Yield penalty when corn follows corn
Economic and political forces are collectively pushing for more corn production in the U.S. This will come about primarily through an increase in corn following corn acres. As more acreage is devoted to corn, it is necessary to understand how multiple years of corn affect yield.
Highest corn yields are associated with the traditional, corn-soybean system. Multi-year corn production should always have lower yields (to some degree) in comparison to corn grown in a corn-soybean system (Figure 1). Yield reductions typically range from 5 to 15% for corn following corn compared to first year corn (Benson, 1985; Nafziger et al., 2005; Pedersen and Lauer, 2003). A compilation of all corn system research was recently published by Purdue University. Average yield loss was 8% for continuous corn, with a range of yield loss from 2 to 19%. Twenty six studies were included in the study, yet only two cited yield advantages to continuous corn.
Figure 1. Corn yields over time from multi-year corn production. Different environments and yield levels are shown within the graph. The x-axis shows different rotations as (L to R): 1st year corn in a corn-soybean rotation, 2nd year corn, 3rd year corn, 4th year corn, 5th year corn, and continuous corn. Compilation of data from Pedersen and Lauer, 2002, 2003; Porter et al., 1997.
Although in general, we expect corn to yield less when following corn there are exclusions to this statement. Many corn yield-contest winners obtain their record yields in continuous corn production systems. Yet, honing in on one or two key management practices such as tillage, nutrients, pest management, or plant populations has not proved to be the magic answer in making the system work. To consistently produce high corn yields (across locations and years) will require intensive management of the overall system by producers and agronomists.
More research is necessary to discern the implications of cropping systems based primarily on corn. Although past research is useful in understanding the system, new developments including hybrids demand further investigation.
Useful resources
Benson, G.O. 1985. Why the reduced yields when corn follows corn and possible management responses? Pg. 161-174. In. D. Wilkinson (ed.) Proc. 40th Corn and Sorghum Res. Conf. Chicago. 11-12 Dec. American Seed Trade Assoc., Washington D.C.
Erickson, B. and J. Lowenberg-DeBoer. 2005. Weighing the returns of rotated vs. continuous corn. Top Farmer Crop Workshop Newsletter, Purdue University, February 2005.
Nafziger, E.D. 2004. Can we increase both corn acres and yields? 2004 Integrated crop management conference. University Extension, Iowa State University.
Nafziger, E.D., E. Adee, R.E. Dunker, and L.E. Paul. 2005. Managing continuous corn for high yields. University of Illinois, Urbana, IL.
Pedersen, P., and J.G. Lauer. 2002. Influence of rotation sequence and tillage system on the optimum plant population for corn and soybean. Agron. J. 94: 968-974.
Pedersen, P., and J. G. Lauer. 2003. Corn and soybean response to rotation sequence and tillage system. 2003 Integrated crop management conference. University Extension, Iowa State University.
Pedersen, P., and J.G. Lauer. 2003. Corn and soybean rotation effect on row spacing and tillage system. Agron. J. 95: 965-971.
Porter, P.M., R.K. Crookston, J.H. Ford, D.R. Huggins, and W.E. Lueschen. 1997. Interrupting Yield Depression in Monoculture Corn: Comparative Effectiveness of Grasses and Dicots. Agron. J. 89:247-250.
Text written for the ISU Corn Production website by Lori Abendroth and Roger Elmore. February 2007.
