Desalination for agriculture: water quality and plant chemistry, technologies and challenges

The growing scarcity of fresh water has motivated the use of non-conventional and re-used water resources for agriculture by applying some efficient technologies. The desalination technologies for agricultural irrigation play a major role in satisfying growing water demands in water scarce regions. Due to stringent ionic concentration standards for agricultural irrigation water, desalination for agriculture is more energy demanding and additional post-treatment is requisite. Reverse osmosis (RO) has emerged as an efficient technology, but the burning of fossil fuels to fulfil the energy requirements is becoming expensive and emission of greenhouse gases is recognized as harmful to the environment. Thus, efforts should be directed towards cost reduction by integrating renewable energy resources into the process. Many of the bench and pilot scale trials like integrated RO with low energy such as forward osmosis (FO), nanofiltration (NF), microfiltration (MF) and solar energy revealed significant improvements in cost savings. However, all these modern technologies have their own problems which can be overcome by further research and development. This paper aims to review the main benefits and constraints associated with desalination technologies for agriculture. The available water resources, the desired qualities of water for agriculture and the challenges and future of desalination in agriculture are discussed.