Let’s Protest the Rape of Our Soils
Let’s Protest the Rape of Our Soils
July 28, 2014
While discussions about climate change are serious and must be addressed, they are distracting us from an even more important issue.
The deterioration of the soil that feeds us is being ignored.
It’s time we took a stand about the rape of our soils before there’s widespread starvation in the world this century. Let me explain.
About 90 percent of our food comes from annually sown crops and, in the next 20-30 years, nations must find a way to produce more food from the same amount of soil. We simply haven’t addressed the urgent need to feed another 50 percent of our population by 2050.
Soil feeds us, it’s as simple as that. Yet for generations the world has been stripping the soil of carbon and organic matter and giving nothing back.
Every time we cultivate the soil we oxidise some of its carbon and discharge it into the atmosphere as carbon dioxide. This source of carbon dioxide contributes up to 20 percent of the total carbon dioxide entering our atmosphere annually.
Our politicians get on the global warming bandwagon yet never address one of the main causes that can be reversed.
Carbon is an essential ingredient of organic matter yet it’s being wasted and the quality of our soil is declining as a result.
The culprit is ploughing and aggressive tillage. Most of the world’s arable soils that, have had 6-16 percent of organic matter before ploughing, now have 0.5-2 percent as a result of tillage operations.
That low level of organic matter won’t support the soil biology which lives on organic matter. By soil biology I mean the microbes and other soil organisms like earthworms. They play a significant part in maintaining the health of our soil but they’re being destroyed.
The key question is whether the cumulative stripping of soil organic matter can be reversed. Spreading lots of organic manure on the ground helps but the world’s arable soils are far too extensive for this to be the total solution.
Plants play a vital role in the regeneration of soil. They gather carbon dioxide from the atmosphere and combine this with rainfall and the sun’s energy in the process of photosynthesis. It’s nature’s way of recycling carbon.
When farmers harvest a food crop like wheat about half of the plant’s carbon is removed as food but the other half remains available for recycling in the form of cut straw, stubble and other forms of crop residue. This is the crucial bit. Ploughing the residues in usually loses more carbon than the soil gains. And burning them is even worse.
It’s this stage of the process that’s essential to regenerating the soil and reversing the rape of its nutrients and water holding capacity. In turn this will lead to increased food production. When that happens we can feed the world.
The secret is that the plant residues must remain on top of the soil to decompose naturally and let the soil fauna and microbes take it into the soil.
Low disturbance no-tillage is the answer. A low disturbance no-tillage drill sows seeds into undisturbed soil. It penetrates through the residue to create seed slots. It sows the seed while dropping fertiliser in a separate band at the same time, covers the slot, traps the humidity, preserves the micro-organisms and soil life and prevents most of the existing carbon from escaping into the atmosphere.
Compared to traditional methods crops grow faster and yields can increase by up to 50 percent. No-tillage is the equivalent of keyhole surgery, ploughing is invasive surgery.
The key fact is that such machines exist already. Anything less will simply perpetuate the continued rape of our soils and eventually lead to famine in some areas of the world with marginal food supplies.
This message of how healthy soil can feed the world is the outcome of 30 years research at Massey and Washington State Universities.
I’ve championed it at the US Senate, been awarded the Queen’s honours for my research, spoken about it on BBC radio, been nominated for the World Food Prize but, more than anything else, I need politicians to do something before it’s too late.