The House Agriculture and Forest Products Committee took testimony on a topic of great concern this week – the effects of persistent herbicides on compost. We heard from the composting community about the problems that have arisen as a result of composting horse manure, in particular, and other organic materials.
In Vermont, we have several very successful composting facilities including Green Mountain Compost (GMC), which is part of the Champlain Solid Waste District, the Vermont Compost Company in Montpelier, Champlain Valley Compost Company in Charlotte, Highfields Center for Composting in Hardwick, and Grow Compost of Vermont in Moretown.
Composting is an important part of the food cycle. In fact, the Farm to Plate Initiative includes the Farmland Access and Stewardship working group and its Close the Loop task force – a coalition working toward universal recycling. Last year, the Legislature passed Act 148, which mandates 100% removal of organic matter from the waste stream by 2020 – composting is a critical piece of that goal.
The first indication of a problem came in June of 2012 when customers contacted GMC letting them know of damage to broadleaf plants. Tomatoes and other broad leaf plants, after being planted in or amended with their compost, wilted, shriveled, and sometimes died. GMC had no idea what was happening and contacted the Vermont Agency of Agriculture, Food, and Markets (AAFM) for assistance. After testing, it was discovered that horse manure that GMC had accepted for composting was contaminated with aminopyralid, a relatively new class of herbicide. Aminopyralid, which is sold under a number of names including Milestone, is used to control weeds, such as dandelions, in hayfields, pastures, golf courses, and lawns.
This class of herbicide is called “persistent” because of its ability to remain active for prolonged periods of time and under surprising circumstances. Aminopyralid products, which are made by Dow Chemical and DuPont, remain active after having been eaten and digested by horses and gone through the heat of the composting process. In fact, its life is shorter if it is spread on the ground and subjected to sunlight or soaked in water for fifteen hours. The other interesting detail is that because these products are used on crops such as wheat and corn, they exist in food scraps like bread and pizza crust, and could affect home compost piles.
Working with the US Environmental Protection Agency (EPA) and Dow Chemical, who has been very cooperative, the AAFM has been able to test compost for the presence of aminopyralid, which is destructive when present in compost at .5 parts per billion. Dow can detect its presence down to 1 ppb and the AAFM lab down to 2ppb.
The composters have worked very hard to solve this problem. GMC reimbursed its customers for their losses, as well as the resellers of their products. It has cost them approximately $1 million. The Vermont Compost Co. has not had the same problem, it is thought, because their composting process is slower and happens at a lower heat.
The important thing for home gardeners to know is that if you are mulching your garden with compost or manure from a neighboring farm, you should check that the animals were not consuming forage or grain that was treated with aminopyralid products. Likewise, if you are using grass clippings from your lawn, make sure the lawn wasn’t treated with these products. If you have a lawn care service, they will know which products were used.
The Senate has sent two bills and one resolution for us to consider. They include a bill that would allow the delivery of raw milk by Tier 2 producers to customers at farmers’ markets. This is a small step to allow farmers another delivery option for pre-existing, prepaid customers. It may also encourage some Tier 1 producers to become Tier 2.
The second bill asks the AAFM to issue permits to farmers who wish to grow hemp. To be clear, hemp, which is a relative of marijuana, is defined as having very low levels of delta-9 tetrahydrocannabinol (THC). Hemp is being grown in Canada, as well as many other countries, and has a myriad of beneficial uses, which provide economic opportunity.
The maple grading resolution reaffirms the AAFM’s ability to promulgate rules regarding the grading and labeling of maple syrup. In Vermont, the number of maple taps has more than tripled in the last decade and our production has increased as a result. Improved technology, such as new taps, developed by UVM, and reverse osmosis, has also increased our yield and we have an abundance of maple syrup to sell. In order to market that increase, we need to sell outside Vermont, which means we must conform to international labeling requirements.
The larger producers are in favor of the change but some smaller producers have concerns. Last year, we heard from the smaller producers and were able to gain an important concession. The old grading system could continue to be displayed as a descriptor on the package as long as the new grading labels were also used.