Until recently the most common rate of agricultural lime application is one tonne per hectare as a blanket application across the surface of the whole paddock (Taking soil acidity seriously - results of grower surveys 2012, page 118).
This amount is often insufficient to recover and maintain soils above recommended targets of pH 5.5 and 4.8 in topsoil and subsoil, respectively.
A 2015 phone survey of 20 growers, conducted by this project, found teh majority of growers are now using 2t/ha lime in order to speed the repair of soils.
As a result of Caring for Country project SP11-01226, growers in Western Australia are increasingly testing pH of soils below 10cm.
Growers understand the importance of lime in restoring soil pH, as seen by the increase in sales of lime in the northern wheatbelt (Liebe group technical audit results 2012).
Preliminary work by Davies, 2012 (Developing and assessing agronomic strategies for water repellent soils, page 71) has shown the applicability of a number of innovative techniques, including mouldboard ploughing and rotary spading, for incorporation of lime to depth.
Lime on the topsoil can be incorporated to a depth of 30cm enabling management of pH at this depth.
This trial is one of six similar trials throughout the northern wheatbelt. It will help establish best practice methods and promote the effectiveness of these techniques throughout the rainfall zones of the northern agricultural region (NAR).
To showcase to growers different methods for deep incorporation of lime to ameliorate sub surface, below 10cm, acidity and improve soil health.