A study published in Agronomy by João N. G. V. Canedo et al. evaluated how biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More and mulch affect soil hydrology, erosion, and phytotoxicity using different application strategies. The research found that applying a mulch layer, especially with a biochar underlayer, is most effective in reducing runoff and erosion while enhancing soil health.

Agricultural intensification in Mediterranean regions often leads to soil degradation, including erosion and loss of organic matter. Mulch and biochar are used to combat these effects; however, the best application methods and their combined effects require more study. This study examined four treatments: biochar mixed into the soil, a biochar layer on the surface, a mulch layer on the surface, and a mulch layer on top of a biochar layer.  

Rainfall simulations were conducted on sandy loam soils from a vineyard and olive orchard to measure runoff and erosion. The leachate from these simulations was used to test phytotoxicity.  

The results showed that treatments with a mulch layer significantly reduced runoff and erosion. Biochar increased root length, indicating improved soil habitat. The combination of mulch and biochar layers proved most effective, demonstrating their complementary benefits in mitigating soil degradation.  

This research suggests that layering mulch over biochar is an optimal strategy for reducing soil degradation and improving soil health in agricultural soils.  

Source: Canedo, J. N. G. V., Coelho, L., Castro, L., Verheijen, F. G. A., & Prats, S. (2025). Biochar and Mulch: Hydrologic, Erosive, and Phytotoxic Responses Across Different Application Strategies and Agricultural Soils. Agronomy, 15(4), 926.