Humified phenol-rich plant residues and soil urease activity

A greenhouse experiment was conducted to examine the comparative effects of phenolrich and phenol-poor plant residues after prolonged decomposition, on the urease activity of an acid soil. Addition of organic residues increased soil urease activity over that of control; but soils amended with phenol-rich residues had a urease activity which was about 50% lower than that of soils amended with phenol-poor residues. This reduction in soil urease activity was attributed to the higher content of soil polyphenols present in the soils amended with phenol-rich residues.