Seasonal changes in litter fall and its quality from three sub-tropical fruit tree species at Nelspruit, South Africa

摘要

Litter fall from upper storey trees in agroforestry systems contributes to nutrient cycling for the benefit of all components of the system besides serving as mulch. This study examined the seasonal changes in the quantity and quality of leaf litter fall from three sub-tropical fruit trees viz: avocado (Persea americana L.), mango (Mangifera indica L.) and litchi (Litchi chinensis L.) which have potential for use in agroforestry. Leaf litter production was estimated using nylon mesh litter traps erected over five randomly selected trees of each species in a completely randomised design. Litter quality was determined by analysing ash content and polyphenol, carbon, cellulose, lignin and nutrient concentrations over a 2 year period (2007–2008). Total annual leaf litter production during the study period (dry matter basis) was 8.3, 6.3 and 5.6 t ha−1 year−1 for litchi, mango and avocado, respectively. In both years, leaf litter fall was greatest during autumn and lowest during winter in all species. There were no significant differences in S, Ca, Mg and Mn concentrations in the leaf litter, but polyphenol, N, P and K concentrations differed significantly (P < 0.05) between species. It was concluded that litter quality from all three tree species was low and would require appropriate management to improve its quality.