Abstract:We analyzed the effects of burrowing activity of plateau pikas on inorganic nitrogen in soils by measuring the total nitrogen content,N-NH4+ content,and N-NO3- content in different sorts of mounds soil and in soil 0 - 10 cm below the mounds,and estimated increased sizes of inorganic nitrogen by mean mounds density rate. The results showed that total nitrogen contents were not changed in different sorts of mounds soil,and the trend for NH4+ nitrogen content,NO3- nitrogen content,inorganic content were:in new mounds > in two-year mounds > in multiyear mounds > in control soil. The one way ANOVA results showed that NH4+ nitrogen content was not changed in different sorts of mounds soil,but NO3- nitrogen content in new mounds soil and in two-year-old mounds soil was greater than it was in multiyear mounds soil and in control soil in May (F = 14.55, P < 0. 001,df =3,12),and inorganic content in new mounds was greater than it in control soils in May and September (FMay =14.55, P <0.001,df = 3,12; FSept.= 3. 92, P < 0.05,df =3,12). N-NH4+ content reduced gradually from May to August,and increased in September,N-NO3- content and inorganic nitrogen content showed the trends of “high-low-high-low-high”from May to September. The one way ANOVA results showed significant differences between months. N-NH4+content, N-NO3- content and inorganic nitrogen content in soils 0 - 10 cm under different sorts mounds showed the same change as in mounds soils among months and treatments,but N-NO3-content and inorganic content were greater in soils 0 - 10 cm under new mounds soil than it was in control soil (P < 0. 05) in the same month respectively, and N-NH4+content,N-NO3- content and inorganic nitrogen content showed significant differences between different months of the magnitude of the changes in N-NH4+ content,N-NO3- content and inorganic nitrogen content were 162.6 mg/ kg, 355.1 mg / kg and 497.7 mg / kg respectively in new mounds soil.