Table 2 Alpha diversity indices of soil microorganisms.

Chao1 index

\(\:{S}_{chao1}={S}_{obs}+\frac{{n}_{1}({n}_{1}-1)}{2({n}_{2}+1)}\:\left(1\right)\)

http://www.mothur.org/wiki/Chao

Shannon index

\(\:{H}_{shannon}=-\sum\:_{i=1}^{{S}_{obs}}\frac{{n}_{i}}{N}\text{ln}\frac{{N}_{i}}{N}\:\left(2\right)\)

http://www.mothur.org/wiki/Shannon

Simpson index

\(\:{D}_{simpson}=\frac{{\sum\:}_{i=1}^{{S}_{obs}}{n}_{i}({n}_{i}-1)}{N(N-1)}\:\left(3\right)\)

http://www.mothur.org/wiki/Simpson