Determination of phosphorus in some calcareous soils by Diffusive Gradients in Thin films (DGT) method

Diffusive Gradients in Thin films (DGT) method is used as a method of phosphorus determination in some soils. This method was used to evaluate P in 10 different calcareous soils; Extractable phosphorous by this methods was compared with 5 other methods and P uptake by wheat plant in a glasshouse pot experiment. The results showed that the range of P concentration extracted by DGT method (CDGT) was between 23.4 and 494.6 µg L-1 affected by soil types. Because of these changes, no correlations were observed between P concentration extracted by DGT with other methods and P uptake by wheat plant. However, in a separate investigation in some soils with low CDGT, the correlation was highly increased. Therefore, it can be supposed that using of DGT method is recommendable for evaluation of P in calcareous soils with CDGT lower than 250 µg/l, due to strong correlations between this method and other methods, especially phosphorous uptake.