EFFECT OF HERBICIDE TREATMENTS ON DANDELION, ALFALFA AND SAINFOIN YIELDS AND QUALITY

Abstract

Sainfoin (Onobrychis viciaefolia Scop.) and alfalfa (Medicago sativa L.) were seeded in 1978 and 1979, respectively. Weed control treatments initiated in sainfoin in 1979 and in alfalfa in 1980 included annual applications of terbacil, metribuzin, simazine, hexazinone and chlorsulfuron until 1985 plus an untreated check. Dandelion (Taraxacum officinale Weber) was the main weed infesting check plots in the sainfoin and alfalfa stands. Quackgrass (Agropyron repens L. Beauv.) and nonpalatable weeds such as foxtail barley (Hordeum jubatum L.) produced 4.5 and 4.0% of the total yield, respectively, where chlorsulfuron selectively controlled broadleaf weeds. In hexazinone, metribuzin and chlorsulfuron treatments, alfalfa and sainfoin stands were almost free of dandelions. In sainfoin plots, dandelion control produced large increases in sainfoin and total herbage yield. In alfalfa plots, dandelion control had no effect on alfalfa yield or total yield. In sacco dry matter digestibility in a 72-h experiment was higher for dandelions than for alfalfa, whereas protein digestibilities were similar for these herbages. The protein content was less in dandelions than in alfalfa at the first harvest. Thus, dandelion control in sainfoin may increase yield, whereas dandelion control in alfalfa does not seem to increase yield but may increase protein content and marketability.Key words: Control, protein, digestibility, hexazinone, terbacil, metribuzin