EFFICACY OF DIFFERENT HERBICIDES ON WEED CONTROL, GROWTH INDICES AND FORAGE YIELD IN ALFALFA (MEDICAGO SATIVA L.)

Abstract

In order to investigate the chemical management in alfalfa newly planted, an experiment in a randomized complete block design with four replications was conducted in the research farm of Iranian Research Institute of Plant Protection located in Meshkindasht, Iran (2014-2016). Treatments includes EPTC (5 l/ha), Metribuzin (750 g/ha), 2,4-DB (3 and 3.5 l/ha), Bentazon (3 l/ha) and Imazethapyr (0.5 and 1 l/ha) on newly planted and established alfalfa, as well as control treatments without weeds control and with manual weeding during alfalfa growth season. The results revealed that the most effective herbicides to decrease the broadleaf weeds density were Metribuzin (99 and 97% in the first and second cuttings, respectively) and Imazethapyr (1 l/ha) (91 and 90% in the first and second cuttings, respectively). The lower effect was related to EPTC application (44 and 36% in the first and second cutting, respectively). As regards the the effects on narrow-leaf weeds density the highest herbicides efficiency was related to EPTC (100% in both cuttings), Metribuzin (87 and 91% in the first and second cuttings, respectively), Imazethapyr (1 l/ha) (81 and 90% in the first and second cuttings, respectively). In conclusion, Imazethapyr application (1 l/ha) was more suitable than other herbicides.