The Effect of different concentrations of magnesium in irrigation water on vegetative indices, some chemical properties of soil and nutrient elements of pistachio seedlings of Badami Zarand and Ghazvini

The quality of irrigation water affected by salinity and high concentration of soluble salts is one of the important problems of pistachio areas in recent years.
In this regard, the gradual increase in the concentration of soil magnesium in pistachio areas which irrigated with inappropriate and salty quality groundwater has become one of the most serious challenges ahead. Since there are very few studies on the effect of high concentrations of magnesium on soil properties and vegetative traits of pistachio, so this study investigates soil properties and growth characteristics of two bases of pistachio Badami Zarand and Ghazvini, under the influence of different concentrations of magnesium in irrigation water, as well as selection the superior and more resistant bases to high concentrations of magnesium.
The experiment was split plot based on a randomized complete block design with two factors each with three replications. The first factor consists of two pistachio bases including Badami Zarand and Ghazvini and the second factor was made of five levels of magnesium in water (0, 0.5, 1, 2, 3 mM from magnesium sulfate source). vegetative traits were measured before the treatments (end of the eighth week) and after 6 months from the beginning of the treatment, and their changes were investigated during the application of the treatments, dry weight of the aerial parts (leaf and stem) and root, concentration of some The nutrient elements of the plant leaf and the soil chemical properties of the pots, such as electrical conductivity, pH, concentration of sodium, potassium, calcium, magnesium, soluble phosphorus and calcium to magnesium ratio were measured at the end of the experiment.
Results showed that in general the effect of different levels of magnesium in the irrigation water was significant on soil EC and the concentrations of calcium, magnesium and sodium in the soil solution. In addition, at concentrations of 0.5 and 1 mM magnesium sulfate, the growth of pistachio plant (vegetative shoot and shoot dry weight plus roots) improved while by increasing the concentration of magnesium in the irrigation water (level 2 to 3 mM Mg), shoot growth and root dry weight, shoot꺊 weight reduced compared to the control. Also, soil soluble calcium to magnesium ratio showed significant difference at 0 mM magnesium of irrigated water compared to other treatments. The results showed that changes in soil pH, absorbable potassium and available phosphorus in the soil experienced no significant influence by pistachio base, magnesium levels in water and their interactions effect.
The results of this study revealed that for two bases of Badami Zarand and Ghazvini, there is a threshold value of magnesium concentration. It was found that under the influence of different concentrations of magnesium in the irrigation water, the best growth in both pistachio bases was observed at 0.5 and 1 mM magnesium sulfate. With increasing the concentration from 2 to 3 mM, both bases showed a decline in growth. Overall, the results of this study indicated that the concentration of magnesium in irrigation water mare than 2 mM can reduce pistachio growth and lead to the complexity of the leaf, and burn margins and tips of the leaves, which can be considered by researchers and farmers.