Weed Control in Established Alfalfa(Medicago sativa)

Abstract

Several soil-applied and two foliar herbicides were evaluated for weed control in established alfalfa(Medicago sativaL.) in two experiments for two consecutive years. Most of the soil-applied herbicides effectively controlled weeds in the first harvest year following application; however, there was little carry-over into succeeding years. Except for the low rate of secbumeton [N-ethyl-6-methoxy-N′ (1-methylpropyl)-1,3,5-triazine-2,4-diamine] in the first alfalfa cutting of 1973, no herbicide treatment significantly increased alfalfa yields over the control plot. In fact, some herbicides caused injury to alfalfa at high rates of application, as did reapplication a second year at the original rate of application.