Comprehensive Application to Grow Calliandra calothyrsus by Using Cow Dung Biochar and Solid Waste from Silica Sand Purification on Critical Mining Land

The synergistic combination of cow dung biochar and solid waste to fertilize Calliandra calothyrsus is the right choice for rejuvenating critical ex-mining land. The growth rate of C. calothyrsus is one of the indicators under biological control for the assessment of toxic materials contamination, soil nutrition conditions, microbial respiration, and cellulase enzyme activity. The preparation of biochar and solid waste was conducted under a physical method, in which the 60% solid waste is mixed with 40% biochar (60:40 w/w). This study has collected experimental data including determination of barium (Ba) metal content in growing media, distribution of Ba metal in C. calothyrsus, acid content in growing media, and biochemical identification to evaluate media nutrition and microbial activity. Based on these results shows that the biochar has a good ability to reduce Ba metal when mixed with solid waste. Monitoring time during the fourth month shows a decrease in Ba concentrations. In addition, C. calothyrsus plant also indicated a high absorption of Ba metal with increasing weeks. Moreover, the identification of acidic media was evaluated, where the biochar and solid waste increased in the fourth week. Microbial biomass was also identified to observe biochar can improve chemical composition when mixed with solid waste. Where, 15.82% carbon, 46.67 nitrogen, and 60.82% phosphorus were identified in biochar and solid waste as fertilizer media. This will also certainly increase the activity of cellulase enzymes and microbial respiration in the environment for the same handling and high chemical composition on critical ex-mining lands.