Submitted to: Agronomy Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/27/1999
Publication Date: 1/1/2001
Citation: Wesley, R.A., Elmore, C.D., Spuurlock, S.R. 2001. Deep tillage and crop rotation effects on yield and net return from cotton,soybean, and grain sorghum on clayey soils. Agronomy Journal. 93(1):170-178. Interpretive Summary: In the lower Mississippi River alluvial flood plain, most of the clayey soils are planted to monocrop soybean and grown in dryland environments with conventional (disked) tillage. Yields from this production system are usually low and marginally profitable. The objective of the research was to determine the effect of fall deep tillage (subsoiling) on yields and net returns from monocrop cotton, soybean, and sorghum and rotations of cotton and soybean with sorghum grown on beds spaced 0.75-m apart. Yields from cotton, soybean, and sorghum crop sequences grown in production systems with fall deep tillage respectively averaged 25, 18, and 13% greater than comparable crop sequences grown in conventional systems. Net returns from cotton, soybean, and sorghum crop sequences with fall deep tillage averaged 79, 27, and 48% greater. This research is important to midsouth producers because it indicates fall deep tillage incorporated into monocrop cotton and soybean crop production sequences maximized net returns to these crops on Tunica clay.
Technical Abstract: A 5-year study (1993-1997) was conducted on Tunica clay (clayey over loamy, montmorillonitic, nonacid, thermic Vertic Haplaquept) to determine the effects of fall deep tillage and crop rotation on yields and net returns. Treatments included monocrop cotton, soybean, and sorghum, and biennial rotations of cotton and soybean with sorghum. Yields of cotton, soybean, and sorghum crop sequences grown in deep till production systems respectively averaged 25% (2725 vs. 2184 kg/ha), 18% (3508 vs. 2983 kg/ha), and 13% (5987 vs. 5300 kg/ha) greater than comparable crop sequences with conventional fall tillage. Net returns to all crop sequences in deep till production systems also averaged greater. Net returns from monocrop cotton ($552/ha) and soybean ($462/ha) averaged highest. Rotations of cotton and soybean with sorghum increased yields and net returns from the cotton and soybean component in the rotation in both production systems. However, when combined with the low net returns from the sorghum component in the rotations, the average net returns from the rotations were lower than returns from monocrop cotton and soybean grown with fall deep tillage. Thus, fall deep tillage should be incorporated into monocrop cotton and soybean crop sequences to maximize net returns from these crops on Tunica clay.