Climate change conditions such as drought, rising temperature, and high solar radiation cause increasing salinity levels, which are considered the main factor that limits agricultural production. Therefore, to prevent food security in arid and semi-arid areas from being subject to climatic hazards, optimal water management is essential. To surmount this problem, research is focused on innovation likely to improve efficiency water use and protect the water resources. In order to overcome the problems of contaminated water and salinization problems, the researchers used a new technique based on a magnetic field. Thus, magnetized water used for irrigation can improve water productivity and increase the production of agricultural crops, thus sustaining the water resources for the future in view of the expected global water scarcity. In this context, this chapter discusses the characteristics linked to magnetic treatments on irrigation water by studying the parameters of water quality and their effects on productivity and fruit quality of the citrus orchards.
TopIntroduction
Agricultural production is one of the most basic elements contribute to the economic income and food security, despite the problems that accompanied such as lack of water, desertification, salinity and low yield. Recently, depleting water resources and the increased demand for food to meet human needs are the most critical problems in the world. Water globally is plentiful, but there is 97% saline, 2.25% is trapped in glaciers and ice, while, only 0.75% remains in aquifers, rivers, and freshwater lakes. Most of this freshwater (69%) is used for agricultural production, 23% for industry and 8% for domestic use. In the Mediterranean region, Water resources represent an important component in the field of agriculture, drinking water, and industry. It should be noted that agriculture represents the most water-consuming activity in the region. However, the scarcity of water resources particularly in south Mediterranean, in both quality and quantity, as well as its distribution in time and space, are among the main factors limiting the development of agriculture.
This problem is intensifying with recent climate change. Indeed, research is directed more and more towards strategies, which aim at the preservation, conservation and enhancement of both the quantity and the quality of these water resources, and even innovations likely to improve the efficiency and the productivity of irrigation water.
In order to meet this urgent need for water saving, several techniques and approaches are used, hydraulic techniques (irrigation system, dose and frequency of irrigations, drainage, etc.), biological techniques (varieties of plants tolerant to drought and salinity, supply of organic matter, etc.), physical techniques (soil amendment), chemical techniques (supply of gypsum, etc.). Magnetic water treatment technology is one of the solutions that can be used to remedied the water shortage resources, this technique has become the focus of researchers compared the physical and other chemicals treatments, due to it is simplecity, as ecofriendly, and safety.
The use of magnetic water leads to change or break down hydrogen bonds between molecules. This leads to change the properties of water, such as electrical systems, increasing the proportion of oxygen dissolved in water, increase the ability to dissolve salts and acids, polymerization, the surface tension, change in the speed of chemical reactions, properties of evaporation, moisture, elasticity, electrical insulation and increased permeability. Later, these changes will effect on the qualities of the material that enters the structure through its effect on the qualities physical or in chemical or physiological processes and biochemical (Al-Jbouri et al., 2006). Cai et al., (2009) who reported that magnetic field (at 500 mT) caused changes in physicochemical properties of water; these changes include decreasing water surface tension and increase viscosity. More that their results suggested an increase of activation energy and water molecule size due to extra hydrogen bond formation; this effect is linear with exposure period. The importance's of physical treatment of saline water using magnetic devices become feasible. Magnetic water (MW) is considered as environmentally friendly technique (Nimmi and Medhu, 2009). MW is produced when water passes through the magnetic field of magnetic permanent device or electromagnetic one, installed on feed pipeline, where all water and salt molecules have internal vibration (Babu, 2010). The used of magnetic water to soil have the removal of excess soluble salts. Bringing down of pH esteems and the dissolving of slightly soluble components such as phosphate, carbonates and sulphates. Moreover, the attractive strategy of magnetic method for saline water is allegedly a successful technique for soil desalinization (Mostafazadeh et al., 2011). The application of irrigation magnetic water to soil salinity was increased leaching of excess soluble salts, lowered soil alkalinity and dissolved slightly soluble salts and increasing of macro-micronutrients available in soil (El-Sonbaty 2021).