Oil palm is a plantation crop widely cultivated, including in Riau, and often grown on marginal lands such as Dystrudepts soils. The low nutrient content and limited water-holding capacity of Dystrudepts soils pose significant challenges. The use of Polyhalite fertilizer, which is slow-release and contains K, Ca, Mg, and S, is one potential solution. Due to the low potassium content in Polyhali…