Tri-State Project - Impact of Salinity on Horticulture in the Lower Murray
The project, started in November 2003 and to finish in early 2007, is split into two stages and deliverables are spread over agreed milestones.
Stage 1: Specific tasks and main deliverables for Stage 1 are:
- A detailed literature review of the salinity relationships for the commonly grown crops (grape, citrus, stone fruit, melon and vegetables) in the Lower Murray region;
- Identify the knowledge gap in salinity relationships;
- Explore the salinity implications of the leaching efficiency and its variance and prepare a focussed plan for field studies; and
- Develop a framework for the economic assessment of the salinity hazard.
Stage 2: As a follow up of stage 1, the original project submission listed the following three main activities for stage 2:
- Use chloride as a natural tracer in the soil profiles at suitable field sites (where the season’s irrigation practices have been recorded) to estimate leaching efficiency and its variance;
- Use the models ‘VineLOGIC’ and ‘Swagman’ (for Citrus) to simulate salinity inputs versus outputs on selected vineyards and orchards; and
- Assess the implications of the project outcomes in relation to the salinity and drainage management strategies.
The original submission identified that stage 1 findings may lead to revision of the stage 2 field investigations. It is now proposed that the stage 2 investigations also include field experimentation for measuring and subsequent modelling of the soil-water-plant-atmosphere transport processes.
An economic analysis was carried out on this project, looking at the following benefits: productivity and profitability; environmental; and social. Download economic analysis.
- To determine the salinity relationships for irrigated horticulture along the lower Murray: Riverland, Sunraysia and NSW
- Determine the variance of EC (soil water) in the field under known soil conditions and irrigation management
- Simulate the performance of the main crops under different scenarios of river salinity at Morgan
- Provide input to the implementation of the Salinity Strategy and Integrated Catchment Management Plan of the Murray-Darling Basin and the Living Murray initiative.
The project is substantially improving our understanding of leaching efficiency and the amount of water required as a leaching fraction. The results of the project will inform the new NPSI project Root zone water, salinity and nutrient management under precision irrigation (SRD8).
Irrigated horticulture in the Lower Murray (Riverland-Sunraysia) region contributes a ‘gate-value’ of about $ 2.5 billion a year to the national economy. As a consequence of improved irrigation practices over the years, there is a risk emerging of a salinity build-up in the root zone, threatening the sustainability of this region. During the past two decades the water use efficiency (WUE) of irrigated horticulture in this region has gradually increased from about 50 to 80% as a consequence of improved irrigation systems and management. With the objective to manage the irrigation impact on the river water quality and health of the floodplains, the River Murray Catchment Water Management Board introduced an 85% target of WUE in the current Water Allocation Plan.
In the Lower Murray Region the irrigation water salinity is typically about 0.4 dS m-1 and with 15% leaching the average salinity (ECe) in the root zone should be around 0.6 dS m-1. However field surveys indicate that the root zone salinity is often greater than 1.3 dS m-1 with considerable variance. In order to understand and manage this salinity hazard, a ‘Tri-State Salinity’ syndicate of Government agencies from western NSW, Victoria and South Australia (with support from federal agencies) was formed to undertake laboratory and field scale studies for irrigated horticulture in this region.