https://journal.uhamka.ac.id/index.php/bioeduscience/ BIOEDUSCIENCE, 7(1): 1-7, 2023. DOI: https://doi.org/10.22236/jbes/7111185 ISSN: 2614-1558 | 1 BIOEDUSCIENCE ISSN: 2614-1558 http://journal.uhamka.ac.id/index.php/bioeduscience The Effect of Coal Bottom Ash and Compost Soil Media on the Growth of Red Chili Plants (Capsicum annuum) Nunung Eni Elawati 1* , Carmelia Santania Fahik 1 , Arifah Nurul Izza 1 , Fika Ainur Rahmawati 1 1 Biomedical Science study Program, Ivet University, Jl. Pawiyatan Luhur IV No.16, Bendan Duwur, Kec. Gajahmungkur Semarang, Indonesia, 50235 * Correspondence: nunungenie@gmail.com Abstract Background: Coal burning activities at PLTU leave large amounts of waste every year, which can become a problem of environmental pollution. Bottom ash is known to contain nutrients needed by plants. This study aims to determine the effect of adding a mixture of compost to ameliorate bottom ash on the pH and plant growth of Capsicum annuum. Methods: The study used a completely randomized design (CRD) with three replications and four formulations, namely B0 = coal waste (200g); B1 = 100g of bottom ash: 100g of planting medium; B2 = 50g bottom ash: 150g planting medium, and B3 = 150g bottom ash: 50 g planting medium. Parameters observed included plant height, number of leaves, root length, number of roots, total Biomass, and pH. Results: The results showed that treatment B0 had the highest pH and B2 had the lowest pH. Treatment B2 successively showed the most heightened plant height, the largest total Biomass, and the most increased root length and had a significant effect on leaf number but had no significant effect on root number. Conclusions: The application of bottom ash with soil compost media impacted the pH and the growth of C. annuum plants, especially in plant height, number of leaves, total Biomass, and root length of C. annuum plants. Keywords: Bottom Ash; Capsicum annum; Coal; Plant Growth. Introduction Coal-burning activities at PLTU leave large amounts of waste every year. Coal combustion produces around 5% of solid pollutants in fly ash and bottom ash (Damayanti, 2018), of which around 10-20% is bottom ash and about 80-90% of fly ash of the total ash produced (Noviardi, 2013). Increasing the supply of electrical energy by constructing new power plants correlates with an increase in coal waste produced. If coal waste is not used optimally, it will become a problem of environmental pollution (Utami, 2018). Chemically, coal ash is an aluminosilicate mineral that contains many elements such as Ca, K, and Na while also containing small amounts of parts C and N (Hermawan, Sabaruddin, Marsi, Haryati, et al., 2014). Other nutrients in coal ash that are needed in the soil for plants include Boron (B), phosphorus (P), and elements such as Cu, Zn, Mn, Mo, and Se (Dwivedi & Jain, 2014). Generally, coal ash is alkaline (pH 8-12). Physically, it has a silt-sized particle size and has moderate to high water-binding capacity characteristics (Yuyun, 2015). So far, research on coal waste has been used for agriculture and construction (Prasetia et al., 2014). Several studies have focused a lot on the use of fly ash in agriculture, such as research by Utami (2018), which states that using fly ash as a mixture of organic fertilizers can increase the pH of the fertilizer, namely with a pH of 8.52. However, fly ash does not affect the amount of N content, P, and K. Bottom ash is still limited to its use as a building construction material (Ria Nur et al., 2020). Fly ash is more often used than bottom ash as a soil conditioner in recent research on coal ash because fly ash has a smaller size, namely 0.001 – 100 m, compared to bottom ash Article history Received: 22 Feb 2023 Accepted: 29 Apr 2023 Published: 30 Apr 2023 Publisher’s Note: BIOEDUSCIENCE stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Citation: Elawati, N.E, Fahik, C.S., Izza, A.N., & Rahmawati F.A. 2023. The Effect of Coal Bottom Ash and Compost Soil Media on the Growth of Red Chili Plants (Capsicum annuum). BIOEDUSCIENCE, 7(1), 1-7. doi: 10.22236/jbes/7111185 ©2023 by authors. Lisensi Bioeduscience, UHAMKA, Jakarta. This article is open- access distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license.