|Author:||Khan, S. ; Tariq, R. ; Cui, Y. L. ; Blackwell, J.|
|Book Group Author:||NA|
A close examination of water balance components of three irrigation systems in Australia, China and Pakistan show that surface water efficiency is highest for the Murrumbidgee Irrigation Area (MIA) - around 80% - whereas for Rechna Doab (RD) in Pakistan and Liu Yuan Kou (LIA)in China it is less than 50%. All these systems are dependent on direct or indirect use of groundwater. The direct shallow groundwater uptake by crops is very high in the LIS and MIA. For both the MIA and LIS, the continued direct use of groundwater for crops will accelerate the rate of salinisation of soils. There is a need to quantify regional water quality trends, downstream environmental impacts and the trade-off between yield reduction and direct regional groundwater use by crops in these systems. The most cost-effective option may be to become more efficient users of water and reduce negative impacts on the environment, thereby reducing the associated costs of maintaining our natural capital. Under present operational conditions none of the three systems presented in this paper are sustainable in the long term.
crop yield, environmental impact, groundwater extraction,irrigation requirements, irrigation systems, risk assessment,salinization, soil degradation, soil fertility, soil water, waterbalance, water costs, water quality, water table, water use efficiency,Australia, China, Pakistan, Australasia, Oceania, Developed Countries,Commonwealth of Nations, OECD Countries, East Asia, Asia, DevelopingCountries, South Asia, environmental effects, soil moisture, watercomposition and quality, Soil Water Management (Irrigation and Drainage)(JJ800) (Revised June 2002) [formerly Soil Water Management], NaturalResource Economics (EE115) (New March 2000), Policy and Planning(EE120), Soil Fertility (JJ600), Pollution and Degradation (PP600),Water Resources (PP200), Soil Physics (JJ300)