Effects of elemental sulfur, phosphorus, micronutrients and Paracoccus versutus on nutrient availability of calcareous soils

This study was carried out in the laboratory to investigate the effects of elemental sulfur (S⁰), Paracoccus versutus (Pv), phosphorus (P) and micronutrients (DTPA extractable Fe+Mn+Zn) both singly and combined on nutrient availability of calcareous soils. Soils were collected from Al Semaih, Al Dhahrah and Melaiha in United Arab Emirates (UAE) and all soils were incubated at 40±2⁰C for 32, 64, 96 and 128 days. Soil pH dropped and S concentration increased significantly with the addition of S⁰ alone or in combination with Pv, P and micronutrients in all types of soils. Elemental S application considerably increased the electrical conductivity (EC) of Al Semaih and Melaiha soils but reduced EC in Al Dhahrah soils at 128 days after incubation (DAI). Phosphorus availability was higher and prolonged with the application of S⁰ along with P. Zinc (Zn) and manganese (Mn) availability did not increase with the individual application of S⁰ or P. Inoculation of Pv influenced S and P availability but had no effect on iron (Fe), Mn and Zn. The study suggests that S⁰ is an effective agent for the amendment of sandy calcareous soils. Application of S⁰ accompanied with Pv, P and micronutrients are essential for nutrient availability in calcareous soils.