Soil acidity is one of the few soil constraints to agriculture for which there is a profitable solution. However, treatment and management of subsurface acidity requires a more direct and aggressive approach than surface or topsoil acidity. This project will work with a number of grower groups to understand more fully and improve the effectiveness of tillage to incorporate lime to depth and if subsurface amelioration of acidity can be improved through the addition of organic matter or other novel products. The extent to which acidification rates might be able to be reduced through the use of 'alkalising' fertilisers, such as calcium nitrate, will also be determined as a possible economically viable adjunct to traditional amelioration. Detailed controlled environment studies will be undertaken to test and develop recommendations for the field trial treatments.