Biodegradation of Some Lignocellulosic Wastes during Composting and Their Valorization as Plant Growth Media

Abstract Purpose The purpose of this study was characterization of lignocellulosic agricultural wastes biodegradation during composting process and evaluating composts as alternative growth media. Methods In this study, agricultural wastes such as spent mushroom (reishi) substrate (SMS), hazelnut pruning waste (HPW), and spent coffee grounds (SCG) were used for composting. K1, K2, and K3 composts were obtained from mainly SMS, HPW, and SCG, respectively. Chemical content and FTIR and TGA evaluation of final composts were compared to initial mixtures or agricultural wastes as controls. Height and dry biomass of tomato seedlings and fresh weight of shoots, fresh yield, and dry biomass of microgreens cultivated in growth media with different proportions of compost fertilizers were compared to those cultivated in peat moss (control). Results Holocellulose/lignin of all initial mixtures decreased in final compost fertilizers. Absorption bands belonging to carbohydrates, aliphatic and nitrogen compounds that changed were evaluated between agricultural wastes and final composts. Dry biomass of tomato seedlings in growth media of SMS1 (90% K1 + 10% sand), SCG1 (90% K3 + 10% sand), SCG2 (45% K3 + 45% peat + 10% sand) and 15 + 15 + 15 (compound fertilizer) was higher than the control. Fresh yield of Lepidium sativum microgreens was higher in growth media of SCG1, SCG2, and SCG3 (20% K3 + 70% peat + 10% sand) at 1.890, 1.908, and 1.799 kg m -2 compared to control. Conclusions Biodegradation of lignocellulosic agricultural wastes could be characterized by chemical and analytical methods. As peat moss is not a sustainable source, all compost fertilizers in this study could be used sustainably as growth media for soilless cultivation.