Many farmers and home gardeners have reported damage to vegetable and flower crops after applying horse or livestock manure, compost, hay,or grass clippings to the soil. The symptoms reported include poor seed germination; death of young plants; twisted, cupped, and elongated leaves; misshapen fruit; and reduced yields. These symptoms can be caused by other factors, including diseases, insects, and herbicide drift. Another possibility for the source of these crop injuries should also be considered:the presence of certain herbicides in the manure, compost, hay, or grass clippings applied to the soil.The Herbicides of Concern Aminopyralid, clopyralid, fluroxypyr, picloram, and triclopyr are in a class of herbicides known as pyridine carboxylic acids.
They are registered for application to pasture, grain crops, residential lawns, commercial turf, certain vegetables and fruits, and roadsides They are used to control a wide variety of broadleaf weeds including several toxic plants that can sicken or kill animals that graze them or eat them in hay. Based on USDA-EPA and European Union agency evaluations, when these herbicides are applied to hay fields or pasture, the forage can be safely consumed by horses and livestockâ€”including livestock produced for human consumption. These herbicides pass through the animalâ€™s digestive tract and are excreted in urine and manure. They can also remain active in the manure even after it is composted.http://www.ces.ncsu.edu/fletcher/progra ... ryover.pdfhttp://www.dirtdoctor.com/organic/garde ... ch/id/199/http://pubs.ext.vt.edu/2909/2909-1413/2909-1413.htmlhttp://www.pesticides.montana.edu/Refer ... edsoil.pdfhttp://orange.ces.ncsu.edu/files/librar ... ryover.pdfhttp://www.beyondpesticides.org/gateway ... cloram.htmhttp://www.beyondpesticides.org/gateway ... clopyr.htmhttp://www.beyondpesticides.org/gateway ... oxypyr.htmhttp://www.beyondpesticides.org/gateway ... yralid.htm