South Australian Research and Development scientist, Dr Tapas Biswas, says timing is the key in flushing salt out of the root zone.

Dr Biswas says growers traditionally apply additional water for leaching salt in summer.

However, SARDI research has shown that leaching in winter is more effective.

"A bucket of water during the wettest winter month may be as effective as ten buckets in summer," he says.

"The trick is to know whether or not natural rainfall itself is leaching all the salts.

"If it is, growers have a chance to save on that supplementary water."

Dr Biswas says good July rains have provided growers with the first chance to watch the movement of salts and fertiliser within the root zone without relying on supplementary irrigation water.

"The recent development of a root zone watch tool by SARDI - which accurately measures salts and fertiliser in the root zone – provides irrigators and researchers with the first real opportunity to accurately monitor how rainfall naturally flushes the salt through the soil, without losing fertiliser," he says.

"Yields will not be compromised and valuable information will be gained to help reduce water use even further in the future."

Root zone salinity is a multi-million dollar problem emerging under highly efficient irrigation systems which has been exacerbated by the drought.

It affects citrus and grape crops, and if left unchecked can kill the plants.

As a general rule, leaching is necessary when the salts levels in the plant’s root area are above the tolerance level.

* A two-hour information exchange workshop on new techniques being used to monitor fertiliser movement and salt leaching within the soil profile, to be held at the McLaren Vale Visitor Centre on Tuesday, August 12, from 10 a.m. to noon.