3.1 Effects of grazing on the GRSP concentration
The concentration of T-GRSP and EE-GRSP were determined for each grazing succession stage (Fig. 1). Analysis of variance showed that the mean concentrations of T-GRSP and EE-GRSP in soils were significantly different (P < 0.05) between the surface (0-10 cm) and subsurface (10-20 cm) soils. T-GRSP (10.42% (FB)-81.25% (KC)) and EE-GRSP (12.63% (FB)-70.31% (K)) were higher in the surface than in the subsurface soil. T-GRSP and EE-GRSP were highest in GK community sites (14.71±0.67 and 3.69±0.15 mg/g, respectively, in surface soils, and 8.85±0.92 and 2.30 ±0.19 mg/g, respectively, in subsurface soils). The concentration of T-GRSP and EE-GRSP in surface soils had a significant decreasing trend from GK, K, KT, KC to FB. However, the contents were not significantly different among K, KT, and KC. T-GRSP in surface soils was lowest in KT and FB, while EE-GRSP was lowest in KC community sites. Overall, GRSP contents gradually decreased with increasing intensities of grazing.