An incubation experiment was conducted on P solubilization from rock phosphate (RP) through different organic acids such as oxalic acid, citric acid, acetic acid, humic acid and sulphur in the laboratory of the Department of Soil and Environmental Sciences, KP Agricultural University Peshawar during fall 2011. The experiment was laid in a complete randomize design. There were three replications with six treatments. The organic acids were used at the rate of 2 % for 50 g RP in 250 ml conical flasks. These samples were kept in an incubator at 250c for four months and analysed for Mehlic-3 extractable P and pH values after 20 days interval. Statiscal analyses were made and maximum P concentration of 1.52% was observed in the treatment of oxalic acid mixed with RP followed by the treatments of RP mixed with humic acid with P concentration of 0.368% (Fig. 1). Rapid increases in P solubility from RP by mixing with oxalic acids were noted up to 60thdays of incubation period and then remained stable after this period. Solubilization of P from RP by mixing with other organic acids was inconsistent. The pH in treatment of citric acid mixed with RP was noted as 5.64, followed by the treatments of oxalic acid with pH values of 6.31. A dramatic increase in pH value of 9.33 was observed in the treatment of RP mixed with humic acid. It is because the humic acid contains sodium salt and sodium hummate causes increase in its pH values.

Abstract. In order to investigate the soil fertility status of Swabi district the present research was carried out. A total of 32 soil samples were collected from 16 different locations surrounding Swabi area at 0-20cm and 20-40cm depths and analysed for different chemical properties and fertility status in the laboratory of soil and environmental Sciences University of Agriculture Peshawar. Results revealed that soil of Swabi was moderately to strongly calcareous in nature and alkaline in reaction. The O.M content was found deficient to marginal, being deficient in 75% and marginal in 25% samples at both soil depths. AB-DTPA Extractable phosphorous was found sufficient (40%) at surface soil while at sub surface it was found 15% deficient. No potassium deficiency was observed at surface as well as at sub surface soil, being sufficient in 37 % samples at surface soil and 43 % samples at sub surface soil. AB-DTPA extractable Cu was found adequate in almost all soil samples, Fe was found sufficient in 78% soil samples and medium in 9% samples and was found low in 12% soil samples at both soil depths. AB-DTPA Extractable Zn was found 12% deficient, 6% medium and 31% adequate at all surface soil samples while at sub surface it was found 19% deficient, 22% medium and 12% adequate. Proper fertilization and application of FYM and green manure is highly recommended for the areas low in Organic matter and respective nutrients.