Biochar from argan shells: production and characterization

Purpose The agricultural practices in south western Moroccoreserve a majority of the water resources to be usedfor irrigation. The extent of irrigated agriculture combinedwith high evaporative rates, lead to the depletion of waterresources and degradation of soil quality. To remedy to thisproblem, biochar, a pyrolysed biomass, is highly consideredto improve retaining water and nutrients in soils. Forthis biochar research, argan shells obtained after extractionof argan oil were used as the biomass source to producebiochar. According to the best of our knowledge, noresearch to date has been carried out on the production andcharacterization of biochar produced from argan shellswastes.Methods To produce biochar, we have used a pyrolyticstove fabricated in Morocco from locally available materials.The biochar sample collected was then crushed,sieved (2 mm) and its physical, and chemical characteristicswere analysed and compared with those of othermedia (soil and peat).Results The physical and chemical properties of the arganshells biochar revealed a highly alkaline pH, high electricalconductivity, high content of K, Na, Mg and NaNO3, lowcontent of Ca, KH2PO4 and low content of heavy metalscompared to sandy soil and peat. In addition, by increasingbiochar application, the water holding capacities of biochar-sand mixtures also increased.Conclusions The use of argan shells biochar to enrich thesoil will be expected to improve both nutrient and waterretention especially that South Western Morocco is subjectto frequent drought.