SUMMARY Salinity is a major problem that negatively impacts agricultural activities in many regions in the world, and especially the Near East and North Africa region. Generally, salinity problems increase with increasing salt concentration in irrigation water. Crop growth reduction due to salinity is generally related to the osmotic potential of the root-zone soil solution. This will lead to certain phenological changes and substantial reduction in productivity. Salinity also affects the soil physical properties. Sewage treated wastewater is an alternative water source for irrigation. Using such wastewater will provide a new water resource to expand agricultural activities as well as reduce the environmental pollution. Each country in the region has a unique system of rules and regulations to protect the quality of water resources. Important aspects that should be taken into account when using wastewater for irrigation are discussed, including some information on the different irrigation systems used in ...

The Use of Saline Water in Agriculture in the Near East and North Africa Region: Present and Future

In ali Mediterranean countries there are areas where the soi!s have become saline. This can pose a great problem for soi! use and conservation, especially as their salinity is continually increasing due to the characteristic cIimate of dry, hot summers and mild, wetter winters. The excessive presence of salts, especially sodium salts, alters or destroys the soi! structure as well as increasing the swelling and dispersion of cIay aggregates. These smaller soil particIes, which are almost always richer in nutritive elements and in organic matter, become more liabIe to be transported away by water or wind. The soil thus loses its fertility and the environment can become desertified. During the summer, high temperatures cause a considerable increase in evaporation and this, together with the lack of summer rainfall, favours salt accumulation. In the autumn-winter period, rain is often of short duration but of considerable volume and intensity, causing cIay and organic colloids to swell and deftocculate, altering the soil structure. Intense rainfall events produce torrents that wash the easily eroded soil away, sometimes causing landslides and rockfalls. In soils affected by salinization, cultivation is rendered difficult in the short term. The majority of crop species suffer due to the change in the water/oxygen ratio. Plants are subject to water and salinity. stress, and to consequent nutritional deficits, reducing yields considerably. In the medium term many plants cannot survive and the symptoms of land degradation emerge, while in the long term desertification occurs.

Soil salinization in the mediterranean: soils, processes and implications

Unsaturated soil hydraulic parameters and functions used in numerical models to simulate water flow and solute transport in the unsaturated zone are generally considered invariant of soil water salinity levels. This study uses 5 years of field soil water salinity levels at three observation sites from the Land Retirement Demonstration Project (LRDP) (2006) located in western Fresno County, California, to test the hypothesis that field unsaturated soil hydraulic properties are also a function of soil water salinity level. The HYDRUS-1D software package for simulating one-dimensional (1D) movement of water, heat, and multiple solutes in variably saturated media, and Parameter Estimation (PEST), a model-independent parameter optimizer, is used to optimize the soil hydraulic parameters and downward bottom flux corresponding to three different average soil salinity levels at each site. The results show that at the same pressure head, soil water content is less with higher soil water salinity as compared with l...

Effects of Soil Water Salinity on Field Soil Hydraulic Functions

How to relevantly characterize hydraulic properties of saline and sodic soils for water and solute transport simulations

Water salinity is a limiting factor stressed plants and associated with low wheat productivity in new reclaimed areas in Egypt such as North Sinai. Sea water is available water resources and renewable and non-exploited, it is necessary to maximize use of this water through scientific research for use in irrigation of wheat, to increase the cultivated area and thus, increase production towards self-sufficiency. So, two field experiments were carried out at Faculty of Environmental Agricultural Sciences, EIArish, Suez Canal University, during 2012/2013 and 2013/2014 seasons aiming to investigate the response of three wheat cultivar (Triticum aestivum. L.; Masr1, Masr2, Sakha93) to four mixing ratios between well-water and sea water (control, 3:1, 2:1 and 1:1). Plants were subjected to salinity treatments at 60 days after sowing (DAS). Results showed that Masr2 and Masr1cvs were superior for yield and its attributes, the superiority was obtained from Masr2 cv as well as seed content of proline and protein. Also, dry leaf content of Na and Cl were higher for Masr2 as compared to the other studied cultivars under low mixing ratio (3:1 Well water: Sea water), while, the K concentration was decreased with the same treatment of Masr2. For soil analysis, EC, Na , Mg, K, HCO3 -2 and Cl increased but Ca decreased under the highest mixing ratio (1 Well water: 1 Sea water). So, it could be recommended to cultivate Masr2 wheat cultivar under North Sinai conditions, using mixing ratio 3 Well water : 1 Sea water to maximize the benefit of sea water and gain economic productivity of bread wheat in this area and similar regions.

https://sinjas.journals.ekb.eg/article_78629_5def8cc2612b2fd477330392a580990d.pdf

Response of some bread wheat cultivars to salinity stress by re-use of sea water under north sinai conditions

In the Mediterranean environment, characterized by hot and dry summers, a soil salinity research has been carried out on clay loam soil classified as Haplustolls. Spring-summer vegetables were irrigated with NaCl solutions of 0%, 0.125%, 0.25%, 0.5% and 1% with intervals of 2, 5 and 10 d. During the extreme treatments (0% and 1%, 2 and 10 d), soil samples were taken in duplicate at depths of 0-10 and 20-30 cm. Water retention and unsaturated hydraulic conductivity characteristics were measured for each sample and Van Genuchten parameters were determined. Significant differences were observed between the mean values of most of these parameters, particularly for the treatments with 0% and 1% at intervals of 2 d.

M. Menenti

Papers

Sustainable irrigation scheduling: effects of saline water on soil physical properties