Mechanism of Soil Eco-Functional Stability Under Pyrene/Cadmium Simplex and Combined Pollution Stress

Abstract

In current scenario,the soil pollution has become very severe and its effects on agricultural and ecological security issues cannot be ignored as various contaminants are discharged into soil.Thus,the soil pollution is exigent and has to be solved.This research took soil resistance (Rt),resilience (Rl) and stability (Sb) as evaluation indexes for judging soil quality by exerting different concentration (concentration ratio) gradient of pyrene (PYR),cadmium (Cd) and pyrene/cadmium (PYR/Cd) combined pollutants.A sympathetic description was showed from the aspects of microbial activity,diversity and abundance of soil ecosystem,and the models were constructed to describe the dose-response relationship between PYR-Sb and Cd-Rt.The research showed that different types of pollutants had certain inhibition on soil DOC content.In Cd and PYR simplex pollution,soil microbial mean biomass and colony number decreased with increasing concentration of pollutants.In PYR/Cd combined pollution,the ratio of PYR and Cd had a negative correlation with the decreasing rate of DOC and resistance,meanwhile Cd had a prominent influence on the above-mentioned correlations,in other words,the soil with higher concentration of Cd had lower DOC decrease rate and resistance,and Cd would have dominant inhibition effect on microorganisms under PYR/Cd combined pollution.In addition,this study found the significant correlation of cPYR-Sb and cCd-Rt,and built the binomial forecasting model to describe the dose-response relationship of cPYR-Sb and cCd-Rt.