The Influence of Hg on Soil Enzyme Activity under Different Nitrogen Levels

The effect of heavy metal Hg on activities of soil urease, catalase and invertase in corn field with different nitrogen supplying levels.. The concentrations of Hg2+ were 0, 0.3125, 0.625, 1.25, 2.50 mg·kg-1 dried soil, respectively. The three enzymes responded differently to Hg stress under different N treatments, the inhibition effect of Hg on urease activity was most significant, while the inhibition on catalase only existed at high nitrogen levels, the response of soil invertase under Hg stress firstly increased and then decreased. Under different nitrogen levels, the inhibition of Hg on three soil enzymes activity were as follows: urease > invertase > catalase. The results suggested that soil urease and soil invertase can be used as Hg pollution ecological monitoring index, early warning Hg pollution degree, while, soil catalase was not suitable as a soil Hg pollution warning index.