MANAGING WEED CONTROL INPUTS WITH WeedSOFT

This session of the conference is focused on evaluating the economics of production inputs. Of these inputs, herbicides and their application comprise a sizable expense in corn and soybean production. Although these costs may account for only 10 to 20 % of the total cost of crop production, it could be argued that effect of weed management decisions on crop yield can be as or more important than other production decisions (Lauer 2000). Obviously, if poor weed management decisions are made, yields can be severely reduced. It has been shown that herbicides can be replaced with a combination of rotary hoeing and cultivation without reducing yield if timing and conditions are optimal (Mulder and Doll 1993). H wever, it is unreasonable to suggest that many Wisconsin growers can adopt this type of intensive management to eliminate herbicides as an input cost. Options for reducing herbicide inputs via reduced herbicide rates combined with cultivation and the success of reduced rate systems have been discussed previously (Doll et al. 1992, Buhler et al. 1995, Proost et al. 1996). The use of reduced rates requires additional management practices such as timely cultivation, which can limit the use of this practice. Another option to evaluate the value of herbicide programs will exist with the WeedSOFT software program that is being adapted for Wisconsin