Defining the terms of conservation

THE long-running wrangle over the mish-mash of terms that apply to conservation agriculture farming systems continued at the 5th World Congress on Conservation Agriculture in Brisbane.
Retired director of CIMMYT’s global conservation agriculture program Pat Wall, Mexico, said it was difficult to achieve consensus on the meanings or worth of terms such as conservation agriculture, conservation tillage, no-till, zero-till, minimum-till, stubbles, residues, straw and trash.
However, a meeting of international farming leaders at the congress attempted to bring a greater standardisation to the terminology.
“Originally in Latin America they called it no-tillage but the general consensus of the meeting was that no-tillage was a term from the past and now we are using the term conservation agriculture. Most people are pretty happy with that,” he said.
“The benefit of a definition is that if I tell anybody we are talking about conservation agriculture they understand what I mean. If we don’t have that understanding then it is completely worthless.”
Dr Wall said there were always pressures on the definition because there were farmers who couldn’t meet all the requirements of the system.
He said the meeting resisted calls for the definition to be watered down to accommodate such shortcomings.
“For instance some have been saying small farmers can’t keep residues so residues shouldn’t be part of the definition of conservation agriculture,” he said.
“But we can’t do that. If you are not keeping the residues, call it something else.”
Dr Wall said most people didn’t have a perfect conservation farming system, so he recommended they stick with conservation agriculture as the core term then add further definition to explain their systems better.
“For instance you might say you have a conservation agriculture system but you don’t have rotation yet,” he said.
“Or you might add that you are grazing most of the residues or you have to plough it every few years. You need to say that so people understand better.
“If people can say they are doing conservation agriculture and then qualify it by saying they disturb 15 percent of the land, leave 70pc residue cover and run a wheat/bean rotation, it gives is a pretty good understanding.”
Dr Wall said there was widespread agreement that the term minimum tillage – which was commonly used in Australia - was too imprecise and meant different things to different people.
“I have come across people in India who used to do 14 passes with a plough and who now do eight and they call that minimum tillage. So it is a very nebulous thing and not a very worthwhile term,” he said.
Dr Wall said language differences further complicated the issue.
“In the European Union when they talk about “agriculture de conservation” people there think they are talking about physical structures such as contours,” he said.
“In Mexico for conservation agriculture they use the term conservation tillage. Then they shorten it and just talk about tillage. So when they say tillage they are often referring to conservation agriculture which seems a contradiction.”


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