The effect of fungicide seed protectants, seeding rates, and reduced ratesof herbicides on no-till soybean

A field study was conducted to determine if fungicide seed protectants, red uced rates of a complete preemergence or a complete postemergence herbicide program, and soybean seeding rates affect weed control and yield in a no-t ill system. Asgrow 3237, Pioneer 9273, and Pioneer 9342 soybean cultivars w ere planted into corn stubble at Urbana, Illinois in 1995 and 1996. Fungici de seed protectants increased soybean population density and reduced time t o canopy closure in 1995, but had no effect in 1996. As seeding rates incre ased from 34.6 to 54.3 seeds m(-2), yields increased, and time to row canop y closure was decreased. In general, adequate weed control and soybean yiel ds were maintained using reduced rates (greater than or equal to0.5X) of he rbicides. In 1996, the purple seed stain fungus, Cercospora kikuchii, was i solated more often from Pioneer 9273 seed and Asgrow 3237 seed harvested fr om the no-herbicide, weedy control plots compared to plots treated with her bicides. (C) 2001 Elsevier Science Ltd. All rights reserved.