Fields from which organic crops are harvested must have distinct, defined boundaries and buffer zones. No prohibited materials can be applied to the land for a period of 36 months prior to harvest of the organic crop. Prohibited materials include synthetic fertilizers and seeds treated with fungicides, as well as most synthetic (chemical) herbicides, pesticides, and fungicides.
Farm Maps
An accurate map of all farm acreage and production units is typically required as part of the Organic Systems Plan, which is a requirement for organic certification. Important map features include the following:
- Consistent scale
- Permanent field numbers or names
- Buildings, roads, and permanent features
- Streams, ponds, irrigation ditches
- Field boundaries
- Adjoining land use: conventional, organic, or fallow
- Buffer zones
Organic crops must be protected from contamination by prohibited substances, such as pesticides and fertilizers, used on adjoining lands. Preventing contamination usually requires a multi-pronged approach for organic systems. Strategies may include one or more of the following:
- Isolation. Fields located at substantial distances from conventional production or roadside spraying are considered to be adequately protected.
- Barriers. Tall plants and trees serve as barriers to airborne contaminants.
- Buffer zones. Buffers are used to separate adjoining crops that are conventionally managed. Crops harvested from buffer zones must be sold as conventional.
- Drainage diversion. Water runoff from conventional fields is diverted.
- Posting of property signage reading “Organic Farm: Do Not Spray” is placed at field boundaries. You may need to assume responsibility for weed control on roadsides and post signs reading “Owner Will Maintain.”
- Formal notification. Written notification of your organic status is provided to neighbors who manage adjoining lands. Copies of formal notification letters must be kept on file.
Regulations do not specify the required width for a buffer zone, but they state that buffers must be “sufficient to prevent contamination.” It is the farmer’s responsibility to assess the risks and take appropriate measures to minimize contamination. Therefore, the width of buffers must be adjusted for individual circumstances.