Weed Management Trials

Published Feb 1, 1992

In the past five years PFI cooperators have compiled an impressive record showing that ridge tillage can be used to raise crops profitably without herbicides. Even in the wet growing season of 1990, only one of eleven trials in ridge-till showed a reduction in yield when chemical control was not used. The wet spring of 1991 presented an even greater challenge, and cooperators adopted a variety of strategies to cope. These included: 1) use of a preplant contact herbicide, with mechanical control thereafter; 2) planting into a “green” field of weeds, relying on those weeds to suppress later weeds and on a well-adjusted planter to clean the row zone; 3) use of those mechanical methods followed by a postemergence herbicide when the situation demanded.

The table shows at least one example of each of these strategies. If there was a lesson to be drawn from this year, it may have been the importance of timeliness of the postemergence application. Three trials in soybeans produced yield reductions because the foxtail and its friends got ahead of the crop before the postemerge herbicide went on. This class of herbicides gives farmers a “safety net,” but like most techniques their use requires good timing