What Is It? Strip cropping is a natural way to control pests without using insecticides. Unrelated crops are grown in narrow strips to increase biodiversity and maximize edge effects. Beneficial insects flourish and eat harmful bugs.
The Edge Effect: Life increases proportionately to the boundary area between different environments. For example, a meadow and a hedgerow are unique ecologies. Each has its own mixture of species. There is an abundance of food and shelter along the edge where the two environments meet. Interaction along this edge promotes large populations and increased diversity.
Ecology Math: Square fields have less edge than rectangular fields. For example, a square field measuring 300 feet on each side has 1,200 feet of edge (300 feet per side x 4 sides = 1,200 feet). Take the same field and stretch it into a rectangle 100 feet wide x 900 feet long. Both fields have the same area (90,000 square feet) but the rectangular field has 2,000 feet of edge (900 + 900 + 100 + 100 = 2,000 feet). The perimeter of the rectangular field is 40% larger than the square field. More edges = more food and habitat = more species and larger populations. Hunters understand this instinctively. Long, narrow fields have more browse (twigs and buds) along their perimeter. More hedgerow = more browse = more food = more deer.
Agricultural History: Farming in the Middle Ages was not easy. Wood plows were heavy and difficult to turn. The solution was to make long, narrow fields. Long fields required fewer turns. Each field was one “furrow” long = 1 furlong = 1/8th mile = 220 yards long x 22 yards wide = 4,840 square yards = 1 acre. A man with a team of oxen took a whole day to plow 1 acre. Adjacent fields were planted to unrelated crops, for example: Peas, Wheat, Turnips, and Pasture. Narrow strips and diverse crops increased edge effects supporting large populations of beneficial insects. The good bugs ate the bad bugs.
Agroecology: Wind the clock back to when knights went clanking around in armor. Northwest France (Normandy) was divided into thousands of little fields surrounded by hedgerows. Each field measured about 1 1/4 acres. This mixture of small fields and hedgerows is called bocage. The bocage landscape contains hundreds of miles of biological edges = vast populations of predatory and parasitic insects. Modern farmers in the bocage rarely have pest problems. Significant outbreaks occur about once every 20 years and are mostly self-correcting without insecticides.
“Altering the geometry of fields costs nothing and can reduce or eliminate pesticide use.”
Practical Polyculture: Plant 4 rows of corn then 4 rows of soybeans. Repeat this pattern across fields and farms following land contours. Result: Pests go down 50% and corn yields go up 15% (because of increased light penetration into the crop canopy).
- Alternate tall and short crops. Insect pests do not like fields with mixed light and shade. Example: Sunflowers — Alfalfa — Barley — Lentils
- Adjust strip widths to fit planting and harvesting equipment. Try to keep strip widths as narrow as mechanically practical. Narrow strips better control insect pests. Plant strips no wider than 200 feet to encourage rapid movement of beneficial insects into fields. Example: Hay (150 feet) + Soup Beans (75 feet) + Safflowers (75 feet)
- Plant adjacent strips to unrelated crops. Plant as many different crops as economically practical. Diverse crops reduce insect pests and spread market risk. Example: Wheat — Peas — Flax — Soy Beans — Barley — Alfalfa
- Seed grains and legumes together. Legumes fix nitrogen, protect soil and control weeds. Example: Winter Wheat + Dutch White Clover — or — Field Corn + Red Clover — or — Oats + Forage Peas — or — Winter Rye + Winter Vetch
- Alternate legumes with non-legumes. Legumes improve soil, feed earthworms and attract beneficial insects. Example: Canary Seed — Lentils — Barley — Soy Beans — Wheat — Field Peas — Flax — Alfalfa
- Plant windbreaks not closer than 50 feet nor farther than 150 feet apart. Windbreaks increase biological diversity and help crops grow better. Windbreaks do not have to be great belts of trees. A single row of shrubs or perennial pampas grass will slow wind and increase crop humidity. Example: Trees (25 feet wide) + Cropland (150 feet wide) — or — Shrubs (10 feet wide) + Cropland (100 feet wide) — or — Pampas Grass (3 feet wide) + Cropland (50 feet wide)
- Alternate strips of native weeds with cropland. Space weed strips not farther than 200 feet apart. Weeds should comprise at least 5% to 10% of total cropland. Native weeds are essential to provide food and shelter for beneficial insects. Example: Weed Strip (15 feet) + Cropland (135 feet)
- Plant several varieties of the same crop together. Choose varieties that have the same harvest date. Varieties can be mixed or drilled in separate rows. Alternatively, plant similar species that ripen together. For example: Winter Wheat + Winter Rye. Genetic diversity reduces the chances of crop failure due to weather, disease or insects.
Try This On Your Farm: Divide big fields into narrow strips and watch your pest problems go away. Strip cropping combines the biological advantages of polycultures with the economic efficiency of farm machinery.
Related Publications: The Twelve Apostles; Maize Polyculture Trial 2007-2016; Managing Weeds as Cover Crops; Trash Farming; No-Till Hungarian Stock Squash; Planting Maize with Living Mulches; Living Mulches for Weed Control; 2012 Tomato and Sweet Potato Polyculture Trial; Crops Among the Weeds; and The Edge Effect.
Would You Like To Know More? Contact the Author directly if you have any questions or need more information about polycultures or strip cropping. Please visit: http://www.worldagriculturesolutions.com — or — send your questions to: Eric Koperek, Editor, World Agriculture Solutions, 413 Cedar Drive, Moon Township, Pennsylvania, 15108 United States of America — or — send an e-mail to: http://www.worldagriculturesolutions.com
About The Author: Mr. Koperek is a plant breeder who farms in Pennsylvania during summer and Florida during winter. (Growing 2 generations yearly speeds development of new crop varieties).