The Vertical Distrubition Of The Phosphorus Forms And Their Relationship With Organic Matter And Enzymes Activity

The different phosphorus forms in the different layers of sediments and soil were separated by the chemical sequential extraction methods and the organic matter,enzymes,Eh and pH were determinated,by which vertical distrubition of the phosphorus forms in the different season and area and its affected factors were analyzed and discussed. The results are showed in the following:the proportions of Org-P to TP varied from 7.71～61.39%, The IP comprised 38.61～92.29% of the TP, Fe/Al-P,Ca-P comprised 9.24～38.71% and 22.55～66.89% of the TP.The different phosphorus forms at S1 was the highest ranged.The variance of different phosphorus forms at sediments in horizontal Erhai lake indicated that phosphorus forms may influence by environmental factors, and phosphorus forms was changing in still migration and transformation.The discrepancy has emerged among vertical phosphorus forms at five sites.The content of TP at S2 was highest than other sites,which shows the degree of pollution in northern of Erhai was higher than other regions. At all five sites,labile P,RSP,Fe/Al-P concentrations had an increasing trend upward toward the sediment surface, then changed slightly below 20 cm depth. labile P concentrations in the surface was highest at S2. The variation tendency of RSP at sediment with depth at Erhai was as the same tendency as Eh,which showed the Spatial distribution of RSP in Eehai lake sediments was main influnce by Eh. The concentrations of Fe/Al-P forms at 5 sites followed the order of S2>S3>S4>S5>S1, The concentrations of Fe/Al-P at S1 was lowest because of root interactions,which indicate that the pollution was lesser and lesser from northern to southern. The concentrations of Ca-P forms at 5 sites followed the order of S2>S3>S4>S5>S1,which indicate that the extent of diagenesis was smaller and smaller from northern to southern. The IP concentration had the same variation tendency as Ca-P. The Org-P concentration was higher in the surface sediments,then decreased in the deeper layers,and changed slightly below 20cm layers.The plant,power of wind,Eh and pH vary with season has influence on distrubition of phosphorus fractions in the north of Eehai lake. Sediment profiles at the S1 and S2 showed that,in different season,labile P,RSP concentration declined rapidly with sediment depth in the 0-8cm sediment layers,and fluctuant changed in the 8-20cm sediment layers, then changed slightly in deeper. Fe/Al-P,Ca-P concentration increased with sediment depth in the 0-20cm sediment layers,and then changed slightly in deeper. At S2, the concentrations of the different season's Fe/Al-P in sediments followed the order:March>Febuary> August>November. The concentration of Fe/Al-P at S1 was higher than S2,which indicated the pollution of S1 was higher than S2。The vertical distrubition of the inorganic phosphorus has the same changes as Ca-P,which indicated that the concentration of inorganic phosphorus in the north of the lake was mainly influenced by Ca-P. Sediment,in the 0-8cm,was anlyzed by statistics,which showed that labile P at two sites has significant different between August and Febuary; RSP has different between August and Febuary at S1,and at S2 Febuary was different with others. Fe/Al-P at S1 has different between August and Febuary and at S2 it has no different among those months. Ca-P at S1 has no different among those months and at S2 November was different with others..The correlation analysis among Organic matter,phosphorus content and different enzyme showed organic phosphorus,labile P had significant positive correlation with total organic matter (OM),Reorganization of organic matter (HFOM) and light fraction organic matter (LFOM)。Fe/Al-P had significant negative correlation with OM,HFOM and LFOM。TP,labile P and Org-P had significant positive correlation with catalase,sucrase,enzyme polyphenol oxides and alkaline phosphatase。The results indicated that OM,HFOM and LFOM has great impact in labile P,Fe/Al-P and Org-P。P was affected by catalase,sucrase,enzyme polyphenol oxides and alkaline phosphatase,the main affected phosphorus forms were labile P and Org-P.