Application of Wood and Vegetable Waste-Based Biochars in Sustainable Agriculture: Evaluation on Nitrate Leaching, Pesticide Fate, Soil Properties, and Brassica oleracea Growth

Environmental pollution is caused by the unsustainable use of nitrogen (N) fertilizers and pesticides. Biochar (BC) is a carbon-based material applied to remove excess nutrients and pesticides from the environment. In pot experimental research, N fertilizer and pesticides alone and different biochar types were applied in the soil to evaluate cauliflower growth, soil quality, and leaching of agricultural contaminants. BC addition had increased nutrient availability based on feedstock origin. The surface structure results by SEM showed that the BC pore size was equal to 8.94 and 7.24 µm for mixed biochar and wood biochar, respectively. Nitrate concentrations in percolation water were 43.78 and 76.82 mg/L in mixed biochar and wood biochar, respectively. In soil treated with fertilizer and pesticides, NO3− was equal to 106.76 mg/L. Biochar’s binding with pesticides depends on its nature and structure. Adding wood biochar significantly reduced the leaching of fungicide compared to unamended soil, with a contraction of 327.86 and 3576 ng/L. Mixed biochar was more efficient for herbicide mitigation. FTIR was used to identify the functional groups on biochar-amended soil that play a role in the adsorption of agricultural compounds. Research shows that the BC application greatly affects the pesticide fate and N compounds of agricultural origin in soil.