Acidity surge in SA

Many areas of SA are reaching soil acidity levels which could have a significant impact on crop and pasture production, according to land management consultant with Primary Industries and Resources SA, Brian Hughes.

Speaking at Farmer Research Updates organised by GRDC and the SA Farmers Federation, Mr Hughes said dangerous levels of acidity occurred when soil pH fell below 5.5 for crops and 5.0 for pastures — these measurements being done in calcium chloride.

He said the regions principally at risk in SA were lower Eyre Peninsula, parts of the northern agricultural districts, Mt Lofty Ranges, Kangaroo Island and the South-East.

"The main causes of acidity are high farm product removal such as hay and grain, high rates of nitrogen, and nitrate leaching, particularly under legume pastures.

"By far the easiest solution where acidity is becoming an issue is to use lime to neutralise it."

Mr Hughes urged farmers to monitor soil pH levels, apply lime sooner rather than later, and not allow acidity to spread to subsoils, as production losses would be high and the problem would take longer to correct as lime moved through the soil only slowly.

Contact: Mr Brian Hughes 08 8389 8800

See Crop Clinic p19 for research news on liming