Edamame beans (Glycine max (L.) Merrill) are legumes with potential as intercrops because they can help improve soil fertility through their effects on nitrogen (N), phosphorus (P), and potassium (K) content. This study aims to determine the changes in soil nutrient content—specifically nitrogen, phosphorus, and potassium—before and after planting edamame beans as intercrops on oil palm immature plants (TBM). The research was conducted on smallholder oil palm TBM land in Bukit Lawang Bahorok, Langkat Regency, from May 2025 to May 2026, using descriptive statistical methods. Edamame was planted on five beds measuring 1 m × 10 m, with 1,500 seeds of the Japanese variety Ryoko 75. During the study, no fertilizer or mulch was applied, but weeding was carried out periodically to maintain plant growth. Laboratory analysis of soil samples assessed the nutrient content of N, P, and K before and after planting. The results showed that nitrogen content decreased from 0.07% to 0.06%, while phosphorus content decreased from 19.78 ppm to 11.87 ppm. These decreases likely occurred because plants absorbed high levels of nutrients during vegetative and generative growth. Meanwhile, potassium content increased from 0.06 me/100 g to 0.15 me/100 g. The primary advantage of this system is its high productivity, yielding 3,068 kg of edamame without any fertilizer or mulch application, demonstrating excellent cost-efficiency. Based on these findings, it can be concluded that planting edamame beans as an intercrop on oil palm TBM land affects soil nutrient dynamics—particularly by increasing potassium content—though it did not significantly increase nitrogen and phosphorus levels during the study period. Therefore, it is highly recommended that farmers adopt this intercropping system to optimize land use and generate early income during the oil palm immature phase. However, a low-dose supplementary application of N and P fertilizers is advised to prevent soil nutrient depletion.