Nyabing Farm Improvement Group assesses a new approach to soil acidity amelioration

With soil acidity being continually identified as a key yield constraint throughout the wheatbelt, growers are continually looking for immediate and cost effective options to raise soil pH.

Through a Caring for Country funded project, the Nyabing Farm Improvement Group (NFIG) sought to investigate the efficacy of liquid calcium products compared to limesand in ameliorating soil acidity issues.

Liquid calcium products, Calsap and Calbud, were assessed as a temporary amelioration for soil acidity when banded below the seed with Flexi N and granular fertiliser and compared to lime sand broadcast prior to seeding.

It was found that Calsap and Calbud did not change the top soil pH at 12 weeks after seeding.

Lime sand (83.5% neutralising value) when broadcast prior to seeding at 4t/ha increased soil pH at 0-10cm significantly at 3 months and 9 months 0.37 to 0.92 after application as compared to the untreated at pH 4.5. Lime sand at 2t/ha increased the pH by 0.3 and 0.5 units at the 0-10cm depth, but was only significantly different 9 months after application.

At the end of the year the soil pH was significantly higher in the furrow than the interrow.

There was no increase in grain yield, screenings or protein from any applied treatments, despite a lift in pH by 0.58 and 0.92 in the seeded furrow by lime sand.

Further monitoring is planned for the 2015 season to determine pH changes in the top soil and sub soil.

For more information contact NFIG coordinator Fiona Martin E: fiona@hobley.net.au.