7ESWARAN H,REICH P,BEINROTH F.Global distrbution of soils with acidity[M]//MONIZ A C,FURLANIN A M C,SCHAFFERT R E,et al.Plant-soil interactions at low pH campinas.Brazil:Society of Soil Science,1997:159-164.
8UEXKULI H R VON,MITERT E.Global extent,denvelopment and economic impact of acid soils[J].Plant Soil,1995,171:1-15.
9TESSIER A,CAMPBELL P G C,BISSON M.Sequential extraction procedure for the speciation of particulate trace metals[J].Anal Chem,1979,51 (7):844-851.
10KISSEL D E,CABRERA M L,FERGUSON R B.Reactions of ammonia and urea-hydrolysis products in soil[J].Soil Sci Soc Am,1988,52:1793-1796.