KAJIAN STATUS HARA MAKRO TANAH GAMBUT PADA PERKEBUNAN KELAPA SAWIT RAKYAT DI KABUPATEN KOTAWARINGIN BARAT

Assessment of Macro-Nutrient Status of Peat Soils in Smallholder Oil Palm Plantations in Kotawaringin Barat

Abstract

Smallholder oil palm plantations on peatlands face major constraints related to low fertilization efficiency due to dynamic soil chemical properties and high nutrient losses, while the use of soil analysis as a basis for nutrient management remains limited. This study aimed to evaluate the status of macronutrients in peat soils as a basis for developing appropriate fertilization recommendations for smallholder oil palm plantations in Mendawai Seberang, Kotawaringin Barat Regency. The study employed a descriptive survey method, with soil sampling conducted using a grid system across 10 zones at three depth intervals (0–15 cm, 15–30 cm, and 30–60 cm), which were composited for each zone. The parameters analyzed included soil pH, total N, available P, available K, available Ca, available Mg, and cation exchange capacity (CEC). The results showed that soil pH was classified as very acidic (3.37–4.22) across all zones and depths. Total N content ranged from low to very low (0.03–0.15%), available P was very low (0.29–3.48 ppm), and available K was also very low (0.38–0.71 cmol(+)/kg). Base cations Ca and Mg were similarly classified as very low, ranging from 0.03–0.67 cmol(+)/kg and 0.10–0.30 cmol(+)/kg, respectively. In contrast, CEC values were moderate to high (19.91–36.58 cmol(+)/kg). Nutrient distribution varied across zones and soil depths without showing a consistent pattern. These findings indicate limited macronutrient availability in peat soils, highlighting the need for improved nutrient management through liming, balanced fertilization, and water management based on soil analysis to enhance fertilization efficiency in smallholder oil palm plantations