Soil Phosphatase Activity,P Fractions and Their Relationships in the Rhizosphere of Chinese Fir Juvenile Plantation

Acid and neutral phosphatase activity(APA and NPA),8 P fractions and their relationships in the rhizosphere of Chinese fir were studied.APA was higher than NPA in soils of the plantations. APA and NPA in the rhizosphere were increased by 1.44,0.66 phenol mg/g(37℃,12 h)compared with those in the bulk.Their R/S values were 1.91 and 2.01, respectively.The contents of total P,DA-P,Al-P,Fe-P and H2SO4-P were significantly higher in the rhizosphere than in the bulk.Their XR-XS values were 203.45,2.21,3.05, 10.93 and 10.33 mg/kg,and their R/S values were 1.61,4.68,3.61,1.97 and 2.48,respectively.Ca-P was markedly lower in the rhizosphere than in the bulk.Its XR-XS value was -2.34 and its R/S value was 0.72.There were no significant difference in I-P and O-P between rhizosphere and bulk soils.In the rhizosphere,APA was related to DA-P and H2SO4-P(r =0.584 and 0.579,respectively),and NPA was positively related to total P,I-P and O-P(r=0.594,0.773 and 0.686,respectively).