Impact of organic and chemical fertilizer combinations on growth, yield, and soil carbon in in oil palm cultivation at Talgaswella estate, Sri Lanka

Abstract

The success of oil palm cultivation hinges on factors such as planting material quality, management practices, and the availability of essential macro and micro-nutrients. Insufficient nutrient supply adversely impacts both vegetative growth and the ultimate yield in terms of quantity and quality. To address this issue, an experiment was conducted at Talgaswella Estate, belonging to Elpitiya Plantations PLC., situated in the Low Country Wet Zone (LCWZ) of Sri Lanka. The objective was to enhance the productivity and profitability of marginal oil palm lands. A ten-year-old oil palm field was chosen as the experimental site, employing a Randomized Complete Block Design (RCBD) with eleven treatments and three replicates, including an absolute control. Each trial plot consisted of six palm trees, totaling 198 trees in the experiment. Treatments involved varying combinations of Empty Fruit Bunches (EFB), Palm Oil Mill Effluent (POME), and Poultry Litter (PL), with and without chemical fertilizer. Soil, plant, and yield parameters were measured, and the data were analyzed using the Minitab statistical tool. After three years, results indicated that 100% organic fertilizer-received plots (T11) and 100% chemical fertilizer-treated plots (T2) exhibited significant increases in average fresh fruit bunch weight (22.81 Kg and 21.82 Kg), soil organic carbon percentage (3.00 and 2.23), and leaf chlorophyll content (78.79 and 75.07) of the 17th frond compared to T11 and T2 treated plots. Intermediate results were observed in the remaining fertilizer combined plots (T3, T4, T5, T6, T7, T8, T9, T10). The findings suggest that the use of organic fertilizer in marginal oil palm lands not only improves crop and soil factors but also contributes to environmental sustainability through the recycling of oil palm waste products. It is recommended to periodically apply organic fertilizer, especially on marginal oil palm lands, to enhance overall crop productivity and land sustainability.