20 November 1998

Soil tests save money

MODERN soil test backing of tensiometers mean they can provide robust, crop specific, irrigation recommendations at one-tenth of the cost of alternatives.

"This system goes back to the basics of measuring soil water potential. It mimics what the plant is doing by measuring the force required to withdraw water from the soil," says UAP project manager Vince Dempsey.

Tensiometers are placed in the field and readings checked on a soil specific slide-rule to show water requirement, he explains. Applications should be made just before readings reach critical values at which crop growth would be limited.

The values are well established for each crop, following years of tensiometer research, he notes. "All the high-tech systems have been calibrated from tensiometers." &#42