Crop Rotation -The Key to Organic Farming

One of the keys to success on any farm will be to have a good crop rotation. Organic farmers depend on their crop rotation to boost yields and to manage pests. Crop rotations can be as simple as having 2 different crops that alternate, or a multi-year plan of several crops and cover crops in a planned sequence to complement each crop in the rotation.

There are many considerations when planning the crop rotation.

1. What are the needs on the farm – feed, straw, and pasture.
2. What are the market opportunities in the next couple years.
3. What are the insect, disease, weed management opportunities.
4. What are the soil quality needs?

Farm Needs

The first need is always to be able to meet the needs of the whole farm system. For example if the farm has a dairy herd there needs to be enough hay or silage each year to feed the herd. Similarly for grain unless there are opportunities to buy feed for less than the cost to grow it. Straw for bedding or pasture requirements and other similar needs always need to be addressed.

Market Opportunities

We always need to look at the anticipated markets for crops and how prices of various crops compare, in order to capture market opportunities. The price this year is irrelevant. The trick is to predict the price for next year. But price is only half of the revenue equation….

Boosting yield consistently over a number of years is the key to a good rotation. Conventional farmers can use fertilizers or pesticides to reduce fertility and pest problems, but organic farmers chose not to use many of these options.

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Insects, Disease & Weeds

Crop rotation has long been known to be the best solution to insects, such as corn rootworm. Diseases such as root rots, white mold, or nematodes can been reduced with a good crop rotation – or made worse with poor rotations. Barley, wheat and spelt are closely related and get similar diseases. They are poor choices to follow each other in rotation, but oats get very few of the same diseases so make a better rotation choice with these crops. Organic farmers who have grown several crops of soybeans in a row will experience heavy weed pressure from annual weeds. A summer-harvested crop such as cereal grains can reduce some perennial weeds by cutting them prior to seed set. It also gives an opportunity for summer tillage and cover crops to interfere with the life cycle of weeds and other pests. Crops with a dense crop canopy can out compete small annual weeds.

Soil Quality

Soil quality covers many aspects. Legume crops and cover crops can add nitrogen to soil to benefit succeeding crops. Some crops such as rye or canola can have detrimental effects on following crops of corn unless properly managed due to allelopathy or the effects on microorganisms such as mycorrhyzae. To improve soil structure chose a crop with a large volume of fine roots, such as a grass crop. Incorporating crop residues into the soil can be most valuable to building soil organic matter to feed soil microorganisms. Most bean crops have small root systems and low volume of crops residue. In general it is best to follow a grass crop with a broadleaf crop and vice versa.

There is no recipe to choosing the right crop rotation sequence for your situation, but make sure you consider the long term (5 year +) benefits to the whole farm system rather than just the costs and revenues over the next 12 months.

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