Practice Highlight: Alley Cropping
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Illustration courtesy of National Agroforestry Center
Alley cropping is an agroforestry practice where rows of trees are planted wide enough to create alleys where other crops can be cultivated. Some examples of trees or shrubs in an alley cropping system include:
Walnuts, Chestnuts, Hazelnuts
Apples, Plums, Cranberry, Currants, Huckleberry, Elderberry, Gooseberry
Christmas trees
Timber or specialty woods for furniture or musical instruments
Softwood species for wood fiber production
Examples of alley crops:
Vegetables, fruits, or flowers
Medicinal plants, such as Oregon grape, Wild Ginger, or Yarrow
Cereal or forage crops for livestock (legumes, grasses)
Floral greens, such as Salal, Deer Fern, or Bear Grass
Alley cropping has a wide variety of benefits:
Diversify Income
Growing more than one crop provides multiple streams of income, which increases resiliency to market fluctuations and crop failures. Crops grown in alleys also provide short-term cash flow while trees and shrubs mature.
Sheltered Microclimates
Rows of trees and shrubs protect alley crops from wind and their leafy canopy intercepts rain and allows it to trickle down slowly, reducing compaction and erosion. The extensive network of perennial roots also hold soil in place, further reducing erosion.
Save Water, Clean Water
The shade provided by trees and shrubs helps retain water in the soil and their roots filter nutrients, pesticides, and other pollutants. Alley cropping has been found to reduce crop evapotranspiration by 15-30% and increase water content in the tillage layer by 5-15%.
Free Fertilizer
Leaf litter adds organic matter to the soil and releases nutrients as they decompose. Trees and shrubs also intercept excess nutrients from fertilizers that are not taken up by alley crops (which often have shallower roots) and absorb and recycle them back to the soil when leaves drop.
Pollination and Pest Control
Trees and shrubs provide corridors, food, and nesting sites for wildlife, pollinators, and other beneficial insects.
Increase Productive Land
Trees and shrubs that tolerate wet soil can provide opportunities for farming where annual crop production is less viable.
Sequester Carbon
Perennial trees and shrubs increase net carbon storage in the soil and vegetation.
When planning an alley cropping system, it’s important to take into account issues like spacing, choosing plants with complimentary needs, and reducing competition through techniques like root pruning.
To get advice on your alley cropping system, or other agroforestry topics, contact Snohomish Conservation District’s Agroforester, Carrie Brausieck, at cbrausieck@snohomishcd.org or 425-377-7014.
