National Organic Program regulation 205.202c requires an organic field or growing area to have" distinct, defined boundaries and buffer zones such as runoff diversions to prevent the unintended application of a prohibited substance to the crop or contact with a prohibited substance applied to adjoining land that is not under organic management." This is one of the many federal rules designed to minimize an organic farm’s risk of contamination from the surrounding landscape and maintain its integrity over the long haul.

A buffer will act as a barrier and filter, reducing or preventing the movement of unapproved chemical substances (i.e., pesticides, herbicides and fertilizers) onto your organic cropland. The unwanted movement of these substances, or drift, is a fact of life. Research has shown that the extent to which it occurs depends on the substance’s chemical formulation, how it is applied, how much is applied with respect to volume and concentration and the weather conditions at the time of application. Pesticide drift seems to have received the most attention due to its potential impact on human health, and aerial pesticide applications are (no surprise) a significant source of drift. It’s estimated that 5 to 75 percent of any aerially applied pesticide lands on nontarget areas that reside from 300 feet to over 5,000 feet from the intended target area. Pesticide drift has also been documented with ground-level applications: up to 200 feet with tractor-powered equipment, up to 740 feet with orchard mist-blowers and up to 640 feet with chemigation. Buffer zones are a tool for intercepting and capturing those unwanted chemicals.

I emphasize the importance of these zones in the prevention of unwanted drift, but they hold tremendous value for a number of other reasons, too: they increase your farmscape’s biodiversity by creating wildlife habitat and travel corridors; they harbor beneficial insects that prey on your pests and pollinate your crops; they trap wind-blown pollen from genetically modified plants; they help with soil management and maintain water quality by slowing runoff and trapping sediment; and they reduce soil erosion by slowing and blocking wind. Whether dominated by grass or native tree and shrub species, buffer zones are beneficial to you, your farm operation and your surrounding landscape.

The NOP does not specify how wide a buffer should be, nor does it require a buffer be in place. Rather, it leaves that decision up to you to assess your farm’s risk for contamination. Each and every farm is a unique entity surrounded by a unique landscape, and this intentionally murky buffer zone regulation is an attempt to recognize that diversity. Stricter state regulations may require a minimum buffer width if your cropland runs alongside a waterway, and state or private organic certifiers may highly recommend a minimum buffer width between your organic operation and your neighbor. Across the country, a 25 to 30-foot-wide buffer is consistently recommended as adequate enough to prevent most contamination from neighboring croplands, and the 50-foot buffer zone is gaining speed. But, your buffer dimensions should be based on those factors particular to your landscape, not what is considered generally adequate enough. Is your neighbor applying unapproved substances? If so, what, where, how and when? What is the prevailing wind direction? What type of vegetation is or will be growing in the buffer zone? Will it be low-growing herbaceous plants or 30-foot trees? What is the slope between that conventional cropland and your organic cropland? How responsible is your neighbor and how well do you communicate?

Keep in mind the extent to which drift can occur, and do your homework to ensure adequate protection for your investments. There are many published, independent assessments of buffer zones and how they function under various conditions. Pay a visit to your neighbor and sit down over a cup of coffee to discuss crop management practices. Then, do some research. It is not your neighbor’s, certifying agent’s or government’s responsibility to safeguard your crops; it is yours. If contamination is suspected and residue testing demonstrates the presence of a prohibited substance at a level greater than 5 percent of the EPA’s tolerance for that residue, your crop cannot be sold as organic (NOP regulation 205.671). The last thing you want is to learn your crop is significantly coated with a nonorganic residue. Not only is it a drop in revenue, it is a blow to your farm’s integrity.

You must include buffer zone details (including maps, an adjoining land use verification form and signed statement from your neighbor) in your farm’s organic system plan. Those zones will then have to be verified and approved by an organic inspector. Keep in mind that buffer zones do not have to be a complete loss with respect to income. You can sell a crop grown within a designated buffer, but its sale must be explicitly documented, and it absolutely cannot be sold as organic.

Organic farming takes a tremendous amount of effort and you don’t want that effort to go down the drain because you did not allow for enough space between you and your neighbors. Talk with your neighbors, and as long as you take adequate steps to prevent drift from occurring, you will not lose your certification.

The author is a biologist who lives and farms in Vermont’s Northeast Kingdom.