Doublecropped vs. Monocropped Soybeans
Most doublecropped [DC] soybeans in the U.S. are grown in the southeastern part of the country [Alabama, Georgia, Kentucky, Maryland, North and South Carolina, Virginia, and Tennessee]. The vast majority [>95%] of soybeans grown in the midsouthern U.S. [Arkansas, Louisiana, and Mississippi] are monocropped [MC], presumably because soybeans grown in this region are planted early [prior to May 1] before normal wheat harvest time of early June and later.
An article titled A review of double-crop soybean production in comparison to full-season system in the United States offers some interesting perspectives on DC vs. MC soybeans. The following are points from the article that are worthy of consideration by Midsouth producers who are contemplating use of a DC system.
• This review of published research on DC systems in the U.S. focused on identifying management factors that are critical for maximizing soybean yields from a DC system.
• Wheat residue had adverse effects on DC soybean yields. The most effective management tools to reduce the impact of this effect were planting soybeans no-till, maintaining wheat stubble height less than 12 in., and uniformly spreading wheat chaff during harvest.
• Immediate planting of soybean after wheat harvest was a prime factor in mitigating low soybean yields that will occur when soybeans are planted in a DC system.
• Planting DC soybeans in rows that are less than about 8 in. apart is a significant agronomic practice to minimize DC soybean yield loss.
• Seeding rate was identified as a consistent contributor to DC soybean yield, with higher seeding rates/plant populations required for DC plantings vs. those used in full season plantings.
• Application of a small amount of starter nitrogen [N] fertilizer enhanced early-season soybean growth and canopy development.
• Drought stress was nearly always a significant factor for nonirrigated DC soybeans, and sometimes led to complete crop failure.
• The judicious application of insecticides and fungicides was considered essential to maximize DC soybean yield.
• And finally, the authors strongly recommended extensive DC research across diverse geographical regions to evaluate/emphasize 1) early harvest of high-moisture wheat, 2) development and use of early-maturing wheat varieties, 3) determine precise N and potassium timings for irrigated and nonirrigated DC soybeans, and 4) return on investment to evaluate DC vs. full-season soybeans.
The results of this review indicate that soybeans grown in a DC system will be as expensive or moreso to grow than will those in an MC system since required inputs [seed, fertilizer, irrigation, pest management] to maximize DC soybean yield will be equal to or more than those needed to maximize MC soybean yield. This, coupled with the lower yield from DC soybeans, indicates that an annual economic assessment of a DC system that uses soybeans and a small grain vs. an MC soybean system is paramount before deciding to use a DC system of soybeans-small grain in any region of the U.S. This necessary annual assessment will also involve knowing the potential selling price of the commodity crops used in the DC system. Also, if small grain is harvested at a high moisture content to accommodate the earliest possible DC soybean planting time, its dockage at the selling point will detract from DC system income.
Click here and here to access articles on this website that provide additional details about doublecropping in the Midsouth. An alternative to growing soybeans in a DC system is presented here.
Composed by Larry G. Heatherly, May 2025, larryh91746@gmail.com