AU - Hejazi Mehrizi, Majid AU - Shariatmadari, Hossein AU - ََAfyuni, Majid TI - Cumulative and Residual Effect of Sewage Sludge on Inorganic P Fractions and P Availability in a Calcareous Soil PT - JOURNAL ARTICLE TA - JSTNAR JN - JSTNAR VO - 17 VI - 64 IP - 64 4099 - http://jstnar.iut.ac.ir/article-1-1647-en.html 4100 - http://jstnar.iut.ac.ir/article-1-1647-en.pdf SO - JSTNAR 64 AB  - Application of sewage sludge has been considered as an organic fertilizer in arid and semi-arid regions of Iran. This study was conducted to investigate cumulative and residual effects of sewage sludge on soil inorganic fractions and their relation to phosphorus (P) availability. Two levels of application (50 and 100 Mg ha-1) and three consecutive times of sewage sludge application (1, 3 and 5 years) with a control treatment were studied in a randomized complete block split plot design with three replications. Composite soil samples were collected from 0-30 depth at the end of 5th year of application. Increasing the rate and application year of sewage sludge enhanced dicalcium phosphate (Ca2-P), octacalcium phosphate (Ca8-P), apatite (Ca10-P), aluminum phosphate (Al-P), iron phosphate (Fe-P) and available P but decreased occluded P (OC-P). Residual effect of sewage sludge application resulted in increased inorganic fractions in blocks treated for 1 year compared to control. Positive correlations were observed between inorganic P fractions and Olsen P, wheat yield and P uptake (except OC-P). We concluded that inorganic P fractions and P availability increased in sewage sludge amended soil. CP - IRAN IN - LG - eng PB - JSTNAR PG - 33 PT - Research YR - 2013