Australia's water resources are in a serious state, both in reduced quantity and declining quality due to

rising salinity levels. In the future, the availability of good quality irrigation water resources will be exposed

to further risk from reduced rainfall and increased evaporative demand as a result of dimate change. To

ensure sustainable crop production in the future. it is imperative that rrore efficient methods of irrigation

are identified and theirimpaclon water use, rootzone salinky and nutrientloss thoroughly evaluated.

The aim of this project was to increase our understanding of the effects of supplementing saline water

sources, such as winery wastewater, for irrigation of vines and orchards. The project specifically

addressed the impacts of saline and wastewater application via drip irrigation on soil salt distribution.

These outcomes were achieved through the monitoring of existing field sites and the interpretation of

current dabsets.

Four sites, allocated in South Australia, were investigated during the course of this project. Each site has

been treated as a separate module in this report. The sites under investigation were:

. MCLaren Vale (vineyard). The site was subdivided into two sites (BBl and BB2) which were

irrigated with reclaimed water from the Willunga Basin Water Company using conventional and sub

surface drip irrigation, respectively.

. Willunga (almond orchard). The site was drip irrigated using saline bore water from three surface

dripper lines (site SS, ) and from a single surface dripperline (site SS2).

. Currency Creek (vineyard). The site was subdivided into fourtreatment blocks each irrigated with

Finniss River water using conventional drip irrigation. Treatment I received water from rainfall and

irrigation, plus an additional Ieaching irrigation, Treatment 2 received the same as Treatment I plus

mulch, Treainient 3 received water from rainfall and irrigation, and Treatment 4 received the same

as Treatment 3 plus mulch.

. Langhome Creek (vineyard). The vineyard was irrigated with darn water from Lake Alexandrina

using conventional drip irrigation. As salinhy levels in Lake Alexandrina increased, the irrigation

water was mixed with less saline water from other sources.

Summary

Monitoring of salt distrlbution through the soil profiles was undertaken at each site using SoluSAMPLERN

solution extractors. The extractors were installed at 30, 60 and 90 cm depths at between three and seven

locations within each site. Where pre-existing data were available, the soil water solution electrical

conductivities (ECsw) measured were compared with electrical conductivity values determined from

saturated soil paste extracts (ECe) or 1:5 soil/water suspensions (ECts). Where possible, attempts were

made to establish the relationships between ECsw and ECe/EQ, 5 values at each site.

The data obtained were used to produce plots of the spatial and temporal EC distrlbutions through the root

zones. The outcomes from this project have led to an increased understanding of the impacts of using

saline and wastewater sources in conjunction with drip irrigation techniques. With the addition of further

monitoring and analyses, the results of this study will assist in overcoming the constraints of saline and

wastewater use imposed by its effects on salt distribution and soil properties.