If you are into gardening, odds are you are very careful about what you do with your soil. Composting is a good way to recycle nutrients back into the soil. Adding manure can be an especially good ingredient — or it can kill off your plants. How? More blow-back from using herbicides for weed control.
Some background
Exposure to herbicides based on glyphosate have been linked to non-Hodgkin lymphoma in humans. Lawsuits are pending. Glyphosate seemed like a good idea. It kills broad-leafed weeds, and combined with food crops that had been developed to withstand it, offered the promise of an easy way to higher crop yields.
As might have been predicted, one of the consequences of using glyphosate herbicides was that it killed off weeds with no resistance — which selectively bred for those that survived because they did have some resistance and no longer had to compete with their brethren. The chemical arms race saw farmers having to use higher doses as weeds became increasingly resistant.
It turns out — on this level at least — that resistance is NOT futile. It’s evolution in action.
This kind of selection for resistance is seen over and over; one strategy is to switch between different chemicals so that the target population doesn’t begin to adapt to any one of them. But that’s not the only problem — as we are seeing with manure.
When good sh*t turns out to be bad sh*t
I ran across this story in one of my news feeds. Yeah, occasionally Facebook lets useful material seep through. (The article notes it was updated November 5, 2021, but it appears the events described in it took place some years earlier.)
The author — David the Good — obtained a load of manure and used it on a number of different plants. They began to do really badly. To cut to the chase:
...I called the farmer who had sold me the manure and asked him if he’d sprayed anything on his hay fields. He told me he had tried a new product recommended by the University of Florida for the elimination of spiny pigweed, an obnoxious recurring weed in his pastures. “It worked really well,” he told me.
I shared that all my plants were dying and asked if he could find out what he’d sprayed. I was pretty sure I knew already, but when he sent me a picture of the label, I knew for sure.
It was Grazon, an aminopyralid-based toxin from Dow AgroSciences.
To quote from the wikipedia aminopyralid article:
Aminopyralid is a selective herbicide used for control of broadleaf weeds, especially thistles and clovers. It is in the picolinic acid family of herbicides, which also includes clopyralid, picloram, triclopyr, and several less common herbicides.[2][3] It was first registered for use in 2005, in the USA under the brand name "Milestone"[4] and later under various names starting with "Grazon".[5]In the UK it is sold under the brand names Banish, Forefront, Halcyon, Pharaoh, Pro-Banish, Runway, Synero, and Upfront.
Aminopyralid is of concern to vegetable growers, as it can enter the food chain via manure, which contains long-lasting residues of the herbicide. It affects potatoes, tomatoes, and beans, causing deformed plants, and poor or non-existent yields...
emphasis added
For extra reading, here’s a link to a 2009 EPA communication on labeling for Grazon. A 2020 bulletin from North Carolina has more information on “Herbicide Carryover in Hay, Manure, Compost, and Grass Clippings”. It’s not just manure you have to worry about.
David the Good relates in the report via Tenth Acre Farm how the manure had a wide-ranging effect on a variety of his plants and concludes with warnings on what to avoid.
“Better living through chemistry” has to be one of the more deceptive advertising campaigns ever foisted on the public — as was intended:
DuPont used the "Better Living Through Chemistry" slogan not to promote particular products, but to change viewers' opinions about the role of business in society. In the words of DuPont's advertising director, Charles Hackett, the advertisements sought to address "unspoken fears of bigness in business", which were based on "an emotional rather than a rational foundation".[3]
emphasis added
We are all involuntary participants in an ongoing experiment on the effects of chemicals on our bodies and our ecosystems. We can’t do without the products of industrial civilization — but we are far from knowing what the real costs are. (See Kauffman’s Rules 1, 2, 3, 5 and especially 7.)
Grazon and related herbicides were developed to ‘solve’ a problem: controlling weeds on pasture lands and pasturage crops. Apparently no one thought it important to study the downstream effects of these compounds once they established grazing livestock could eat treated plants with no obvious health problems.
And how many other chemicals have gotten the same kind of regulatory “oversight”? Oversight is one of those ambiguous words. You can practice oversight by overseeing something, or you can miss something critical because you overlooked it and committed an oversight.
It’s autumn in the northern hemisphere. Here’s hoping 2022 will be a good year for gardens — and that this post will save people from some real problems. If you’d heard about this, feel free to share in comments. Same if you’ve had an experience like the one described above.
And if you want to share some tips on getting gardens prepped now to be ready to go for the growing season to come. please do so as well.