AU - Sh. Mahmood-Soltani, AU - A. Samadi, TI - Determination of Phosphorus Fractions in Some Calcareous Soils in Fars Province and their Relationships with Soil Physico-chemical Properties PT - JOURNAL ARTICLE TA - JSTNAR JN - JSTNAR VO - 7 VI - 3 IP - 3 4099 - http://jstnar.iut.ac.ir/article-1-448-en.html 4100 - http://jstnar.iut.ac.ir/article-1-448-en.pdf SO - JSTNAR 3 ABĀ  - Knowledge of forms of phosphorus (P) is important in the evaluation of soil P status and also in understanding soil genesis and fertility. Amounts and distribution of P in different organic and inorganic fractions were examined in 39 soil samples of Fars province. Soils were sequentially extracted to determine organic P and inorganic P fractions. Total P with an average of 597 mg/kg soil was lower in the light soils (482 mg/kg) as compared with the heavy soils (690 mg/kg). Organic P constituted considerable portions of TP (27%). Calcium phosphates with an average of 424 mg/kg soil and being comprised of 71% inorganic P was the dominant form of soil phosphorus. Simple regression analysis indicated that there were significant positive relationships between organic P, Ca phosphates and Al-Fe phosphate values with CEC and clay content. Stepwise multiple regression analysis showed that a combination of soil properties such as clay content and equivalent calcium carbonate (CCE) increased correlation coefficients (R). Alghough multiple regression model was significant (at P CP - IRAN IN - LG - eng PB - JSTNAR PG - 119 PT - Research YR - 2003