Acid Soils Program
Why acid soils?
Soil acidity affects more than 50% of intensively used agricultural land in NSW and approximately 23% in Victoria, and is especially prevalent in the higher rainfall areas in our region. If we do not address acid soils now, further acidification will threaten future agricultural production.
Recent research on soils in the NSW Southern Slopes suggests that in most cases, current rates of lime application are not addressing the current soil acidification rate. An effective liming program should aim to increase soil pH (CaCl2) to a target of 5.5 in the top 10 cm, not 5.0 as has been the current practice. This will provide sufficient lime to raise pH in the surface soil and allow for excess lime to leach into deeper subsurface layers (5 – 20 cm) and slowly increase pH at depth.
Lime that is top-dressed moves very slowly into the subsurface layers, depending on soil type, rainfall and lime application rate. It is known that effective incorporation of the lime after spreading ‘speeds up’ the reaction of lime with the soil, to the depth of cultivation.
HLN in conjunction with NSW DPI have set up two new trial sites that will be looking at these questions – different liming rates, top-dressing lime vs incorporating and the effects on crop and pasture growth. Another issue being looked at is pH stratification – acidic layers in the soil that may be impacting crop and pasture growth but are not being detected by traditional soil tests that bulks samples into 10 cm intervals.
A background on each of the projects can be viewed by clicking the site icons below.
Current & Past Acid Soil Project Sites
Burrumbuttock Lime Trial Site
Established in March 2020, the replicated farm-scale site at Burrumbuttock consists of 7 treatments investigating 4 different liming rates, as well as the effect of lime incorporation compared to surface applied in a moderately acidic paddock … READ MORE
Topdressed Lime Demonstration Sites
Established in February 2021, the demonstration sites near Mannus and Holbrook are investigating 3 different topdressed liming rates in permanent pasture paddocks.
The third demonstration site near Rosewood consists of multiple lime strips applied by the farmer since 2017 … READ MORE
Morven Lime Trial Site
Established in October 2019, the replicated farm-scale site on ‘Boorook’, near Morven consists of 7 treatments investigating 4 different liming rates, as well as the effect of lime incorporation compared to surface applied. This site had no previous liming history and has uniform soils across the paddock that are severely acidic … READ MORE