Potential of Using Fly Ash as an Additional Mixture for Planting Medium

Increased use of coal has an impact on the environment because of the waste from coal combustion residual. It also has an impact on the management of waste due to limited land for the temporary storage of waste owned by the coal user industry. In the Government Regulation of the Republic of Indonesia Number 22 of 2021 concerning the Implementation of Environmental Protection and Management, fly ash and bottom ash are registered as non-hazardous waste. The addition of fly ash to the planting medium can affect soil fertility and biota in the soil. The number of heavy metals contained in the soil to which fly ash is added depends on the amount of fly ash so that it can affect the heavy metals in plants. The number of microbial populations in the soil such as fungi and actinomycetes in the soil decreases with the added concentration of fly ash which is due to changes in soil pH such as denitrifying microbes [1]. In this research, cocopeat, and guano growing media were used in a ratio of 1:1. The addition of fly ash to the planting medium were 20%, 30%, and 40%. In addition, this research also evaluated the effect of the addition of EM4 and the selected microbes on the growing media mixture. The planting medium was aerobically fermented for one week, two weeks, and three weeks. Then it was tested for macro elements, the number of bacteria, moisture, and pH every week. The mixture of planting media was tested on mustard pakcoy for one month to see the growth of the plant indicated by the number of leaves and plant height. From the results of this research, it was found that bacteria affect the growing media (pH, the number of microbes, phosphate, and potassium) and the plant growth in the height and total of leaves. Variations in the addition of fly ash to the growing media affect phosphate and aluminium content.