plow size for 7020

Tillage effects on yields

Figure 3. Corn grain yields for each tillage treatment in 2004 and
2005.

In 2004:
Corn grain yields were significantly affected by tillage treatments at six of the ten sites in the record cool growing season of 2004 (Appendix: Table F and Table G). Averaged across the sites that used four tillage treatments, corn grain yields, ranked smallest to largest, were: no-till (167.8 bu/acre) < one-pass (174.2) = strip-till (174.6) < chisel-plow-plus (177.4), (Fig. 3 and Appendix: Table F). These data are very similar to results from 31 site-years of small plot research at the University of Minnesota‘s Southern Research and Outreach Center at Waseca (Vetsch and Randall, unpublished). They found chisel-plow-plus yielded 13 bu/acre greater than no-till, but only 3 and 4 bu/acre greater than one-pass and strip-till, respectively. At the three sites where only strip-till and chisel-plow-plus were compared in 2004, the chisel-plow-plus tillage treatment yielded 16 bu/acre greater than strip-till (Appendix: Table G).

The unusually cool growing season of 2004 undoubtedly had an effect on the performance of the three reduced tillage systems in this study. Other research has shown (Randall and Vetsch, 2005) that reduced tillage systems can have significantly lower yields compared with conventional tillage in unusually cool or wet growing seasons, especially when long-term no-till or reduced tillage systems are used. In the six sites in 2004 where chisel-plow-plus increased corn yields compared with strip-till, four of the six sites had a long-term no-till or reduced tillage history.

http://www.extension.umn.edu/agriculture/tillage/on-farm-comparison-of-conservation-tillage-systems-for-corn-following-soybeans/