Rousk et al. (2010) found that Alph

Rousk et al. (2010) found that Alphaproteobacteria and
Gammaproteobacteria showed positive relations with soil pH,
while Betaproteobacteria grew faster with large amounts of
available nutrients (Fierer et al., 2007). This detection was further
supported by the changes in soil characteristics after compost
application in our experiment. The phylum Chloroflexi is ubiqui-
tous in various soil samples, and its relative abundance was
frequently higher than that of Bacteroidetes, as reported by Roesch
et al. (2007) and Janssen (2006) using 16S rRNA gene clone
libraries or pyrosequencing, in contrast with the
findings in the
present study. However, Zhao et al. (2014) found that Chloroflexi
was predominant rather than Bacteroidetes in a rice-wheat
cropping system. They attributed this to the practice of periodic
flooding. Björnsson et al. (2002) considered that species of
Chloroflexi were ubiquitous in activated sludge and were always
related to bulking and foaming problems. The biological functions
of Acidobacteria are not well known, because most microorganisms
of this group have not been cultured (Yamada and Sekiguchi,
2009). Interestingly, it was always difficult to influence these levels
via organic amendments. Sun et al. (2014) reported that their
relative abundance showed no significant differences among all
the six treatments with different application rates of manure, and a
similar
finding was determined in this study.