NEW NORWAY, Alta. – In organic farming, crop decisions revolve around weeds.
When to plant, what to plant and when to plow are all decisions based on weeds, said organic farmer Steven Snider.
“In organic, there’s no such thing as controlling weeds. You manage weeds through rotation and tillage,” he said. Snider’s family has farmed organically for the past 15 years.
The hot July days and frequent evening showers have made weeds plentiful on Snider’s farm.
“The bottom line is you’re never going to get rid of your weeds,” he said, referring to conventional farmers who use chemicals but continue to struggle with weeds each year.
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He fights weeds with tillage. Much of his equipment was once considered necessary for conventional tillage, but has been abandoned in favor of one-pass or zero tillage systems.
One of his most useful implements is a 30-ft. rotary hoe used to thin weeds after the crop has emerged. The spinning spoons of the machine, traditionally used in American row crops, are set about 1.3 centimetres deep to root out weeds. The crown of the cereal crop root is slightly deeper, at 3.3 to five cm deep, and is somewhat protected from the churning machine.
The machine does thin the cereal crop but it also knocks back weeds and gives the crop a chance to get ahead of competing plants.
It doesn’t work on shallow-rooted crops like canola nor does it control deep-rooted weeds like Canada thistle or quackgrass.
For those, Snider uses a vibra-shank cultivator with a rod weeder and mounted harrows that pull the weed roots from the ground.
The cultivator spikes, which go 10 cm into the soil, pull the long quackgrass roots to the surface. He also uses the rod weeder to create a firm seedbed.
Snider uses a Noble Blade, a tillage machine that preserves moisture and was once common in southern Alberta. The wide, flat blades cut the roots just below the surface, but allow stubble to stand and catch moisture.
An offset disc is used to turn fields of green manure, which add nitrogen to the soil. Because organic farmers can’t use conventional fertilizer, they must find other ways to add nitrogen. Generally, it is added by plowing down a crop of peas or other legumes.
Timing of the plowdown depends on the weeds. Snider lets the weeds and the crop grow as long as possible but plows before weeds go to seed.
“Typically, wild oats set seed first. That’s the marker for when to plow down.”
On a recent tour of Snider’s farm, visitors saw a 60-acre field that had a history of weed problems. The field was sown with a mixture of 60 pounds per acre of faba beans, 40 pounds per acre of peas and 30 pounds per acre of fall rye for plow down. The combination gives Snider a heavy growth and the legumes take nitrogen from the air and fix it in the soil.
Given poor fall rye prices, Snider doesn’t like to grow a lot of rye, but the tall crop usually chokes out weeds.
A typical six-year rotation starts with a plow down, then moves to a crop of fall rye. In the third year he seeds a cereal and legume mixture, typically oats and peas.
In the fourth year he seeds another plow down crop, then spring wheat and in the final year another legume and cereal mixture, usually barley and peas.
“It’s been tremendous for us,” he told the group.
Snider’s rotation is a combination of plowdown, short season crops and long season crops.
Canola isn’t included in the rotation because Snider worries about cross contamination from genetically modified crops. Canola also causes weed problems.
“There is no advantage against the weeds with the canola and then you have residual problems,” he said, pointing to a field that looks like a healthy canola crop.
Canola was seeded in the field three years ago and it’s still yellow with volunteer plants.
