Abstract:
Soil microbial functions are considered to be effective in assessing the severity of heavy metal pollution.
Therefore, this study was carried out to examine the effect of heavy metals on nitrogen mineralization by
measuring the releasing pattern of inorganic nitrogen (NH4
+
-N and NO3
-
-N) in a soil treated with heavy
metals. A factorial combination of two heavy metals (Zn and Cd) treated with three concentrations (50, 100
and 150 µmol g-1 soils) was used in a laboratory incubation. Nitrogen mineralization was determined at 3, 7,
14, 21, 28, 42 and 56 days after the treatments replicated four times. Soil sample free from heavy metals was
served as the control. The amount of nitrogen mineralization from heavy metal treated soils was found to be
decreased at an increasing rate during the first 21 days of incubation. However, as the incubation progressed,
nitrogen mineralization was found to be decreased at decreasing rates. Furthermore, during this period,
nitrogen mineralization in Cd treated soils was significantly lower (P≤0.05) than that of the control. Soils
treated with Cd at the concentration of 150 µmol g-1 showed the lowest N mineralization throughout the
incubation. Nitrogen mineralization in Zn treated soils (50 µmol g-1) was found to be higher than the other
heavy metal treated soils. On the base of present findings, nitrogen