Local Authorities Yet to Recognise Soil Quality

Local Authorities Yet to Recognise Soil Quality

November 19, 2013

New Zealand local authorities are missing something when they prepare their environmental policies.

International soil scientist, Dr John Baker, says, while most local bodies have robust policies that address air and water quality, they overlook soil quality.

He points out that poor soil quality affects water quality through run off and air quality through dust.

Dr Baker, who has a MAgrSc in soil science and Ph.D in agricultural engineering from Massey University, points out the single most important factor that maintains and preserves soil quality is the biology of the soil. The food stuff for plants, soil fauna and microbes that grow in soil is its organic matter.

“Maintaining soil health is all about maintaining organic matter,” Dr Baker says. “If you want quality air and water and sustainable food production, you can’t do it without quality soil.”

“That’s why any environmental policy should include the impact of quality soil coupled with the ongoing destruction by conventional tillage.”

He warns that conventional tillage such as ploughing progressively destroys soil organic matter by oxidation and therefore regional councils and rural local authorities should be discouraging it.

Ploughing releases carbon into the atmosphere and depletes the micro-organisms which enrich the soil. Eventually it will lead to crop failure, soil erosion and famine.

“When a farmer ploughs and cultivates a paddock it releases CO2 into the atmosphere. The vast majority (95 percent) is released from soil with the other five percent coming from tractor exhausts,” Dr Baker says.

“The amount of CO2 released by cultivation during reseeding a paddock can be approximately three tonnes per hectare. Annually approximately one million hectares are reseeded in New Zealand and about 80 percent cultivated. This means we are currently releasing about 2.4 million tonnes of CO2 into the atmosphere.

“It’s important to realise that 20 percent of the CO2 in the world’s atmosphere comes from ploughing which makes it an appalling statistic.”

Further Dr Baker says it doesn’t need to happen. Instead he has researched low-disturbance no-tillage for 40 years and invented and manufactured a no-tillage drill which penetrates through crop residue on top of the ground and sows seed and fertiliser directly into unploughed ground.

“No-tillage is the equivalent of keyhole surgery as opposed to ploughing which is invasive surgery,” he says.

No-tillage causes minimal disturbance to the soil, traps the humidity, preserves micro-organisms and soil life, largely prevents carbon from escaping into the atmosphere and significantly improves crop yields.

From his Feilding plant, Dr Baker exports to 17 countries including Australia, the United States and Canada and, this year, was a finalist in the World Food Prize, announced at the US State Department in June. His technology is recognised by the United States Food and Agriculture Organisation (FAO) and the United States Department of Agriculture as the best available.

“If promoting soil quality and discouraging conventional tillage was included in all environmental policies, then local authorities would be making an investment in the future prosperity of the region because healthy soils produce greater pasture and crop yields,” he says.

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