We need to commit to sustainable land and water management practices to reverse rates of soil degradation and healthy soil loss.
Do you give much thought to the ground beneath your feet? Unless you’re a gardener, probably not. That’s because we tend to worry about the quality of the air we breathe and the water we drink, but we take for granted that the Earth’s crust is forever renewable.
Soils under pressure
Not so, says the Food and Agriculture Organization of the United Nations (FAO), which endorsed the first annual World Soil Day on December 5, 2013. The FAO warned that food security around the world is threatened by continuing to ignore the intense pressures we humans have placed on our soils.
The FAO has reviewed the problem and concluded that one-quarter of the world’s land areas are highly degraded because of human activities, including farming. This assault on our soils comes from bad agricultural practices that have resulted in water and wind erosion, loss of organic matter, topsoil compaction and pollution due to—among other things—salinisation and chemical overuse.
It also comes from a lack of concern and interest in what we’re doing to the thin crust of the Earth’s surface. The last time an international agency surveyed the state of our soils was in the late 1970s and early 1980s. Since that time, the world population has exploded, as has our capacity to produce food.
But this has come at a steep price created by industrial mega-farms, monocropping, deforestation and chemical pesticides and herbicides. All are a huge part of our current agricultural model and contribute to the poisoning of our waters, the loss of huge swaths of oxygen-producing forests and the desertification of once productive land, according to The State of the World’s Land and Water Resources for Food and Agriculture (SOLAW), the FAO’s 2011 report outlining the need for action.
In Australia, agricultural land is under constant pressure from soil erosion, loss of natural vegetation cover, over-use of irrigation and introduced invasive species. According to the report by the Commonwealth Intergovernmental Working Group for the UN Convention to Combat Desertification, agriculture accounts for 60 per cent of land use in Australia, while the cities and towns where 80 per cent of us live, take up less than 1 per cent of the total land area.
Only 6 per cent of our land is arable without irrigation. Added to that, we are the world’s driest continent (apart from Antarctica), with a wide variation in annual rainfall, but are among the highest per capita consumers of water in the world.
Half of the world’s topsoil has been lost in the last 150 years, says the World Wildlife Fund. It notes that soil erosion results in sediment buildup and blockage of streams and rivers, threatening fish and other species, as well as lessening the ability of the soil itself to hold water, leading to more flooding and further threatening biodiversity.
And never mind “peak oil,” says the Soil Association, a United Kingdom organisation campaigning for “healthy, humane and sustainable food, farming and land use.” Soil degradation is the biggest potential disaster facing us all, said Soil Association president Monty Don at its annual conference in October 2013. “If we are to feed the world, we must have good soil. As a soil scientist said to me only last week, we have reached ‘peak soil’ and we can’t produce any more.”
To underscore that view, the FAO has projected that, by 2050, “rising population and incomes are expected to call for 70 per cent more food production globally, and up to 100 per cent more in developing countries, relative to 2009 levels.” The FAO report emphasises that all nations on Earth must commit to sustainable land and water management practices. We all must find the political will to encourage widespread adoption of responsible agricultural practices if current rates of soil degradation and loss of healthy soil are to be reversed.
According to the Columbia University’s Earth Institute, unsustainable agricultural practices are the chief causes of land degradation:
- Land clearing and deforestation for crop planting removes vegetation and changes soil composition.
- Over-tillage destroys soil’s top layers, speeding up erosion.
- Irrigation and soil drainage cause soil salinisation (crops absorb water and leave salt behind).
- Overuse of nitrogen fertilisers and acid rainfall create acidic soils.
- Pesticides and chemical fertilisers change soil consistency and destroy organisms needed to aerate the soil.
- Heavy farming equipment compacts soils.
In addition, overgrazing can strip the soil of vegetation, leading to erosion from wind and water, creating desertification and dust storms.
All evidence points to this: we must learn to step more lightly on our common earth if we are to restore and preserve its ability to sustain us.
Take personal responsibility
One inch (2.5 cm) of topsoil takes 500 to 1000 years to form as bedrock, topography, climate and living organisms interact. So what can each of us do to ensure the earth that harbours and feeds us will remain clean and productive for generations to come? Perhaps the best way is to educate yourself about your own impact on soil health. Ask yourself the following questions:
- Do you recycle?
- Do you use water wisely?
- Do you support sustainable agriculture by buying from farmers and other food producers who use good agricultural and production practices?
- If you’re a gardener, do you use organic methods to grow your own food or other plants?
Tips for building and maintaining healthy soil
1. Take the time to build good soil.
Few of us are blessed with great soil when we begin a garden. Building good soil takes time, so be patient. If you aren’t having success with certain crops, it may be related to the soil’s pH, which is how alkaline or acidic it is. Generally speaking, most crops do best in a balanced soil, and that balance can be achieved over time with generous applications of organic matter.
2. Determine what kind of soil you have.
Is it heavy and clay-based, porous and sandy, or silty? Each has its up- and downsides. The best way to improve the structure of any soil is to regularly amend it with cover crops, compost and well-rotted manure. Spread the latter two on the soil, and let the worms and other creatures pull the matter down into the soil.
3. Avoid heavy tilling of your soil.
Although turning the soil regularly to work in amendments such as green manure or compost would seem to be a good thing, too much will destroy the web of life beneath the soil that helps to keep it healthy and productive.