3.1 Soil properties at the three steppe sites
Soil physical and chemical properties differed among the three sites (Table 1). Soil bulk density was higher in wet typical steppe than other steppes (P <0.05). Soil moisture and the SOC content increased, while soil pH decreased, from desert steppe to dry typical steppe, and wet typical steppe (P <0.05). The bioavailable Si content in soil showed no significant difference among the three sites.