A growing population demands more food and water; with the reduction of conventional water resources, it will be essential to increase the efficiency of nutrient use in conventional systems. Iran is located in the mid-latitude belt of arid and semi-arid regions of the Earth and such arid and semi-arid regions cover more than 60% of the country. As a result, water is the most important limiting factor for biological and agricultural activities and the use of unconventional water in agriculture is inevitable and important under our country's conditions. Unconventional waters are not directly usable and must be adapted for use, including the removal of biological contamination, heavy metals, salinity and pH amendment. The aim of this study was to evaluate the effect of magnetic water on the essential nutrients uptake by maize (Zea mays) in saline conditions.
Materials and methods:
Magnetic water was supplied by a magnetic device with an electromagnetic field intensity varying from 8 to 10 mT. The experimental design was two factors factorial (2x3) arranged in a randomized complete block design. The combinations of the treatments were at two levels of water - non-magnetic (normal) and magnetic - and three levels of salinity (800, 1300 and 2100 ppm NaCl) with three replications. Soil physicochemical properties including texture, organic carbon, cation exchange capacity, electrical conductivity, pH, nitrate, sulfate, chlorine, phosphorous, iron, zinc, manganese, copper, and soluble and exchangeable calcium, magnesium, sodium and potassium, as well as elements present in the plant, including total nitrogen, phosphorus, potassium, sodium, calcium, magnesium, iron, zinc, manganese and copper, were all measured using standard methods.
Results and discussion:
The results of chemical water analysis showed that the electromagnetic field had no significant effect on its chemical properties. Regarding soil properties before and after harvest, magnetic water had a significant effect on soluble and exchangeable sodium, chlorine, calcium and magnesium. The results, also showed that with increasing salinity, macronutrients uptake and protein percentage were reduced, while micronutrient uptake and sodium levels increased; moreover, comparisons of treatment means showed that magnetic treatment increased uptake of all the nutrients and the protein percentage in leaves and seeds of maize plants, but no significant changes were observed in their roots and shoots. The results showed that magnetic water reduces sodium accumulation and its destructive effects on the reproductive organs of maize plant. Due to the accumulation of sodium in roots and stems, the plant's resistance to salt stress increased.
Due to the poor water quality in the agricultural section, it appears that utilization of magnetic water in arid and semi-arid regions of Iran can lead to improved yield and water productivity; therefore, it is recommended that further research be undertaken in this areas.