Some computer models for predicting agricultural chemicals' movement through soil may need to be revised. Groundwater can be contaminated when applied chemicals move quickly through wormholes, cracks, and other large fissures in the soil. Computer models used to predict this rapid movement require a lot of information to run properly. So an ARS scientist has tested methods that can be used to obtain the information needed to run models like the "root zone water quality model," or RZWQM, developed by ARS scientists at Ames, IA. Effective methods for obtaining input for models include measuring the rate that water moves through unsaturated soil and using image analysis to characterize the size and number of soil holes. Some measurements fell outside the range of the models, indicating that revisions may be needed. By predicting when groundwater contamination may occur, the models can alert farmers to the need to modify agricultural management practices appropriately.

National Soil Tilth Laboratory, Ames, IA
Sally D. Logsdon, (515) 294-8265, logsdon@nstl.gov

The good news is that newly harvested wheat is generally not infested with insects. The bad news: Insects enter grain bins within 30 days of harvest. ARS entomologists used traps to monitor 34 grain bins on 12 different Kansas farms. The traps counted insects entering through openings near the roof. Bin sizes ranged from 1,000 to 8,000 bushels. An average of 14 rusty grain beetles, 6 lesser grain borers, 6 foreign grain beetles, and 22 hairy fungus beetles entered these bins each day during the first month of storage. This information, which can help reduce insect pest management costs, will be added to Stored Grain Advisor (SGA). This is a personal computer model developed to help grain managers select the best timing for control methods. SGA Pro, developed for use in large grain elevators, is being provided to grain elevator managers in ARS' Kansas-Oklahoma areawide IPM project. Each year, over 2 billion bushels of wheat are produced in the United States, with most of it being stored at one time or another in an elevator. Stored-grain insect pests such as the lesser grain borer, rice weevil, red flour beetle, and rusty grain beetle cost the U.S. wheat industry about $500 million annually.

Grain Marketing and Production Research Center, Manhattan, KS
David Hagstrum, (785) 776-2718, hagstrum@usgmrl.ksu.edu