The effect of liming on the inorganic phosphorus fractions in acid soils

Phosphorus is an essential element for plants. It is also one of elements under absolute deficiency. As a result of the acidic nitrogenous fertilizers used in agricultural production in the Black Sea Region of Turkey, soils gradually become acidified and their productivity decreases. The fertility of this type of soils can be reclaimed by liming practices. Soil pH changes the availability of soil phosphorus and its distribution among the geochemical fractions. It is in such context that this study examined the effect of liming on phosphorus fractions over a period of 6 months by an incubation study. A total of 11 acidic soils was used in the experiment. After determining the lime requirement of the soils, analytical CaCO3 was applied to 150 g of soil at 0% (control), 50%, 75% and 100% of the lime requirement. Each application was done in 3 replications. The trial was established in a 11 x 4 factorial design in random plots. The avalability of phosphorus and the interfraction mobility were investigated by a sequential extraction procedure after 7, 15, 30, 60, 120, 150 and 180 days. An interfraction mobility was evident in relatively plant available fractions. These transformations were found to be a function of physico-chemical properties of soils, lime application rate, and incubation period. The relationships between the different fractions were largely driven by long-term fertilization. Overall, liming practices can be an efficient tool for partial control of P availability and mobility in acid soils.