Strip Intercropping Corn and Alfalfa

Strip intercropping annual row crops can improve productivity, but the effect of strip cropping grain and perennial forage crops has not been thoroughly investigated. This study was conducted to evaluate the productivity and profitability of strip intercropping corn (Zea mays L.) and alfalfa (Medicago sativa L.). Alternating strips of corn and alfalfa of three widths (10, 20, and 40 ft) were compared in a field trial conducted from 1988 through 1990. Corn silking dates, heights, grain yields, and moisture were determined for each row within strips. Alfalfa yields and forage quality were determined for harvest strips within plots and for whole plots. Land equivalent ratios (LER) and gross returns to both strips and sole crops were calculated. In the drought of 1988, neither corn nor alfalfa yields differed due to strip width or from the sole crop yield. In 1989, corn yields were lowest for the sole crop (146 bu/acre), increased 3% in 40‐ft strips, and 10% in 10‐ and 20‐ft strips. In 1990, corn yields were also lowest for the sole crop (123 bu/acre), and increased 6% in 40‐, 11% in 20‐, and 17% in 10‐ft wide strips. Alfalfa yields did not differ due to strip width or from the sole crop yield in 1989. In 1990, alfalfa yields in strips vs. the sole crop were reduced 10% only for the 10‐ft wide plots. Land equivalent ratios were lowest in 1988, with values below 1.00 for 10‐ and 40‐ft strips. All strip widths had values above 1.00 in subsequent years. Maximum LERs were 1.02, 1.08, and 1.06 for 20‐ft strips in 1988, 1989, and 1990, respectively. In all years, 20‐ft wide strips had the greatest economic advantage, returning $6, $29, and $17/acre over sole crops in 1988, 1989, and 1990, respectively. Increases in prices received for crops always increased the advantage of strip intercropping. Research Question Strip intercropping helps conserve soil and has the potential to increase economic returns from row cropping systems, but little is known in the USA about intercropping annual crops with perennial forage legumes. Objectives of this research were to determine the effects of strip intercropping corn and alfalfa on the growth and yield of each crop, on alfalfa forage quality, and to identify an economically optimum strip width. Literature Summary Strip intercropping is the production of more than one crop in strips that are narrow enough for the crops to interact, yet wide enough to permit independent cultivation. Agronomically beneficial strip intercropping sy