Influence of biochar on the physical, chemical and retention properties of an amended sandy soil

Soil porosity plays an important role in soil-water retention and water availability to crops, potentially affectingboth agricultural practices and environmental sustainability. The pore structure controls fluid flow and transportthrough the soil, as well as the relationship between the properties of individual minerals and plants. Moreover,the anthropogenic pressure on soil properties has produced numerous sites with extensive desertification processclose to residential areas.Biochar (biologically derived charcoal) is produced by pyrolysis of biomasses under low oxygen conditions,and it can be applied for recycling organic waste in soils and increase soil fertility, improving soil structure andenhancing soil water storage and soil water movement.Soil application of biochar might have agricultural, environmental and sustainability advantages over the use oforganic manures or compost, as it is a porous material with a high inner surface area.The main objectives of the present study were to investigate the possible application of biochar from forestresidues, derived from mechanically chipped trunks and large branches of Abies alba M., Larix decidua Mill.,Picea excelsa L., Pinus nigra A. and Pinus sylvestris L. pyrolysed at 450 C for 48h, to improve soil structural andhydraulic properties (achieving a stabilization of soil).Different amount of biochar were added to a desertic sandy soil, and the effect on soil porosity water retention andwater available to crops were investigated.The High Energy Moisture Characteristic (HEMC) technique was applied to investigate soil-water retentionat high-pressure head levels. The adsorption and desorption isotherms of N2 on external surfaces were alsodetermined in order to investigate micro and macro porosity ratio.Both the described model of studies on adsorption-desorption experiments with the applied isotherms modelexplain the increasing substrate porosity with a particular attention to the macro and micro porosity, respectively.