A preliminary experiment on controlling weeds in nurseries of pines and firs by chemicals.
During the early growth stages of pines [Pinus] and Chinese firs [Cunninghamia lanceolata], orthogonal trials and comparative experiments with complete randomized blocks were conducted on the post-planting and pre-emergence herbicides nitrofen, trifluralin, delachlor, benthiocarb [thiobencarb] and glyphosate for control of common crabgrass [Digitaria], Alopecurus, barnyardgrass [Echinochloa crus-galli], Cyperus, Galium aparine, Amaranthaceae and knotweed [Polygonum]. Two or three applications were made in a year. The highest percentage of control was 99.8%. At the seedling stage, however, only 75% of the weeds were eliminated. The cost of chemical weeding was 23.5-35.5% less than that of manual weeding.