WEED CONTROL AND HOW IT FITS IN

ART PASK

ESTERHAZY, SASK.

When planning a no-till weed control program, an individual has to accept a couple facts of life:

1. Weeds are opportunistic - they are always in the background waiting for their chance.
2. Weeds are a lot tougher than most of the crops that we try to grow.
3. That as a no-tiller you are a lot smarter than the average weed and you can set up a program to combat the weeds.

So before you go load up your sprayer, sit back and look at the bigger picture:

1. Take inventory of what weed problems you have, what your weed problems will be next year, and the year after.
2. Put the weed problems down as records - know what is where. Field maps, scratches in your notepad, or a program on your computer are all good ways to track your weeds.
3. Know how much of each weed you have. Do you have 1 sprout or 10 per square metre.
4. Know what the weeds really are. Become proficient at weed recognition and their growth habits.
5. Know what chemicals have been used on the land. Know which ones worked and which ones did not. Know if you have any herbicide resistance.
6. Keep track of how your weed populations are shifting. You will notice weeds that start to flourish that you never noticed before. Remember, they are opportunistic! Watch for hawks beard, wormwood, scentless chamomile, and volunteer grains. You will find your old enemies such as green foxtail and, to a lesser extent, wild oats tend to fade away.

Once you have your groundwork done, you can begin to implement your strategy.

Ask yourself, what can I grow on this field?

Match your rotation around your weeds, as well as your markets. Plan on where you want to hit your hard to kill perennial weeds, such as sow thistle in your rotation. Remember it makes more sense to hit your "hard to kills" two or three times in a rotation with a pre-harvest treatment than chasing them in-crop.

Grow a crop that the weeds do not like. If you have a broadleaf problem, such as red-root pigweed, lambs quarters, or mustards, consider seeding a crop like oats instead of canola. You will find it much cheaper to control the broadleaves in a competitive cereal crop than an oilseed. The next year you should find your broadleaf weed populations down to the level where you can grow canola with no in-crop broadleaf control needed.

Plan around your volunteers. They always seem to show up to help you when you need them the least. For example, barley in flax is easier to manage than barley in wheat.

Seriously consider forages in areas that are hard to farm, ie: wet flats, saline seeps. Weeds tend to like these areas. Forages compete well with thistles, scentless chamomile, resistant wild oats, etc. Keep in mind, forages seldom drown out, so they can provide you with multi-year weed control and still bring in a respectable income per acre.

Keep up on the varieties you use. Fast starters will give you quick ground cover. A good competitive crop will cope with most weed problems. Try increasing your seeding rates to help get a more competitive crop started, especially in your oilseeds. For example; 8 pounds of Argentine canola instead of 5, or 50 pounds of flax instead of 35, have helped us achieve a lot quicker ground cover and also higher yields.

We always try to use good agronomic practices, such as certified seed, cutting headlands where possible, cleaning equipment, etc. These are just common sense approaches that you use whether you no-till or not.

Lastly, use chemicals that match your weeds. Do not under kill, and just as important, do not overkill.

An example of a four year rotation and how it works on our farm:

Year one:

cereal - Oats

• out competes volunteer flax.
• volunteer wheat is not a serious problem.
• broadleaves are easily controlled.
• can pre-harvest if perennials pose a threat to next year's canola.
• heavy trash cover helps keep down winter annual numbers.

Year two:

Broadleaf - Canola

• uses heavy trash from oat crop to keep weeds down.
• few broadleaves, if controlled in previous crop.
• volunteer oats and wild oats are easily controlled together.
• pre-harvest tends to be unsatisfactory likely due to crop density.

Year three:

Cereal - Wheat

• volunteer canola easy to control with Rustler type burn down.
• pre-harvest can stomp on thistles and quack grass ahead of next year's flax.

Year four:

Broadleaf - Flax

• heavy trash from wheat helps keep weed population down.
• volunteer wheat easy to control.
• pre-harvest helps to kill the flax-speeding up harvest and more importantly lowers the germination of next year's volunteer flax.
• pre-harvest also takes care of any perennials that are around.

Note the rotation uses a high residue crop followed by a low residue crop. This helps prevent an over buildup of residue that tends to harbour disease and insects. Also, too much residue can create seeding problems such as wet ground, plugging boots and the like.

Note any of the crops; wheat, canola, flax, and oats are only grown one in four years so all the residue should be gone before the same crop is seeded a second time.

In this type of rotation on our farm I have found winter annual control is near impossible to do in October, as we are always combining. I have to rely on my pre-harvest to nail the early weeds and my spring burn down to control the rest. A heavy residue cover from the oats and wheat crops also help to keep the weed population down. On the canola, mustard, and flax stubbles I can get on the fields earlier to seed, and then, burn down.

So, in conclusion my weed control system is not just a load up and go spray system. Instead, that is the last thing I do. The first half, and most important part, is the planning and the last half is the actual spraying. This concept has worked much better than chasing fires. This system has proven to be effective in controlling weeds on my no-till farm.