Brazil�s Northeast region is often exposed to rigorous drought. Although it rains in the region during two or three months per year, the presence of soils with low water holding capacity and the strong sunlight incidence provoke water downward infiltration, rapid evaporation and water deficiency throughout the rest of the year.In this work, we propose the use of agriculture and industry wastes to increase soil hydration. Three soil amendments were investigated. They were two biochars produced from green coconut shell (CS) and water hyacinth (WH), and charcoal residues (CR) from the metallurgical industry. The soils used were an Inceptisol soil (IS) and a Quartzarenic Neosol (QN), with sandy textures (sand total contents of 77% and 82%, respectively). After mixing 10% of amendments with the soil, the field capacity in the resulting mixtures increased with respect to that of the initial soils: 11%, 21% and 48% in the IS soil, and 29%, 40% and 97% in the QN soil, after adding CR, CS and WH materials, respectively. The capacity of these materials for metal pollution stabilization and wastewater treatment was also investigated. From sorption isotherms obtained at a wide range of initial metal concentration (between 0.025 and 5 mM). It was observed that the WH biochar and the CR presented high sorption capacity for Cd(II), Cu(II), Pb(II) and Zn(II). This metal removal was above 95% from metal ion solutions, with low sorption reversibility. The results of the present study indicated that the CS and, especially, WH biochars are promising materials to increase the water holding capacity in soils, whereas CR and WH biochar may also be considered for the stabilization of metal pollution and treatment of contaminated soils and, especially, wastewaters, which could also be reused to water agricultural soils during drought periods.

Reducing the Brazil's northeast drought effects in soils through the use of charcoal and biochar amendments

248th National Meeting (2014)

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