Abstract
Water is an important constituent of cell and plays an important role in almost all biochemical processes. High salt concentration in the root zone impedes the water movement from soil to aerial parts of the plant by reducing the available water for plant uptake. Salinity is among the major limitations for plant growth and productivity all around the globe and the damage caused by high salinity is witnessed as either loss of plant productivity or plant death. Soil salinization is the result of different soluble salts accumulation in the root zone. soil salinization is increasing at a rate of 10% annually and more than 50% of the arable land would be salinized by the year 2050. Approximately 4.5 million acres of cropland in California have been reported to be affected by saline soils or saline irrigation water. The scenario in Pakistan is also alarming where 1.89 out of 19.43 Mha irrigated cropland is salt affected. A pot experiment was carried out in the greenhouse at the University of California, Riverside. Tomato was used as the study plant and the experiment included nine treatments representing different combinations of three irrigation water salinity levels and three nitrogen fertilization rates. High salinity stress causes the stress on plant growth and productivity due to the effective increment in the osmotic stress, ion toxicity, and alterations in soil physical and chemical properties.