PRACTICAL EXPERIENCE AND ON-FARM RESEARCH WITH WEED MANAGEMENT IN AN IOWA RIDGE TILLAGE-BASED SYSTEM

The weed management system of most producers is complex and represents the summation of years of experience and informal observation. The ri dge tillage, row crop system described here is especially complex beca use it seeks to use cultural and mechanical weed controls in preferenc e to herbicides. Both experience and formal experimentation have contr ibuted to the development of the system. Fundamental are two working h ypotheses that may appear counterintuitive: (i) that tillage can stimu late weeds and (ii) that weeds can be used to control other weeds. Res ults of on-farm trials on the Thompson farm have supported these hypot heses. Additional on-farm trials have pointed toward conditions in whi ch rotary hoe tillage can be used to best effect to eliminate weeds. R esults of 51 replicated on-farm trials by Practical Farmers of Iowa (P FI), an organization that generates and shares information about profi table, environmentally sound farming methods, showed that ridge tillag e without herbicides is an effective and economical system for weed ma nagement and row crop production. Experience gained developing this al ternative weed management system can be summarized in guidelines apply ing, respectively, to the overall system, the planter, the rotary hoe, first cultivation, and second (tay-by) cultivation.