative action that anyone can take, is to add carbon, in the form of compost and biochar, to our gardens and farms.
By looking after our soil, so the soil will look after us.