Irrigating field crops in the presence of saline groundwater

Abstract

Irrigating crops in the presence of saline groundwater presents unique opportunities and challenges. As the world demand for water increases, it is incumbent on agriculture to maximize the use of water of all qualities. Traditional irrigation and drainage water management in saline environments was designed to provide leaching of salt from the root zone and the discharge of saline drainage water in an uncontrolled fashion. This practice is no longer acceptable and management options were developed to maximize the use of water of all qualities and to reduce the subsurface drainage discharge volume to a minimum. This paper describes the integrated management of irrigation and drainage systems in saline soil environments to reduce total drainage flow without reducing crop yields. Methods used include using saline drainage water for supplemental irrigation, increasing in-situ crop water use of groundwater, installing control structures on a subsurface drainage system to control the water table position and reduce drainage flow. In a field without subsurface drainage crop production was sustained using subsurface drip irrigation which maintained yields and reduced deep percolation to the groundwater. Salt in the root zone is effectively managed using pre-plant irrigation in areas with and without subsurface drains.