Herbaceous Weed Control Trials with a Planting Machine Sprayer and a Crawler-Tractor Sprayer--Fourth Year Pine Response.
Operational trials of herbaceous weed control treatments by machine application were studied at two southern alabama locations for establishing loblolly pine (Pinus taeda). The first study tested the feasibility of a spray attachment for planting machines to apply banded treatments while planting in February and March. Two rates of sulfometuron (Oust), 2 oz and 4 oz ai/a, and two bandwidths, 3 ft and 5 ft, were evaluated. Fourth-year pine growth was significanlty increased with all banded treatements when compared to the untreated check. The best treatment, 2 oz sulfometuron and 5 ft bands, resulted in twice the pine volume of no treatment, although trees growing within adjacent windows had almost 10 times the volume of the best treatment. The second study compared unsrayed plots with broadcast applications of sulfometuron plus hexazinone (2 oz Oust + 1.5 qt Velpar L/a) by a crawler-tractor sprayer over newly planted loblolly pines. Broadcast applicatoins with the tractor sprayer increased pine volume by 2.4 times over the untreated check. Both application systems hold promise for operational applications in the late planting season.