Research Article
Effects of 24 Years of Conservation Tillage Systems on Soil Organic Carbon and Soil Productivity
Table 4
Effect of different tillage treatments on corn and soybean yields during 1989–2012 at Dixon Springs.
| Tillage | Crop yield (Mg ha−1) |
| Corn year | 1989 | 1991 | 1993 | 1995 | 1997 | 1999 | 2001 | NT | 8.99b* | 6.57a | 11.79a | 11.60a | 9.87a | 8.12a | 9.73b | CP | 9.99b | 6.10a | 11.61a | 11.55a | 9.32a | 6.78b | 9.60b | MP | 11.26a | 6.60a | 10.98a | 10.37a | 9.59a | 6.98b | 10.34a |
| Year | 2003 | 2005 | 2007 | 2009 | 2011 | 12-yr ave. | % of MP yield | NT | 6.67a | 11.40a | 6.46a | 13.10a | 6.13a | 9.18a | 96 | CP | 7.33a | 11.82a | 6.80a | 13.60a | 6.85b | 9.24a | 97 | MP | 7.82a | 11.41a | 7.33a | 14.03b | 7.68ab | 9.53a | 100 |
| Soybean year | 1990 | 1992 | 1994 | 1996 | 1998 | 2000 | 2002 | NT | 2.37a | 3.74a | 2.87a | 2.63a | 2.63a | 2.32a | 2.37a | CP | 2.62a | 3.46a | 1.81b | 2.27a | 2.63a | 2.38a | 2.07a | MP | 2.62a | 3.65a | 1.49b | 2.43a | 2.75a | 2.32a | 1.98b |
| Year | 2004 | 2006 | 2008 | 2010 | 2012 | 12-yr ave. | % of NT yield | NT | 0a | 3.17ab | 2.84a | 2.94a | 2.65a | 2.54a | 100 | CP | 0a | 3.37a | 2.84a | 2.79a | 1.96b | 2.35a | 93 | MP | 0a | 3.10b | 3.04a | 2.88a | 1.82b | 2.34a | 92 |
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*For each crop means in a same year followed by the same letter is not significantly different at the probability level.
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