A three-year project led by the Department of Primary Industries and Regional Development (DPIRD) has addressed soil acidity in the Avon River Basin.
Research Scientist at the Department, Alice Butler said the results, from more than 40,000 soil samples collected from 182 farms, had demonstrated the effectiveness of using agricultural lime to increase soil pH.
“These sampling results highlight the positive efforts made by growers in the Avon River Basin to address soil acidity,” Ms Butler (pictured) said.
She said the project had been part of the Department of Water and Environmental Regulation’s Watering WA – Clean Waterways program.
“Soil acidity has a significant impact on agricultural productivity due to its impact on plant root growth and nutrient use efficiency,” Ms Butler said.
“Agricultural lime is commonly used to increase soil pH. However, current lime usage in WA is only 60 per cent of what is estimated to be required annually to combat soil acidification.”
She said an earlier research collaboration led by DPIRD analysed a soil pH dataset for the WA grain growing region which offered insights into the state of soil acidity.
“That report found only about 30 per cent of topsoils (up to 10cm) had a pH level above the recommended minimum target of 5.5, and about 50 per cent of subsoils (10-to-30cm) had a pH above the recommended minimum target of 4.8, indicating higher acidity,” Ms Butler said.
“This served as a benchmark for the recent work conducted on soil acidity.”
She said the latest project found 56 per cent of topsoil samples were above the target pH level — a significant improvement compared to the earlier study.
“Similarly, there was improvement in subsoil pH levels, with 72 per cent of samples at 10-to-20cm and 78 per cent of samples at 20-to-30cm being above the target pH level,” Ms Butler said.
“It should be noted that the growers are the ones who are being proactive in testing and managing soil acidity.”
She said the latest research helped growers assess the best method to apply lime for management of soil acidity, with a focus on mixing, or deeper incorporation, of lime to accelerate the remediation of acidity in sub-surface soil.
