Nutrient cycling in primary, secondary forests and cocoa plantation in the Ashanti Region, Ghana

Primary forest (reserved area), secondary forest and cocoa plantation land uses characterize uplands of Dwinyama watershed in Ghana within the dry semi-deciduous forest zone. The nutrients recycled in the land uses were studied through leaf litter fall, nutrient release, nutrient fluxes estimation and topsoil nutrient contents leading to the identification of appropriate land use in upland regions that may potentially influence lowland farming. Mean annual leaf litter produced by the primary and secondary forests was both 7.9 t ha-1 and that for cocoa plantation was 6.9 t ha-1. The primary forest leaf litter showed rapid decomposition than the secondary forest and the cocoa leaf litter. Nutrients released from the decomposing leaf litters were fast for N, P, K, Ca and Mg for the primary and secondary forests. Less leaf litter production and high rainfall regimes in South America and southeast Asia probably contributed to the lower annual nutrient fluxes recorded than that of the dry semi-deciduous tropical forest in Ghana. The soil under cocoa plantation was higher in Ca than in the secondary and primary forests soils. The primary forest recorded higher contents of top soil N, P. K, and Mg nutrients due to non-frequent removal of the vegetation, presence of organic matter that increases soil carbon content and cation exchange capacity. Generally, trends of nutrients released and the quantities of nutrient fluxes estimate in the land uses in Ghana suggested that nutrient cycling was better in the primary forest followed by the secondary forest and cocoa plantation. The trend in the land uses was primary > secondary > cocoa, suggesting that forests in uplands will protect watersheds, and, through leaching and erosion, nutrients may be transported to the lowlands for continuous and sustainable cropping with little or no inorganic fertilizer application

Distribution characteristics of mineral elements in tree Species from two contrasting secondary forests in Ghana

Tree species in two contrasting forests were evaluated on three plots of 0-19 ha (0.57 ha) in each secondary forest. Tree species populations were 44 in Akyaakrom (AS), 29 in Dopiri (DS), and families were 18 in AS and 16 in DS. Tree densities were 121 and 99 in AS and DS, respectively, in 0.57 ha. In terms of tree species population, diversity and density, AS was superior to DS. The distribution of major mineral elements in the leaves showed mean concentrations in decreasing order of K > Ca > Mg > P > N in AS and Ca > K > Mg > P > N for DS. The bark samples showed concentrations in decreasing order of Ca > K > Mg > N > P in both forests. Generally, concentrations of Ca in the tree species bark samples of both forests were about three times higher than they were in the leaves. Soil nutrients showed that Ca, Mg and N concentrations were higher in the DS than in AS within 0-60 cm soil depths. However, at 30-45 cm depth, Ca, Mg, K and N concentrations were higher in AS than in DS. The nutrient element concentrations were high at 0-15 cm than further down the soil depths for the two forests. The land quality indexes of the principal nutrients N, P, K, Ca and Mg were higher in AS than in DS. Thus, eight tree families in AS and five in DS, and tree species numbers 23 and 12 were peculiar to each site. This may suggest the higher tree population and diversity recorded for AS than for DS

PAH Quantification and Estimated Carcinogenic Risks at Selected Fuel Stations in Tamale Metropolis, Ghana

The research aim was to quantify PAHs levels and assess their associated carcinogenic health risks in fuel filling stations located in both high and low vehicular traffic areas in the Tamale Metropolis of Ghana. Dust particles were collected from ten fuel filling stations and extracted using an Accelerated Solvent Extractor (ASE). PAH analysis was conducted using a GC-MS system. Cancer risk assessment was done using the Incremental Life-time Cancer Risk (ILCR) model. The average PAH concentration recorded in the high and low vehicular traffic areas were 158,080±102,650 μg/kg and 370,220±218,140 μg/kg respectively. Benzo(a)Anthra­cene was the most occurring PAH congener recorded in both traffic areas. Dermal contact as a route of PAH exposure recorded the highest potential cancer risk for both adults and children. Amongst the fuel filling stations, Gab Energy recorded the highest carcinogenic risks of 2.50 (adults) and 2.67 (children). In all, the average cancer risk values for adults (1.02) was slightly higher than that of the children (9.26E-01) with no significant difference. The mean ƩILCR val­ues for both populations indicated a high to very high potential carcinogenic risk to the people living or working in and around the study areas

Phytochemical Screening and Antimicrobial Activity of False Yam (Icacina oliviformis) Extracts on Microbes

This study compares the phytochemicals and antimicrobial activity of Icacina oliviformis tuber and seed extracts on Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aerugino­sa, Escherichia coli and Candida albicans. False yam tubers were washed and peeled and the mesocarp removed to obtain the seeds. Methanol was used to obtain tuber and seed extracts of the false yam, after they were pulverized. Phytochemical screening showed the presence of tannins, saponins, alkaloids and glycosides in both extracts but the proportion of tannins and alkaloids were relatively higher in false yam seed extract than tuber extract. Antimicrobial assay showed that both extracts had antimicrobial activity justifying its use in the treatment of diseases in Northern Ghana. False yam seed extract had a relatively higher antimicrobial activity than tuber extract. The least minimum inhibition concentration recorded was 1.56 mg/ ml for false yam seed on Gram-positive bacteria and Candida albicans. False yam seed extract exhibited a higher antimicrobial activity against the microorganisms than the tuber extract, this provides a cheaper source of antimicrobial agent to treat infectious diseases. Keywords: False yam tuber, False yam seed, Icacina oliviformis, Phytochemical screening, Minimum Inhibition Concentration (MIC), Microorganisms &nbsp

Waste Management Practices of Construction Companies at the Airport Hills and Sakumono Areas in Accra, Ghana

Waste generated in the construction industry is a major environmental problem but its research is rather limited. Thus, this research was conducted to assess the waste disposal practices of construction companies at the Airport Hills and Sakumono areas in Accra, Ghana. These areas were chosen because of the increasing and fast development of housing projects there. A convenience sampling technique was used in choosing the companies to achieve the research goal. Questionnaires and field observations were used to gather information about the construction companies and their waste management practices. Forty construction companies were identified in both study areas. Majority of the companies recorded a total of 60-80 cubic meters of material waste per month. Eleven companies stated amounts of between USD 250 - 350 as cost of material waste management per month. Several reusable materials were identified at construction sites. Twenty-six companies practised sorting and recovery of waste before final disposal. It was revealed that there was no statistically significant relationship between the educational levels of waste management teams of the construction companies and their practice of proper waste management methods. A significant relationship however existed between the educational level of waste management teams and their use of waste management plans. It is recommended that waste management training programmes are developed by the Environmental Protection Agency of Ghana for construction companies to curb the problem of poor construction waste management

Black-wattle growth in reponse to application of nitrogen, phosphorus and potassium

Due to the lack of information about Black-wattle fertilization, this study evaluated black-wattle plants growth in response to different fertilization levels of nitrogen, phosphorus and potassium six years after implantation. The statistical design used was a randomized blocks with trifatorial distribution. Total height (m), diameter at breast height (DBH) (cm) and stem volume with bark (m³ ha-1) were evaluated. Black-wattle showed a positive and significant growth response to N and P (interaction) fertilizations and absence for K. m To obtain the maximum development of black-wattle, for the soil and climate condition studied, it is required the use of the maximum dose of nitrogen (40.0 kg ha-1 N) and 78.9 kg ha-1 phosphorus, not requiring the addition of potassium

Strategies for increased fodder production from Leucaena and Gliricidia to eliminate dry season feed shortages in the humid tropics

Fodder tree legumes are valuable sources of high quality feed in the dry season when pasture productivity can be low and of poor quality. To ensure sustained fodder availability from Leucaena leucocephala (Lam.) de Wit and Gliricidia sepium (Jacq.) Walp in the dry season (November-February) the best strategy is to allow hedges to grow for 9 months through the rainy season after a uniform pruning in January, then cut and sun-dry. The copice growth should then be cut again 3 months later in January and fed as green-chop

Nitrogen and phosphorus fertilization promotes rapid initial growth of leucaena on Alfisol

Determines whether small quantity of nitrogen fertilizer in combination with phosphorus will enhance rapid early growth of Leucaena leucocephala, especially, on the highly weathered, low organic matter and low available P soils; and concludes that fertilizer N and P application increased growth rates sharply thus hastening shoot and root dry matter accumulation

Vertisols of Ghana: Uses and potential for improved management using cattle

Describes soil characteristics, uses, management, and productivity of vertisols in Ghana and discusses the potential for improved management using draught oxen. Includes recommendations