Wool pelletisation: valorising Manech coarse fleeces as soil conditioner

This study presents a simple, locally applicable valorisation route for coarse Manech Tête Rousse wool, a currently underutilised by-product of dairy systems in the northern Basque Country. Raw fleeces were converted into wool pellets to enhance density and handling for soil amendment applications. Two fleece types-obtained from ewes bred under two farming systems-were mechanically ground without chemical or thermal pre-treatment and then pelletised at different compression ratios and moisture contents. A clear processing window was identified, enabling stable pellet formation with good mechanical properties, high attrition resistance and suitable bulk density for handling and field application. The pellets exhibited a high water-holding capacity (up to 288% w/w) and markedly delayed soil drying under simulated drought when mixed into a soil. A friction-driven densification mechanism is proposed to explain the influence of processing parameters on pellet density and durability. Overall, this work demonstrates a technically simple pathway to transform low-value coarse wool into high-density soil conditioners that enhance water retention. Further research is needed on agronomic performance, nutrient release and sanitary safety.