الفهرس 
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Abstract
Effect of irrigation with saline water and some amendments on soil solution composition and plant growth in the newly reclaimed soils of Egypt
The demand for fresh water is increasing worldwide due to fast population growth and improvement in living standards. Conflicts between water use for irrigation and other uses have created interest in exploring the use of sea and other recyclable sources such as waste water. However, use of poor quality water for irrigation may lead to soil salinity and its associated problems. Irrigation management practices aim for the efficient use of saline water by maintaining salt accumulation in the root zone at lower levels and cultural practices may dramatically improve the performance of crops in saline environments. Barley is an important salt tolerant cereal crop grown under various climatic, soil and water conditions. Thus it is more amenable to irrigation with saline water than most crops. However, excessively saline water may hinder its growth and yield. We are not aware of studies into the use of such soil amendments to mitigate the impacts of low-quality (saline) water on the productivity of agricultural crops.
The objectives of this study were thus to investigate the effects of zeolite, compost and unisal on the total dissolved salts (TDS) and the contents of some selected ions of the equilibrated solutions in mixtures of soil with the tested amendments treated with saline waters. Also to determine if the growth of barley irrigated with saline water can be improved with the selected soil amendments.
To acheive these objectives a laboratory and pot experiments were carried out.
In the laboratory experiment, different mixtures of soil with each soil amendment (Zeolite, Compost, Unisal) were prepared using 0, 2, 4, 6, 8, 10 and 12 percent of each amendment by weight. The constant amounts of mixtures were treated with constant volumes of the prepared saline waters separately. All samples were replicated three times. Fifty grams of each mixture were shaken with 100 ml of the prepared saline water for two hours. All suspensions were filtered and the TDS, cations (Na+, K+, Ca+2 and Mg+2) and anions (Cl- and HCO3-) were determined in the equilibrated solution. Also, the retained amounts of the previous parameters were calculated.
In the pot experiment, plastic pots, 30 cm deep and 13 cm in diameter with holes in their bottom, were filled with 1.0 kg of the soil mixed with the selected amendments leaving the upper 5 cm without soil. The selected amendments (Zeolite, Compost and Unisal) were mixed with the soil at the rates of 0, 4, 8 and 12 % before cultivation. After a week, the barley seedlings were thined to four plants and irrigated with the saline waters (2.5, 5.0 and 7.5 dS/m) using tap water (0.44 dS/m) as a control. This study was designed as a three factors experiment, amendment type, amendment rate and irrigation water salinity. The treatments were replicated 3 times in a completely randomized block design. The soil of each pot was fertilized with 120 mg N Kg-1 soil in the from of NH4NO3, 150 mg K Kg-1 soil in the from of K2SO4 and 30 mg P2O5 Kg-1 soil in the from of Ca (H2PO4)2. The crop was irrigated every day to keep the soil at 70% of its field capacity by regular weighting of pots. After 8 weeks of growth, plants were cut and the fresh weights were determined. The dry biomass was estimated after drying shoots in an oven for 48h. Samples of the dried grounded plant materials (0.5 g) were wet-digested with H2SO4 - H2O2 digest and the following determinations were carried out in the digested solution, (Na+, K+, Ca+2, Mg+2, Cl- and SO4-2) . Also, soil samples were removed from each pot after harvest and extracted with distilled water to determine EC, in the filtrate solution.
The important obtained results can be summarized as follows:-