Rethinking Weeds - What Are Your Weeds Telling You?
When we see weeds as symptoms, They can help us find the root of the problem
a young lanceleaf ragweed (not flowering)
The last time you had a fever, did you reach for the bottle of Advil? That used to be a common practice - taking an anti-inflammatory to reduce the fever. Some medical professionals recommend new advice - "let the fever do its job.” Because the fever isn't the problem, a fever is the cavalry riding in to fight those invaders. What happens if we disrupt that natural process with an anti-inflammatory? I like to think of weeds like a fever - they’re the first line of defense when our soil is sick. If we can get to the bottom of why those weeds are there, we can help our soil heal.
Weeds. It’s funny how we’re drawn to them like a heat-seeking missile. I can recall many interactions with a landowner that went something like this: “What is that weed? And “How do I kill it?” Maybe we’re not asking the right questions, because I’m not sure we’re winning the war on weeds. What would happen if we thought about those weeds the same way we think about fever - a symptom?
That was the question posed at a ranch I was working on. Our fever was lanceleaf ragweed. A native annual that appeared abundant on the uplands, particularly in the dormant season where it cast a dismal gray across the grassland. It couldn’t be ignored. The abundance of the weed made us all wonder, “Why is this plant here?”
By asking the right questions we can get to the root of the problem. If you find a weed in your pasture or field, here are a few questions you can start with.
1. Are these weeds telling us the whole story?
Ok, it can be easy to see a few weeds and see a problem. For us, that lanceleaf ragweed was impossible to ignore. But how abundant are those weeds? From the road, those weeds may look like they’re taking over, but what about when you walk through and look down? Is it a solid stand or is it scattered? It’s important to put that weed in context. If it’s abundant and tells a pretty good story for the overall pasture or field then it’s time to get curious. In the lanceleaf’s case, it looked pretty abundant from the road, but when we got out and walked through we noticed that the ragweed wasn’t choking out the grass. Was the lanceleaf ragweed affecting our grass in any way? How long had it been there and was it increasing or decreasing over time? Those were questions we didn’t have answers to, at least not yet.
the view looking down at the skeletons of lanceleaf ragweed scattered through the warm season grasses
The view looking across the paddock. The skeletons of the prior year’s lanceleaf ragweed are scattered throughout the grasses, but is not a solid stand
2. Are these weeds increasing or decreasing over time?
A great way to answer this is to get a good baseline by setting up a transect. A transect allows you to return to the same spot and monitor your progress over time. This can be as simple as taking a photo from the same spot looking down and looking across the field. You just want to make sure you have a GPS, fence post, or some other way to mark your spot so you can return to it. Have questions about setting up a transect? Drop us a line.
3. Who’s winning?
Are your weeds outcompeting your desired crop or grass? We can find out with a tool called a refractometer. A refractometer measures sugars and dissolved solids (brix) in a leaf giving us an idea of how well that plant is photosynthesizing. If the brix is higher in our weed than our desired grass then that’s a good indication that our weed is winning. Check out Integrity Soil’s Guide to learn how to use a refractometer.
A refractometer is a great tool for measuring plant health and how well our plant is doing its job
4. Is it on the menu?
Are livestock eating that weed? Even if a plant doesn’t make up a significant proportion of a diet, it can still be valuable as medicine. Many plants produce phytonutrients, valuable compounds that have medicinal properties for grazing livestock (check out Dr. Fred Provenza’s book Nourishment). If livestock have access to weeds they can self-medicate. Something to think about when you feel the urge to grab the sprayer! For our situation with the lanceleaf, the cattle, sheep, and goats weren’t interested in it.
Number 4: Why?
If we’ve looked across the pasture, noticed an abundant weed, and decided it’s either a potential problem or could be telling us something then the next question to ask is “Why?” Why is this “fever” here in the first place? Is this weed indicating a more serious issue in our soil, could it even be fighting a problem in our soil? So why do weeds occur? What can a weed tell us about the health of our soil? We’ll be diving into that in our next blog, stay tuned!
