Herbaceous weed control trials with a planting machine and a crawler-tractor sprayer - fourth year pine response.
Field trials conducted at 2 sites in the Middle Coastal Plain Province of Alabama, USA, showed that 2 or 4 oz of sulfometuron (Oust)/acre applied simultaneously with the planting of Pinus taeda seedlings by a spray system that was attached to the planting machine and delivered a 3 or 5 ft band, effectively controlled grass (Andropogon virginicus and Panicum spp.) and broadleaved (Ambrosia artemisiifolia and Diodia teres) but not woody (Rubus spp., Rhus spp., Nyssa sylvatica, Carya glabra and Diospyros virginiana) weeds for 1 year. The best weed control was by the 4 oz and 5 ft treatment. All treatments increased the height and diameter but not the survival of Pinus taeda after 4 years, the greatest tree volume (twice that of unweeded controls) and most economic return being achieved with the 2 oz and 5 ft application. Broadcast applications of sulfometuron + hexazinone (2 oz + 1.5 quarts Velpar L/acre) over newly planted seedlings by a crawler-tractor sprayer also increased yield by 2.4 times relative to the control.