Tillage Has Destroyed Humidity For Centuries

Tillage Has Destroyed Humidity For Centuries

December 1, 2014

One of the great assets of nature is being destroyed every time soil is disturbed for cultivation.

For more than 40 years, international soil scientist, Dr John Baker, has been researching the most effective means of growing food to feed the earth’s population and says the barbaric method of tilling the soil loses carbon and humidity into the atmosphere.

Dr Baker says nature was very clever in preserving those essential ingredients but cultivation over generations has depleted the soil of its nutrients and the end result will be crop failure and famine in some areas of the world.

Dr Baker, who’s been a World Food Prize finalist, is alarmed that, with a 50 percent increase in the global population by the year 2050, there won’t be enough food to go round.

He says that only four percent of the world’s surface is arable land and the only way for millions of people to survive is by farming it smarter.

It can only be achieved by trapping carbon and humidity in the soil and progressively eliminating traditional methods of cultivation or tillage such as ploughing.

In fact, in recent studies, Dr Baker says most seeds don’t need soil or even liquid water to germinate. He disputes the common belief that seeds need to be buried in the soil to prosper. Instead the key to germination is humidity.

“Most seeds can germinate without touching anything at all – including soil – as long as they are surrounded by 90-100 percent relative humidity or RH,” he says.

“Humidity is vapour water suspended in air (eg fog). All soil has humidity-laden air trapped in the spaces between its particles called pore spaces and seeds thrive in it.”

Dr Baker says that when farmers cultivate the soil they allow most of the pore space RH to escape into the atmosphere. Germinating seeds must then rely entirely on liquid water that surrounds soil particles. When soils dry, less germination takes place.

“Cultivation actually makes the soil more hostile to seed germination rather than better yet, only in recent times, have scientists realised that pore space humidity has been available for thousands of years but no-one, until 1970, had figured out how to use it,” he explains.

Now to compensate, Dr Baker has observed farmers using strips of plastic in an attempt to trap pore space humidity in the soil when sowing maize into cultivated soils.

“Not only is this an expensive option but, if the soil had never been cultivated in the first place, it wouldn’t have lost its humidity in the seed zone,” he says. “Trapping it would have been achieved at no additional cost by using dead surface residues or vegetation which is nature’s superior moisture barrier.”

Further these residues are biodegradable and, as they decompose, they add soil organic matter (SOM), which stores huge amounts of water, to the soil. SOM is the foodstuff of soil microbes which, in turn, bind the soil together and stop it blowing or washing away as well as creating the pore spaces in which soil humidity can be trapped he says.

While researching soil science at Massey University 40 years ago, Dr Baker and one of his Ph.D students – former MP, Dr Ashraf Choudhary – were two of the first scientists in the world to realise the importance of retaining humidity.

They then discovered that direct drilling or no-tillage retained humidity and carbon among many advantages. No-tillage is the equivalent of keyhole surgery as opposed to ploughing which is invasive surgery.

Direct drilling of seeds causes minimal or low disturbance to the soil, traps the humidity, preserves the micro-organisms and soil life and largely prevents carbon from escaping into the atmosphere.

Further by leaving the stubble and straw from the previous crop to decompose on the surface of the ground, it helps sequester new carbon into the soil. Studies show that 15-20 percent of CO2 in the atmosphere comes from annual ploughing throughout the world.

The result of no-tillage is increased yields and the near elimination of crop failure and soil erosion. This leads to sustainable food production which can feed millions of families.

Dr Baker, who has a MAgrSc in soil science and Ph.D in agricultural engineering, researched and developed Cross Slot no-tillage drills which, resulting from his research, penetrate through crop residue or vegetation on top of the ground and sow seeds and fertiliser in different bands at the same time.

Dr Baker has spoken to the US Congress on the issue and long been an advocate of encouraging the New Zealand Government to support no-tillage as this country falls further and further behind its own goals of reducing carbon emissions.

Through his own MP, Ian McKelvie, the MP for Rangitikei, Dr Baker is calling on the Prime Minister to help feed the world by providing an incentive for farmers to purchase a no-tillage drill or engage a contractor.

In turn this initiative reduces carbon emissions, sequesters new carbon into the soil by removing it from the atmosphere, increases crop yield and creates work for at least five companies that manufacture no-tillage drills in New Zealand.

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