Zinc desorption kinetics in wheat (Triticum Aestivum L.) rhizosphere in some sewage sludge amended soils

The objectives of this study were to determine Zn desorption characteristics and the correlation of these parameters with Zn extracted by DTPA-TEA method in bulk and rhizosphere amended soils with sewage sludge under greenhouse conditions by using a rhizobox. For amended soils 10 g of sewage sludge was added to 1 kg of 10 soil samples. The kinetics of Zn desorption in bulk and rhizosphere was determined by successive extraction with DTPA-TEA in a period of 1 to 504 h at 25 +/- 1 degrees C. The results showed that Zn extracted using successive extraction in the rhizosphere were significantly (p<0.01) higher than in the bulk amended soils. The best model for describing extraction data for bulk and rhizosphere soils was the power function equation. The results indicated that Zn desorption rate in the wheat rhizosphere soils more than bulk soils. The results showed that significant correlation (p<0.05) between Zn desorption characteristics and DTPA-TEA-Zn were found in the bulk and rhizosphere soils. The results of this research revealed that Zn desorption characteristics that are help to estimate the Zn supplying power of soils in the wheat rhizosphere, are quite different than bulk amended with sewage sludge.