1 October 1999

pH soil analysis risks

LABORATORY soil analysis results can lull growers into a false sense of security over pH, warns a leading agronomist. Identifying the true reading, and correcting it if necessary, reduces inputs and boosts yields, he says.

"If the pH isnt right, nothing else will work. Growers cant ignore it," says Hutchinsons Dick Neale.

Nutrient status tests often include a pH result, but such tests grind the soil. Any chalk particles in the sample will skew the reading upwards, and do not reflect the true pH in the rooting zone, he warns.

For example, one fen land beet growers lab samples were showing a pH of 6.5-7, says Mr Neale. "He never thought he had a pH problem. But areas of the field were as low as 4.5. It has taken four years to correct, but now he says he has never seen the beet so even."

Using a quick-test kit is a better method to check pH, especially if patches of crop performance are sub-optimal, he advises.

. If a problem is identified, get a specialist company in to test the field, he advises.