Nutrients in the litter on jarrah forest soils

Abstract

The amount of litter and its nutrient composition have been measured at seven sites on various lateritic soils within the jarrah (Eucalyptus marginata Donn ex Sm.) forest near Dwellingup, Western Australia. The weight of litter accumulated during 6 years ranges from 9 tonnes/ha for forest growing on yellow sand to 18 tonnes/ha for forest on reddish gravels. The litter on the reddish gravels contains more than twice the amounts of N, P, K and S in litter on yellow sand and grey and yellow gravels. The proportion of fine material in the forest floor litter increases with total litter weight. Phosphorus, which is less mobile than other nutrients tends to accumulate in this fine component. There are large differences between the foliar nutrient levels of jarrah and Banksia grandis Willd. (e.g. P: 0.041%, 0.025%; K: 0.57%, 0.34%; Mg: 0.43%, 0.21%; Mn: 177 μg/g. 730 μg/g). However, these differences are not reflected in the litter from sites with and without B. grandis understorey. Soil differences and the predominant contribution of the overstorey to the litter appear to be the main factors affecting the litter composition.