Study on methods of increasing of phosphorus efficiency in Qazvin calcareous soils

Since the calcareous soils of Iran used much phosphorous fertilizer in the past that leading to accumulation of phosphorous in these soils. Therefore this accumulation can caused environmental polution and decrease of some nutrients in these soils. In order to study of ways of increase efficiency phosphorous in calcareous soils of Qazvin this research designed. The experiment carried out during 2007-2009 in factorial experiment and randomized complete blocks design. At first twenty soils samples selected and determined characteristics of fertility, chemistry, and classification of soils. Then choosed two soil samples (high calcareous, low calcareous). The experiment had 24 treatment with three replication. Treatment including having two levels of soil (high and low CCE), three levels of P-fertilizer sources (without P, Super phosphate triple and apatite), two level of Biological fertilizer factors (with and without thiobacillus application), two level of manure factors (with and without vermicompost application). The treatments were incubated for one year under FC moisture conditions. The effects of soil levels of P fertilizer sources, sulfur with thiobacillus and vermicompost application on Olsen-P after 1, 2, 5, 10, 20, 40, 80, 140, 205 and 365 days measured, feractionus of P and Olsen P and PH soils after 80 and 365 days measured. Effect of soil levels of P fertilizer sources and sulfur with thiobacillus, vermicompost application on Olsen-P and inorganic P forms were significant during time. At first, application of super phosphate triple (MCP) increased Olsen-P and it was decreased during the incubation time. But under condition of without P and apatite application, Olsen-P gradually increased. This increase was more pronounced after one year. Decrease of soil pH in sulfur with thiobaillus treatment in soil with low CCE was more than soil with high CCE. For the MCP and sulfur with tiobacillus interaction Olsen-P increased after 140 days. Ca2-P increased in MCP treatment and sulfur with thiobacillus application decreased P fixation in soil after 80 days. This treatment strongly decreased soil pH so that after one year it was 3.82.