About Salinity

The following introduction to dryland salinity issues is reproduced with permission from the book 'Dryland Salinity: Economic Issues at Farm, Catchment and Policy Levels' (Eds. Graham, Pannell & White). This book is available on CD and in hardcopy by order from the CRC.

Dryland salinity in Australia: Overview and prospects

David J. Pannell, Michael A. Ewing and Anna M. Ridley

Dryland salinity is one of the most prominent and intractable problems facing farm managers in the extensive non-irrigated farming systems of southern Australia. The issue was ignored by policy makers until late in the twentieth century, but is now the sole or partial subject of government programs with budgets totaling several billion Australian dollars. Salt occurs naturally at high levels in the subsoils of most Australian agricultural land. As a result of clearing native vegetation, groundwater tables have risen, mobilising the salt and causing adverse impacts to farmland, infrastructure, water resources, and biodiversity. The main action required to prevent groundwater tables from rising is establishment of perennial plants, either herbaceous (pastures or crops) or woody (trees and shrubs). Recent technical and economic research has emphasised how difficult it will be to establish sufficient perennials to get control of groundwater tables. Where watertables are already shallow, the options for farmers are salt tolerant plants (e.g. saltbush for grazing) or engineering (e.g. deep open drains). The existing options for farm-level salinity management are reviewed. There are also a number of good prospects for development of new and better options for plant-based management of salinity, and these are described. Past and current policy programs are described, and a number of changes to future policy programs are proposed to better meet the needs of farmers suffering the impacts of dryland salinity.

Introduction

This paper provides an overview of the dryland salinity problem in southern Australia. It focuses on the issue at the farm-level but also touches on a range of off-farm issues, including the impacts of dryland salinity on a range of public assets, particularly water resources, infrastructure and biodiversity. The paper is primarily relevant to winter rainfall and mixed winter/summer rainfall systems. Although dryland salinity occurs in the tropics, some of the issues are a little different there.

The paper briefly outlines the causes of dryland salinity and provides recent quantitative estimates of its main impacts. We describe how policy responses to salinity have developed over time and summarise the results of rapid recent advances in technical and economic research. These results highlight weaknesses in the existing policy approaches of government, and weaknesses in the suite of salinity management options available to farmers. We describe the array of farm-level responses to salinity currently available and discuss their viability at the farm level. Finally we discuss the various possible approaches to salinity policy, focusing to some extent on prospects for R&D to develop new management options for farmers that are more economically attractive than the existing options.

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