Al-Kaisi M, Archontoulis SV, Kwaw-Mensah D, Miguez FE, 2015. Tillage and crop rotation effect on corn agronomic response and economic return at seven Iowa locations. Agron J, 107: 786–798.
To investigate the effect of tillage and crop rotation on corn yields and economics across in Iowa and quantify the yield penalty under continuous corn.
In collaboration with Dr. Mahdi Al-Kaisi research group we statistically analyzed a comprehensive long term corn dataset (2003–2014) that included the effects of 7 sites (Sutherland, Kanawha, Nashua, Ames, Lewis, McNay and Crawfordsville) x 5 tillage systems (no-tillage, strip-tillage, chisel plow, deep rip, and moldboard plow) x 3 cropping systems (continuous corn, corn-soybean and corn-corn-soybean) on corn yields and economics in Iowa. The experiments were replicated (n=4) and are still on-going and maintained by Dr. Mahdi Al-Kaisi.
Corn yields varied from 39 to 251 bu/ac across treatments with no detectable increase over time (Fig. 1). Corn yields were higher in the corn-soybean rotation, followed by the corn-corn-soybean and finally by the continuous corn system (Fig. 2). Higher corn yields and economic returns were found in northern locations compared to southern locations but there was substantial year-to year variability as indicated by the coefficient of variation (Fig. 1). The corn yield penalty, defined as yield difference between yield in corn-soybean and continuous corn, was found to be location specific and varied from 11 to 28%. Corn yields and economic penalty were greater with no-tillage than conventional tillage in the northern locations (poorly-drained soils) than locations with well-drained soils. The findings suggest a location specific adoption of tillage and crop rotation for achieving optimum yield. Read more here.