RESPONSES OF SOIL β-GLUCOSIDASE ACTIVITIES TO SIMULATED INCREASED PRECIPITATION IN A SEMI-ARID TEMPERATE GRASSLAND

In concurrent with global warming, precipitation regimes are predicted to change as well around the world. In this study, two experimental sites were selected with different nutrient availability along a slope to study the effects of simulated increased precipitation on soil P-glucosidase activities in an Inner Mongolian grassland. Soil samples were adjusted to 55% of water holding capacity and incubated at 22 C in the dark for 32 days. Soil beta-glucosidase activities were measured prior to and after the incubation. Results showed that soil beta-glucosidase activities had differential responses to increased precipitation with a significant increase in the down-slope site, but not in the upslope site. Correlation analysis showed that the initial soil beta-glucosidase activities exerted a significantly negative relationship with soluble organic nitrogen (N). Our results indicated that both water availability and soil soluble N availability played important roles in regulating beta-glucosidase activities in this semi-arid region.