Fig. 3

Effects of grazing intensity on nitrogen compounds and nitrate nitrogen contents in roots and leaves of Stipa breviflora. a and c proline content (mg g^− 1 FW), b and d nitrate nitrogen contents (µg g^− 1 FW), e and g soluble protein content (mg g^− 1 FW), f and h free amino acid content (µg g^− 1 FW). Different lowercase letters indicate significant difference at P<0.05. “Ns” in the figure indicates that there is no significant difference among grazing treatments. CK, LG, MG and HG refer to no grazing, light grazing, moderate grazing and heavy grazing, respectively