Decomposition of Entandrophragmacylindricum Tree Prunings in Agroforestry System in Onne, Rivers State

Abstract

A study was conducted at Swamp Forest Research Station, Onne, Forestry Research Institute of Nigeria, to evaluate the rate of decomposition of E. cylindricumtree prunings. The experiment was a 2x8 factorial in a randomized complete block design with three replications. The first factor comprises two placement methods (surface-placed and soil-incorporated) and the second factor comprises eight biweekly sampling intervals (2 – 16 weeks). The litterbag technique was employed. Results indicated that the Total leaf decomposition (100.0%) of soil incorporated leaf litter was obtained at 16th week after litter placement (WALP). Soil-surface placed had 98.00% at 16th WALP. Leaf half-lives of the soil-surface placed and soil incorporated were 5.08 and 2.10 WALP respectively. The turnover coefficients (k1) of the soil surface-placed and soil -incorporated leaf litter of E. cylindricum were 6.93yr-1 and 17.33 yr-1 respectively. The high rate of fresh leaf decomposition and subsequent release of nutrient make E. cylindricum leaf pruning a good source of organic manure for soil fertility restoration.