Soil Nutrients in African Oil Palm Polyculture and Monoculture Matched-Pair Experiment in Costa Rica

In the last two decades, Costa Rica has emerged as a significant site for oil palm production. As global demand for vegetable oils only increases, the oil palm sector in Costa Rica is only projected to expand, specifically in the Osa and Golfito cantons in the Zona Sur. However, traditional monoculture oil-palm plantations (OPP) have been found to cause pollution, biodiversity loss, and soil degradation. Furthermore, small farmers entering the oil-palm sector face many financial and food security challenges due to the lack of profit produced by young OPPs. Thus, there is a need to explore oil-palm production methods that minimize ecological and societal harms. Specifically, polyculture, where multiple crops, shrubs, and trees are grown simultaneously, has been proposed as an alternative agricultural system. Over the past 6 years, The African Palm Laboratory Project (LAPA), a collaboration between the Stanford Woods Institute for the Environment and the Osa and Golfito Initiative (INOGO), has researched this. In a seven-site-wide experiment conducted by LAPA across the Osa and Golfito cantons, researchers have found increased biodiversity, lessened risk of zoonotic disease, and increased food production associated with oil palm polyculture plots. However, a soil analysis to understand how oil-palm polyculture impacts soil health has not yet been conducted in this ongoing experiment.
I conducted a comparative analysis of soil health with the goal of deciphering how oil palm polyculture impacts the land and communities in the Osa and Golfito regions. Specifically, I analyzed the availability of total C and N, plant available N, and pH between polyculture and monoculture oil-palm systems. The data recorded are located in this repository. This body of work thoroughly highlights soil health differences between the two agricultural systems across experimental periods—land dynamics regarding OPPs that are not well-understood. This information is key for considering the feasibility of the implementation of oil palm polycultures at a larger scale.