[Effects of earthworm activity on phosphorus fraction and available phosphorus content in red soil]

By the methods of incubation test and Hedley's phosphorus fractionation, this paper studied the effects of inoculating earthworm (Pheretinma pingi) on the phosphorus fractions and available phosphorus contents in red soil. The results showed that during a 100-day incubation, earthworm inoculation combined with organic materials (rice straw RS, peanut residue PR, and rape residue RR) amendment increased significantly the content of soil available phosphorus. Statistics analysis showed that there was a significant difference in soil available phosphorus content between treatments PR or RR with and without earthworm inoculation. Compared with the contents of anion-exchange resin P(trace), NaCO3-soluble P(14.5 mg x kg(-1)) and microbial P(1.0 mg x kg(-1)) in CK, those in treatments of earthworm inoculation plus organic materials amendment increased to 10.5 - 17.8 mg kg(-1), 23.5-35.6 mg x kg(-1), and 6.8 - 9.7 mg x kg(-1), respectively, organic phosphorus content enhanced from 37.9 mg x kg(-1) to 50.7-59.3 mg x kg(-1), whereas residual P was reduced. Earthworm performed an activated effect on the availability of phosphorus in red soil.