Figure 6

Bacterial diversity index of alfalfa rhizosphere soil under different treatments. (a) Is the Shannon index, (b) is the Simpson index, (c) is the Ace index, (d) is the Chao index, (e) is the Shannoneven index, (f) is the Simpsoneven index. CK, G1, G2 and G3 represent 0, 2%, 4% and 6% γ-polyglutamic acid additions in aeolian sandy soil, respectively.