Indonesia is the largest producer of oil palm in the world, with Riau Province particularly Siak District being the major contributor. The study focused on oil palm plantations within Siak District, characterized by a tropical rainforest climate of high humidity. The soil type in this area was a peatland with sapric and hemic maturity. The planting material used primarily consists of the DxP Marihat variety, which was planted between 1995-2005, with an average potential fresh fruit bunch productivity of 29.00 tons/ha/year. Variations in nutrient contents in oil palm leaf were observed across each block of the study location. Diagnosis and recommendation integrated system (DRIS) analysis was conducted on found number 17 to determine the key nutrients required to increase oil palm productivity. This method consists of several stages, including norm analysis, DRIS index, nutrient balance index (NBI), optimum leaf nutrient value, and leaf nutrient interval. Data was obtained from 312 leaf nutrient analyses and fresh fruit bunch productivity across 39 blocks for the period between 2015 and 2022. A value of 26.33 tons/ha/year, derived from DRIS norm calculation, indicated the border between high and low productivity blocks. The results showed that the order of macronutrient and micronutrient requirements in high productivity blocks was N>P>K>Ca>Mg and B>Cu>Zn, while in low productivity blocks, it was Ca>Mg>N>K>P and B>Cu>Zn. Regression of DRIS index and leaf nutrient content obtained optimum nutrient values of 2.78%, 0.16%, 1.02%, 0.66%, 0.35%, 29.51 ppm, 3.65 ppm, and 15.37 ppm for N, P, K, Ca, Mg, B, Cu, and Zn, respectively. Therefore, nutrients Ca and B were prioritized to increase the achievement of oil palm fresh fruit bunch productivity.
Read full abstract