An age-old production method often associated with Native Americans has been validated by study results from the Texas A&M AgriLife Extension Service.
Companion crops, or intercropping, blends two or more vegetable or non-vegetable crops in a plot to increase production.
“The idea behind companion cropping is to create a mutually beneficial ecosystem and functionally diverse plant community to increase individual plant production. When we have different crops that fill different functional niches, we find diverse planting can produce more overall and decrease input costs.” says Dr. Jose Franco, a U.S. Department of Agriculture Agriculture Research Service agroecologist, Mandan, North Dakota, who conducted the two-year study of intercropping at the Texas A&M University Horticulture Farm in Bryan for his doctoral dissertation.
His work was under the guidance of Dr. Astrid Volder, former Texas A&M University faculty and current University of California at Davis plant physiologist; Dr. Stephen King, a former professor and vegetable breeder with Texas A&M department of horticultural sciences, College Station; and Dr. Joe Masabni, AgriLife Extension small acreage horticulturist, Overton.
Franco’s study included intercropping peanuts, watermelon, okra, cowpea and hot peppers.
He tested five mixes within the same rows: peanuts and watermelon; peanuts, watermelon, and okra; peanuts, watermelon, okra, and cowpeas; and a row with all five test crops. Franco also tested alternating single rows of watermelon and peanuts.
Individual plants were spaced about 12 inches apart in a staggered row pattern so the same species would not be along side each other.
The legumes are an important part of this study due to their nitrogen-fixing qualities; the watermelon helps with weed suppression; and the hot peppers acted as a potential pest barrier.
“We found that three to four species consistently yielded higher per-unit land area compared to crops grown alone,” Franco says. “We reduced inputs like fertilizers and herbicides. We actually used minimal fertilizer and no herbicides, and the only major input we utilized was irrigation. So we enhanced resource use efficiency by planting the crops together.”
Masabni said intercropping is an ideal method for small-acreage growers with limited land space.
“The results are encouraging for these growers because we proved you can get better yields if you choose the right crop combinations of nitrogen fixing legumes, tall plants and smother crops,” he said. “It makes me wonder how they knew to do this, but Native Americans knew exactly what they were doing, and we’ve proved the concept works.”
Intercropping with three or four species performed best, Franco says.
“Productivity declined with one or two and more than four, and the plots with peppers showed an overall decline in productivity, so choosing the right combination is important,” he says.
Franco’s publication, Harvest Gains from Intercropping, is available in PDF form on the AgriLife Extension bookstore website.