Farmers dig deep to combat salinity

Environmental scientists are digging deep to fi nd a way to recover lands affected by salinity.

Based on some preliminary results by farmers, researchers from Murdoch University are contributing to a coordinated approach to investigating the possibilities of using deep drains to lower the groundwater table and restore saline-affected soils.

Associate Professor Richard Bell and research offi cer Carlos Raphael are working in conjunction with researchers from the Chemistry Centre WA and the Department of Agriculture WA to identify the effectiveness of the drain concept.

'The drains have to be deep enough to intercept the groundwater, cutting into the water table at about 2-3 metres,' Professor Bell said.

'The fi rst experimental drains made by farmers were only about 1-2 metres deep and were not effective at all at lowering the water table. However, in about 1999 farmers started reporting success with deeper drains, which inspired this systematic research study.'

The Engineering Evaluation Initiative of the WA Government has installed drains around the Wheatbelt in areas with differing soil properties and rainfall levels, on properties in Dumbleyung, Pithara, Beacon, Morawa and Date Creek.

'By comparing changes in soil properties, and the yield of crops, we can establish whether these drains actually do restore soil productivity after drainage and the zone of infl uence of land around the drain,' Professor Bell said.

'Ultimately we are aiming to produce some operating guidelines for these drains, to identify the conditions which would be most effective for their use.'

A freshwater ecology expert from Murdoch University, Associate Professor Jenny Davis is also working with the team to examine the ecological implications downstream of the water drainage discharging into streams. This may led to recommendations that farmers build evaporative ponds with the drainage system.

Researchers are on target to fi nish their study by March 2007.

This project is funded by the Engineering Evaluation Initiative, a joint State and Federal government activity that is coordinated by the WA Department of Environment