Trends in the surface irrigation systems in the Australian irrigated agriculture

摘要

Surface irrigation methods are simple, mostly gravity driven and therefore have lower energy requirements. However, these systems are often seen as being inefficient both in labour and water usage. As the competition for the scarce water resources and greater emphasis on environmental conservation gain ground, more focus has been directed towards surface systems. On the one hand, some irrigators have converted to pressurised systems which are seen to be more water efficient. This is reflected in the decline of 28% of the proportion of irrigated land in Australia under surface irrigation in the last two decades and a decrease from 30 to 19% in the proportion of agricultural establishments using the system between 2002 and 2009. This trend has been corroborated by data obtained from US irrigation surveys. On the other hand, the surface system has experienced improvements ranging from upgrades of physical irrigation infrastructure and hardware to advanced management practices including computer simulation modelling. There are also emerging concepts and on-going research in surface systems that have the possibility to confer significant benefits to the users of these systems. Conversion of the irrigated land from surface to pressurised systems and the decline of the proportion of the irrigators using the system is expected to continue into the future. However the surface system will nonetheless remain important. Selected crops such as rice require to be grown using surface methods. There is also a chance that the rising energy costs might curtail the adoption of pressurised systems.