Effects of Humus on Heavy Metals Absorption of Maize in Heavy Metal Contaminated Soil

Abstract

To investigate the effect of humus (HS) on the growth of corn in heavy metal-contaminated soils, the present study first used sodium hydroxide (NaOH) to extract soluble humus (PHS) from peat soil and soluble humus from weathered lignite (LHS). Elemental analysis and Fourier transform infrared spectroscopy (FTIR) were used to analyze the chemical composition and functional group differences of the two HSs. Then, pot experiments were conducted to study the effects of LHS and PHS on soil carbon and nitrogen content, and on maize growth and the absorption of heavy metals in different plant parts. The main results showed that: (1) Compared with the control, corn biomass increased significantly when exogenously added 200mg/kg HS. The effect of HS on plant height and root length was different in both HS. The more hydrophilic PHS mainly affected the plant height of maize, while the more hydrophobic LHS mainly promoted the growth of maize root; (2) When PHS was applied At 100mg/kg, the Cd content of aerial parts of maize decreased significantly; when the application concentration of PHS was 200mg/kg, the content of Cu in the underground part of maize and the content of Cu and Zn in aerial parts decreased significantly; when the application concentration of PHS was 500mg/kg The content of Zn in the underground part of corn was significantly reduced. When LHS was applied at a concentration of 200mg/kg, the content of Zn in the underground part of maize was significantly reduced. When LHS was applied at a concentration of 500mg/kg, the content of Cu in the underground part of maize and the content of Zn in the aerial parts were significantly reduced.