A comparative study on the inter-relation between copper status and the properties of some soils at El Fayoum governorate, Egypt

الملخص EN

This work aimed to identify Cu status in the major soil types of varying characteristics at the five districts of El Fayoum Governorate (Tamia, Sannoris, Ibshawai, Etsa and El Fayoum), with special reference to evaluate some methods of available Cu extraction.

To achieve this target, twenty representative surface soil samples (0-30 cm) were selected to represent the main sediments of El Fayoum depression.

Some physico-chemical properties of these soils, total amount of Cu and available Cu extracted with NH4OAc, DTPA and EDTA were determined.

A greenhouse pot experiment, using wheat as the indicator plant, was set up to find out the most suitable method for Cu extraction.

The obtained results revealed that the total amounts of Cu ranged 8.21-60.30 mg/kg, with an average of 33.66 mg/kg.

In general, soil content of total Cu was more related with the texture class, where the relatively high content was associated with the clayey soils, while the moderate and low contents were found in the medium and relatively coarse textured ones, respectively.

A significant positive correlation was found between total Cu and each of clay fraction, silt + clay and organic matter contents.

A similar trend was found with available Cu extraction.

However, a negative correlation between total or available Cu and each of CaCO3 content and pH value was observed.

Data obtained of available Cu indicated that the DTPA was the most suitable extractant used for identifying the available content of Cu in soil, under the conditions of the current greenhouse experiment, which gave the highest correlation coefficient with Cu uptake by wheat plants (r = 0.64**).