The aim of this research was to evaluate the competitive indices in the intercropping of borage (Borago officinalis L.) and peanut (Arachis hypogaea L.) under two plant nutrition systems: chemical and organic. The experiment was conducted in a factorial arrangement using a randomized complete block design with 3 replications at the research farm of the Kurdistan University, Iran in 2021 and 2022. The experiment included three fertilizer treatments (control, organic fertilizer, and chemical fertilizer) and four intercropping patterns (sole cropping of borage, sole cropping of peanut, 50%, and 100% additive intercropping patterns). The results showed that intercropping treatment with fertilizer increased borage seed yield by 35.12% compared to sole cropping without fertilizer. The partial land equivalent ratio (LER) for borage was higher in both intercropping patterns compared to peanuts, demonstrating the dominance of borage and the positive effect of intercropping with peanuts on borage. The values of the area-time equivalent ratio (ATER) also highlighted the advantage of organic fertilizer and 100% intercropping pattern. In the intercropping patterns, borage exhibited higher aggressivity index (A) and competitive ratio (CR) compared to peanuts. Based on the results of the mean comparison regarding the effect of fertilizer on the system productivity index (SPI), organic fertilizer was able to compete favorably with chemical fertilizer.
