Suppression of labile aluminium in acidic soils by the use of vermicompost extract

Abstract

Chelation combined with pH‐induced precipitation to reduce the levels of labile aluminium (Al) in several acidic soils upon treatment with vermi‐compost aqueous extract (VCE). Significant reduction was observed for very acidic soils in which VCE did not produce a pH rise sufficient to induce Al precipitation, chelation effects being solely responsible. The effects of vermi‐compost (VC) fractions (VCE, washings and residues) on the labile Al of an acid soil were examined. The results did not reflect a simple additive relationship between the fractions in that an increase in labile Al reduction was observed over that for the original VC. An increase in relative effectiveness in immobilising labile Al with successive washings of VC was also observed.