Simbolon, T.A., Mutryarny, E. and Purnama, I. 2025. Effectiveness of Combined Shallot Skin Compost and NPK Fertilizer on Cayenne Pepper (Capsicum frutescens) Plants in Ultisol Soil. Journal of Bioprocess, Chemical and Environmental Engineering Science. 6, 1 (Mar. 2025), 1-12. DOI:https://doi.org/10.31258/jbchees.6.1.1-12.