Abstract

By 1994, an estimated 1.8 million hectares of cleared land in Western Australia was affected by secondary dryland salinity to some extent. The area affected is likely to double in the next 20 years. The cause of this salinity is excessive recharge under traditional agriculture, leading to rising groundwater levels. To effectively reduce land and water salinity a deep-rooted perennial is needed to mimic the temporal and spatial distribution of leaf area that existed prior to clearing. Previous studies have shown lucerne lowers groundwater levels in areas with favourable conditions.

We present data showing that lucerne lowered groundwater levels in 4 different landforms and under unfavourable conditions. All sites had very saline groundwater, high sodium chloride chemistry and high groundwater levels. This paper shows that the effectiveness of lucerne in salinity control measures depends on the attributes of the groundwater flow system.