Litter production and nutrient input in Bambusa Vulgaris Schrad.Ex J.C. Wendl. Stands in a secondary rainforest at the Obafemi Awolowo University,Ile Ife,,Nigeria.
The pattern of litter fall production, litter standing crop at the peak of rainy and dry seasons, nutrients contents in the litters, and the soil properties in the Bambusa vulgaris stands located within the secondary rainforest were assessed. This was with a view to providing information on nutrient cycling pattern in the bamboo stands. Two plots (25 m x 25 m) in Bambusa vulgaris stands and another two in the secondary forest where bamboos are not located were established. Litter fall production was determined monthly from June 2014 - May 2015 using litter traps of 1 m × 1 m × 30 cm, the collections of litter fall materials were done. Litter standing crop was also randomly collected at five points using quadrats of 50 cm × 50 cm in each plot at the peak of dry and rainy season. The collected litters were sorted into leaves and twigs, oven-dried at 70°C to a constant weight and weighed. The oven-dried samples were ground and analyzed for C, N, P, K, Na, Ca, Mg, Fe, Mn, Cu and Zn; lignin and cellulose. Soil samples were randomly collected at five points within each plot at a depth of 0-15 cm, air-dried, sieved and analyzed for pH, particle-size distribution, organic carbon, organic matter, total nitrogen, available P, exchangeable cations (Ca2+, K+, Mg2+ and Na+), other cations : Fe, Mn, Zn and Cu using standard methods. The results showed that annual litter fall production (t ha-1 yr-1) was 13.35 (total), 9.87 (73.9%) (leaf); 3.48 (26.1%) (twig). The litter standing crop (t ha-1) at the peak of dry season was 2.38 (total), 1.59 (leaf), 0.79 (twig), and 2.01 (total), 1.17 (leaf), 0.84 (twig) at the peak of the rainy season. Leaf litter had highest concentration of Ca, K, Na, P, Mn, Zn and Cu, while C, Mg, Fe and N were highest in twig litter fall fraction. The annual depositions (Kg ha-1yr-1) of the nutrients in the litter fall are: C (4529.5), Ca (213.2), N (186.9), Mg (94.3), K (56.2), Fe (0.90), P (0.40), Mn (0.07), Zn (0.03), Cu (0.009) and Na (0.001). The nutrients concentrations were higher at the peak of dry season than that of the rainy season; leaf litter had the highest nutrients concentration in the litter fall and in litter standing crop. The following soil properties: Exchangeable cations, pH, sandy content, organic C were significantly (P < 0.05) lower in soil of the bamboo stands, while total N, available phosphorus, silt and clayey content were higher in the bamboo stands. The study concluded that the litter fall production pattern, litter standing crop, nutrients concentration and depositions showed seasonal variations with the leaf component having the highest production. Bamboo was also shown to be better conservers of C, N and P if properly managed as a nutrient recycler to the ecosystem.