1. Introduction
Worldwide, food and water availability are vital for the survival of humanity and to ensure adequate living standards. Population increase, climate changes and ongoing industrialization are putting pressure on the existing water resources. Fresh water resources are sufficient only in limited parts of the world (such as in Scandinavia).
It is estimated that 50% of the world population will live in water stressed regions in
2025, which highlights the importance of adequate water management
and treatment [1]. When water resources are limited, irrigation is penalized.
Of the agricultural, municipal and industrial sectors, agriculture uses 70% of the total amount of water withdrawn [2]. In Europe the average usage is 33% with an increase in the southern part of Europe where the consumption can be as high as 80% [3]. In these regions the greater part of the water used in agriculture goes to irrigated crops.