Journal of Agriculture and Ecology Research International

Little information on allometric relationships for estimating stand biomass in the savannah of Cameroon was available. Allometric relationships for estimating stand biomass were investigated in the sudano-guinea savannah of Ngaoundere, Cameroon. A total of 90 individual woody from sixteen (16) contrasting plant species belonging shrubs and trees were harvested in Dang savannah across a range of diameter classes, from 3 to 35 cm. Basal diameter (D), total height (H) and tree density were determined and considered as predictor variables, while total above-ground biomass, stem, branch and leaf biomass were the output variables of the allometric models. Among many models tested, the best ones were chosen according to the coefficient of determination adjusted (R2adj), the residual standard error (RSE) and the Akaike Information Criteria. The main results showed that the integration of tree height and density with basal diameter improved in the degree of fitness of the allometric equations. The fit allometric stand biomass model for leaf, branch, stem and above ground biomass were the following forms: Ln(LB) = -5.08 + 2.75*Ln(D) – 0.30*Ln(D2Hρ); Ln(BB) = -7.81 + 1.29*Ln(D²H) – 0.39*Ln(ρ); Ln(SB) = -5.08 + 2.40*Ln(D) +0.50*Ln(H) and Ln(TB) = -5.07 + 3.21*Ln(D) – 0.12*Ln(D²Hρ) respectively. It is concluded that the use of tree height and density in the allometric equation can be improved for these species, as far as the present study area is concerned. Therefore, for estimating the biomass of shrubs and small trees, the use of basal diameter as an independent variable in the allometric equation with a power equation would be recommended in the Sudano-guinea savannahs of Ngaoundere, Cameroon. The paper describes details of shrub biomass allometry, which is important in carbon stock and savannah management for the environmental protection.

Few studies on effects of termites on litter decomposition have been done in African savannahs, particularly in the Adamawa savannahs of Cameroon. In the framework of management of resource quality to restore or improve soil fertility of farming systems of Sudano-guinea savannahs of Ngaoundere, Cameroon, study on termites’ control of leaf litter decomposition of eight plant species was conducted on the field. The selected plant species are Bixa orellana, Erythrina sigmoïdea, Ficus polita, Maytenus senegalensis, Mucuna stans, Piliostigma thonningii, Vitex madiensis and Vitellaria paradoxa. Leaf litter samples were incubated in situ using litterbags of 2 mm mesh during 24 weeks in two plots out of canopy, corresponding to two treatments, with and without termites. Experimental design was split-plot with three replications. Collected data was carried out on litter dry mass remaining (LMR). Results showed total mass loss at the end of incubation time (24 weeks) and decomposition rate constants (k) differed significantly among plant species for the two treatments. The values ranged respectively from 23.05% and 0.012 week^-1 in V. madiensis to 61.93% of initial dry mass and 0.046 week^-1 in P. thonningii for treatment without termites and from 43.88% and 0.022 week^-1 in B. orellana to 91.51% and 0.095 week^-1 in P. thonningii for treatment with termites. These macro organisms fasted litter decomposition in all plant species, with intensity variation according to species. Litter mass loss and decomposition rate constant (k) correlated with litter thickness, density, area and specific area mass, and these relationships were influenced by the presence of termites. Globally litter decomposition was influenced by termite activities and resource quality. These results contributed to understand litter decomposition process in the sudano-guinea savannahs of Ngaoundere in order improve soil fertility, nutrient cycling and some plant species domestication.

The current study was aimed to inventory and document the flora of Tutti Island (the study area) During a field survey conducted between August 2016 to December 2018. A total of 155 species belong to 120 genera and 41 families were inventoried. A number of 135 species were Dicotyledonous belong to 115 genera and 37 families. However, 20 species were monocotyledonous belong to 17 genera and 4 families. The most representative families were Fabaceace (23 species), Poaceae (14 species), Amaranthaceae (13 species), Asteraceae (10 species), Malvaceae (9 species) and Euphorbiaceae (8 species) respectively. Herbs comprise the predominant type of growth habit (52.34%) followed by shrubs (30.87%), vines (10.06%) and trees (6.71%) respectively. Botanical names of species and families were updated.

The study resulted in a number of species not previously recorded in the flora of the study area. The inventory led to a new generic record to the flora of Sudan; that is Macroptilium lathyroides (L.) Urb. Despite flora of the study area is rich, the study noticed that, there are some negative impact factors can affect this richness over time, these factors represented in human activities including overgrazing, agriculture and population expansion that beside to the annual flood.

Tropical montane forests are considered to be one of the most species diverse ecosystems. These areas pose specific edaphic and environmental characteristics which enable these areas to harbour wide varieties of organisms. Some of these organisms are threatened and others are endemic to the area. The quest for food and other resources has resulted to indiscriminate exploitation of these montane forest. This study aimed to investigate the stand structure, distribution patterns and regeneration status of six tree species (Nuxia congesta, Pittosporum mannii, Podocarpu slatifolius, Prunus africana, Schefflera abyssinica and Syzygium guineense) along altitudinal gradients in the Kilum-Ijim Forest Reserve, Cameroon. A total of six study plots of one hectare (100 x100 m) each were laid across a 120 m elevation gradient. Two plots were established at each altitudinal gradient with elevations 2377 m, 2437 m and 2497 m. Measurements were taken for tree height, diameter at breast height (DBH 1.3 m) for the tree and poles. The digital Vernier callipers were used to measure collar diameters of seedlings and saplings. The highest tree density of 385 stems/ha was recorded for N. congesta at altitude 2497 m while the least was 20 stems/ha for S. abyssinica at altitude 2377m. The highest seedling density was 1563 stems/ha recorded for P. mannii at altitude 2377m and the least was noted for S. abyssinica at all the three altitudinal gradients.  Nuxia congesta had the highest basal area of 8809.23m²/ha at altitude 2437 m and the least of 74.82m²/ha for P. latifolius at altitude 2437 m.  The highest IVI occurred in N. congesta (131.91) was recorded at altitude 2377 m and the least (24.91) occurred in P. latifolius at altitude 2437 m. The spatial distributions of studied tree species were generally clumped and irregular. The regenerations of species were generally poor, though fair regenerations were noticed for N. congesta and P. mannii. The results showed that the six tree species were highly disturbed by anthropogenic activities. It is therefore imperative to develop and implement effective conservation measures to sustain the biodiversity of this reserve.

The overexploitation of agricultural lands have necessitated the use of fertilizers to enhance food production. However, due to the cost and environmental impacts of mineral fertilizers, the utilization of readily available organic wastes as soil amendments have become necessary. The effect of the sole or combined application of yam, cassava and plantain peels on soil properties was evaluated in an on-farm study conducted at Akufo farm settlement, Ibadan, southwestern Nigeria. The experiment was laid out in a Randomized Complete Block Design with fifteen treatments which consisted of seven amendments (peels of yam (Y), plantain (P), cassava (C), Y+P, Y+C, C+P, Y+C+P) applied in two forms (ground and unground) at a uniform rate of 4 t ha^-1 and a control (without amendment). After 3 months of application, the soils were analyzed to determine the effect of the applied treatments on soil properties, after which they were sown to okra. All the amended soils had relatively higher organic carbon, nitrogen, phosphorus and exchangeable bases than the control, but ground treatments performed relatively better than unground ones. Also, irrespective of treatment and form of application, okra yield was considerably improved by the utilized amendments, with ground Y+C recording the highest (14.33 t ha^-1). This study showed that the sole or combined use of yam, plantain and cassava peels, either ground as powder or used as mulch, has the potential to improve soil fertility and crop yield and may provide an effective and simple means to utilize organic wastes as soil amendments, especially among poor farmers who cannot afford composting technology.