Two Herbicides Reduce Weeding Costs in Washington Nursery Trials

Weed control in forest nurseries is essential, but high costs of present methods require that better means be found. Herbicides are often cheaper, more convenient, and less damaging to nursery stock than the conventional machine cultivation, hand weeding, and contact sprays. The indiscriminate use of promising herbicides, however, can be dangerous. Many herbicides are very insoluble and may build up to toxic levels, particularly in heavy soils. Other herbicides are effective only against a few weed species. New herbicides need to be evaluated, first, for their weed control effectiveness, and secondly, for any damage to tree seedlings. Many evaluations have been made of new herbicides in forest nurseries (1, 2, 5, 6, 7, 8, 9, 11, 12) . However, most of this research evaluates a herbicide only for its potential use and not for costs. Because a chemical gives some degree of weed control does not necessarily mean it may be economical to use. Such factors as price, method of application, appli-cation cost, and quantities used need to be considered. Preliminary weed control research at the L.T. "Mike" Webster Forest Nursery, near Olympia, Wash., has evaluated potential herbicides for weed control and seedling injury over a period of several years. It utilized small plots, with limited replications, and rated weed control and plant damage by a numerical index based on visual observation (4). The economic values of the chemicals were not rated. Because of this, the following experiment was established on an operational basis with four promising herbicides to determine their economic worth.

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Author(s): Harry W. Anderson

Publication: Tree Planters' Notes - Volume 19, Number 1 (1968)

Volume: 19

Number: 1