Biochar Derived from Sugarcane Bagasse Can be Used to Reduce Peat Use without Compromising Growth in Marigold

Biochar, the product of pyrolyzed organic materials, has environmental benefits of sequestering carbon while stabilizing materials for use in agricultural settings. However, the feedstock used can influence the final biochar product characteristics. This research investigated the impact that biochar derived from bagasse has on an ornamental crop as a soilless substrate component to identify potential uses for sugarcane bagasse, which is the fibrous remains of the plant after sugar extraction. Peat-based commercial substrate was amended with bagasse biochar at 0%, 15%, or 30% (by volume) and used to grow marigold ( Tagetes patula ‘Janie Gold’) plants for 6 weeks under low (100 ppm N) and high (300 ppm N) fertigation regimes. The results indicated that there were no deleterious effects of biochar incorporation on plant growth and suggested that there may be added nutrient retention from fertigation in substrates amended with biochar. The biochar incorporation ratio had less of an effect on foliar concentration than fertility management; in almost every case, greater fertility concentrations resulted in more concentrated foliar nutrition. Plants grown in 30% amended biochar substrates had greater foliar potassium ( P < 0.0001) under high fertigation rates. Increasing biochar incorporation proportions increased nutrient retention and extended release when compared with conventional peat-based substrates. Increasing biochar rates decreased container capacity ( P = 0.0017) despite containing greater finer particle proportions (