Ash alkalinity of animal and plant products

The export of farm produce from farming systems results in the removal of excess cations over anions from the soil. This removal of bases from the soil will eventually cause an increase in the acidity of the soil. Ash alkalinity data for a range of farm products are presented in this paper and lime replacement values calculated. Of produce from mixed farming enterprises in north-eastern Victoria, hay required the greatest amount of lime (270-1260 kg CaCO3/ha.year) to replace lost alkali from the soil. By comparison, removal of cereal produce required much less lime (7-20 kg CaCO3/ha.year) to replace lost alkali, as did removal of wool and lamb (0.8 and 6.0 kg CaCO3/ha.year respectively). Management strategies that include a lime replacement value for exported farm produce should be considered in overall farm management strategies to reduce soil acidification.