VEGETATION ANALYSIS AND EFFICACY OF METSULFURON-METHYL 20% HERBICIDE TO CONTROL WEEDS IN THE SMALLHOLDER RUBBER (Hevea brasiliensis Muell. Arg.) PLANTATION IMMATURE TREE

Abstract

Indonesia is a world’s largest rubber plantation area, but it is contrary with the productivity. One aspect of cultivation that causes a decrease in rubber productivity is competition with weeds, therefore the utilization of a chemical herbicide (metsulfuron-methyl 20%) has the effective potentially to controlling weeds in rubber plantations. This study aimed to evaluate the vegetation and composition of weeds, obtain the dose of metsulfuron-methyl 20% herbicide which is effective and efficient in controlling weeds in immature smallholder rubber plantations, and aware the phytotoxicity of rubber trees due to the application of it. The present research was conducted at the smallholder rubber plantation located in Tanjung Limau, Ampek Koto Village, Pulau Punjung Sub-district, Dharmasraya Regency and the Laboratory of Andalas University 3^rd Campus, Dharmasraya. This research was designed based on a Randomized Block Design (RBD) with seven treatments were repeated four times, i.e., metsulfuron-methyl 20% herbicide at 37,5 g/ha, 50 g/ha, 62,5 g/ha, 75 g/ha, 87,5 g/ha, manually weeding and control plot. The observations data were analysis of variance and it was continued by Duncan’s New Multiple Range Test (DNMRT) at 5% significance level. The results showed that there were five weed species that dominated in the immature rubber plantations, and metsulfuron-methyl 20% herbicide had an effect on two species of weeds, namely Borreria latifolia and Clidemia hirta, with a more effective and efficient dose of 37,5 g/ha. The results of phytotoxicity observations on immature rubber trees showed no symptoms due to application of metsulfuron-methyl 20% herbicide.