Abstract

The objectives of this study were to examine litter, decomposition, net mineralization and microclimate by two leguminous species planted for the restoration of degraded area. The total annual litter fall in A. mangium site was 11.44±0.59 (mean ± standard error) t ha^-1 yr^-1and A. auriculiformis site was 8.72±0.57 t ha^-1 yr^-1. Decomposition constant (k) of A. mangium and A. auriculiformis were 1.27 and 1.12, respectively. Seasonal variation of net mineralization was pronounced, with peak values occurring in September at Acaciaplantation site. Grassland showed higher air temperature, relative humidity and soil temperature as well as a larger variation per hour in these parameters compared to theAcacia plantations. The highest air temperature, relative humidity and soil temperature were measured in April during the dry season. These results showed that planting Acaciaimproved site qualities (litter fall, decomposition, and net mineralization) and microclimate factors (air temperature, soil temperature, and relative humidity) and decreased the variation rate of these factors in the study sites. Therefore, this study suggests that this type of plantation is efficient in improving site qualities.

Key words: Decomposition, litter, microclimate, nitrogen mineralization.