We have been working on ways to ameliorate dense clay subsoils that constrain crop and pasture production in southern Australia. Our research commenced in 2005 and has led to the development of a new practice called subsoil manuring.
This involves the incorporation of high rates of organic manures into the upper layers of the clay B horizon in Sodosol soils that are widespread across south west Victoria. The increases in grain yields with this soil practice are in the order of 50% above yields for commercial crops, with the yield advantage being greater in dry springs when the crop depletes plant-available water in the root zone.
Our research is directed towards the development of cost-effective on-farm sources of organic amendments to use for subsoil manuring.