Reviewed by: Douglas Buhler, USDA/ARS National Soil Tilth Laboratory, Ames, Iowa; Robert Hartzler, Iowa State University Extension; Michael Horak, Kansas State University, Manhattan, Kansas; and Loyd Wax, University of Illinois, Champaign-Urbana, Illinois.

Photos by: Donald Pratt or Donald Pratt and Anna Gardner

Online version by: Brent Pringnitz., Iowa State University Extension.

Printing and distribution costs for this publication have been paid by the Iowa Soybean Promotion Board using soybean checkoff dollars.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Many materials can be made available in alternative formats for ADA clients. To file a complaint of discrimination, write USDA, Office of Civil Rights, Room 326-W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-9410 or call 202-720-5964.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Stanley R. Johnson, director, Cooperative Extension Service, Iowa State University of Science and Technology, Ames, Iowa.