S. Supriyadi, B. W. Widjajani, and E. Murniyanto, “The Effect of Rice Husk Biochar and Cow Manure on Some Soil Characteristics, N and P Uptake and Plant Growth of Soybean in Alfisol”, j Trop. Soils, vol. 27, no. 2, pp. 59–66, Mar. 2022.