Utilizing rice husk biochar and selected phosphate fertilizer to increase phosphate status of ultisol and shallots (Allium ascalonicum L.) productionIdwar, Zulfatri, Elza Zuhry, Sri Yoseva, Rahma Fitrianti and Irwin Mirza UmamiBIO Web Conf., 99 (2024) 05011DOI: https://doi.org/10.1051/bioconf/20249905011