Effects of eggshells, empty fruit bunch ash and their combinations on growth of oil palm seedlings in the nursery

This study investigated the effects of eggshells (ES), empty fruit bunch ash (EFBA), and their combinations on the growth performance of oil palm seedlings in the nursery. Pot experiments were employed using a completely randomized design with a split-plot arrangement, replicated three times. The ES treatment levels included: 22.50 g, 26.79 g, 31.07 g, 35.40 g, and a control, while the EFBA treatment levels were 26.25 g, 31.25 g, 36.35 g, 41.25 g, and a control. Combinations (11.25 g ES + 13.13 g EFBA), (13.40 g ES + 15.65 g EFBA), (15.54 g ES + 18.13 g EFBA), (17.70 g ES + 20.63 g EFBA) and a control were also tested. Data on pre- and post-cropping soil properties, leaf nutrient levels, and growth parameters were collected. Initial soil analysis showed a moderately acidic pH of 5.7, high organic carbon (14.70 g kg⁻¹) and nitrogen (1.37 g kg⁻¹), low phosphorus (3.19 mg kg⁻¹), and high concentrations of the exchangeable bases (calcium, 2.40; magnesium, 1.12; potassium, 0.30; and sodium, 0.65 cmol kg⁻¹). In the first year, the application of ES level 4 (35.40 g) led to the greatest plant height (75.28 cm) and leaf area (419.60 cm²), while ES level 2 (26.79 g) resulted in the highest number of leaves (11.40) and stem girth (8.06 cm). In the second year, ES level 2 continued to promote growth, with the combination of ES and EFBA level 3 (15.54 g ES + 18.13 g EFBA) producing the largest leaf area (357.70 cm²). These findings highlight the potential of these organic amendments to improve oil palm seedling growth and soil fertility sustainably.