1. Grain Marketing and Production Research Center, USDA-ARS, Manhattan, KS 66502. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that also may be suitable.
2. Corresponding author. Phone: 785/776-2753. Fax: 785/776-2792. E-mail: fdowell@usgmrl.ksu.edu
3. Agricultural Engineering Department, Texas A&M University, College Station TX 77843-2117.