Wednesday, November 7, 2007 - 11:00 AM
262-4

Tillage System Impacts on Crop and Soil Responses to Crop Rotations: The View from Long-Term Experiments.

Tony J. Vyn, Purdue Univ, Dept. of Agronomy, 915 W State St., West Lafayette, IN 47907-2054, Joseph G. Lauer, University of Wisconsin, Agronomy, 1575 Linden Drive, Madison, WI 53706, Warren Dick, 1680 Madison Ave., Ohio State University - OARDC, Ohio State University, School of Natural Resources, Wooster, OH 44691-4096, and Glover Triplett, PO Box 9555, Mississippi State University, Mississippi State University, Agronomy Department, Mississippi State, MS 39762.

Long-term crop rotation experiments that have been established in the last 20 to 40 years have often included a tillage treatment variable.  Tillage impacts on crop and soil quality responses have frequently been larger than those resulting from crop rotation alone.  In many productive soil situations, soil C and N concentrations are often more dependent on the length of time in a particular tillage system than they are affected by crop rotation treatments. However, the most interesting feature of these rotation and tillage interaction studies has been the presence of significant interactions that have resulted in improved scientific understanding of the true nature of the crop rotation benefit for various field crops.  Crop rotation studies in the Eastern Corn Belt, for instance, have confirmed that the rotation yield advantage for corn is not a uniform 10 percent, but is highly dependent on tillage.  The yield penalty associated with continuous corn is generally least with moldboard plow, intermediate with chisel plow, and greatest in the no-till system even when there are no treatment effects on plant populations.  However, the same rotation and tillage interaction-response pattern has not been observed with soybean, and soybean rotation responses have generally been less dependent on the tillage system employed.  These studies confirm some of the unique challenges associated with continuous no-till adoption in rotation systems involving more corn than the traditional corn-soybean sequence that was so prevalent in the 20-year period before 2007.  We will also discuss whether the so-called “rotation yield advantage” has declined with time as more stress-tolerant cultivars are employed, and as other aspects of crop management improve over time.

Back to Symposium--Scientific Advances in Crop Rotation Research During the Last Century: Where Do We Go from Here?: II/Div. C03 Business Meeting
Back to C03 Crop Ecology, Management & Quality

Back to The ASA-CSSA-SSSA International Annual Meetings (November 4-8, 2007)