Irrigated agriculture produces about 40% of all food and fibre on about 16% of all cropped land. As such, irrigated agriculture is a productive user of resources; both in terms of yield per cropped area and in yield per volume of water consumed. Many irrigation projects, however, use (divert or withdraw) much more water than consumed by the crop. The non-consumed fraction of the water causes a variety of undesirable effects ranging from water-logging and salinity within the irrigated area to downstream water pollution.
Photo: The equilibrium between rainfall plus applied irrigation water versus capillary rise determines either a good wheat yield or salinity at the soil surface
Bos, M.G., R.A.L. Kselik, R.G. Allen and D.J. Molden, 2009. Water requirements for irrigation and the environment. Springer, Dordrecht, pp 174. ISBN 978-1-4021-8947-3
CRIWAR simulates the water balance of an irrigated field
This book discusses all components of the water balance of an irrigated area; evapotranspiration (Chapter 2), effective precipitation (Chapter 3) and capillary rise from the groundwater table (Chapter 4). Chapter 5 then combines all components into a water management strategy that balances actual evapotranspiration (and thus crop yield) with the groundwater balance of the irrigated area (for a sustainable environment). Chapter 6 presents CRIWAR 3.0, being a simulation program which transfers the estimated evapotranspiration of the cropped area into the water requirements of an irrigated area.