Due to the size and nature of the agricultural industry in Australia the adoption of subsurface trickle

irrigation (SDl) in this country has been limited due to bad experiences of early installations (Arithony,

1996). Underpinning these experiences was the failure of research at the time to fully identify and

communicate the potential benefits of the drip systems (Bristow et a1. , 2000). For these reasons it has taken

twenty years for SDlto re-establish itself as a viable irrigation alternative in the Australian cotton industry.

The large body of research from Israel and the USA has indicated that substantial increase in yield and water

use efficiency can be achieved through the installation on SDl for a number of crops (Camp at a1. , 2000). in

Australia some of these promised benefits have not materialised because surface irrigators here have been

described as the among the most efficient water users in the world (Arithony, 1996) and poor SDl

performance has been attributed to suboptimal management based on observed cotton water deficit stress

(HuIme and O'Brien, 2000).

The use and management of SDl on Vertosols in Australia is poorly understood and many comparative

studies have been treated with scepticism, (HuIme and O'Brien, 2000). Only two water balance studies have

been conducted on the system. A study on lighter soils in the Emerald Irrigation Area, (M. MCCosker, pers.

comm. ) demonstrated an increase in cotton yield and a doubling in WUE with SDl when compared with

flood irrigation. On a Vertosol, total water used was 20-30% less with SDl, however water and nitrate fluxes

(deep drainage), were significantly greater than under flood irrigation (Ian Gordon, pers. comm. ).

Research by the cotton industry funded program "Minimising Pesticides in the Riverine environment"(1993-

1996) found unacceptable levels of sediment and chemical pollutants in surface runoff water from furrow

irrigated cotton. Carroll et al. (1988) identified up to 80% of erosion was associated with rainstorm events,

particularly soon after flood irrigation, and pesticides and nutrients are transported with the runoff and

eroded sediment.