Koreh, A. A.; Widowati; Julianto, R. P. D. Long-Term Residual Effects of Biochar from Tobacco Scraps on Red Spinach (Amaranthus Tricolor) Growth in Entisols: A Five-Year Field Experiment With Urea Fertilizer Addition. J. Ilm. Pertan. 2023, 20, 153-164.