Long Term Effects of Liming On Soil and Plant Chemistry in Stressed Areas of a Mining Region.

Knowledge of the levels of metal bioavailability is extremely useful for metal risk assessment program and in understanding the possible effect of liming on biota. In the present study, the long term effects of liming on soil chemistry and plant toxicity were assessed in eroded and stable uplands stands. Analytical results revealed that total metal and nutrient in the soil matrix are not dominantly in forms available for plant uptake for all the sites. Landscape topography, site stability and smelter proximity all play an important role in metal accumulation in surface horizons of regional soils. No significant differences between limed and no-limed areas were found for total metal and nutrient content. The levels of metals in plants were consistent with the concentration of bioavailable metals in soil. Interestingly, in the higher pH limed areas, levels of bioavailable Al, Co, Cu, Fe, K, Mn, Ni, Sr, were significantly lower than on unlimed areas even 30 to 40 years following applications of the dolostone liming materials. Overall, soil toxicity continues to play a key role for plant growth even if the amount of bioavailable metal and nutrient is limited.