College of Agriculture & Natural Resources

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Conversion of Natural Forest to Cocoa Agroforest in Lowland Humid Ghana: Impact on Plant Biomass Production, Organic Carbon and Nutrient Dynamics
(2009) Dawoe, Evans
This study was conducted to assess the effects of forest conversion to shaded-cocoa system on plant biomass, nutrient fluxes and soil physico-chemical properties along a chronosequence (forest, 3, 15 and 30-year-old cocoa farms) in the Moist Semi-deciduous Forest Zone of the Ashanti Region, Ghana. It also explored farmer indigenous knowledge and perceptions of soils and soil fertility dynamic processes. Plant biomass and above-ground organic carbon and nutrient pools significantly declined following changes in land-use compared to soil pools. Tree biomass constituted the largest pool ranging from 12.7 ±1.6 Mg ha-1 for the 3-year-old cocoa system to 209.3±33.3 Mg ha-1 in the forest. Soil Organic Carbon (SOC) in 0-60 cm soil depth did not change significantly over a 30-year period and ranged from 49.0±2.3 to 67.4±1.1 Mg C ha-1 in 3 year-old shaded cocoa system and forest respectively. SOC significantly declined only in the top (0-10 cm) soil at 3 years after conversion but recovered at 15 years. Thirty-year-old shaded-cocoa systems yielded up to 151 Mg C ha-1 primarily stored in established trees (both cocoa and shade trees) and soil pools. Total N declined only in the 10-20 cm soil depth in 3 and 15 year-old treatments but remained stable in all other soil depths across the chronosequence while available P stocks declined significantly. Soil exchangeable Ca, K and Mg stocks remained relatively stable with a tendency to improve, and cation exchange capacity (CEC) and base saturation increased more or less along the chronosequence. Soil bulk density (gm cm-3) increased significantly with increasing age of plantation only for the top 0-10 cm soil layer but did not differ among sites for similar depths. Despite the apparent stability of soil C stocks and nutrients (0-60 cm) along the chronosequence, soil quality declined under cocoa land-use at 3 years. Microbial biomass demonstrated a strong seasonal variation. However, conversion of forest did not result in a significant decline in microbial biomass. Mean annual litterfall and stand litterstocks differed significantly among land-uses. Litterfall ranged from 5.0 Mg ha-1 in 3-year-old cocoa to 10.4 Mg ha-1 forest systems while stand litterstocks were from 3.6 to 5.9 Mg ha-1 in 3 and 15-year-old farms respectively. Annual decomposition coefficients (kL) were similar in cocoa systems (0.221-0.227) but greater under forests (0.354). Estimated nutrient inputs from litterfall was 4 to 165 kg ha-1yr-1 of P and Ca respectively in 15-year-old and forest plots respectively. Turnover of fine roots was 3,591, 1,427, 2,466 and 4,066 kg ha-1yr-1 for forest, 3, 15 and 30-year-old plots respectively. Nutrient inputs through turnover of fine roots were estimated to be 16-31 kg N ha–1year–1, 2 -5 kg P ha–1year–1, 9-36 kg K ha–1 year–1, 18-47 kg Ca ha–1year–1 and 3-25 kg Mg ha–1year–1 across the chronosequence. There were significant differences in incident rainfall, throughfall and stemflow chemistry. Mean annual inputs of nutrients fluxes in incident rainfall were 5.7 kg N, 0.14 kg P, 13.6 kg K, 9.43 kg Ca and 5.6 kg Mg ha-1 yr-1. Rainfall loading or net canopy exchange was negative for total N at all sites while concentrations of P and the basic cations increased in throughfall relative to incident rainfall. Throughfall on average constituted about 95% of the total solute inputs of rainfall origin to forest floor. The mean N and P input-output balances were negative showing the system’s ‘no external input’ character. Farmers in the study had a well-developed knowledge system of their soils and related fertility processes. They derived their knowledge from observable plant and soil characteristics namely; soil color, crop yield, water retention capacity, difficulty to work soil, type and abundance of indicator weeds, leaf color or deficiency symptoms observed on crops and presence and abundance of soil macro-fauna. The qualitative perceptions of farmers matched scientific assessment of fertile or infertile soils. The results suggest the integration of local and scientific knowledge to facilitate the processes for formulating policies and development plans for agriculture truly participatory, gender sensitive and collaborative approaches. Enhancement farmers’ capability to adopt improved farm management and land preparation methods is required to conserve the soil and sustain long-term productivity.
Relationships between Some Anatomical, Physical and Durability Properties of the Wood of Some Lesser Utilised Ghanaian Hardwoods
(2009) Quartey, Gladys Ama
This thesis is the result of a comprehensive study of some anatomical structures as well as some of the properties of wood utilization of selected species and the interrelationship amongst them. The natural durability of ten lesser-known West African Species, namely Albizia ferruginea (Guill. & Perr.) Benth. (Awiemfosamina), Amphimas pterocarpoides Harms (Yaya), Antiaris toxicaria Lesch. (Kyenkyen), Blighia sapida Koenig (Akye), Canarium schweinfurthii Engl. (Bediwonua), Celtis zenkeri Engl. (Esa), Cola gigantea A. Chew. (Watapuo), Petersianthus macrocarpus (P. Beauv.) Liben (Esia), Sterculia oblonga Mast. (Ohaa), Sterculia rhinopetala K. Schum. (Wawabima), and as reference Teak (Tectona grandis), were evaluated by the field test according to EN 252 (1989) for a period of 6 months. Structural size samples were tested for their mechanical properties according to EN 408 (2003). Their water sorption properties were determined at relative humidity conditions of 30, 45, 60, 75, and 90 % at a temperature of 25oC and compared with Albies alba, Picea albies, Fagus sylvatica (European species). Three of the ten species, Albizia ferruginea, Blighia sapida, and Sterculia rhinopetala were selected for anatomical investigations based on their performance in the durability and mechanical strength tests. Microscopic sections of the transverse and tangential planes were made on a Leica sliding microtome, stained and permanently mounted in Canada Balsam. The micrographs were analysed using the stereological technique described by Ifju (1983) and Steele et al. (1976). Maceration was also done. The results from the field test indicate that some of these less utilized species could be used as substitutes for the more standard commercial species in their end use applications. It was found that Albizia ferruginea was very durable, Sterculia rhinopetala was durable and Blighia sapida was moderately durable. A general trend found in the ten species was that, the denser the species the less water/moisture it takes up and the more durable it is, combined probably with specific polyphenolic substances. An exception to this trend was Albizia ferruginea, having the highest sorption of the three mentioned species but at the same time the highest durability and Sterculia rhinopetala the least. The best correlations found between the mentioned properties/features are between density and bending strength, followed by density and sorption, sorption and durability and to a lesser extent density and durability. As could be expected, durability (as a result of natural impregnation with protective substances) was in fact not completely correlated with density: Albizia ferruginea although the lightest of the three specially tested species, had the relatively highest durability according to the graveyard test. Blighia sapida was found to have crystals which could be harmful for working tools. This could explain its brittle behaviour under stress. It had a bending strength of 61.4 N/mm2 at a moisture content of 29 % with an average density of 0.899 g/cm3. A peculiar form of cell wall thickenings has been found in the vessels of this species with the help of scanning electron microscopy. In a third position, Albizia ferruginea had lowest bending strength of 50 N/mm2 at a lower average density of 0.740 g/cm3. In conclusion, Sterculia rhinopetala was used for a pedestrian bridge constructed at the KNUST campus in Kumasi due to its performance in most of the tests carried out and even though most of the tested lesser utilized species were not durable; their durability could be enhanced by impregnation with protective substances in order to be used for external applications.
Soil fertility and microbial biomass carbon, nitrogen and phosphorus dynamics under different amendments and cropping systems In Ghana
(2009-02-05) Logah, Vincent
Optimizing manure quality for increased food production on small holder farms in the upper east region of Ghana.
(2009-07-13) Ewusi – Mensah, Nana
The beneficial role of cattle manure to improving soil fertility has long been recognized. Its uses however have several drawbacks. One of such drawbacks is the nutrient content which is generally low and variable depending on the feed of the animal and manure management. This study focused on improving the quality of cattle manure for increased maize yields and consisted of five parts: 1. Assessment of the resource quality of cattle manure in seven districts of the Upper East region. 2. Composting of cattle manure. 3. Laboratory - incubation studies to determine nutrient release patterns of compost. 4. Field decomposition studies of buried compost in litter bags. 5. Assessment of the effects of compost, cowdung and NPK fertilizer on crop growth and yield. A survey was conducted in seven districts of the Upper East region using structured questionnaires to seek information on management practices likely to influence manure quality such as storage and handling. The survey revealed that nitrogen losses up to 100% were sometimes obtained by the time the manure was incorporated into the soil. An initial resource quality analysis of the manure sampled from the seven districts was conducted in the laboratory using standard protocols. The results indicated that N and P contents of the manure ranged from 0.27 to 1.14% and 0.28 to 0.76% respectively, which were all below the critical levels for net mineralization. Polyphenol levels on the other hand were lower than the critical value of 4%. Decomposition and nutrient release from the manure showed immobilization of total N during the first four weeks, suggesting the need to improve the quality by composting or by applying it in combination with mineral fertilizers. In an attempt to improve the quality of the manure, composting with Stylosanthes guinensis using the aerated pile method was carried out. Two main compost types (1:1 and 2:1 ratios of cowdung to plant material) were prepared. Total N and P contents of the composts at the end of study period ranged from 1.10 to 1.46% and 0.28 to 0.31% respectively. Mineralization studies on the resultant composts were conducted under laboratory (leaching tube method) and field (litter bag technique) conditions. Under laboratory conditions, both compost types showed net N and P immobilizations during the first two weeks of incubation. However, under field conditions, net N and P mineralization rates were observed throughout the study period for both compost types. Half life values (time required for 50% of the initial mass to decompose) of 8 and 10 days respectively were recorded for the 1:1 and 2:1 compost types. Furthermore, the 1:1 compost had a higher decomposition rate constant (k = 0.085) than the 2:1 compost (k = 0.056). In all cases, negative correlations were observed between the mass of composts remaining and nutrient released. The contribution of the composts to improving the fertility of the soil and hence crop growth was evaluated by comparing maize response to various rates of the composts with optimum mineral fertilizer combinations. The results showed that the 1:1 compost treatment at 3 t/ha, produced the highest maize grain yield (4.99 t/ha). Maize grain yields obtained from both compost types compared very well with NPK fertilizer suggesting that composting of cattle manure with Stylosanthes guinensis enhanced its quality and nutrient release potential for increased crop yield.
An Analysis of Yam consumption Patterns in Ghanaian Urban Communities
(2009-07-14) Aidoo, Robert
This study examined the major factors that drive changes in yam consumption patterns across income groups, seasons and urban centers in Ghana to inform food policy formulation. The study, among other things, sought to provide evidence on whether or not yam had become a luxury food commodity in Ghanaian urban communities. Special attention was also given to the question of whether household income allocation between males and females had any significant effect on yam consumption. Quarterly household panel data collected from four urban centers were used to conduct a complete demand system analysis by employing the Almost Ideal Demand system (AIDS) and Quadratic Almost Ideal Demand System (QUAIDS) models through the use of the Ordinary Least Squares (OLS) method. The study estimated yam expenditure elasticities for the pooled/aggregate data and the four different urban centers across different income groups to test Engel’s law. Results of the study showed that majority (>80%) of yam consumers in Ghanaian urban communities preferred white yam to yellow and water yams, and the most important reason for their preference was taste. Boiled yam (ampesi) was the most preferred yam product in Ghanaian urban centers followed by pounded yam (fufu). Rice was identified as the most important substitute for yam in urban communities. In a typical Ghanaian urban center, household food budget formed about 51% of the total household budget. Yam constituted about 12% of household at-home food budget and 13% of its away-from-home food budget. The shares of food budget that households allocated to yam generally increased during the peak harvest season and dropped during lean season across all urban centers in Ghana. Yam expenditure elasticity for the pooled sample was found to be inelastic (0.76), suggesting that yam is a basic food commodity in a typical Ghanaian urban center. Yam expenditure elasticity was lowest for Tamale (0.64), a less urbanized center, and highest for Accra (1.01), a more urbanized center. Generally, across urban centers, the study supported Bennett’s law which posits that households switch from less to more expensive calorie consumption as their incomes increase. However, in each particular urban center, Engel’s law was affirmed; yam expenditure elasticity was higher for low-income households and lower for high-income households. Yam expenditure elasticity was found to vary across seasons; yam was expenditure elastic during the lean season and expenditure inelastic during the harvest season. Women’s share of household income was found to be positively related to household yam budget share. Evidence from this study did not support the hypothesis of economies of household size with respect to household yam budget share when the pooled data was used for analysis. However, the hypothesis of economies of household size was supported in the seasonal consumption analysis where households were found to enjoy economies of size during the relatively yam abundant period of August to December and diseconomies of size during the lean season. The study showed that yam budget share was own-price elastic but expenditure inelastic. Urban households were more responsive to changes in yam prices than changes in household income, implying that the substitution effect is stronger than the income effect. The high price elasticity for yam budget share stresses the importance of food price changes for households, and it is important that households’ reactions are taken into account in the development of comprehensive agricultural and food policies in Ghana. Based on the findings of the study, recommendations have been made to help improve the Ghanaian yam sector and household food security in urban centers.
Conversion of Natural Forest to Cocoa Agroforest in Lowland Humid Ghana: Impact on Plant Biomass Production, Organic Carbon and Nutrient Dynamics
(2009-07-14) Dawoe, Evans
This study was conducted to assess the effects of forest conversion to shaded-cocoa system on plant biomass, nutrient fluxes and soil physico-chemical properties along a chronosequence (forest, 3, 15 and 30-year-old cocoa farms) in the Moist Semi-deciduous Forest Zone of the Ashanti Region, Ghana. It also explored farmer indigenous knowledge and perceptions of soils and soil fertility dynamic processes. Plant biomass and above-ground organic carbon and nutrient pools significantly declined following changes in land-use compared to soil pools. Tree biomass constituted the largest pool ranging from 12.7 ±1.6 Mg ha-1 for the 3-year-old cocoa system to 209.3±33.3 Mg ha-1 in the forest. Soil Organic Carbon (SOC) in 0-60 cm soil depth did not change significantly over a 30-year period and ranged from 49.0±2.3 to 67.4±1.1 Mg C ha-1 in 3 year-old shaded cocoa system and forest respectively. SOC significantly declined only in the top (0-10 cm) soil at 3 years after conversion but recovered at 15 years. Thirty-year-old shaded-cocoa systems yielded up to 151 Mg C ha-1 primarily stored in established trees (both cocoa and shade trees) and soil pools. Total N declined only in the 10-20 cm soil depth in 3 and 15 year-old treatments but remained stable in all other soil depths across the chronosequence while available P stocks declined significantly. Soil exchangeable Ca, K and Mg stocks remained relatively stable with a tendency to improve, and cation exchange capacity (CEC) and base saturation increased more or less along the chronosequence. Soil bulk density (gm cm-3) increased significantly with increasing age of plantation only for the top 0-10 cm soil layer but did not differ among sites for similar depths. Despite the apparent stability of soil C stocks and nutrients (0-60 cm) along the chronosequence, soil quality declined under cocoa land-use at 3 years. Microbial biomass demonstrated a strong seasonal variation. However, conversion of forest did not result in a significant decline in microbial biomass. Mean annual litterfall and stand litterstocks differed significantly among land-uses. Litterfall ranged from 5.0 Mg ha-1 in 3-year-old cocoa to 10.4 Mg ha-1 forest systems while stand litterstocks were from 3.6 to 5.9 Mg ha-1 in 3 and 15-year-old farms respectively. Annual decomposition coefficients (kL) were similar in cocoa systems (0.221-0.227) but greater under forests (0.354). Estimated nutrient inputs from litterfall was 4 to 165 kg ha-1yr-1 of P and Ca respectively in 15-year-old and forest plots respectively. Turnover of fine roots was 3,591, 1,427, 2,466 and 4,066 kg ha-1yr-1 for forest, 3, 15 and 30-year-old plots respectively. Nutrient inputs through turnover of fine roots were estimated to be 16-31 kg N ha–1year–1, 2 -5 kg P ha–1year–1, 9-36 kg K ha–1 year–1, 18-47 kg Ca ha–1year–1 and 3-25 kg Mg ha–1year–1 across the chronosequence. There were significant differences in incident rainfall, throughfall and stemflow chemistry. Mean annual inputs of nutrients fluxes in incident rainfall were 5.7 kg N, 0.14 kg P, 13.6 kg K, 9.43 kg Ca and 5.6 kg Mg ha-1 yr-1. Rainfall loading or net canopy exchange was negative for total N at all sites while concentrations of P and the basic cations increased in throughfall relative to incident rainfall. Throughfall on average constituted about 95% of the total solute inputs of rainfall origin to forest floor. The mean N and P input-output balances were negative showing the system’s ‘no external input’ character. Farmers in the study had a well-developed knowledge system of their soils and related fertility processes. They derived their knowledge from observable plant and soil characteristics namely; soil color, crop yield, water retention capacity, difficulty to work soil, type and abundance of indicator weeds, leaf color or deficiency symptoms observed on crops and presence and abundance of soil macro-fauna. The qualitative perceptions of farmers matched scientific assessment of fertile or infertile soils. The results suggest the integration of local and scientific knowledge to facilitate the processes for formulating policies and development plans for agriculture truly participatory, gender sensitive and collaborative approaches. Enhancement farmers’ capability to adopt improved farm management and land preparation methods is required to conserve the soil and sustain long-term productivity.
Local Domestic Chickens: Their Potential and Improvement
(2009-07-15) Adomako, Kwaku
This study was conducted to assess the potential of indigenous chickens and improve their performance in traits of economic importance by incorporating in them the naked neck and frizzle genes, and also genes from a commercial layer (exotic breed) through crossbreeding (local naked neck/frizzle males × commercial females). Study One A survey was conducted to assess the current performance of local chickens in the Ashanti Region of Ghana. One-hundred and thirty five (135) local chicken keepers from Bosomtwe Atwima-Kwanwoma, Ejisu-Juaben and Asante-Akim South Districts were interviewed. All the keepers practised the extensive system of production with flock sizes averaging 22 in the ratio of 4: 6: 12 for cocks, hens and chicks respectively. A small amount of feed supplement was given either everyday or occasionally. Mortality of chicks (between day-old and six weeks) and total mortality (annual mortality for the entire flock) were 50% and 65% respectively. The average weights of cocks, hens and eggs were 1.55kg, 1.13kg and 42.80g respectively. The clutch size per bird ranged from 9-13. The major challenges faced by the keepers included diseases, predation, lack of funds to increase stock and construct structures, small sizes of birds and eggs, low numbers of eggs laid and poor fertility of eggs. Local birds provide immense benefits for keepers but their productivity is significantly hindered by genetic and management problems. Study Two Another survey was conducted to evaluate the potential of indigenous naked neck (Nana) and frizzle (Ff) birds within the indigenous chicken population in the Ashanti Region of Ghana. The study involved ninety (90) interviewees who were local chicken keepers in Bosomtwe Atwima-Kwanwoma, Ejisu-Juaben and Asante-Akim South Districts. Average body weight of Nana cocks did not differ significantly (P>0.05) from Ff & nana/ff (normal feathered) ones while Nana hens were significantly (P>0.05) heavier than Ff birds, but nana/ff birds did not differ significantly (P>0.05) from the two genotypes. Nana layers were significantly superior (P<0.05) in egg size, number of eggs per clutch and number of eggs per bird per year to Ff layers which were significantly better than nana/ff layers. However, clutches of eggs per year did not show any significant difference (P>0.05) among the three genotypes. Eggs from Ff layers had a significantly higher (P<0.05) hatchability compared to those from Nana & nana/ff layers. Eggs from Nana layers were significantly better (P>0.05) in Haugh unit and egg shell thickness compared to those from Ff & nana/ff layers and eggs from Ff layers were significantly better (P>0.05) in Haugh unit compared to those from nana/ff layers. Mortality was significantly lower (P>0.05) in Nana birds followed by Ff & nana/ff birds respectively. The carcass of Nana birds had a significantly higher (P>0.05) dressing percentage than that of Ff and nana/ff birds. Naked neck and frizzle genes improve the productivity of local birds but the naked neck gene appears to be more effective than the frizzle gene. Study Three The first mating in Experiment Three was between four indigenous naked neck males and thirty-six Lohmann commercial females in a ratio of 1: 9. This produced offspring in the proportion of 48.7% Nana to 51.3% nana in the F1 generation. Nana birds were significantly better (P<0.05) in body weight, body weight gain, number of eggs per clutch, hen-housed and hen-day rates of lay, egg size, Haugh unit, shell thickness, survivability and carcass yield, than their nana counterparts. However, age at first egg and egg size to body weight ratio were significantly better in the nana birds compared to the Nana ones. In the second mating, ten males and one hundred females of F1 Nana birds were selected and mated inter se in a ratio of 1:10. This produced 16.8% NaNa, 54.5% Nana and 28.7% nana offspring in the F2 generation. It was observed that Nana and NaNa birds were significantly higher (P<0.05) in body weight, body weight gain, number of eggs per clutch, hen-housed and hen-day rates of lay, egg size, Haugh unit, shell thickness, survivability and carcass yield, compared to their nana counterparts. However, chick survivability was significantly better (P<0.05) in the nana birds compared to Nana and NaNa ones. Using birds that show the naked neck phenotype in local chicken production will enhance productive and reproductive performances significantly. Study Four Five local frizzle males were mated to forty Lohmann commercial females in a ratio of 1:8. This produced almost equal numbers of offspring, that is 50.2% Ff and 49.8% ff in the F1 generation. The Ff birds were significantly superior (P<0.05) to their ff counterparts in terms of body weight, number of eggs per clutch, hen-housed and hen- day rates of lay, Haugh unit and carcass yield. However, survivability was significantly better (P<0.05) in the ff birds compared to the Ff birds. The second mating was made between ten males and one-hundred females of F1 Ff birds. It was done inter se in a ratio of 1:10. This produced offspring in the proportion of 22.4% FF, 51.5% Ff and 26.1% ff in the F2 generation. The F2 Ff and FF birds were significantly higher (P<0.05) than their ff counterparts in number of eggs per clutch, hen-housed and hen-day rates of lay, Haugh unit, shell thickness, survivability and carcass yield. However, body weight, body weight gain, egg size and chick mortality did not differ significantly between the frizzles and the ff genotypes. Using frizzle (FF, Ff) hybrids in local chicken production will increase productivity markedly, though to a lesser extent than the naked necks (NaNa, Nana). Study Five In a comparative study involving all the five genotypes (NaNa, Nana, FF, Ff and nana/ff) reared under intensive, semi-intensive and extensive management systems, it was observed that the NaNa and Nana birds performed better (P<0.05) than their FF and Ff counterparts in body weight, body weight gain, number of eggs per clutch, hen- housed and hen-day rates of lay, egg size, Haugh unit, shell thickness, carcass yield and economics of production. It was also economically most profitable to rear all the genotypes (NaNa, Nana, FF, Ff & nana/ff) under the semi-intensive system followed by the extensive and the intensive systems respectively. Aside genetic improvements, rearing local birds under the semi-intensive system will improve profitability significantly.
Effect of decomposing crop residues on soil properties and crop productivity in the semi−deciduous forest zone of Ghana
(2009-08-09) Arthur, Alfred
A study was carried out to examine recycling of crop residues as a major component of integrated soil fertility management. The objectives of the study were to determine the quality, rates of decomposition and nutrient release patterns from residues of cassava leaves, cowpea haulm, groundnut haulm, maize stover, mucuna and soyabean haulm typical of cropping systems in Ghana as sources of plant nutrients. The study aimed at i). estimating the time course of nutrient release from crop residues to improve synchrony and increase maize yield, as well as ii). examining the changes in soil physico – chemical properties by applying some of the residues (maize stover and cowpea haulm) either alone or in combination with NPK (15–15–15) fertilizer. Laboratory and field experiments were conducted. The field experiments were conducted at the Central Agricultural Station, Kwadaso, Kumasi, in the semi – deciduous forest zone of Ghana. The laboratory experiments were conducted at the Soil Science laboratory, KNUST, Kumasi. The field studies were conducted on Asuansi soil series (Ferric Acrisol) in the minor season of year 2006 and repeated in the major and minor seasons of 2007. Total N content of the crop residues ranged from 0.74% in maize stover to 2.95% in cowpea haulm. Organic carbon ranged between 44.70% in groundnut haulm and 47.50% in maize stover. Total phosphorus ranged from 0.22% in groundnut haulm to 0.38% in maize stover. The C: N ratio of the residues ranged from 15.3 in mucuna to 65.1 in maize stover. In the major season, the decomposition rate constant (k) was 0.224 and 0.305 week-1 for surface – placed and buried maize stover respectively and 0.475 and 0.502 week-1 for cassava leaves. In the minor season, the k values were 0.210 and 0.240 week -1 for maize stover, 0.421 and 0.523 week-1 for cowpea haulm and 0.541 and 0.659 week-1 for cassava leaves. The values recorded in the dry season were 0.145 and 0.158 for maize stover, 0.206 and 0.258 for cowpea haulm and 0.233 and 0.290 for cassava leaves. Burying of the crop residues reduced the half – life (t50) from 4.37 to 3.88 weeks for maize stover, 3.07 to 2.77 weeks for cowpea haulm and 2.62 to 2.34 weeks for cassava leaves. Microbial biomass C and N were higher under the various treatments compared with microbial biomass P. Most of the microbial biomass P was locked up in the microbial cells. Combined application of the high quality cowpea haulm and low quality maize stover was able to increase the microbial biomass P. Mean grain yield was highest (1.69 t ha-1) under maize stover + ½ NPK treatment followed by cowpea haulm + ½ NPK treatment (1.62 t ha-1) with the control treatment recording the lowest (0.83 t ha-1). The results showed that all the treatments had significant effects on soil pH after cropping for three seasons. The level of organic matter increased under fertilizer treatment, while it decreased under the control treatment. Total N remained almost unchanged in all the plots after cropping. Available P decreased from initial value of 26.00 mg kg-1 to 25.09 mg kg-1 where no fertilizer was added but increased by 35 – 80% under fertilizer treatments. Exchangeable Ca, K and Na decreased in all the plots irrespective of the type of amendment. The combination of maize stover + ½ cowpea haulm increased the ECEC by 3%, remained unchanged under maize stover + ½ NPK treatment while it decreased in all other plots. Though maize grain yield increased under the combined application of crop residues and NPK fertilizer in this study, data on changes in soil properties after cropping suggest the need to increase the duration and the level of organic material added to sustain the fertility of the soil.
The Agronomic qualities of the Mexican Sunflower (Tithonia diversifolia) for soil fertility improvement in Ghana: an exploratory study
(2010) Partey, Samuel Tetteh
Soil fertility depletion remains a major biophysical constraint to increased food production in Ghana even when improved germplasm has been made available. With the growing concern of the potential of low input agriculture in mitigating soil fertility challenges, exploratory researches are imperative in selecting best quality organic materials that meet this expectation. This study was conducted to assess the suitability of Tithonia diversifolia green biomass as a nutrient source for smallholder agriculture in Ghana using both on-station and on-farm trials. The on-station research comprised an evaluation of the decomposition and nutrient release patterns of T. diversifolia in comparison with well-known leguminous species of agroforestry importance: Senna spectabilis, Gliricidia sepium, Leucaena leucocephala and Acacia auriculiformis. Concurrently, field trials were conducted to appraise the quality of T. diversifolia green biomass in relation to its biophysical effects on soil properties and the agronomic characteristics of crops. This was a comparative study with S. spectabilis, G. sepium and mineral fertilizer on a ferric acrisol. Field trials were also conducted to determine best practices for optimum biomass production of T. diversifolia using different pruning regimes and cutting heights as factors. The on-farm research was conducted at Dumasua in the Brong Ahafo Region of Ghana to appraise 200 farmers’ preliminary knowledge of T. diversifolia and evaluate the effect of T. diversifolia green biomass on soil fertility indicators and crop yields. The results of the decomposition study confirmed significantly high N, P, K concentrations in T. diversifolia comparable to levels recorded for the four leguminous species. In addition, T. diversifolia recorded the highest decomposition and nutrient release rates which differed significantly (p < 0.05) vii from rates of the four leguminous species. Although decomposition and nutrient release rates of species were related to quality of leaf material, P and Mg concentrations in particular were most influential in decomposition and nutrient release based on significant results. The on-station trials showed significant effect of the green manures (particularly T. diversifolia) on soil properties and the biomass and fruit yield of okro (Abelmoschus esculentus). These results were comparable and in some cases greater than fertilizer treatments. Total yield response in T. diversifolia treatment was 61% and 20% greater than the control and fertilizer treatments respectively. From the pruning experiment, it was evident that height of cutting, pruning frequency and their interaction significantly affected dry matter production of T. diversifolia. Dry matter production was highest (7.2 t ha-1yr-1) when T. diversifolia was pruned bi-monthly at 50 cm height. Results from the sociological survey confirmed farmers’ general knowledge on T. diversifolia at Dumasua was poor. Although majority of respondents had seen the plant growing, none could give a common name. Only the ornamental importance of T. diversifolia was identified. Meanwhile, the on-farm trials revealed a significant synergistic effect of combining T. diversifolia and fertilizer on soil nutrient availability and harvest index of maize. The results showed that the application of Tithonia either alone or in combination with fertilizer can increase yield by 24% and 54% respectively compared to plots which received no inputs.
The ecology and management of elephants (loxodonta africana matschie) in the bia – goaso forest enclave of western ghana
(2010-05-22) Sam, Moses Kofi
Elephants are important mega fauna whose role in an ecosystem could ensure the health and survival of diverse species. However, drastic declines in their numbers since the 19th Century in Africa in general and West Africa in particular has necessitated the need to understand their ecology in the local context to help improve their survival. This study was therefore conducted in the Bia-Goaso forest enclave in Ghana to contribute to the achievement of the objectives of the Elephant Conservation Strategy of Ghana (2000) and the “Action plan for the Management of the Transfrontier Elephant Conservation Corridor of Bia-Goaso-Djambarakrou,” which contain activities geared towards ensuring the survival of forest elephants in Ghana and West Africa respectively. In February 2004, a dry season survey on elephants and an investigation into the different levels of human and ecological variables that affect their abundance and distribution was conducted in an extensive network of eleven forest reserves and two wildlife reserves in the Bia–Goaso enclave of western Ghana. These activities were repeated twice, first in the rainy season of 2007 and the following dry season which started in 2007 and ended in 2008 mainly to understand seasonal effects in distribution of elephants in the area. During this period, the most up-to-date method for surveying forest elephants, the retrospective method was employed. A desk-top exercise was then undertaken not only to prove the importance or otherwise of the elephant populations in the study area in comparison with other elephant populations in West Africa but also to determine factors that govern their abundance. A preliminary investigation into the feasibility of creating corridors between reserves in the study area and neighbouring Ivory Coast was initiated in May 2004. As part of this, the movements of elephants from Ghana into Ivory Coast along the Bia river was monitored every quarter between August 2005 and December 2006, as well as an investigation into the rate of forest degradation. The nature and extent of human – elephant conflicts in the Bia Conservation Area was also studied through administration of questionnaires using interviews and field measurements. One hundred and thirty (130) transects were systematically distributed in three strata (high, medium and low density) based on dung pile density estimates in an initial reconnaissance. Two models (rainfall and steady state assumption models) were used to estimate elephant dung pile density and numbers in the study area. However, the rainfall model is preferred since it iii makes no assumption about the state of the forest. Two major elephant populations were observed to be residing in the study area, with the possibility of a tiny third population of less than 10 elephants (in the Bia North FR). In the 2004 survey, a mean population estimate of 115 (CL: 90 - 148) elephants was obtained for the Bia Resource Reserve. The eastern portion of the Mpameso Forest Reserve (medium density stratum) had an estimate of 57 (CL: 33 - 100) elephants. Elephant numbers could not be estimated for the rest of the reserves (low-density stratum) because of inadequate number of dung piles on transects. In the 2007/8 survey, estimates of 133 (CL: 104 - 162) elephants and 137 elephants (CL: 98 - 170) elephants were obtained for Bia CA during the dry and wet season surveys respectively. While for the Mpameso elephant range, estimates of 83 (CL: 41 - 125) elephants and 90 (CL: 49 - 131) elephants were obtained in the dry and wet seasons respectively. Merged estimates for both seasons were 135 (CL: 114 - 156) elephants for Bia and 87 (CL: 58 - 116) elephants for Mpameso. Altogether, a total population of 172 (CL: 123-264) elephants were estimated to be occurring in the entire study area. Elephants were found to be clumped more to the southeast of BRR, the eastern part of Mpameso and the Bia Shelterbelt FR. Elephants were found to be more widely spread out in the wet season than in the dry season within BCA. Analysis of dung pile distribution in relation with human and ecological variables in both the 2004 and 2007/8 studies showed that within the reserves, water availability explained a high proportion (ca. 90%) of the variance in elephant density, with elephants being clumped around watering points created as a result of logging. Additionally, in 2004, distance to the Bia River was inversely correlated to the number of dung piles seen per km in the Mpameso Forest Reserve. Illegal activities (such as snaring and snail picking), however, did not affect elephant abundance but rather had a negative correlation with watering points, that is, they were undertaken away from these watering points. This suggests that poachers were avoiding areas of high water availability, possibly because of high elephant activity around those areas. Outside reserves, the distance to major towns and roads accounted largely for variances in elephant density in 2004. In 2007/8 on the other hand, logging roads and availability of raphia also entered the model as significant variables, though they did not add much power to the models. By all standards, the Bia population on its own is a very important one in the sub-region. The Goaso population is smaller. However, the security of its range, and the possibility of linking it with others makes it also even iv more important for the overall conservation of forest elephants in West Africa. It was established during the study that elephant abundance in West Africa depends on the size of a population‟s range, to whether the range is protected, its geology and the quality of governance in the country where it occurs. Elephant crop damage is a serious problem in the area, especially to cluster of farms that border the southern portions of the Bia Resource Reserve, resulting in conflicts between farmers and nature conservation. Food crops such as plantain, cassava, cocoa and maize suffered severest damage. These are most preferred by the elephants when in the matured state and the quality is excellent. For each community, that suffered crop-raiding, the extent of crop-raiding depended not only on the area of land under cultivation but also the mean distance of farms from the reserve boundary, as well as the number of different crops planted on the farm. Interviews conducted in 2004 indicated that most migrant farmers do not see any advantage in preserving elephants and would do little to conserve them. While they were not willing to sacrifice part of their already overburdened farmlands for establishing elephant corridors, they also feared a possible increase in human-elephant conflicts in the future. However, most villages adjacent to streams/rivers showed a strong interest in restoring the riparian forest since they faced water and fish shortages in the dry season. More lately, there have been several forest restorative activities going on in the study area in the hope of returning wildlife into communal lands. Hence, there has been a generally increasing level of awareness concerning the conservation and protection of lands to serve as corridors. Of six potential corridors considered, one along the Bia river linking the Goaso population to those in Ivory Coast and from Bia Resource Reserve to Krokosue Hills Forest Reserve have the greatest potential in the short to medium term, and it is also likely that with a high level of interventions, two others could be achieved over the long term. A more detailed spatial analysis in combination with ground truthing is required before a conclusive decision on viable corridors can be made. Also a more participatory information gathering strategy (such as Timelines, H-Diagram) for soliciting community opinions on corridors have been suggested to complement the use of questionnaires. Recommendations also include a detailed study of elephant movements in the Ivorian side of the corridor.
Evaluation of productive Performance of Crossbred Naked-Neck and Frizzle Chicken Genotypes
(2010-07-13) Hagan, Julius Kofi
Two studies (survey and experimental work) were conducted to determine the frequency and incidence of naked-neck and frizzle genes existing in the indigenous chicken and to evaluate the performance of crossbred naked-neck and frizzle birds. In the first phase of the work a survey covering a three month period was conducted in six randomly selected districts in the Ashanti Region of Ghana. From the survey it was observed that the heat-tolerant genes, though dominant in nature, had very low frequencies of 0.03 and 0.05 for frizzle and naked-neck respectively. With regard to the experimental work, two studies (on-station and on-farm) were carried out to evaluate the egg production, growth and carcass characteristics of four crossbred naked-neck and frizzle genotypes, namely: (i) Na/naF/f, (ii) Na/naf/f (iii) na/naF/f and (iv) na/naf/f. These crossbred cockerels were generated from a reciprocal crossing between crossbred heterozygous naked-neck (50% indigenous naked-neck and 50% Lohman Brown) and frizzle (50% indigenous frizzle and 50% Lohman Brown) stocks. In the first on-station experimental study, one hundred and twenty (120), nine-week old crossbred cockerels (thirty each of the four genotypic groups) were randomly assigned to nine deep litter pens in a Completely Randomized Design for six weeks and their growth and carcass characteristics evaluated. The birds were provided with grower mash ad lib throughout the experimental period. At the end of the six-week trial, 3 cockerels from each of the four genotypic groups were randomly selected and slaughtered and their carcass parameters determined. The results indicated that there was no significant phenotype effect on initial body weights. iv However, the naked-neck frizzle phenotypes were significantly heavier at 14 weeks than the other phenotypes. The double heterozygous cockerels also gained significantly more weights than the other genotypes. The double heterozygous frizzled naked-necks (Na/naF/f) consumed significantly (P<0.05) more feed than the single heterozygous frizzles and naked necks (Na/na and F/f) and the normally feathered birds (na/naf/f). The double heterozygotes were significantly better converters of feed into meat than their single heterozygote and normally feathered counterparts. With respect to carcass yield characteristics, the double heterozygous cockerels had significantly (P<0.05) higher values in terms of percent leg yield, breast yield, thigh yield, dressed weight and dressing percentage. The second part of the on-station experimental work involved one hundred and twenty (120), eighteen-week old crossbred pullets (thirty each of the four genotypes) which were randomly assigned to a CRD experiment for a period of up to 60 weeks. The selected pullets were put in a partitioned deep-litter house, with 10 pullets in each compartment and provided with layer mash ad lib throughout the experimental period. The double and the single heterozygous pullets laid their first egg significantly (P<0.05) earlier than their fully feathered counterparts. The double heterozygotes produced significantly (P<0.05) more eggs (130) than the single heterozygotes (121 and 122) which also produced significantly more eggs than the normally feathered birds (113). Feed was more efficiently converted into eggs by the double heterozygous pullets than the other genotypes. There were no significant (P>0.05) differences among the genotypes in terms of eggshell thickness, albumen height, yolk height, Haugh unit and yolk v colour. Another on-farm study was carried out to compare egg production performance of the crossbred naked-neck and frizzle pullets and normally feathered local pullets under the semi-scavenging system. In this trial, 240, 10-week old randomly selected crossbred pullets (eighty each of naked-neck frizzle, naked-neck only and frizzle only) were distributed to some 10 selected farmers in the Ashanti Region of Ghana. The crossbred double and single heterozygous pullets were reared alongside the farmers’ own normally feathered local pullets that were of the same age as the crossbred pullets. Results on total eggs laid up to 60 weeks of age showed the crossbred pullets laying significantly (P<0.05) more eggs (105 eggs) than the local hens (78 eggs). There was a significant difference (P<0.05) between the crossbred pullets (181 days) and the local pullets (217 days) with respect to age at first lay. The crossbred layers produced eggs at a significantly (P<0.05) higher rate (43%) than the local layers (37%). Eggs laid by the crossbred layers were significantly (P<0.05) bigger than those laid by the local hens throughout the entire laying period. The farmers’ local pullets recorded significantly (P<0.05) lower deaths than the crossbred pullets, but between the crossbreed pullets (double and single heterozygotes), there were no significant differences. There was a genotype-environment interaction for rate of lay and mortality for the crossbred naked-neck and frizzle genotypes when the performance of the birds was compared under on-station and on-farm conditions. Estimates of heterosis showed that F2 offspring from the F X Na reciprocal cross were better than the offspring from the Na X F main cross in terms of body weights, egg weight and egg production parameters measured.
Groundnut varietal response to spacing in the Guinea Savannah and Forest Zones of Ghana
(2010-08-10) Konlan, Sampson
Field experiments were conducted at the KNUST Agricultural Research Station and Savannah Agricultural Research Institute (SARI) in 2006 and 2007 major seasons to assess the influence spacing on different groundnut varieties. The design was a factorial experiment laid out in randomized complete blocks with three replications. Two factors were tested; variety (6) and spacing (3). Nkosuor and Kpanieli recorded high pod yields at KNUST, significantly improving pod yield by 18.18 and 15.63% over their respective treatment means in 2006 and 2007. Spacing1 and Spacing2 significantly increased pod yields by 36.85 and 6.99%, over their respective treatment means in 2006 and 2007. At Nyankpala, Adepa and Manipintar significantly increased pod yield by 9.19% and 40.25% over the mean of treatments, respectively in 2006 and 2007. SP1 improved pod yield in 2007 by 16.08% over the mean of treatments. Jenkaar increased stover N by 4.08% whilst SP1 increased the stover N by 4.41 and 7.38% over treatment mean in 2006 and 2007, respectively. Jenkaar and Nkosuor recorded large stover N at Nyankpala, significantly increasing stover N by 40.83 and 31.86% over mean of treatments in 2006 and 2007, respectively. SP2 significantly increased stover N at over mean of treatments at Nyankpala by 24.76 and 4.66%, respectively in 2006 and 2007. In 2006, Azivivi increased mean 100 seed weight over the mean of treatments by 19.03% at KNUST, whilst Manipintar improved mean 100 seed weight by 12.7% over treatments mean in 2007. SP3 increased mean 100 seed weight by 4.24 and 8.32% over mean of treatments in 2006 and 2007 respectively. At Nyankpala, Adepa and Kpanieli significantly increased 100 seed weight by 0.54 and 9.98% over their respective treatment means in 2006 and 2007 respectively. Although all treatments recorded benefit-cost ratio (BCR) of over 1.00 at KNUST, Nkosuor and Kpanieli had the highest BCR (4.48 and 7.49, respectively) in 2006 and 2007. SP1 recorded the highest benefit-cost ratio 2006 (5.13) and 2007 (6.79). At Nyankpala, Adepa and Manipintar recorded the highest benefit-cost ratios (8.76 and 4.90, respectively) in 2006 and 2007. SP1 again recorded the highest benefits-cost ratios (8.51 and 3.89, respectively) in 2006 and 2007. The economics of production among the different spacing were in decreasing order of spacing1>spacing2>spacing3. Based on the results, the recommended groundnut variety for the Humid Forest was Nkosuor. For the Guinea Savannah, the recommended groundnut variety was Adepa. SP1 was however the recommended spacing for both the Humid Forest and Guinea Savanna agro-ecologies.
Genetic control of morpho-physiological, histological and biochemical factors of resistance to black pod disease in Cocoa (Theobroma cacao L.)
(2011-08-19) Nyadanu, Daniel
Black pod disease caused by Phytophthora palmivora and Phytophthora megakarya is an important disease of cocoa of which host plant resistance is considered the most effective method of controlling the disease. However little is known about host factors conferring resistance and the type of gene action governing them. The objective of this study was to identify morpho-physiological, histological and biochemical traits conferring resistance to black pod disease in cocoa and to study their genetic controls. Twelve cocoa genotypes and their hybrids in 6x4 North Carolina Design II and 6x6 diallel design were evaluated by leaf discs and detached pod inoculations at penetration and post-penetration stages of infection and natural field infections. The cocoa parents and their hybrids were also evaluated for morpho-physiological, histological and biochemical characters. The morpho-physiological, histological and biochemical factors evaluated were correlated with resistance to black pod disease. Morpho-physiological factors such as pod husk thickness and epicuticular waxes on abaxial and adaxial surfaces of leaf and on pod surface were significantly and negatively correlated with black pod disease. Epicuticular wax on pod husk was significant and negatively correlated with penetration infection of Phytophthora species but was not significant with post-penetration infection suggesting its role in restricting penetration of the fungus. Percentage moisture content was significant and positively correlated with black pod disease. Histological factors such as width and length of vascular bundles, epicarp thickness, distance between vascular bundles and epicarp, number of cells in epicarp and number of cells in mesocarp showed a significant negative correlation with black pod disease. Number of vascular bundles and cell width were positively correlated with black pod disease. Susceptible genotypes were observed to have thinner epicarp and higher numbers of vascular bundles suggesting their porosity to Phytophthora species. The cells in epicarp and mesocarp were arranged more compactly in resistant than highly susceptible genotypes. The cell walls of resistant genotypes stained deep red with phloroglucinol, a lignin specific stain, suggesting the presence of lignin. Biochemical factors such as amount of nitrogen, protein, soluble and insoluble sugars, total polyphenol, flavonoids, tannins and lignin in leaf and pod of cocoa were significant and negatively correlated with black pod disease. This suggests that as biochemical factors increase, susceptibility to black pod disease reduces. The biochemical contents in leaf and pod increased after P. megakarya infection, suggesting their role in resistance to Phytophthora species. Principal components analysis suggested that amount of epicuticular wax on pod and leaf surfaces, endocarp thickness, percentage moisture in leaf and pod husk, number of vascular bundles, epicarp thickness and number of cells in epicarp, cell width, insoluble sugar, flavonoid, tannin and lignin were the reliable parameters to select cocoa genotypes for resistance to black pod disease. In general, additive genes were more important than non-additive genes in the inheritance of resistance to black pod disease and its related morpho-physiological, histological and biochemical traits. Recurrent selection procedures and inter-crossing aimed at general combining ability would be more suitable for these traits.
Studies on the ecology, conservation, cultivation and management potential of thaumatococcus daniellii for agroforestry systems
(2011-10-21) Boadi, Samuel
As the healthiness of chemical sweeteners is often questioned, there is an anticipated increased demand for natural sweeteners like thaumatin, which is obtained from Thaumatococcus daniellii. Studies were therefore conducted on the conservation, site conditions, provenances, growth performance, yield potential of leaves and fruits as well as integration of T. daniellii into Agroforestry systems. The first study was conducted in the Western Region of Ghana on soil characteristics, fruit sources and conservation of T. daniellii in off reserves. Soil pH, N, P, K, Ca, Mg, Total base saturation and Effective cation exchange capacity and organic matter differed significantly among sites. Soil texture significantly differed among sites and ranged from silt loam to sandy loam. Major sources of fruits were predominantly from seven communities within Aowin-Suaman and Wassa Amenfi West districts. Also, no records of conservation, cultivation or integration of T. daniellii into farming systems were obtained for previous or current fruit supplying communities but for Samartex plantations. The second study determined foliage harvesting effects on T. daniellii fruit yield (number and weight), flower production and specific leaf area. The study also estimated potential incomes that could be obtained from leaf and fruit collection. A randomized complete block design was used. Treatments involved harvesting and maintaining a specified petiole population per plot. The percentages of foliage harvest were: No harvesting (Control), 25%, 50% and 75%. Foliage harvest significantly influenced flowering. Mean number of flowers ranked as: Control - 18 > 25% - 6 ≥ 50% - 1 ≡ 75% - 0. No harvest stands produced significantly high number of fruits (11458/ha) compared to 8958/ha for 25%, 4792/ha for 50% and 4583/ha for 75% harvested stands. Total fruit weight ranged v between 59.7 - 127.9 kg/ha. No significant differences in specific leaf area were obtained for all treatments. For both fruit and leaf collection, the highest total income was GH ¢ 24411.36 for 50% followed by GH ¢ 17480.40 for 75%, GH ¢ 15640.33 for 25% harvest stands and GH ¢ 153.48 for the no harvest stand. The third study determined spacing and shade effects on survival, lamina length and width, petiole length and number of tillers. There were three shade levels provided by tree stands: Leucaena (73%), Senna (86%), Carapa (98%) and four spacing treatments: 0.75 m × 0.75 m, 1.0 m × 0.75 m, 1.0 m × 1.0 m, 1.25 m × 1.25 m. Shade significantly (P < 0.001) influenced survival, leaf sizes (lamina widths and lengths), petiole length and number of tillers. Survival were 71% for Leucaena > 60% for Senna > 20% for Carapa. Leaf sizes were also larger for 73% (width-17.6 cm, length-27.1 cm) than 86% shade (width-15.9 cm, length-25.2 cm) and 98% shade (width-11.4 cm, length-18.0 cm) levels. Similarly, significantly longer petioles, 43.6 cm, were obtained for 73% shade compared to 38.8 cm for 86% and 20.4 cm for 98% shade levels. Tillering decreased with increased shade. Similarly, spacing significantly influenced leaf sizes and petiole lengths. The fourth study was on provenances and NPK fertilization on survival, lamina width and length, petiole length and diameter, and tiller production. Provenances differed significantly in lamina length, lamina width, petiole length and petiole diameter. Lamina lengths of provenances were Western-23.7 cm ≡ Volta-21.1 cm > Ashanti-17.2 cm. Lamina widths were Western-14.3 cm ≡ Volta-12.9 cm > Ashanti-9.0 cm. Petiole lengths were Western-37.7 cm ≡ Volta-36.1 cm > Ashanti-24.8 cm. Petiole diameters were Western-5.6 mm ≡ Volta-5.4 mm > Ashanti-3.8 mm. Fertilization also significantly enhanced the growth of lamina width, petiole diameter and tiller production.
Feeding two nerica rice straw varieties to sheep: Effects of supplementation with leguminous foliages on digestibility, nutrient utilization and growth performance
(2011-11-29) Victoria, Attoh-Kotoku,
Five experiments were carried out to evaluate the nutritive value of shade-dried Samanea saman and Stylosanthes hamata foliages as supplements for rams fed Nerica 1 and Nerica 2 rice straws as basal diets on the growth performance of these rams. Four rumen fistulated Djallonké rams weighing averagely 22.5 kg, were used in a randomized complete block design (RCBD), within a 2x2 factorial arrangement of treatments (2 legumes and two levels each of the supplements), in Experiment 1 to determine the digestibility of DM, OM, N and NDF of the different treatments. The treatments were TSA360 (360 g S. saman foliage), TSA480 (480 g S. saman foliage), TST360 (360 g S. hamata foliage) and TST480 (480 g S. hamata foliage). The digestibility of the nutrients ranged from 60.9 to 88.4 %. The digestibility coefficients were significantly (P<0.05) higher for TST360 for DM, N and NDF. Nitrogen balance was positive for all the four levels of offer but significantly (P<0.05) lower for TSA360. Nitrogen efficiency was very high and differed significantly (P<0.05) between the treatments and ranged from (99.7 to 99.86). The rumen pH values for the higher levels of offer of the two foliages were significantly (P<0.05) different TSA480 and TST480 (6.35 and 6.31) when compared to the lower levels ie (6.23 and 6.20) for TSA360 and TST360 at 0 h post feeding. At 4 and 6 h post feeding the rumen pH values were significantly (P<0.05) v different for S. saman and S. hamata foliages as well as their two levels of offer. The rumen NH3-N level peaked at 4 h post feeding for all the four levels of offer but was significantly (P<0.01) higher for TSA480 (9.6 mg/100 ml) and significantly (P<0.01) lower for TST480 (7.8 mg/100 ml). The blood urea nitrogen (BUN) level was significantly (P<0.01) higher for the two offer levels of S. saman compared to the S. hamata offer levels. The purine derivative excretion was significantly (P<0.05) higher (23.33 mmol/d) for sheep on the higher level of offer of S. saman foliage compared to the others. Rumen degradation of DM for S. saman, S. hamata, Nerica 1 and Nerica 2 rice straws were evaluated using RCBD within a 2 x 2 factorial arrangement of treatments (2 legumes and two levels each of the supplements giving 4 rumen environments) in experiment 2. The degradability of the DM of all the 4 feed samples increased with time. The potential disappearance (P) and the potentially degradable but insoluble fraction (b) was significantly (P<0.01) low for all the 4 feed samples (S. saman, S. hamata, Nerica 1 and Nerica 2 rice straws) under TST480. The rate of degradation (c) was significantly (P<0.05) higher for TST480 ie (0.005, 0.037, 0.024 and 0.035 %/h) for S. saman, S. hamata, Nerica 1 and Nerica 2 respectively but significantly (P<0.05) lower for TST360 (0.002, 0.032, 0.022 and 0.032) for S. saman, S. hamata, Nerica 1 and Nerica 2 respectively. The rate constants for S. saman was significant (P<0.01) lower than the others. The washing loss was significantly (P<0.01) higher (22.6 %), for S. hamata and significantly (P<0.01) lower (4.4 %), for Nerica 2. S. saman had the vi highest potential disappearance (91.15 %) followed by (85.2 %) for S. hamata and (71.35 and 60.44 %) for Nerica 1 and Nerica 2 repectively. In Experiment 3 four fistulated Djallonké rams were used in a 4 x 4 (4 animals and 4 mordanted feed samples) Latin Square Design to evaluate the passage kinetics of S. saman, S. hamata, and Nerica 1 and Nerica 2 rice straws. The transit time (TT) was significantly (P<0.05) higher for Nerica 1 and significantly (P<0.05) lower for S. saman. The fractional passage rate (k1/h) in the fore gut was significantly (P<0.01) higher for Nerica 1 (0.025/h) and similar for S. saman and Nerica 2 (0.019/h). The fractional passage rate (k2/h) in the hind gut was significantly (P<0.05) higher for Nerica 1 (0.033/h) and similar for S. saman and S. hamata (0.029/h).The MRT was significantly (P<0.01) different for all the four feeds. Nerica 2 had a significantly (P<0.01) higher value of (125.80 h) and S. saman had a significantly (P<0.01) lower value of (110.81 h). The growth performance of 48 rams of an average weight of 13. 99 kg and 18 months of age was evaluated in Experiment 4 using a CRD in a 2 x 3 factorial arrangement of treatments (two rice straw varieties and three levels of offer of the foliage, S. hamata [240, 360 and 480 g]). There were six (6) treatments and these were randomly assigned, with eight (8) replicates per treatment. The average daily gain (ADG) and gain on metabolic weight basis were significantly (P<0.05) lower for the rams on T240 and significantly (P<0.05) higher but similar for the rams on T360 and T480 for Nerica 1 rice straw variety. The average daily gain (ADG) and gain on vii metabolic weight basis were significantly (P<0.05) lower for the rams on T240 and significantly (P<0.05) higher for the rams on T360 for Nerica 2 rice straw variety. The straw intake was significantly (P<0.05) lower for the highest level of offer of S. hamata for both straw varieties. The intake of S. hamata increased significantly (P<0.05) as the offer level increased. The total intake on LW and metabolic weight basis followed the same trend as the legume intake for both rice straw varieties. Forty eight (48) rams of an average weight of 13. 03 kg and 17 months of age, were used in a growth performance assessment in Experiment 5, using a CRD in a 2 x 3 factorial arrangement of treatments (two rice straw varieties and three levels of offer of the legume foliage, S. saman [240, 360 and 480 g]). The final weight and the ADG were significantly different between the 3 treatments. The increase in weight and the daily gain increased significantly (P<0.01) with increasing levels of S. saman foliage. Intake of straw was similar between the 6 treatments for the 2 rice straw varieties Nerica 1 and Nerica 2. Intake of S. saman and total intake on metabolic weight basis were significantly (P<0.05) different between the treatments. It is concluded that 480 g/d of S. saman supplemented with Nerica 1 and Nerica 2 was beneficial in young Djallonké rams as it resulted in positive nitrogen balance and a high efficiency of rumen microbial protein synthesis to improve their daily viii gains. S. hamata when fed at 360 g per day to young Djallonké rams elicited the best performance.
Compatibility of Jatropha Curcas in an Agroforestry System
(2011-12-04) Abugre, Simon
Jatropha curcas is gaining importance as a potential biofuel crop in Ghana. Already skeptics are talking about the impact of the crop on food crops. It is important that the compatibility of J. curcas in agroforestry systems is investigated to provide answers to some of the potential problems being advanced. Experiments were conducted to determine the compatibility of J. curcas on the growth and yield performance of Zea mays. To determine the growth and yield of Z. mays under J. curcas hedgerows, an experiment using a Randomized Complete Block Design (RCBD) with three hedgerow spacings of 2 m x 1 m, 3 m x 1 m, 4 m x 1 m of J. curcas and a control (No hedgerow) was conducted. This was replicated 3 times. The results of the study showed that J. curcas spacing had no significant effect (P ≥ 0.05) on plant height, plant diameter, number of leaves and number of nodes/plant of maize in the first year. In the second year, however, increases in plant height of 17.19%, 22.39% and 23.38% were realized for 3 m x 1 m, 4 m x 1 m and the control (No hedgerow) respectively with respect to 2 m x 1 m. Diameter at first node however, increased by 19.69%, 16.87% and 18.46% for control, 3 m x 1 m and 4 m x 1 m respectively with respect to 2 m x 1 m. Maximum grain yield of maize was 4.47 tons/ha in the first year at the control treatment, which differed significantly from the 2 m x 1 m, 3 m x 1 m, 4 m x 1 m treatments. Chemical properties of the soil did not record any significant decline after two years of cultivation for pH, organic carbon, total nitrogen, organic matter, exchangeable cations, total exchangeable bases, exchangeable acids and base saturation. The highest Land Equivalent Ratio (LER) was recorded at 4 m x 1 m for both years, making it the most suitable plant spacing for J. curcas with maize while the highest economic returns were obtained at 4m x 1m and 3m x 1m spacing. The influence of storage period, fertilizer and spacing on the growth and yield of J. curcas propagated from seed were evaluated in a second experiment using two different designs. Seeds of J. curcas were stored for 1 to 12 months, sown on beds in a RCBD, replicated four times and their viability and germination energy tested. The results showed a progressive decline in germination from 98% after one month to 52% when stored for 12 months. The highest germination energy was obtained during the first two months of storage. Fertilizer and spacing effects were also evaluated in a split plot design in RCBD and replicated three times. Three plant spacings (D1=1m x 1m; D2=2m x 1m; D3=3m x 1m) and two fertilizer application levels (F0: 0kgNPK/ha, F1: 150kgNPK/ha) were used. Fertilizer and spacing interaction did not significantly (P ≥ 0.05) affect yield components of J. curcas. The fertilizer treatment however, had a significant effect on yield components and increased seed and fruit yield by 56.4% and 51.75% respectively. Spacing did not significantly affect seed yield. A third experiment on the variation in seed sources of J. curcas and polybag size on the growth of seedlings was laid out using a split plot design in RCBD with 3 replicates. The results showed significant variation in seed weight from the various seed sources but no differences in seed length and seed width. Seedling growth of J. curcas was highest when larger polybag size was used, however, it did not differ significantly from medium polybag size. Based on the results obtained medium polybag size would be ideal for raising seedlings. In a fourth experiment the decomposition trend of J. curcas leaves was assessed by placing 80 g fresh leaves in a 0.30 m x 0.30 m nylon litter decomposition bags of 2 mm mesh size under closed and open canopies. The total quantity of litter produced in a year at different spacings were 2.27 ton/ha, 1.10 tons/ha and 0.79 tons/ha for 1 m x 1m, 2 m x 1m and 3 m x 1m, respectively. The month of November had the highest litter fall (508.8 kg/ha) for 1 m x 1 m. J. curcas under open canopy had 97-99% of leaf litter decomposing by the end of the experimental period and a half-life of 25 days. Open canopy had the highest decomposition constant (k) of 0.020. In a final experiment the effect of aqueous extracts from leaves and roots of J. curcas on four traditional crops (Phaseolus vulgaris, Zea mais, Lycopersicon lycopersicum and Abelmoschus esculentus was examined. Aqueous extracts at concentrations of 2%, 4%, 6%, 8% and 10% applied to the test crops affected all the crops. Extracts at higher concentrations of J. curcas had a strong inhibitory effect on germination, radicle and plumule length of all the test crops. The inhibitory effect suggests the presence of allelochemicals that could inhibit the growth of the crops. Generally, it can be concluded that J. curcas is compatible with maize in an alley cropping system but closer spacing of planting J. curcas can reduce maize yields. Management practices such as pruning could be applied to get the optimum benefit from the system.
Evaluation of Ceiba Pentandra for stem dieback disease resistance and characterization by molecular markers
(2013-09-04) Abengmeneng, Cosmas Sorngmenenye
Ceibapentandra (L.) Gartn is an important multi-purpose tree species in Ghana and demand for it is rising daily. However, the occurrence of stem dieback disease at the nursery and plantations, coupled with the absence of adequate information on resistance levels and the genetic diversity within and among populations, has limited the success of efforts geared at devising efficient strategies for its sustainable management. This study assessed resistance levels through progeny evaluation at both the nursery and in the field. Narrow sense heritability and genetic gain in stem height were also estimated. The diversity among accessions was characterized using five morphological traits. The genetic diversity and gene flow within and among five populations of the species were also studied using Random Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Repeat (ISSR) markers. The study also looked at markers that are linked to stem dieback resistance. Screening at the nursery from September to November (SNS) showed survival level ranged from 0.20% to 79.20 %. March to May screening (MMS) showed that all the 59 accessions screened had varied levels of survival ranging from 24.4 % to 100 %. Mortality rate was generally higher in the SNS than the MMS. Field study showed that 5 (13.51 %), 9 (24.33%) and 23 (62.16 %) accessions, out of 37 screened, had survival levels between 70.00 and 100 %, 50.00 and 69.90 % and below 50.00 %, respectively. There were significant differences in mean mortality rates among accessions in the nursery and field studies and also in mean stem height and mean diameter growth (P < 0.001). Narrow sense heritability was 0.56 and genetic gain in height ranged from -29.58 to 20.89 cm/yr. Mean population diversity index, using the Shannon Information Index (I), was 0.425 ± 0.024, 0.306 ± 0.027 and 0.371 ± 0.018 for the RAPD, ISSR and the combined RAPD and ISSR, respectively. Gene flow estimates showed low to moderate differences among populations with Gst values at 0.0751, 0.0736 and 0.0799 for the RAPD, ISSR and combined RAPD and ISSR, respectively. Ninety-eight percent of the population differentiation was attributed to within population variation with RAPD polymorphism. ISSR and the combined RAPD and ISSR both showed that a high proportion of genetic diversity resided within populations. Chi-square and G-square tests showed differences among population. Percentage polymorphic loci, Ewens-Watterson Neutrality Test, Nei diversity and Shannon diversity indices, showed Dry Semi-deciduous Forest Inner Zone as the most diverse population. Principal component analysis, defined by axes 1 and 2, accounted for 67.15% of the total variation among accessions. None of the ten markers used was able to differentiate between resistant and susceptible accessions. Nine accessions were identified for conservation as seed trees. Dry Semi-deciduous Forest Inner Zone (DSDFZ-Inner) < Dry Semi-deciduous Forest Outer Zone (DSDFZ-Outlier) < Guinea Savanna Zone (GSZ) < Moist Semi-deciduous Forest Zone (MSDFZ) < Moist/Wet Evergreen Forest Zone (M/WEFZ), in order of decreasing importance, should be preferred in C. pentandra seed collection expedition. Decision making for long-term conservation of C. pentandra should be made on the basis of both morphological and molecular considerations. Sampling for seed trees should be concentrated on selecting resistant and unrelated accessions within populations rather than collecting bits from the entire range of the species. Known resistant and susceptible lines should be used in further assessment for dieback resistant markers. A large number of dominant markers and the use of co-dominant markers should also be investigated.
The changing nature of work and the state of labour standards in Ghana
(2014) Osei, Hannah Vivian
The state of employment within countries and the world at large is of considerable importance to both governments and international organisations. In recent years, the nature of work has become flexible and insecured. The juxtaposition of the two apparently contrary targets, flexibility and security, raises concern...
Aspects of the ecology of noack’s roundleaf bat (Hipposideros Aff. Ruber) in Ghana
(2014-07-20) Nkrumah, Evans Ewald
The roost of bats in five caves in the central parts of Ghana were investigated. A total of 10,226 bats belonging to nine species were mist-netted within two years. There was a significant difference in species composition of the caves. The Noacks’s roundleaf bat, Hipposideros aff. ruber was found to be the most dominant species roosting inside the cave and some aspects of its ecology were further investigated. The flight activity of Hipposideros aff. ruber was limited to certain periods of the night at Kwamang cave one while it was uniform at Kwamang cave two. The estimated mean home range size of this species using radio-tracking was thirty-six hectares with a foraging range of 1.2 km. There was no significant difference in the home range sizes of the males and females. Hipposideros aff. ruber used 50% of its home range as the foraging area and 2% as the core area. Pregnant females had smaller home ranges and foraged not more than 0.2 km away from the roost cave. Hipposideros aff. ruber used all available habitats around its roost but strongly preferred to forage in fallow lands ahead of other habitats. This bat used tree farms such as cocoa as flight paths to commute between roost caves and foraging areas and exhibited a trimodal activity pattern foraging at dusk, midnight and dawn. Hipposideros aff. ruber is a strong flyer commuting over longer distances. A three kilometre radius around its roost should be included in the protection of its home range. In highly impacted agricultural landscapes, fallow lands are recommended as conservation units to support this bat. In such landscapes, provision of canopy trees as flight paths is recommended to allow them to commute between roost and habitats that support higher prey densities
Impact of selective logging on plant diversity, natural recovery and vegetation carbon stock: the case of Bobiri Forest Reserve
(2014-07-20) Djagbletey, Gloria Djaney
This research examined the effect of selective logging on the floristic composition, structure and the vegetation carbon stock recovery of a moist semi-deciduous forest in Ghana. The research was carried out in the Bobiri Forest Reserve, in the moist semi-deciduous southeast sub-type, in southern Ghana. Sites were selected to reflect the following chronosequential manner of 50, 43, 30, 21, 10 years’ post-logged-sites, as well as recently post logged site (ranging between 6 and 12 months) and a strict nature reserve (SNR-unlogged site). Plots that had been used for Tropical Shelterwood System (TSS) were also selected to depict an extreme case of logging.Ten Temporary Sample Plots (TSPs) were established in each of the selected compartments using an identified stump from previous logging as the centre in the logged forest while a tree of exploitable size was used as the centre for the plots in the SNR and the TSS. The main plot size was 50 m by 50 m (2500 m2) which was divided into four sub-plots of size 25 m by 25 m (625 m2) and the sub-plots were further subdivided into sub-sub plots of size 12.5 m by 12.5 m (156.25 m2), forming a nested plot design. The main plots were used for the assessment of trees ≥ 20 cm diameter at breast height (dbh) of 1.3 m, as well as standing dead trees of similar size. A sub-plot of 25 m x 25 m was used for the assessment of trees < 20 cm dbh, and a sub-sub-plot of 12.5 m x 12.5 m was used to assess plants ≤ 10 cm dbh but with height not less than 2.0 m. Five quadrats of 1.0 m x 1.0 m were laid in a ‘Z- shape’ in the main plot for the assessment of undergrowth vegetation and forest floor litter. Phytomass of individual trees was estimated from stem dbh and was used to compute the biomass of various compartments. The herbaceous and litter biomass was calculated from the data obtained from the quadrat. Carbon (C) content values were used to convert the biomass of the various plant functional types to C equivalent. The study revealed that tree basal area (BA) increased with increasing post-logging years with a mean BA of 32.95 m2 ha-1. Trees contributed the highest C-stock, followed by litter with the herbs contributing the least. Total carbon stock (Mg C ha-1) increased in the order of the following: Year1 (165.63) < Year10 (171.08) < SNR (181.57)

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