The decomposition of plant litter is one of the most crucial source of nutrients in forest ecosystems. Acacia senegal, a nitrogen fixing tree with potential to improve poor soil is planted in semi-arid zone of Nigeria for the production of Gum Arabic. However, there is dearth of information on litterfall, litter decomposition and mineralisation under plantation which this study investigated. Monthly variations in litterfall of Acacia senegal were studied for a year. Decomposition and mineralization of litterfall were studied using litterbag technique. Litter fractions were collected, oven dried at 70°C for two days, ground, sieved and analyzed for N, P, K, Ca and Mg. Data obtained were analyzed using descriptive statistics, regression and ANOVA at P = 0.05. Total litterfall was 3,111 kg/ha/yr. Litter decomposition rate was faster in the early stage of decomposition with 43.59% litter loss. Mean macronutrients (P 34.127; K 0.324; Ca 6.513; Mg 3.345cmol/g) in the soil under the decomposed litter (0-15cm) were higher than what was obtained in the decomposed litter (P 0.1584; K 0.3195; Ca 3.0547 and Mg 0.4847) except for nitrogen. The study revealed that Acacia senegal through litterfall and mineralization improved soil nutrient status under the plantation.
Key Words: Litterfall, Mineralization, Decomposition, Acacia senegal, litterbag