picloram and grazeon?

goudanandaApril 29, 2010

Hello, this is my first post to this forum and I'd like to thank all of the contributors over the last year. I've poured through this archive and learned alot that's allowed me to be successful at vermicomposting so far. In the future, I'll make a detailed post about what I'm doing and include pictures.

My question is this. My herd lives off of restaurant vegetable scraps and leaves that I collect in fall. My small farm is growing and I'm experimenting with outdoor windrows. I hear again and again that manure is an excellent source of worm food and having a large amount of worms/compost appeals to me. Being able to bring in truckloads of curing horse or cow manure and feed it to the worms and harvest later for free sounds wonderful. This biomass would be a great input.

My concern is picloram and grazeon. In Austin this past summer we had a bad drought. Farmers were importing hay from farther and farther away and these broadleaf weedkillers are sometimes sprayed on fields where hay is harvested. The problem I'm told is that both of them pass through the animals without being broken down and even hot composting the manure will give you perfectly good compost that you can't grow vegetables in. It's still in the compost and still an issue.

I know of no one off hand that uses manure as a source of compost materials here locally due to this. I do know that large scale nurseries that sell compost test for picloram and grazeon but the tests are expensive and apparently not reasonable for a backyarder like myself.

This leads me to...worms and bioremediation. I've seen videos that show how earthworms are being used to clean land as part of bioremediation. I've also heard that ef's or redworms will clean things like lead out of the materials they consume. So, my question is...if I'm doing these large outdoor windrows and add some manure, if picloram or grazeon are present will the worms deal with it? I would only harvest once every 6 months or so and have plenty of time for them to consume the material. Need I worry about these two weedkillers?

Thanks in advance for any input!


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...snip.... However, in recent years, there have been several cases of significant soybean injury as a result of manure applications from livestock fed ditch hay that was treated with picloram or clopyralid. This injury has reduced grain yields, and in some cases, resulted in total yield loss.
...snip....Aminopyralid is in the same herbicide family as picloram and clopyralid, and poses the same potential to cause injury to broadleaf crops from contaminated manures. However, sensitive crop injury from aminopyralid contaminated manure has not yet been reported in Minnesota
...snip....When animals are fed ditch hay that has been treated with either picloram or clopyralid, these chemicals pass quickly through the animal without significant degradation and end up in the manure via the urine, usually within a day or two. ...snip.... However, if sensitive crops (i.e. soybeans, lentils, peas, legumes, potatoes, tomatoes or peppers) are planted in fields where contaminated manure has been applied, injury or crop death can occur.
...snip....Both picloram and clopyralid are persistent and mobile in the soil....snip....Composting or storing manure that contains clopyralid, picloram, and/or aminopyralid may not speed herbicide degradation, as these products do not break down quickly in compost.
....snip....In laboratory tests, picloram causes damage to the liver, kidney, and spleen. Other adverse effects observed in laboratory tests include embryo loss in pregnant rabbits, and testicular atrophy in male rats. The combination of picloram and 2,4-D causes birth defects and decreases birth weights in mice.....snip...In tests of subchronic (21-day) dermal(skin) exposure in rabbits, picloram caused swelling and redness at every dose
level tested.
SOUNDS LIKE worms might ingest the material through soil or water.No mention of changes, but the microbial action in a compost pile will not change the material, so I'm guessing that a worm's digestive microbes/enzymes will likewise not change the material.
SOUNDS LIKE worms might be affected in the same way mice and rabbits are ... if the worms either die or do not reproduce, they will not effectively compost the material.
THIS STUFF SOUNDS VERY TOXIC. AMAZED THAT ITS USE IS STILL ALLOWED. Can you find horse owners who refuse to use hay/grass sprayed with this stuff? How about 4-H clubs as a source of fertilizer/compost?

Here is a link that might be useful: use caution

    Bookmark   April 29, 2010 at 9:45PM
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At issue is the fact that if I ask most farmers they're unconcerned about this stuff. If they're already running an organic operation they will sell their manure or compost themselves. If I'm dealing with a guy who has horse stalls for extra income he's not in the least concerned with the hay he feeds as long as it's cheap.

Asking a farmer if he uses dewormers, if the feed is organic or contains herbicides or pesticides seems tantamount to insulting to some. They'll answer no but then I'm not always sure they know where the hay comes from since they were importing it from further and further away due to last summers drought.

I can search around, find something else. In TX there are lots of cattle and horses. The organic operations usually pasture their animals so the manure is already out in the fields. Any manure will do, I just have to do lots of research and find someone sympathetic to my cause. Having a way to "clean" the material saves lots of biomass and provides a higher quality product for locals to use.

I'm unfamiliar with 4-H clubs but any tips are great.

    Bookmark   April 30, 2010 at 1:37AM
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This article is not about compost worms, but worms raised for fish bait. But it is a huge operation and the man feeds his 'herd' entirely with corn. If there are other kinds of agricultural 'waste', that might also be an alternate food source.
....snip....Durant grows 300 acres of corn here, to feed his worms, .....snip...he is clearly making money. A truckload of worms can be worth $30,000 wholesale, and a truck is on the road to customers at least weekly.

Here is a link that might be useful: A worm farm rewrites the start-up rules

    Bookmark   April 30, 2010 at 2:23AM
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Thanks for the link Barb, a very interesting read!

    Bookmark   April 30, 2010 at 10:53AM
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Pete ... found another link ... looks like this stuff lasts in the soil after a treatment and will continue to affect the hay/grass grown on that soil for several years. YIKES! That means that even if your manure supplier assures you that his hay/grass feed was not sprayed with herbicide, the effect will still be there in the manure. In the articles that I read, didn't find anything about the effect on soil-based critters. But worms and soil biology are mostly invisible ... the effect on the $$$ bottom line is not a clear cause/effect path.
Herbicide Carryover in Hay, Manure, Compost, and Grass Clippings
....snip.... the forage can be safely consumed by horses and livestock  including livestock produced for human consumption. These herbicides pass through the animalÂs digestive tract and are excreted in urine and manure. They can remain active in the manure even after it is composted. They can also remain active on hay, straw, and grass clippings taken from treated areas. The herbicides leach into the soil with rainfall, irrigation, and dew. As with many other herbicides, they can remain active in the treated soil.
....snip.....Crops known to be sensitive to picloram, clopyralid, or aminopyralid are: Beans; Carrots; Compositae family; Cotton; Dahlias; Eggplant; Flowers, in general; Grapes; Legumes; Lettuce; Marigolds; Mushrooms; Peas; Peppers; Potatoes; Roses, some types; Spinach; Sugar beets; Strawberries; Sunflowers; Tobacco; Tomatoes; Umbelliferae family; Vegetables, in general.
....snip....Livestock and Horse Owners -- If you buy hay for your animals, ask the farmer or seller which herbicides, if any, were used in producing the hay. Consult a copy of the herbicide label from a farmer or online. A simple indicator that these herbicides were not used in the production of hay is the presence of legumes, such as lespedeza, clovers, or alfalfa. If the hay has legumes in it, it has not been treated with any of these herbicides. The absence of legumes in hay, however, does not mean that these herbicides are present. If you do not know the herbicide "history" of the hay, do not sell or give away the manure from animals who consumed the hay for use in rowing plants or to make compost as it may contain one of the herbicides of concern. Manures that contain these herbicides can be safely spread on grass pastures or grass hayfields. Note: It takes 4 to 7 days for most animals digestive tracts to clear and the manure produced to be free of any herbicide residue.

Here is a link that might be useful: Herbicide Carryover in Hay, Manure, Compost, and Grass Clippings

    Bookmark   May 1, 2010 at 10:33AM
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greginnd(Z4 ND)

I've done a lot of research lately on this herbicide. It is a problem when folks harvest hay from roadsides and ditches. That is where picloram (trade name Tordon) is most often sprayed. It does not affect grasses at all but kills sensitive broadleaf plants. Tomatoes and beans are particularly sensitive.

The bad news is that there are no good ways to do bioremediation. Worms don't eat the stuff and microbes break it down very slowly. So it can persist in the soil for years. It is most quickly degraded by sunlight. So, if you can till contaminated soil every couple of weeks over a summer it may help to alleviate the problem.

The good news is that it is really non-toxic to animals (and us). It has a similar LD50 as table salt (lethal dose that kills 50% of the test animals). It rapidly is excreted through the urine unmetabolized by mammals. Hence the problems with it showing up in manure. Vegetables that grow in soil with picloram are edible and safe. You can grow wheat and corn just fine! It will not affect them.

If you have contaminated garden plots or compost the easiest way to test for it is to do a bioassay. Take some of the suspected soil or suspected compost mixed with potting mix (~2:1) and pot it up. Plant some beans or peas in it. Plant some also in pure potting soil for comparison. Let them grow for about 4 weeks or so until you see 2 or 3 sets of true leaves. If they grow normally the soil is fine. Beans and peas are sensitive to picloram at the part per billion concentration (very low). So if they don't show growth problems the herbicide is essentially gone.

Be wary of "ditch hay".

    Bookmark   June 19, 2012 at 5:51PM
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Normally I hate it when someone revives a long dead thread. But in this case it is great you posted because you brought new factual, helpful, useful information to the subject. The whole if a bean will grow it is safe and if a bean will not grow it is not safe is a great money saving tool that everybody can use. It was a pretty esoteric yet important topic. Please post more things of interest on this site.

    Bookmark   June 21, 2012 at 1:30AM
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dowbright(z6 in Missouri)

Personally, the things we do to this planet we live on, and to the creatures and plants that inhabit it and feed us and fertilize our gardens, and the myths that persist about the benefits of huge agro-culture and how good it is...

It sickens me. It's the only reason I'm glad to be almost 60! When things really go to hell biologically on earth, I hope I won't be around to worry about young family members who are just beginning their lives, and the family kids who will come of age in a decade or so.

The ocean environment and loss of the Arctic Circle and the constant production of plastic and poisons that don't break down...not to mention pharmaceuticals in our water and genetically altered seed and more...and the plethora of chemicals that are now in our ground water and lakes and rivers...


The fact that this particular toxin is non-toxic to animals but is toxic to the soil bums me out. I don't understand the world. I don't understand the cries from the right to eliminate the EPA and any kind of standards. To REMOVE even our minor regulations!

I think this world will end, and not in a good way. I hope i'm not around. Though it seems another Dust Bowl is developing, and woe to the economy and everything else if this happens. Starvation and bad water are in the U.S.'s future, if we let this continue. Scientists already know it's too late to reverse.


    Bookmark   July 13, 2012 at 1:48AM
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