EFFECTS OF EUCALYPTUS ON SOIL PROPERTIES AND LITTER DECOMPOSITION PROCESSES

Abstract

This study investigated the effect of plantation of exotic species Eucalyptus
(Eucalyptus spp.) on the physico-chemical properties of soil by collecting field
data and also on litter decomposition and nitrogen mineralization rates of the
other selected species by following microcosm experimental design. Effects of
Eucalyptus plantation on soil properties were studied by comparing soil
properties of plots planted with Eucalyptus and other two species Acacia (Acacia
auriculiformis A. Cunn. ex Benth.) and Lagerstroemia (Lagerstroemia speciosa (L.)
Pers.) located at Madhupur, Tangail and Singra, Dinajpur, respectively. Effects of
Eucalyptus litter on decomposition and nitrogen mineralization rates of litter of
Axonopus (Axonopus compressus (Sw.) P. Beauv), Swietenia (Swietenia mahagoni
(L.) Jacq.) and Teak (Tectona grandis L.f.) were studied by incubating leaf litter of
these species with that of Eucalyptus at room temperature for 12 months. Results
showed that soil moisture content was significantly lower in plot planted with
Eucalyptus than that with Lagerstroemia. However, no significant difference
appeared when soil moisture content was compared between Eucalyptus and
Acacia indicating that plantation effects varied with the identity of species. Soil
pH, total P (%) and organic C (%) contents were significantly lower in plots
planted with Eucalyptus. Although mixing of leaf litter of Eucalyptus with that
of A. compressus, S. mahagoni and T. grandis did not affect significantly, it affected
mass loss rate of these three plant species significantly and such effect could be
explained by the chemical composition of the litter used in the incubation study.
Overall, the results of the present study indicated that plantation with
Eucalyptus might have potential influence on altering soil properties and litter
decomposition of other plant species, nevertheless, such effects varied with the
species with whom the comparison was made.