A new aspect of agricultural utilization for a desert area irrigated with contaminated industrial wastewater at one of the new industrial cities of Egypt

الملخص EN

The current study is of importance to support the local knowledge, concerning the best use of land and available water resources whether be under demand for agricultural utilization or be planned for later on use.

Also, it represents an environmental problem at a new industrial city of El Asher min Ramadan area, i.

e., the utilization of contaminated industrial wastewater used as an irrigating source for an adjacent agricultural desert area.

In that concerning a hazardous that may cause toxic effects on both crop products and human health.

Consequently, it should be executed a suitable soil amendment practices to minimize such possible adverse effects.

In this connection, two soil sites are of sandy loam and sandy clay loam texture grades as well as 7 and 13 years land use periods in agricultural utilization, respectively, and directly irrigated with contaminated industrial wastewater after being passed through an oxidation pond were undertaken in this study.

These soils are encompassing by the aeolian deposits, and classified as Typic Torriorthents, coarse (soil site 1) or fine loamy (soil site 2), mixed, thermic.

According to a parametric evaluation system, they could be evaluated as moderately (S2s1s3s4) and highly suitable (S1s1s3s4) for soil sites 1 and 2, respectively, with an intensity degree for each of soil texture, CaCO3 and gypsum as soil limitations lies in the range of slight-moderate (rating = 90-75).

An elemental composition analysis was executed on each of the studied two soil sites, besides the industrial wastewater used for irrigating them, and it was found that available contents of Fe, Mn, Zn, Cu, Pb, Cd and Ni within the permissible limits, with one exception for Cd content whose laid at the upper critical limit for soil site 1 and exceeded it in soil site 2, since the soluble Cd content in the available irrigation water source is more than the permissible limits.

That means both the studied irrigation water source and soils are Cd-polluted ones.

Thus, Zn-soil amendment was a matter of concern in this work due to support the antagonism phenomenon between Cd and Zn through their uptake by plant roots.

Hence, a field experiment was conducted on the chosen two soil sites, where wheat (Triticum astivum, c.

v.

Giza 163) and barley (Hordeum vulgare, c.

v.

Giza 126) were sown during the winter season of 2005-2006.

The investigated soil plots were irrigated with industrial wastewater in randomized complete block design, with three replicates.

The agricultural management practices were conducted as usual.

Zn was applied to soil plots under study at three rates, i.

e., 0, 5 and 10 kg Zn fed-1 in form of zinc sulphate (22 % Zn) as soil application.

The obtained results showed a beneficial effect of Zn, especially at a high Cd level on the grown plants.

Also, applied Zn caused more pronounced increments in lengths or dry weights of shoots and the biological yields of wheat and barley crops and their Zn contents at the expense of Cd.

The results revealed also that wheat was more sensitive to both Zn-deficiency and Cd toxicity as compared to barley.

Cadmium toxicity in the shoots was alleviated by Zn application, but this was not accompanied by corresponding decrease in shoot concentrations of Cd.

In addition, increasing Zn : Cd in the soils tended to decrease Cd concentrations in plant organs.

It could be deduced that Zn protected plants from Cd toxicity by improving plant defense against Cd- toxicity and its oxidative stress through competing with Cd for binding to critical cell constituents such as enzymes and membrane protein and lipids.