Cadmium Treatment Affected Bacterial Community Structure and Chemical Properties of Unplanted Haplic Cambisols in Concentration- and Time-Dependent Manners
摘要
With the development of industry and agriculture, heavy metal pollution has become increasingly prominent and can have serious impacts on soil and human society, among which cadmium (Cd) pollution is particularly noteworthy. Our aim is to provide a theoretical basis and guidance for the comprehensive exploration of the ecological and environmental effects of Cd on the ecological environment and bacterial community of unplanted Haplic Cambisols in Northeast China. By indoor cultivation methods, unplanted Haplic Cambisols were treated with different concentrations of Cd (0, 1, 5, 25 and 50 mg kg−1) solutions. After 30, 60, and 90 days of Cd treatment (represented as d30, d60, and d90, respectively), the changes in the bacterial community structure and chemical properties of Haplic Cambisols under different Cd concentrations and durations were investigated, and the main bacterial genera that can survive in Cd treatment environment were identified. At d30, the abundance and diversity of the bacterial communities increased with increasing Cd concentration, showed a wave-like increase at d60, and gradually decreased at d90, indicating that Cd treatment time had an inhibitory effect on bacterial abundance and diversity. As the Cd cultivation time increased, the bacterial abundance at different times was ranked as d30 > d60 > d90. The diversity ranking was d30 > d60 > d90, and d30 and d60 were significantly greater than d90. Proteobacteria, Acidobacteria, and Actinobacteria, as the dominant bacterial phyla, accounted for averages of 36.5%, 17.1%, and 15% of the soil bacteria, respectively. In addition, Cd treatment reduced the pH of Haplic Cambisols and increased the content of available phosphorus (AP) but had no significant effect on the content of available potassium (AK). During short-term cultivation (d30, d60), Cd pollution increased the content of hydrolytic nitrogen (HN) in Haplic Cambisols, whereas during longer cultivation (d90), the content decreased. In addition, pH was the first environmental factor that affected the abundance and diversity of soil bacterial communities. Partial Cd treatment had a significant impact on soil bacterial communities and chemical properties of the soil, and varied with its concentration and treatment time. Further research is needed to investigate the effects of Cd on the nutrient decomposition and absorption functions of soil bacteria, as well as the effects of bacteria on soil chemical properties.