Suppressing runoff on sloping loess using morphogenetic porous carbon: A novel nano-engineered, waste-derived soil amendment

The use of engineered biochar as an advanced technology within soil conservation strategies to enhance the effectiveness and efficiency of conventional soil amendments remains insufficiently explored. Therefore, the current research investigated the effect of Morphogenetic Porous Carbon (MGPC) derived from agricultural and industrial wastes on controlling runoff production in loess soils in northeastern Iran. In this study, biochar prepared from eight types of waste was converted into MGPC using KOH as an activator. The five priority MGPCs, selected using the BET test and the game theory approach, were subsequently produced in the required volumes to assess their effectiveness on hydrological components at three levels. The research was conducted in the laboratory, using small experimental plots measuring 0.5 × 0.5 m and three slopes at about 8, 15, and 27%. The study treatments underwent a designed rainfall of about 70 mm h −1 for 30 min, with three replications (i.e., 180 plots) in the Rainfall and Erosion Simulation Laboratory of Tarbiat Modares University, Iran. The hydrological behavior of the treated and control experimental plots, including the start time of runoff, runoff volume, and runoff coefficient, was assessed at 2-minute intervals. According to the study's results, applying five selected MGPCs at rates of 300, 900, and 1500 g m −2 on slopes of 8, 15, and 27% significantly reduced runoff. Among the materials tested, MGPC made from rice straw and palm pruning performed best. At the highest application rate (1500 g m⁻²) and the lowest slope gradient (8%), it reduced runoff by 17.56 times compared to the control under those same conditions, and by 8.82 times under the control conditions at the other extreme—both reductions being statistically significant (p < 0.05). The mean runoff start time in the vineyard pruning, palm tree pruning, sawdust, rice straw, and tissue factory-treated plots at an application rate of 1500 g m −2 and a slope of 8% increased by 17.79, 22.00, 23.19, 24.08, and 12.43 min, respectively, compared to the control treatment. The results also showed that MGPC obtained from rice straw and palm pruning performed significantly higher (p < 0.05) than the other MGPCs studied, especially at 1500 g m −2 , for all hydrological components. Overall, higher application rates of MGPCs and gentler slopes were associated with greater treatment effectiveness, suggesting the potential of these solutions as advanced soil amendments for water management.