Do We Really Need Chemicals to Control Weeds?

With seeding only a mere two weeks away (ish), every farmer’s mind whirls a million miles a minute in a thousand different directions. Do I have all my seed? Did I order enough fertilizer? When will I get into the field? Is my equipment ready to go? What chemicals am I using? And this is only scratching the surface. With seeding creeping up all too quickly, focusing on one thing at a time is vital to keeping your sanity and to ensuring you have all your bases covered. Right now, I’m concentrating on what may be the most important factor in the entire growing season: controlling weeds.

That may sound a little boring, focusing on a task that has been done for thousands of years. But if you cannot keep weeds under control, the crop will simply not be successful. Moreover, controlling weeds is a complicated and frustrating task.

I will admit, when I first graduated from university in 2010, I thought weeds were easy. Just throw in some herbicides and take care of ’em! Since then, I have learned that nothing about weeds is simple. On our farm, we use herbicides as the primary tool in controlling weeds. Of course, other cultural practices are important, such as rotating crops so that no crop is planted in the same field two years in a row (3-4 years between is better), using good quality, clean seed that emerges vigorously, seeding as early as we can to give our crops a head start, ensuring the drill doesn’t have any misses or blocked rows to get the ground covered as quickly as possible, and growing competitive crops that crowd out the weeds wherever possible. Yet, the only reason these practices all work is because of the use of herbicides.

Years ago, when my father was a child, farming was very different. Herbicides were more or less non-existent, except for the old standard: 2,4-D. However, it was so expensive to use that it was really only used for patch treatments to clean up problem areas. Instead of herbicides, the main source of weed control was tillage. Ripping the ground up and leaving it black was a summer-long job for many farmers, with half the farm in this “summerfallow” and half of it seeded to crops like wheat and barley. While this practice did work to control weeds, it was very hard on the soil, causing topsoil to erode from wind and water, and microorganisms in the soil struggled to survive. The famous “Dust Bowl” of the 1930’s was largely caused by tillage. But it was all they had to control weeds; without which, agriculture was doomed.

Everything changed with the advent of glyphosate, or “Roundup”, in the 1970s. This broad-spectrum herbicide changed the world, with its ability to control dozens of weeds at relatively low doses. While it was initially used sparingly due to its high cost, as the price came down, farmers were finally able to move away from tillage and use chemicals to control weeds instead.

I realize this is a tough issue for many of you non-farmers out there. Why do we use herbicides at all? Well, the alternative is organic farming, which does not use herbicides,

but instead uses tillage. Please recognize that the advent of all of our herbicides in the 1980s and 1990s is the reason we are able to practice no-till, which has saved our soils in Western Canada. We rarely have to till at all anymore, which protects our fragile topsoil from the ravages of high winds and heavy rainfall. Is their a resource more precious on this Earth than our soil? Moreover, the herbicides we use are largely safe (yes, even 2,4-D) and, as long as used as directed, have never caused any known injury even to we farmers applying them.

Certainly, herbicides do have their issues. Some were shown to be toxic, but they were removed from sale years ago. All of the herbicides we use are constantly monitored and must go through stringent safety and environmental testing before they are released for

use. Another issue with herbicides that has cropped up in recent years is weeds’ ability to adapt to them. Unfortunately, many farmers choose to grow the same crops over and over again on the same field, using the same herbicides multiple times per year. A random weed just may happen to have a genetic mutation that allows it to survive the application. That weed survives, spreads its seeds, and grows to a larger population the next year. This can quickly spread over an entire field, or more, in just a few years. Glyphosate, one of the world’s greatest discoveries, has become ineffective in many areas because of this.

Herbicide resistance isn’t the fault of the company that produces it. Sure, they could have done a better job of explaining to farmers the risk of overapplication. The onus, however, is on the farmer. It is his/her land and that farmer should have thought about the risk of growing the same cropping system over and over again. It is an unfortunate situation.

Because of the risk of resistance, we use a lot of different herbicides on our farm. There are many different “groups” of herbicides that affect plants in different ways. For example,
2,4-D is a Group 4, which basically causes the plant to grow itself to death. Grasses generally aren’t affected by it, so it can be used on crops like wheat and barley. Using this group over and over on the same field can result in the weeds adapting to it, so we rotate Group 4s with other groups, like Group 2, 6, 27 and some others. This takes careful management, but it is very effective.

Some herbicides are sprayed on top of the crop, while some are sprayed on the soil before seeding, and still others are dry products mixed into the soil in the fall before seeding. All have their fit, and using the right mixture can kill the weeds your specific fields have difficulties with.

Mother Nature has an incredible ability to adapt to whatever we throw at her, and controlling weeds is somewhat of a treadmill; every time we come up with a new way to kill them, they come up with a way to survive it. Frustratingly, they seem to slowly be winning the war, with herbicide resistance popping up more and more every year.

So, every spring I go through the hundreds of different products that are out there to try and determine which ones I will use that year. As I learn more and more about weeds and herbicides, I learn better ways to control them, especially the ones that plague our area, like kochia, wild oats, foxtail barley, stinkweed, Canada thistle, wild buckwheat, and many, many others. Weeds are crafty plants that always seem to find a way to overcome every hurdle you throw at it; but if we challenge them every year with different crops, different herbicides, and different ideas, we can beat them. Agriculture is all about problem solving, and coming up with new and innovative ways to reinvent the wheel. Never stop thinking and never stop learning, and you just may have a shot at making a go of this thing we call farming.

What do you think about herbicides? Should we be using them, or should we go back to tillage? Write your comments below!