Effects of Perennial Intercrops on Oil Palm Agronomic and Yield Traits

Background: Intercropping is wildly practiced in oil palm plantation in Thailand for a long time. However, there are few studies connected to oil palm intercropping. This study evaluated the effects of perennial intercrops on the agronomic and yield traits of oil palm.Methods: The observation used a completely randomized design with eight treatments including oil palm monocropping, oil palm intercropped with Intsia palembanica, Hopea odorata, Swietenia macrophylla, Ternstroemia wallichiana, Azardirachta excelsa, Magnolia champaca and Mesua ferrea. The height and stem perimeter of intercrops were recorded as were the plant height and diameter, number of male and female inflorescences and sex ratio of the oil palms. Those parameters were observed in October 2019, February and June 2020.Result: Oil palm intercropped with A. excelsa produced the highest number of female inflorescences and oil palm intercropped with M. champaca produced the highest sex ratio in October 2019 and February 2020, however, the differences of those parameters were not found in June 2020. There were no significant differences in the diameter, height, the number of male inflorescences throughout the observation. Among the 7 intercrops, M. champaca and A. excelsa produced the highest growth rate of plant height and stem perimeter, respectively. In conclusion, oil palm can be intercropped with perennial plants. However, more research is needed to determine the long-term effects of intercropping in oil palm.