Thursday, May 22, 2008

Trojan Horses

Over the years, we have evolved an extensive written Pinwheel Farm Environmental Policy. It covers a dizzying array of environmental issues that ought to be considered whenever we undertake a project, to help ensure we are not creating future problems. When new, unforeseen problems arise, we re-read it and see if we need to add to or change the policies based on our experience. It is a "living document".

So I read through it, thinking about the proposed water main. What environmental policies might come into play?

At first, everything seemed fairly straight forward and obvious. Easy enough to insist that no chemical herbicides be used.

Then I read the section on biosecurity, and suddenly thought of the bulldozers. The surveyors' boots. The dump trucks. The hay bales for construction runoff mitigation.

Trojan horses.

As many weeds as we already have, there are some we don't. Some that we don't want because they are State noxious weeds, like Jimpson Weed. Some that we don't want because they are Pinwheel Farm noxious weeds, economically damaging to our wool crop, like Burdock. Probably hundreds of others we won't even know we don't want until they have colonized our farm unnoticed. Some we already have, but only in limited areas where we are aggressively controlling them, like bindweed.

How much dirt does it take to carry a weed seed? To see the garden spout up in the spring, you really wonder whether "dirt" is more seed than soil. Who knows what the illicit surveyors have already brought in? Their "gifts" could lie in waiting for years, taking us by surprise after a fire or a prticularly wet or dry season favors their sprouting.

How long can a noxious weed seed last in the soil, waiting to sprout up when conditions are exactly right? In the case of dodder or bindweed, 20 or 30 years.

Even sneakier, what about soil-borne micro-organisms? Many can last for decades in the soil. So far we have never had footrot or soremouth, both devastating sheep diseases that are soil-borne. But disease organisms can have more subtle effects. They can affect every member of the ecosystem: plants, trees, fungi, insects, birds, wildlife, other microorganisms.

When visitors walk in from the parking areas, we assume that any noxious weed seeds will fall out in the yard area, where we will notice alien plants promptly and prevent them from setting seed. If we know visitors are from other farms (excluding a few long-time "partner farms" with whome we share breeding stock and hence all associated parasites and diseases) we ask them to bring clean shoes or to use protective "booties" to prevent cross-contamination between our farms...for their safety as well as ours.

We feed hay in the barn, sheep pen, and garden areas only, where we are working frequently and can be aware of new weeds sprouting. Hay and straw often contain unwanted seeds. In fact, this is most likely how dodder found its way to our property. Dodder is a parasitic weed that the tenants allowed to proliferate on the pasture as well as in the garden. It's like a vegetative virus, reproducing not just from copious seeds with a 30-year life span, but also from any small fragment of stem that falls on a host plant. Parts of the pasture are saturated with dodder seed, waiting for propitious weather conditions to sprout. Do our neighbors want these infesting their soybean field? Construction equipment could be an insidious vector in spreading this virulent plant that is so economically devastating there is a zero tolerance for its seed in commercially marketed seed of any kind in all 50 states...the only such nationwide ban on any particular weed, to my knowledge.

Is this concern unrealistic? Actually, it's based on experience. We started out without ANY bindweed, "Mountain Mint", dodder, Sweet Annie, Moon Flower, or Japanese Hop Vine. These invasive plants have come in and established themselves, requiring untold amounts of labor every year to try to diminish their hold on the farm. One of these came in with dirt clinging to building stone that we purchased...many other plants came from that tiny bit of soil; some we welcomed; some we tolerated for a time and then eradicated them (though we still find seedlings now and then); one we will never be rid of. Some of these were first noticed by the tenants during my sabbatical, but they allowed them to spread unchecked so that they became well-established. A significant portion of our vegetable garden has been taken out of production for the ext couple years to try to contain and eradicate one of them.

We also purchased two insidious, economically devastating sheep diseases in our early ignorance of biosecurity. We have watched a friend go through the heartache of "depopulating" her sheep and goat farm due to a disease, having to wait several years for the soil to clean itself, and then begin again with new breeding stock. Such an outbreak would obliterate the extensive genetic improvement we've made in our flock. We've been working for twelve years to select a flock to exacting standards of performance, standards that are essential to our successful business. There are not other sheep available out there that meet all of our standards, because part of it is selection for thriving in our very specific micro-environment.

I'm having a hard time picturing the meticulous decontamination of every piece of personnel and equipment that crosses our border from neighboring properties that I KNOW harbor noxious weeds that we don't currently have on the pasture, like bindweed. And I know that sterilizing any fill dirt that's brought in won't stop every weed seed from sprouting...when I worked at a local greenhouse, Japanese Hop Vine sprouted regularly from every batch of soil we steam sterilized.