<![CDATA[Weeds are a major factor affecting the growth and productivity of Arabica coffee (Coffea arabica L.) plantations because they compete with cultivated plants for water, nutrients, light, and growing space. Understanding weed species richness and dominance is essential for developing effective weed management strategies in coffee plantations. This study aimed to identify the weed species present and determine the most dominant weed species in Arabica coffee plantations located in Pagar Gunung Village, Kotanopan District. The research employed a qualitative descriptive approach using the plot method. A total of 25 observation plots, each measuring 2 m × 2 m, were established within the plantation area. Data collection involved recording weed species, counting individuals, documenting morphological characteristics, collecting specimens for identification, and preparing dry herbarium samples. The collected data were analyzed descriptively, and weed dominance was determined using the Summed Dominance Ratio (SDR) index. The results showed that 15 weed species belonging to 11 families were identified in the study area. The family Asteraceae was the most abundant, represented by three species, namely Ageratum conyzoides, Mikania micrantha, and Synedrella nodiflora. The families Poaceae and Melastomataceae were each represented by two species, while the remaining families were represented by a single species. Based on SDR analysis, Ageratum conyzoides was identified as the dominant weed species, with an SDR of 11.44%, followed by Imperata cylindrica (9.46%) and Mikania micrantha (9.15%). These findings indicate that the weed community in the Arabica coffee plantation is relatively species-rich, with A. conyzoides showing the highest ecological dominance. Therefore, priority should be given to managing dominant weed species to reduce competition and support sustainable coffee production.]]>
