The history of salinity in the wheatbelt began in the 1920s, with the first emergence of large areas of salinity in the Great Southern and the people that documented salinity were railway engineers whose boiler supplies were first affected and then with the clearing expansion after the Second World War, salinity really began to accelerate. In the 1950s and 1960s, heavy and extensive rainfalls brought water tables to the surface and were the catalyst for the big expansion in salinity. However, it was, in fact, the clearing that had occurred three or four decades earlier that had the major impact.

Primary salinity has been around for at least a couple of million years. We see it as the salt lakes that occur right across the wheatbelt and we see it as vegetation that has adapted to those saline landscapes and those deeply stored salts, we even a small percentage of salt in our rainfall! The clearing of native vegetation has removed a high-water use system with deep roots and that grows 365 days a year. With the expansion of WA’s agricultural industry, we have replaced these native systems with a crop that grows for 120 or 150 days, allowing excess water to infiltrate into the ground, causing the water table to rise. The rising groundwater brings salt up over time as it saturates and fills our valleys and hills. As the water table gets close to the surface, it begins to evaporate and through that evaporation, the salt slowly accumulates in the soils. Those soils eventually reach a concentration where crops are not going to germinate and eventually even the most salt-sensitive pastures and crops will not grow. This then forms what we refer to as a salt scald. Salt can also break out on hillsides as underground water can be blocked by rocks as the water rises to the surface.

Salinity now costs farmers over $500 million a year in lost productivity, while also having significant negative impact on the environment with losses in biodiversity, soil health and reduced water quality.