Crop Rotation on Organic Farms
National Organic Program Standards
Organic producers are required under the National Organic Program (NOP) rules to choose crop rotations on the farm whether they grow field crops, vegetables, hay, cover crops, or all of the above. The NOP defines “crop rotation as, the practice of alternating the annual crops grown on a specific field in a planned pattern or sequence in successive crop years so that crops of the same species or family are not grown repeatedly without interruption on the same field. Perennial cropping systems employ means such as alley cropping, intercropping, and hedgerows to introduce biological diversity in lieu of crop rotation.” Long-term three to seven year rotations provide the most benefit, but short-term rotations may also be compliant. While crop rotation is part of the rule and is an integral part of the Organic System Plan (which is considered incomplete without a plan), there is no one right way to create a compliant and successful crop rotation plan. Simply including a fallow period could be a start, but a sustainable rotation will require more diversity over the long run. Organic production systems will have difficulty meeting crop nutrition needs if crops that require high levels of fertility are grown frequently. Heavy feeders (e.g., lettuces, tomatoes, peppers, corn, etc.) produce more when rotated with light feeders (e.g., carrots, turnips, radishes, beets, etc.) and nitrogen-fixing legumes.
National Organic Program Crop Rotation Practice Standard
National Organic Program (NOP) Crop Rotation (§ 205.205) is defined as “alternating annual crops grown on a specific field in a planned pattern or sequence in successive crop years so that crops of the same species or family are not grown repeatedly without interruption on the same field.” NOP § 205.205 states that a producer must implement a crop rotation including but not limited to sod, cover crops, green manure crops, and catch crops that provide the following functions that are applicable to the operation:
Maintain and Improve Organic Matter
To maintain or increase organic matter in the soil, include sod-forming crops such as perennial grasses (rye) and legumes (alfalfa). Due to their extensive root system, sod crops in rotation build soil organic matter whether they are used as green manures or harvested. In addition, include green manure crops to add organic matter and nutrients to the soil.
Provide Pest Management
To suppress insect pests, diseases, and weeds include crops in different families to break up pest and disease cycles. If diseases exist in the field, then planting less susceptible crops should be included in the crop rotation. Following a cool season crop with a warm season crop allows the grower to alternate tillage thereby affecting weed germination.
Manage Deficient or Execess Plant Nutrients
To manage deficient or excess plant nutrients include a green manure crop in the rotation. Alternate nitrogen fixing crops (e.g., legumes such as peas, soybeans, alfalfa, clovers) followed by high nitrogen demanding crops (e.g., corn, winter wheat, vegetables).
Provide Soil Erosion
To prevent soil erosion, include cover crops in the rotation to help provide continuous soil cover. Use a mix of crops and cultural practices that minimizes the amount of time that soil is bare.
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Topics Within This Chapter:
- Introduction Crop Rotation on Organic Farms
- National Organic Program Standards
- Benefits and Limitations of Crop Rotation
- Management of Diseases with Crop Rotation
- Management of Insect Pests with Crop Rotation
- Mangaement of Nematodes with Crop Rotation
- Management of Weeds with Crop Rotation
- Crop Rotation Considerations