An Implanted Soil Mass Technique to Study Herbicide Effects on Root Growth

An implanted soil mass technique was modified to study the effect of soil-incorporated herbicides on root growth. The technique was used to study the effects of α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) and 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin) on root growth of cotton (Gossypium hirsutumL., var. Auburn 56) and the effects of trifluralin andS-propyl dipropylthiocarbamate (vernolate) on soybeans (Glycine max(L.) Merr., var. Bragg). Vernolate had no effect, but there was only 57% as much soybean root tissue in the soil receiving 1 ppm of trifluralin as there was in the untreated check 2 months after initiating the treatments. Trifluralin and nitralin at 1 ppm reduced cotton roots to 75% and 50%, respectively, of that of the untreated check. The effects of trifluralin and low soil pH were additive, but there was no interaction between them.