Thursday, 13 July 2006

Effect of Applied Elemental Sulfur And Sulfur-Oxidizing Bacteria (Parococcus versutus) Into Calcareous Sandy Soils On The Availability Of Native And Applied Phosphorus And Some Micronutrients.

Abdou A. Soaud, Soil Department, Faculty of Agriculture, Cairo University, El-Gamaa Street, Giza, Egypt

Accumulation of elemental sulfur (ES), as by-product from gas and oil production plants, is serious environmental problem in oil producing countries, due to relatively high production and low price in the world market. Availability of both native and applied nutrients is one of the major constrains for plants growth in calcareous soils. Elemental sulfur is often applied to acidify calcareous soils and relatively cheaper field applications. The acidity produced during ES oxidation increases the availability of nutrients such as P, Mg, Ca, and SO4 and some micronutrients in soils. Wetting and draying incubation experiments were carried out in the laboratory to investigate the effects of ES powder (>150 Ám) application with or without sulfur-oxidizing bacteria (Parococcus versutus) on the availability of native and applied phosphorous and EDTA-Fe (6.0 % Fe), EDTA-Mn (13.0 % Mn) and EDTA-Zn (15.0 % Zn) in three different sandy calcareous soils (AlSemaih, Melaiha and AlDhahrah, United Arab Emirates). Soils were incubated at 40▒20C for 32, 64, 96 and 128 days. ES application alone significantly decreased the pH and increased SO4-2 concentration in the three soils. Also, It increased the EC of AlSemaih and Melaiha soils while reduced it at AlDhahrah soil at 128 days after incubation. The availability of applied phosphorus, EDTA-Mn and EDTA-Zn was higher and prolonged in the three soils with application of ES alone. No significant influence of applied ES on the availability of both native P and Fe in all soils except AlDhahrah soil. In comparison with ES alone, inoculation of soils with Parococcus versutus had no significant effect on nutrient availability. This study suggests that the application of ES powder into studied calcareous sandy soils is essential to increase and prolong the availability of phosphorus and micronutrients for proper vegetation.

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