Soil sterilization and fertility impacts on urease and belowground mass specific phosphatase activity vary among Chinese tallow tree (Triadica sebifera) populations

Invasive plants from introduced populations may utilize soil nutrients more efficiently and increase their performance relative to those from native populations but this may vary with soil biota and soil fertility. In part this may reflect differences in soil enzymatic activity but this has not been examined. Here, we investigated the effects of soil sterilization (control or sterilized) and soil fertility (control or addition of nitrogen and/or phosphorus) on Triadica sebifera plants from introduced (USA) and native (China) populations and their impact on soil enzyme activities (urease and phosphatase) in a greenhouse experiment in China. Native and introduced populations had similar above and belowground biomasses in active (control) soil but soil sterilization decreased them, especially for native populations. Simultaneous addition of N and P increased biomass differences between active and sterilized soil compared with that under fertilization control treatment. Urease activity was higher for native population plants in active soils but an opposite pattern was found in sterilized soil. Belowground biomass specific phosphatase activities were increased by soil sterilization, especially for native populations or when both N and P were added. The dependence of soil enzyme activities on the interactions of soil sterilization, soil fertility and plant population origin suggest that there may have been genetic changes in soil enzyme activities during the invasion process. Because urease and phosphatase showed distinct patterns, T. sebifera may have acquired different strategies for the utilization of soil nitrogen and phosphorus, which likely has implications for understanding and managing invasions.