Precision Irrigation in South Africa

The Republic of South Africa covers an area of 122 million hectare of which 18 million hectare is potential land for cultivation. Eight percent of the potential arable land are under irrigation, which accounts for nearly half of the water requirement in South Africa. With a population of 42 million and an estimated annual population growth of 1,7%, urbanisation and industrialisation will increase the pressure on the availability of water resources and the allocation thereof in South Africa. The purpose of the National Water Act, Act 36 of 1998, is to ensure that the nation's water resources are protected, developed, conserved, managed and controlled. Agricultural production under irrigation in South Africa retrieves water from water resources such as groundwater which irrigates 24% of the irrigable area, while surface water irrigates 76% of the irrigable area in South Africa. Farmers using groundwater for irrigation is currently subjected to a water resource management charge of 0,54 c/m3. Users of surface water buy a water-right and pay an annual water levy, and groundwater belongs to the owner of the farm who can use it at no cost. Precision irrigation as an aspect of precision agriculture, is a relatively new concept in irrigation farming worldwide. It involves the application of irrigation water in optimum quantities over an area of land which are not uniform and has variations in soil type, soil water capacity, potential yield and topography. Precision irrigation provides a sustainable agricultural system which uses resources efficiently and develops and maintains the actual water demands. Precision agriculture is a knowledge-based technical management system which should optimise farm profit and minimise the impact of agriculture on the environment.