A New Model for Disposal of Unconventional Waters for Agriculture in Semi-Arid Areas.

In southern United States, quantity of surface water available for irrigation is getting scarce and groundwater is increasingly used for irrigation. The problem is exacerbated by the multiple years of drought. The quality of groundwater in aquifers is highly variable and mostly saline. It is estimated that 70% of groundwater has EC> 3 dS/m. Salinity and water stresses limit crop productivity across agricultural areas of southern US and low rainfall, high ET, and poor quality of irrigation water exacerbate the yield decline. Apart from improving water use efficiency, augmentation of the water portfolio is needed for sustaining agriculture in the southern USA. The unconventional water sources for irrigating crops include: brackish water, desalinated fresh water, and desalination concentrate. Appropriate cropping patterns are needed that include food and forage crops across the irrigation water quality gradient to ensure food security. This research will present the infromation on leaching fractions, irrigation efficiencies, and threshhold salinity levels for various food and forage crops across a natural water salinity gradient of 06 dS/m to 10 dS/m. The reference ET and it's variations with increasing natural irrigation water salinity will also be discussed.