Enhancing avocado growth and soil sustainability using date palm waste biochar as a climate smart solution for...

Sustainable agriculture demands innovative approaches to enhance plant growth while minimizing environmental footprints. Biochar, a carbon-rich material derived from biomass pyrolysis, has emerged as a promising amendment for improving soil fertility, optimizing crop productivity, and mitigating greenhouse gas emissions. This study evaluates the influence of date palm (Phoenix dactylifera L.) biochar on the growth, physiological traits, and greenhouse gas emissions of Fuerte avocado (Persea americana Mill.) seedlings over two consecutive years. Biochar was produced at two pyrolysis temperatures (300 ℃ and 700 ℃) and incorporated into the growth substrate at four levels (0%, 10%, 20%, and 30% w/w). The greatest improvements in plant height, trunk diameter, leaf number, leaf area, root length, and fresh biomass were observed in seedlings treated with 30% biochar produced at 300 ℃ (T4-300℃), particularly in the second year, where leaf chlorophyll content (0.395 mg•g⁻¹) and carbohydrate content (24.0 mg•g⁻¹) reached peak values. This treatment also significantly reduced total phenol content, a factor that may benefit avocado micropropagation. Furthermore, biochar application at 30% w/w at 300 ℃ markedly decreased nitrous oxide (N₂O) emissions, while biochar produced at 700 ℃ minimized carbon dioxide (CO₂) emissions in 2023. From an economic perspective, the 30% biochar treatment demonstrated potential for cost-effective avocado cultivation, supporting sustainable production systems. These findings confirm that date palm biochar particularly at 30% concentration and a pyrolysis temperature of 300 ℃ offers a viable, environmentally friendly strategy for enhancing avocado seedling growth while mitigating soil greenhouse gas emissions.