Submitted by Alberta Agriculture
Early weed control has many benefits as weeds compete with crops for nutrients, water and light.
“Research on weeds germinating before the crop emerges as compared to crop emerging before the weeds shows a very significant drop in yield loss when the crop emerges prior to the weeds,” says Harry Brook, crops specialist, Alberta Agriculture and Forestry. “A pre-seed burnoff with a herbicide or final cultivation should be as close to the seeding activity as possible to prevent weeds getting the jump on the crop.”
All crops have a critical weed control period, which is the time when the crop is susceptible to significant yield loss from weed competition. The critical weed control period for canola is around 17-38 days after emergence. Peas can be as early as two weeks after emergence. “Other, more competitive crops, like the cereals, have a less defined critical period,” says Brook. “Corn’s critical period depends more on nitrogen availability than anything else. If you can keep the weed pressure down until the critical period is passed, you minimize yield losses from weed competition.”
Field scouting is essential to give an edge battling weeds, notes Brook. “Field scouting tells you what weeds are present and their density. Once a field has been scouted and a weed problem identified, the degree of threat needs to be assessed. An example of an early, non- yield threatening weed is whitlow grass. It’s a very slow growing, small plant that bolts and goes to seed, usually before seeding. It’s not a direct threat to the crop. However, if other weedy plants are also present in sufficient numbers and are a threat to yield, you can choose an appropriate control measure.”
Winter annual weeds like stinkweed, narrow-leaved hawk’s-beard, shepherd’s purse, scentless chamomile and many others can start growing in the fall. They overwinter as a small rosette but are then quickly able to go to seed once spring arrives. “Control of them in the spring requires very early action. You need to know the weeds present to choose the best control method. Crop volunteers from previous years are also an increasingly problematic weed obstacle. Volunteer canola is one of our top weed control issues every year. These and other problem weeds will require additional products when applying a spring burnoff with glyphosate.”
To get the best result from any early herbicide application, Brook says the herbicide must be applied when the weeds are actively growing. “Under cool or cold conditions you can expect poor results from the spray as the target weeds are either dormant or growing too slowly. They cannot absorb and translocate enough active ingredient to kill them. Weeds also have to be large enough to absorb enough herbicide to be killed. Low spray volumes and coarse sprays can lead to insufficient herbicide landing on the plants. Best temperatures for application should ideally be above 12⁰-15⁰ C, when the plants are actively photosynthesizing. If it was frosty in the morning, waiting until a warm afternoon will improve efficacy.”
Another tool in weed control is the competitive nature of the crop itself. “Highly competitive crops can reduce the effects of weeds on yield. Once a crop canopy has covered the soil, sunlight no longer can penetrate to the ground and weeds stop germinating. Heavier seeding rates can also squeeze out weeds. Hybrid canola and barley are our two most competitive crops. You still have to choose a competitive variety. Semi-dwarf barleys are less competitive than regular barleys. Heavier seeding rates always increase the crop’s competitive nature against weeds. Thin crops allow light to hit the ground, stimulating more weed growth.”
For more information, contact the Alberta Ag-Info Centre at 310-FARM (3276).
Moving equipment on public roads
When it comes to moving farm equipment on public roads, a little planning can go a long way toward preventing accidents.
“Farmers should check their route prior to starting out with farm equipment to be sure equipment will fit on all roads and bridges and that there are no low-hanging power lines along the route,” says Nicole Hornett, farm safety specialist, Alberta Agriculture and Forestry. “If equipment is too wide to fit safely into one lane, approaching traffic could clip the machinery or become blocked while crossing a bridge. Equipment that is too tall could come in contact with a power line. Use a pilot vehicle as a guide for large machinery and to warn motorists of oncoming large equipment”
For the safety of all motorists, it is highly recommended that farmers move equipment during high-visibility daylight hours and during periods of light traffic. “Avoid busy roads whenever possible, even if travel time will be longer,” says Hornett. “If your route takes you across a rural railway crossing, be aware that some crossings have poor visibility. Always stop and make sure the way is clear before crossing.”
Anyone moving equipment, particularly on public roads, should be trained in how to use the equipment. “Inexperienced operators can make mistakes when they are not familiar with the speed and maneuverability limitations of farm equipment. It’s advisable to read the operator’s manual for each machine and observe any precautions indicated for road travel. Some tractors free-wheel in higher gears, which can be very dangerous when traveling down a hill. Use lower gear ranges when climbing or descending hills.”
As well, Hornett says it’s important drivers never take extra riders on equipment. “Extra riders on farm equipment are a distraction to the operator and are at risk of falling off the machinery and being run over. Each person in the machine should be secured with a seatbelt.”
Farm machinery operators can make road travel safer for themselves and others by observing safety precautions. Travel at a speed that will allow the operator to maintain full control at all times. Slow down when making turns or rounding curves. If needed, pull over when there is a suitable area to allow backed-up traffic to pass. Make sure the area is sufficiently wide and solid enough to handle the equipment.
“Once on a public road, obey all traffic laws and signs,” says Hornett. “Always wear your seatbelt and use signal lights when turning. Never use a cell phone while transporting equipment. The distracted driving law, along with all other rules of the road, is in full effect while driving farm machinery on public roads and highways.”
This and other information on the safe transportation of farm equipment on public roads is found in Make it Safe, Make it Visible, a publication available from Alberta Agriculture and Forestry (http://www1.agric.gov.ab.ca/$Department/deptdocs.nsf/all/aet12593). Visit www.agriculture.alberta.ca/farmsafety for more information on farm safety.