CARMAN, Man. – They don’t seem like a bunch of radicals.
Their crop tour is much the same as every other July crop tour, in which farmers and agrologists clamber aboard wagons to be pulled around plots of experimentally grown crops.
But the crop plots these public sector scientists are showing off are an attempt to undermine the chemical empire that they believe farmers are slaves to. They’re arguing a revolutionary departure from what most farmers practise.
If they can convince enough farmers to try chemical-free production, some farm inputs might not be as necessary as farmers tend to believe.
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“We’re making a statement by hosting this sort of a day and suggesting that we want to change the way we do things,” said University of Manitoba researcher Rene Van Acker.
Van Acker and other scientists from the university, from Manitoba’s agriculture department and from Agriculture Canada have been developing methods of profitably growing crops without heavy use of commercial fertilizers, herbicides and insecticides. Even though they are in the early years of creating sustainable systems, they are discovering many reasons to believe that intelligent management can replace many expensive inputs.
“We want knowledge-based agriculture,” said Van Acker during the day-long tour, which had no corporate sponsorship.
“There is an awful lot of information out there that is not being captured and extended, because people weren’t being encouraged to capture that information.”
Here are some observations the researchers at Carman have made.
- Intercropping: If a number of crops are grown on the same land, the weed counts dramatically decline.
“As you get more species, you get more stability,” said Van Acker.
Researchers planted various combinations of peas, wheat and canola in a number of plots. In the herbicide-free plots the single-crop plots were quite weedy. Two crops in one plot substantially reduced the amount of weeds. Three virtually eliminated weeds.
This principle has been noted and used in hay production, in which a number of species are mixed together.
But it is not done in annual cropping because of the difficulty separating the grains after harvest and finding varieties that can be seeded jointly and mature together.
But Van Acker said dealing with those problems is easier in the long term than dealing with a herbicide reliant system that encounters ever increasing numbers of herbicide-resistant weeds.
“There are lots of practical, engineering problems,” said Van Acker.
“But engineering problems are immensely more solvable than biological problems.”
- Rotations: U of M weed scientist Martin Entz has been studying the role of rotations in weed suppression. He compared a wheat-canola rotation to a wheat-canola-oats rotation and found dramatically different results.
The addition of oats drastically reduced the weeds in the fields.
Adding nitrogen-fixing forages such as alfalfa also reduced the amount of fertilizer needed, though alfalfa can be a greedy consumer of nutrients.
Reduced tillage also cramped the ability of weeds to grow. Leaving the weed seedbed undisturbed leaves many buried too deeply or in imperfect conditions, allowing the crop to get off to a better start. Undisturbed weed seeds are also more vulnerable to soil microorganisms.
- Reduced insecticide use: Manitoba Agriculture entomologist John Gavloski said spraying entire fields with insecticides may not be necessary.
Preliminary tests with strip and perimeter spraying suggest that big bug populations can be knocked down with less insecticide than is generally used.
Many insects fly all over a field. Others, like grasshoppers, jump all over the place. Treating strips of crop, instead of the entire area, is enough to get a lethal dose into many bugs, saving half the chemical cost.
Spraying only around the edge of a field can be an effective way of killing bugs that invade from the ditches and surrounding fields.
The cropping pattern is also essential. Taking away a necessary food source limits some bug populations.
“Crop rotation is a major strategy,” said Gavloski.
Researchers are trying to discover what rotations most effectively stop bug breakouts.
Insects can also be countered by developing resistant crops, like wheat midge-resistant wheat.
U of M weed scientist Gary Martens said much herbicide cost can be reduced if producers focus on spraying only weedy patches, rather than the whole field.
- Conservative emergence of weeds: Van Acker said most producers believe weeds continually flush throughout the growing season, so the seeding date is only a limited method of controlling weeds. But he showed crop plots seeded on staggered dates that had radically different weed counts.
Wild oats, which ran riot in early seeded crops, were virtually absent in early summer-seeded crops. That suggests weeds may have conservative flush patterns and that, in the case of wild oats, a later seeding date can eliminate much of the problem.
Entz said an oats crop such as AC Assiniboia can be generally seeded late and have a good chance of missing a big wild oats problem.
- Reconsidering everything: Replacing the present input-heavy system with a knowledge-heavy system will not be easy or fast. But developing a system that demands less financial investment from farmers is essential.
Farmers have relied too heavily on chemical pesticides and fertilizers and ignored management techniques that could produce the same result, Van Acker said.
Inputs demand a lot of investment, and that means every crop that is seeded exposes the farmer to risk if the crop fails or prices collapse.
“Your risk position is huge now,” said Van Acker.
“We have to get out of that model. We import technology, we jettison knowledge and we lose value and control of the farm.”
He said farm gross revenues have risen dramatically in the past century, but so have farm costs. The net return for farmers has not increased.
Focusing on profit and limiting exposure makes more sense than focusing on yield alone, he said.
