Bio-availability of Soil Inorganic Phosphorus in the Hydro-fluctuation of Three Gorges Reservoir

A pot experiment was employed to study the phosphate fertilizer absorption in lettuce and different forms of inorganic phosphorus absorption under different phosphorus application level in the hydro-fluctuation of Three Gorges Reservoir Area.Results showed that:With the increase of equal phosphorus applying,compared with treatment without phosphorus(NP0K),the lettuce yield significantly increased by 78%~174%,which indicated that with the same nitrogen and potassium,increasing phosphorus fertilizer cloud improve the lettuce yield.Under different phosphorus application level,the stems phosphorus content was higher than leaves,and that increased with increasing the phosphorus application level.The treatment 9(NP210K)was 13.3g/kg which was the highest content,60%higher than that of control 2(NP0K),but the leaves phosphorus content had no difference in all treatments.It indicated that a large number of phosphorus application significantly increased the phosphorus content of underground part of plant.Under different P levels,nutrient absorption in leaves was greater than stems.The phosphorus absorption in stems and leaves from treatment 3(NP30K)to 9(NP210K)were both significantly higher than that of treatment 2(NP0K),which indicated that under a certain proportion of different fertilizer,appropriate phosphorus could increase the phosphorus absorption in lettuce.The analysis of relationship between the various inorganic phosphorus content and available phosphorus content,biomass,and the change of inorganic phosphorus content in all treatments showed that the bio-availability of inorganic phosphorus forms was Fe-P Ca2-P Al-P Ca8-PO-P,Ca10-P.