Improvement of some chemical properties of an Ultisol of East Kalimantan through application of combined coal fly ash and oil palm empty fruit bunch

Abstract

Coal fly ash and oil palm empty fruit bunch are industrial wastes that enormously available in areas of East Kalimantan dominated by Ultisols with poor soil chemical properties. The objective of this study was to explore the possible improvement of soils chemical properties of an Ultisol of East Kalimantan through application of combined coal fly ash and oil palm empty fruit bunch. Twelve treatments which were combination of four doses of coal fly ash (0, 20, 40, and 80 t / ha) with three doses of oil palm empty fruit bunch compost (0, 10, and 20 t / ha) were arranged in completely randomized design with three replications. Each o combination of coal fly ash and oil palm empty fruit bunch compost was mixed evenly with soil and incubated for 10 weeks. The soil chemistry properties analyzed after 10 weeks incubation were pH, exchangeable Al, exchangeable H, total P, available P, and organic C. The results showed that there were improvements in soil chemical properties that were identified by the increase of soil pH, total P, available P. and organic C contents and of the decrease of exchangeable Al and H. Except for organic C which was only influenced by application of oil palm empty fruit bunch compost, the combination of coal fly ash and oil palm empty fruit bunch compost gave a better effect compared to application of coal fly ash without oil palm empty fruit bunch compost, or vice versa application of oil palm empty fruit bunch compost without cal fly ash. The combination of 80 t coal fly ash / ha and 20 t oil palm empty fruit bunch compost / ha increased pH by (24%), total P (101%), available P (542%) and decreased exchangeable Al (90%) and exchangeable H (53% ) compared to the initial soil chemical properties.