Effect of biochar on water retention in soil, a comparison between two forms: Powder and pellet

Biochar, thanks to its porosity, can have a positive effect in water retention on sandy soils. In this work pellet from Arundo Donax L. was produced at the Biomass Research Centre of the University of Perugia (Italy), then it was used to produce biochar in a pyrolytic stove in the laboratories of the Institute of Biometeorology in Florence (Italy). This biochar was analyzed and characterized at the laboratory of MAC (Minoprio Analisi e Certificazioni) and Richard Pressure Plates were produced to test its action on water retention. Two forms of biochar were tested: pelletized biochar and biochar in powder. While the effect on soil water retention of biochar in powder has already been tested, the effect of pelletized biochar has not. The retention efficiency of biochar pellet was higher than that of the powder. In fact at field capacity an increase in water retention of 20% was measured with biochar in pellet, while the increase was about 4% with biochar in powder. This can bring important advantages to the crops cultivated with biochar as soil amendment, in terms of their water footprint.