Assessment of decomposition rate of Acacia mangium litter for rehabilitating degraded mined sites

Abstract

Acacia mangium, widely used to rehabilitate degraded mined sites, hasbeen reported to be slow in decomposition. The experiment was carried out to establish the rate of decomposition of Acacia mangiumleaf litter and determine the correlation between the stand age and decomposition rate ofits litter.Litter decomposition rate of Acacia mangium under monoculture plantation was studied using the wire mesh frame technique. Wire mesh frames containing 200g of fresh Acacia mangium leaves were set up in three Acacia mangiumstands of ages five, seven and nine years. Ten wire mesh frames were left in each stand using Completely RandomizedDesign.The decay rate coefficient "k" was used to determine the constant potential weight loss of the dry matter. The value of kwas estimated to be 0.0064, 0.0049 and 0.0039 for the 30 th , 60 th and 90 th days respectively, with overall mean of 0.0050 for all the stands. The Half-life estimated for all the stands was 140 days. Analysis of Variance at 5% significant level indicates significant difference between stand age in weight losses on the 30 th and 60 th daysbut no significant effect between the 60 th and 90 th days of observation; there were differences in the decomposition rate between the Acacia mangium leaf litter on the seven and nine years stands.