A length-based fish stock assessment of the Black Volta River in Ghana was undertaken prior to its damming at Bui in 2011. The approach involved estimation of the population parameters and exploitation rates of dominant fish stocks using TropFish R. The targeted species were: Alestes baremoze, Hydrocynus forskalii, Hemisynodontis membranaceus and Labeo coubie. The estimated asymptotic length (L∞) ranged from 30.8 – 48.2 cm standard length (SL) with derived longevity of 11 – 27 years for the assessed species. The estimated growth coefficient (K) value ranged from 0.10 – 0.25 yr-1 which suggested slow growth rates. The estimated length at first capture (Lc50) was lower than the length at first maturity (Lm50) for all the assessed fish species which suggests the presence of recruitment overfishing within the fish stocks. The total mortality rate (Z) was relatively high ranging between 0.51 and 1.34 yr-1 suggesting that the stocks were over-exploited during the pre-impoundment period. The exploitation rate (E) for the assessed fish species were lower than the maximum exploitation rate (Emax) which indicates that the species are far from collapse. These estimates are baseline scientific information for designing a Fisheries Management Plan for the Bui reservoir. Meanwhile, alternative livelihood and employment opportunities such as cage fish culture are to be explored to reduce the fishing pressure on the reservoir.
Studies on seasonal changes in stream structure and its effect on habitat quality, distribution, abundance and biomass of stream fishes in Ghana is limited. Understanding seasonal changes in stream habitat structure and adaptive responses of fish populations is essential for stream protection and conservation of stream ecosystems and their resident fish populations. Seasonal changes in stream structure, physicochemical characteristics and fish community structure were investigated in an urban stream in Sunyani, Ghana. Data was collected monthly from November 2016 to November 2017 at upstream, midstream and downstream sites. High spatial heterogeneity and temporal variability in stream structure affected by the dry and wet seasonal cycles was observed. Twelve species of fish belonging to eight families and ten genera were recorded, with catfishes dominating community biomass. The diet pattern of fish species differentiated the community into herbivore, piscivore and omnivore trophic levels. Herbivores were most abundant and consumed a wide range of plantbased food. Fish habitats disappeared and mortality increased upstream and midstream during the dry season. However, the downstream habitat persisted as a result of the unique morphology which resulted in a relatively deep depth, large canopy cover and presence of water lettuce Pistia stratiotes which minimized water loss. Water quality did not differ significantly across the stream in all seasons. Higher water clarity downstream cooccurred with Pistia proliferation along with elevated fish biomass during the dry season. Stream structure, rather than physicochemical characteristics, controlled fish biomass. Water quality and fish biomass were strongly correlated with seasonal Pistia abundance. Persistence of the downstream pool habitat during the dry season sustained habitat quality and increased fish survival. Maintenance of stream pools along with opportunistic aquatic vegetation in the dry season can sustain stream ecosystems and stabilize their fish communities and biotic structure.
The study was conducted to investigate the biomass yield and quality of two forage species Brachiaria ruziziensis (B. ruziziensis) and Sorghum almum (S. almum) in a Randomized Complete Block Design (RCBD) in two different locations (Bihinayili in the Savelugu District and Zanlerigu in the Nabdam District) in the Savanna agro-ecological zone of Ghana. Agronomic data were collected and representative samples of forage biomass taken at 60 days after planting to estimate dry matter yield and nutritive quality. The two-way interaction effect of forage species and experimental site was not significant for both agronomic and chemical parameters except for tiller number. The average leaf size was broader (P=0.006) in S. almum (299.0 cm2) than B. ruziziensis (85.0 cm2). Number of leaves per plant was higher (P=0.016) in B. ruziziensis (10.75). Number of tillers per plant in B. ruziziensis (9.62) was higher (P=0.001) than S. almum (2.88). Plant height was however, higher in S. almum (183.1 cm) than B. ruziziensis (90.1 cm). Dry matter yield of forages at 60 days after planting was higher (P<0.001) at Bihinayili (8.49 tons/ha) than that at Zanlerigu (2.23 tons/ha). The CP content of the forages at Bihinayili (89.7 g/kg DM) was also higher (P=0.018) than that at Zanlerigu (68.6 g/kg DM). Dry matter yield of B. ruziziensis (4.84 tons/ha) did not differ significantly from that of S. almum (5.88 tons/ha). In conclusion, B. ruziziensis and S. almum performed well within the Savanna agroecological zone and could enhance fodder supply and carbon sequestration.
Many rural and peri-urban areas in developing countries including Ghana face challenges with access to good quality drinking water. These areas often depend on surface water or ground water sources which are often compromised with excess levels of nitrate, chloride and microbial pathogens. This study sought to assess the effect of household latrine system on household water quality of two peri-urban communities in the Upper West Region of Ghana. Geographic Information Systems were used to map the latrine location and elevation of household wells relative to latrines. Latrines and wells were visually inspected. Water samples were also collected from the selected household wells and tested for pH, chlorine, turbidity, colour, conductivity, temperature, total dissolved solids, nitrites and nitrates. Selected community borehole water were used for controls. The study showed average latrine location relative to household well was 13.7 m. The difference in elevation between the wells and latrines is at an average of 0.7m. All the household latrines were improved latrines and household wells with 47% of them having lids to cover them. The water quality observed were all within the WHO drinking water quality for the physicochemical parameters assessed. The study however showed higher levels of nitrate in household wells than bore holes. The need to educate households in locating of Kraals relative to household water systems is needed. Further studies including environmental and geological assessments are required to establish the observations made regarding why areas of high latrine concentrations had lower nitrate levels. Also microbiological studies to establish the safety of water for drinking is required.
This paper examines the relationship between ownership rights and investment in agricultural land from a gender perspective in Ghana, using the Two-Stage Conditional Maximum Likelihood estimation technique and data from the Ghana Household Asset Survey. The results indicate that investment in agricultural lands is generally low in Ghana and tends to occur mostly in agricultural lands owned by men suggesting its inability to enhance tenure security. Furthermore, investment in agricultural lands owned by men is associated with a wider range of ownership rights. However, the same cannot be said about agricultural land owned by women as investments in their land do not significantly improve their rights to the land. Except for economic rights that appear to have a significant negative association with investments in agricultural lands owned by women, all other rights have no significant relationship with investments in agricultural lands owned by both men and women. There is a positive relationship between age and ownership rights for men suggesting that the youth may have challenges securing their tenure. We recommend the strengthening of the current land administration projects to enhance tenure security. Policies that will support the growing of perennial trees, construction of farmhouses and irrigation should be put in place by the government to encourage men to undertake such investments as they tend to improve ownership rights of agricultural lands. More should also be done to secure the ownership rights of the youth if the government wants them to engage in agriculture.
The study focused on improving phosphorus (P) fertilizer recommendation in rainfed lowland rice soils in Togo. Phosphorus adsorption was conducted on four soils to determine their P adsorption characteristics and standard phosphorus requirement (SPR). The adsorption maximum ranged from 143 to 200 mg P/kg. The amount of P adsorbed range from 62.70 to 74.85 mg P/kg. Greenhouse experiment was conducted to determine rice response to phosphorus rates based on the SPR values, and to assess rice P uptake and use efficiency. Five phosphorus rates, Control: 0 mg P kg−1, P recommended rate (RR): 5 mg P kg−1, 4 × RR: 20 mg P kg−1, 50% SPR and 100% SPR were used. Results indicated no significant difference between the Control treatment and the P recommended rate (RR), and between the 50% SPR and the 100% SPR with reference to shoot dry matter yield. P uptake and P use efficiency were significantly and positively influenced by the various P fertilizer rates. From the study, the blanket P recommended rate is inappropriate, however, site-specific P fertilizer rate of 50% SPR may be recommended to improve rainfed lowland rice yields in Togo.
Climate-induced environmental changes are known to support prevalence of disease vectors and pathogens. Temperature, rainfall, humidity and other environmental variables are considered potential drivers of population dynamics of many vectors and pathogens of health importance, especially in the tropics. This study was conducted to understand the variability and trends in atmospheric temperature and rainfall, as well as how these factors may affect the breeding of Anopheles mosquitoes in the urban areas in the future. Accra and Sekondi-Takoradi Metropolitan Areas (AMA and STMA) of coastal Ghana were the selected study sites. Anopheles larvae were sampled from pre-identified breeding sites in the two cities. Atmospheric temperature and rainfall as measured by synoptic weather stations were collected for the two cities. Again, thirty years climate data on daily minimum and maximum temperature and rainfall for both cities from Ghana Meteorological Agency (Gmet) were employed in the study. Using a statistical downscaling approach, the average of the ENSEMBLE GCM outputs AR4-BCM2 and AR4-CNCM3 scenario A1B were downscaled to match with rainfall and temperature observations of AMA and STMA. Results showed that improper solid waste management in the cities promote the breeding of Anopheles mosquitoes. Climate data analysis showed that past rainfall in the cities were below average; in the future, however, up to year 2050, the cities may experience high rainfalls and temperatures above the average. Notably, significant increases may be observed in the total monthly rainfalls as well as a slight shift of rainfall pattern in the minor season. This implies that Anopheles mosquito breeding may no longer be seasonal in the cities but perennial and malaria transmission may also follow the same trend. Poor urban dwellers who find it difficult to adopt preventative measures will be prone to persistent malaria transmission. This will increase malaria transmission among vulnerable populations in urban areas. This study recommends that city authorities must intentionally work at lowering the surface temperatures in the cities through the growing of trees and also to regularly desilt drains in order to reduce the breeding of Anopheles mosquitoes.
Browse species as complete feed for ruminants is uncommon. This may be due to low dry matter (DM) and high condensed tannins (CT) contents limiting its potential to influence weight gain. Drying however improves DM content and reduces CT levels and its astringency. The objective of this study was to determine chemical composition, in vitro parameters and to evaluate the potential benefits of feeding small ruminants on dried browse leaves and their combinations. The browse species were Albizzia lebbek, Gliricidia sepium, Moringa oleifera and Millettia thoningii. Rumen fluid was obtained from two fistulated forest type wethers for the in vitro evaluation. The DM, crude protein (CP), ash, CT, neutral detergent fibre (NDF), acid detergent fibre (ADF), cellulose and lignin were 866-916 g/kg, 101-303 g/kg DM, 74.7-200 g/kg DM, 0.9-1.3 g/kg DM, 202-552 g/kg DM, 205-520 g/kg DM, 94-381 g/kg DM and 105-192 g/kg DM respectively. The organic matter digestibility (OMD), in vitro dry matter digestibility (IVDMD), in vitro gas production (IVGP), metabolisable energy (ME) and short chain fatty acids (SCFA) of the four browse species and their combinations recorded were 314.9-721.6 g/kg DM, 515.4-721 ml/g DM, 139-602 ml/g DM, 314.6-1406.9 ml/g DM and 3.1-14.4 ml/g DM respectively. There were positive associative effects shown by the combined browse leaves between IVDMD and IVGP. The regression analyses revealed that relationships between IVGP and CP and IVDMD and CT and all relationships between OMD, SCFA, ME and IVGP were significant (p<0.05). All the browse species and their combinations had IVDMD values of more than 500 g/kg DM and low gas production. The high CP and ash contents, low CTs, low to moderate fibre components, moderate to high IVDMD and low IVGP of the four browse species and their combinations make them potentially valuable as feed resources for small ruminant production.
Managing waste efficiently is essential for building sustainable, livable and healthy communities but this remains a challenge for many municipal governments due to limited municipal budget and other logistical challenges. Such challenges result in ineffective waste collection and disposal. However, identifying the challenges associated with municipal solid waste management often lead to developing solutions to mitigate the problem. This paper assesses the waste management practices and challenges within the Techiman municipality, the regional capital of the Bono East Region. By sampling residents’ perceptions and experiences it was observed that households and patrons were dissatisfied with Techiman’s Municipal Solid Waste Management (MSWM). Statistically the per capita per day rate of waste generation was 0.48kg/ per capita/per day, being higher than Ghana’s municipal waste generation of 0.40 kg/per capita/per day. Lack of collection of waste from the transfer stations to the landfill sites has resulted in about 67 heaps of uncollected waste in the municipality. The results show that lack of source separation and recycling, broken down trucks, low participation of private sector in waste collection, non-compliance of by-laws, poor road infrastructure leading to the landfill site, and inefficient landfill site have contributed to the waste problem in the municipality. Resorting to source separation, educating the public on waste management bye laws, increasing private sector participation and establishing engineered landfill sites can substantially contribute to sustainable Municipal Waste Management in the Techiman Municipality.
Land use type, climate and soil properties are major determinants of soil carbon storage and productivity, especially in low-input agriculture. In this study, we investigated the interactions among these factors at four (4) locations, namely Accra Metropolis, Ga West, Ga East and Shai Osudoku, within the Coastal-Savannah agro-ecological zone of Ghana. The land use types were maize-based cropping, cassava-based cropping, woodlot/plantations and natural forests. The impact of these on soil productivity at a given location was assessed in terms of soil carbon stocks and a Soil Productivity Index (SPI). The SPI is a composite value derived from routine soil properties such as: soil texture, available water capacity, pH, cation exchange capacity, soil organic carbon, available P, exchangeable K, potentially mineralizable nitrogen, and basic cations, among others. Principal component analysis was used to select soil properties that were used to estimate SPI. The results showed that the locations differed with respect to rainfall regimes and soil types. Locations with slightly heavier soil texture and relatively higher rainfall regimes (Ga East and Shai Osudoku) had significantly higher soil carbon storage and SPI values than the lighter soil textured locations (Accra Metropolis and Ga West). With regards to land use, forest had significantly higher soil carbon storage and SPI than all the other land use types, irrespective of location. The order of soil carbon storage and SPI were: forest > woodlot/plantation > cassava > maize. It was observed that though the Accra Metropolis location hosted the oldest forest, soil carbon was still low, apparently due to the lighter soil texture. We concluded that the soil productivity restorative ability is an interactive effect of carbon management (land use), soil texture and other properties. This interaction hitherto has not been adequately investigated, especially in low-input agriculture.
In the past, soybean varieties released in Ghana were selected primarily for grain yield potential, earliness, seed viability and low phosphorus tolerance. However, most of these varieties are not resistant to pod shattering, resulting in high grain losses. In order to identify traits farmers consider most important when deciding which soybean varieties to adopt, a participatory variety selection approach was used to evaluate varieties in two locations (Nyankpala and Wa) in the Guinea savanna zone of Ghana during the 2010 and 2011 cropping seasons. Twelve medium and 14 early maturing varieties were evaluated. Farmers’ variety selection criteria and ranking did not differ across locations and gender groups. Additionally, four most preferred traits by farmer (grain yield, pod shattering, earliness and pods per plant) out of 12 traits were considered very important by farmers at both locations. In some instances, farmers’ preference for the best varieties was not exactly in line with researchers’ selection. Best four ranked varieties (TGx 1799-8F, TGx 1834-5E, TGx 1445-3E and TGx 1844-22E) were preferred by farmers because they possess positive attributes such as higher grain yields, resistance to pod shattering, numerically more pods per plant and enhanced ability to control Striga hermonthica. These varieties were later released as Suong-Pungun, Afayak, Songda and Favour, respectively for commercial production throughout Ghana. Consequently, soybean breeders should incorporate farmers’ preferred traits in selecting varieties in the breeding process in order to increase likelihood of adoption of the varieties.
This study evaluates the growth and biochemical changes in Aeluropus lagopoidesi (L.) Thawaites. induced by different sodium chloride (NaCl) concentrations to understand the effects and tolerance of the plant to salinity regimes. A. lagopoides stolons were grown on Hoagland media in three replicates. At four weeks after planting, 0, 100, 300, and 500 mM of NaCl were added to the media as treatments, and this was repeated at 2-week intervals. Data were collected and analyzed on growth and biological yield of the plants at 3, 6, and 9 days after the final salt stress. Also, sodium, potassium, and calcium ions present in the root and shoot of the treated plants were determined, while the number of salt crystals extruded from the leaf was counted. The amounts of proline, amino acids, and total soluble sugars in response to salt concentrations were evaluated. There was a significant variation in the growth of A. lagopoides in response to the NaCl concentrations. Generally, a concentration of 500 mm adversely affected plant growth and biomass yield. The concentration of sodium ions in the tissue of treated plants increased with NaCl concentration, while the concentration of potassium and calcium ions decreased. Total amino acid and proline in the plant tissue increased with salinity, while soluble sugar increased from 3-6 days but declined remarkably on the 9th day after NaCl applications. The study demonstrated salt stress tolerance in A. lagopoides and suggested its potential as a biotechnological model plant for salt tolerance improvement of economically important crops in high-salinity zones.
The present study investigates the weed species diversity in four plantations of university of Ilorin, Ilorin, Nigeria using quadrat method. The survey revealed two major life cycles (annual and perennial) and recorded a total of 88 weed species belonging to 32 families. Four species (Azadirachta indica, Daniellia oliveri, Desmodium tortuosum, and Tridax procumbens) were common in all the surveyed plantations while the family Fabaceae was the most dominant. The abundant weed species analysis showed a high importance value index and were more adapted to the plantations. Diversity analysis revealed high species richness in the sugarcane plantation. The non-canopy nature of the plantation, soil structure as well as ability to coexist with many other species may underscore the reasons for this pattern of diversity. The evenness and similarity indices between and across the plantations were generally low, thus, indicating varying diversity. As a result of the recorded variation in weed composition between and across the plantations, the study has provided an insight on the pattern of weed diversity in the studied plantations. The study recommended that the most abundant weed species populations be checked for the plantations to thrive. Finally, there is an urgent need to conserve weed species that are not only rare in abundance but also showed great social and economic values.
Lettuce is one of the most cultivated vegetables (eaten raw) in Mali with a percentage of 69.4 amongst leafy vegetables and 30.4 of all vegetables. Vegetables consumed raw, particularly lettuce, are sources of foodborne pathogens. This study was conducted to assess bacterial contamination of unwashed lettuce and the efficiency of disinfecting it with tap water and varying concentrations of some chemical disinfectants: bleach (0.00285, 0.00570 and 0.00855 ppm), potassium permanganate (170, 340 and 510 ppm), vinegar (0.00285, 0.00570 and 0.00855 ppm) and common salt (500, 1000 and 1500 ppm) based on the three consecutive washing protocol recommended for vegetables in Mali. Lettuce samples were randomly selected from farms irrigated with untreated river water within communities five and six in Bamako. Lettuce leaves were exposed to low concentration of the chemical disinfectants at 15 min, intermediate at 10 min and high at 5 min. A bleach (0.00285 ppm)/vinegar (0.00285 ppm) combination disinfection was also tested at 15 min. Tap water, bleach, potassium permanganate, vinegar and common salt reduced faecal coliform populations by 1.3–2.9, 1.5–3.0 and 1.9–3.5 log CFU/100 g, at 5, 10 and 15 min, respectively. Disinfection treatment using bleach (0.00285 ppm) was found to be more effective than other disinfectants at all contact times. All the disinfectants reduced Escherichia coli populations by 2.0–2.8 log CFU/100 g on lettuce and completely eliminated Salmonella spp. at all treatment contact times. Disinfection treatment using bleach/vinegar combination at 15 min also reduced faecal coliform populations on lettuce by 2.8 log CFU/100 g and completely eliminated E. coli and Salmonella spp. All chemical disinfectants including tap water at 15 min reduced faecal coliform populations below the undesirable ICMSF (2011) level (1000 CFU/100 g wet weight). These could contribute to reduce the health risk associated with the consumption of lettuce in Mali.
The study investigated contributions of sawn wood and herb sellers in Ibadan metropolis to forest restoration. Data were obtained through personal interview and administration of semi-structured questionnaire on 100 sawn wood sellers and 100 herb sellers in five selected markets for each category. Data collected were analyzed using descriptive statistics. The study revealed that 59% of the wood sellers were males and 41% were females whereas 29% of the herb sellers were males and 71% were females. Highest percentage (40%) of sawn wood sellers and herb sellers (46%) had their ages between 41-50% years. Majority (40%) of the sawn wood sellers had secondary education while majority (38%) of the herb sellers had primary education. Timber ranked 1st with 89% as a benefit derived from forests by sawn wood sellers while for herb sellers, medicine ranked 1st with 98%. Also, 59% and 97% of the sawn wood sellers and herb sellers respectively have never planted trees before. Tree species planted by 41% of sawn wood sellers who have planted trees before were Gmelina arborea, Tectona grandis and Terminalia ivonrensis. Identified constraints regarding tree planting in order of importance were non-availability of seeds, lack of funds and non-availability of land. The participation of both sawn wood sellers and herb sellers in forest restoration is still very low therefore there is need for more awareness among general public on benefits derivable from forests. This would likely encourage more responsible use of forests and consequently aid involvement of more people in forest restoration.
Cabbage is an important cash crop to the resource-poor farmers in sub-Saharan Africa and offers a good source of vitamins and minerals. The diamondback moth (DBM), Plutella xylostella L. and the cabbage webworm, Hellula undalis F. are major pests causing significant losses to brassica crops worldwide. During the major and minor seasons of 2015, an experiment was carried out at the University of Ghana Soil and Irrigation Research Centre (SIREC), Kpong to determine the effect of some pesticides (synthetic insecticides-chlorpyrifos and lambda-cyhalothrin, botanicals - hot pepper fruit extract, aqueous neem seed extract, local insecticidal soap - ‘alata samina’ and water as control) in controlling the diamondback moth and the cabbage webworm on cabbage. Cabbage seedlings were transplanted onto 3m x 3m plots, and plots were labelled by randomly assigning treatments to them. The experiment was laid out in a complete randomised block design, consisting of six treatments in three replications. Treatments were applied weekly, two weeks after transplanting and data on the population of the diamondback moth and the cabbage webworm, multiple head formation were collected weekly. At the end of each season the resulting yield was assessed for marketability, and cost benefit analysis carried out to determine the cost: benefit ratio. The results revealed that the highest population of the diamondback moth was recorded in the plots sprayed with chlorpyrifos and lambda-cyhalothrin, with neem recording the least number of diamondback moth and cabbage webworm populations. The highest marketable yield of 13.82t/ha and 28.36t/ha was recorded for the neem sprayed plots with a cost: benefit ratio of 1:48.6 and 1:137.1 for both seasons, respectively, followed by pepper extract (3.92t/ha, 1:10.5) for the major season and ‘alata samina’ (8.86t/ha, 1:36.4) for the minor season. The aqueous neem seed extract can be used by resource-poor farmers in Ghana as the most cost-effective biopesticide against the diamondback moth and the webworm on cabbage.
Kpejeglo series and Agawtaw series are two closely related pan soils in the Lower Volta Basin of Ghana. They have previously been classified variously according to Soil Taonomy and the FAO/World Reference Base (WRB) systems without positively identifying the subsurface hardpan horizons. The hardpans have generally been described as compact clay loam or claypan horizons. This study was designed to 1) identify the hardpan horizons and 2) classify the soils according to the latest Soil Taonomy and the WRB classification systems. Both soils had argillic and natric horizons. Bulk density of the pan horizons was higher than that of the horizons above them. Air-dried peds of the pan did not slake in water and 1M HCl or 40 NaOH. Up to 50 reduction in the size of the peds was only observed after alternating acid and alkali soaking for more than 5 hours. Peds from the lower limits of the hardpan of Kpejeglo Pedon 2, however, slaked in 1M HCl. The slaking characteristics show that the hardpan horizon could be a duripan, which possibly occurred with a petrocalcic horizon. Both soils were classified under Soil Taonomy as Typic Duraqualfs. Natric horizon did not reect in the classification because it is not presently provided at the subgroup level of Duraqualfs. We propose that due to the agronomic importance of natric horizon, Natric Duraqualfs would be more appropriate classification of the soils. The soils were also classified as Gleyic Solonetz (Duric) under the WRB system. Although Gleyic Solonetz places more emphasis on natric horizon than on petroduric horizon, the latter could be more limiting to plant growth. It would therefore be important if petroduric horizon reects in the classification of the soils. Presently, under Solonetz, duric is only recognized as a supplementary qualifier so we propose that duric be elevated to a principal qualifier and should key out before gleyic so that the soils could be appropriately classified as Duric Solonetz.
Cowpea is an important economic crop in northern Ghana. Following reports of a new cowpea root rot, disease in northern Ghana (Northern, Upper East and Upper West regions), surveys were conducted in 2016 and 2017 with the aim of determining the causal organism, prevalence, incidence and severity of the disease across northern Ghana under rain fed and irrigated conditions. Seventeen locations were surveyed and symptomatic plants were taken to the Plant Pathology laboratory in CSIR- Savanna Agricultural Research Institute (SARI), Nyankpala for pathogen identification. The disease was prevalent in all the locations surveyed. There was no significant difference (P > 0.05) between disease incidence and severity (1‒9 scale) under rain fed and irrigated conditions for each year. Disease incidence and severity were however significantly different (P < 0.05) amongst locations surveyed under both rain fed and irrigated production for 2016 and 2017. Under rain fed conditions for 2016, Nyankpala recorded the highest incidence (43.8%), with Feo recording the lowest (17.8%). For the same period, Manga recorded the highest severity (4.3) with Silbelle recording the least (2.1). Under dry season cultivation for 2016, Asumsapeliga recorded the highest disease incidence (44.5%) with Silbelle recording the lowest (11.4%). Sakpari, however, recorded the highest disease severity (3.8) with Feo recording the lowest for the same period. Under rain fed conditions for 2017, disease incidence was highest in Nyankpala (47.7%) and lowest in Lawra (8.7%). For the same period, however, Manga and Yendi recorded the highest severity (4.3) with Lawra recording the lowest (1.6). Under dry season cowpea production for 2017, Sakpari (64.8%) recorded the highest incidence and Silbelle (7.0%) recording the least. Disease severity for the same period was highest in Nafkluga (4.2) and lowest in Silbelle (2.3). Morphocultural characteristics and pathogenicity test confirmed Macrophomina phaseolina as the causal organism of the cowpea root rot disease.
Cabbage is an important exotic vegetable widely grown in Ghana. Despite its importance, cabbage production is constrained by insect pests attack, with the diamondback moth (DBM), Plutella xylostella L. and the Indian mustard aphid, Lipaphis erysimi pseudobrassicae (Davis) as the most important. A field trial was conducted at the Soil and Irrigation Research Centre, Kpong, in Ghana, during the major and minor rainy seasons of 2013 to study the effect of intercropping and soil amendment on the incidence of these key pests, their natural enemies and the yield of crop. The field was laid out as a split-plot design with soil amendment (biochar from rice husk, poultry manure and their combination) as the main plot and cropping system (sole cabbage, sole onion and cabbage-onion intercrop) as sub-plots. Multiple head formation was higher in sole cabbage plots than cabbage intercropped with onion. Similarly, sole cabbage plots supported a higher number of DBM larvae than cabbage intercropped with onion. Cabbage planted on soils without amendment, generally supported a fewer number of DBM larvae and natural enemies than the amended soils. The effect of the different treatments on the aphids population was not significant. The intercrop had the highest number of beneficial insects. The effect of soil amendment on the yield of cabbage and onion was significant with poultry manure plots recording the highest yield. The effect of cropping system was also significant on the yield of onion, with sole onion obtaining higher yields than onion intercropped with cabbage. The use of soil amendment also significantly improved the soil chemical and physical properties. Intercropping and soil amendment, therefore, have a lot of potential in sustainable vegetable production.
The study investigated the changes in properties of rice husk and corn cob biochars applied in urban agricultural field soils in Tamale (northern Ghana) and Ouagadougou (Burkina Faso), respectively. The biochars were both pyrolyzed at 500 °C with a batch reactor. Fine polyethylene mesh (litter bags) filled with 10 g of each type of biochar were buried at 20 cm depth in urban fields trials with a 3 x 2 factorial layout replicated 4 times. Factor 1 involved soil management practices at 3 levels: (1) farmers’ practice (FP), (2) 20 t biochar ha-1 and (3) control (no biochar). The second factor was time (duration) at two levels (6 and 12 months). Aged and fresh biochars were analyzed for volatile matter (VM), ash and fixed carbon (FC) contents, pH, effective cation exchange capacity (ECEC), and total surface acidity (Sa) and basicity (Sb). Dissolved organic carbon contents were determined sequentially by cold (cDOC) and hot water extractions (hDOC), respectively and aromaticities of cold water DOC (cSUVA) and hot water DOC (hSUVA) were determined. There was no significant interaction effect of soil management practices and time on measured ageing biochar properties. Time significantly affected most biochar ageing properties except Sa and Sb in rice husk biochar and ECEC in corn cob biochars at 6 months of exposure. In both biochars, Ash content, Fixed carbon (FC), cDOC, hDOC, cSUVA and hSUVA increased whilst pH and volatile matter contents decreased significantly. The hDOC was 2-3 times higher than cDOC contents for both biochars. Aromaticity of DOC contents of aged rice husk biochar exposed to soil management practices and time in the experimental site in Tamale showed persistence with time compared to corn cob biochar exposed in Ouagadougou experimental site. The results imply that rainfall, soil organic matter contents with interplay of soil minerals are key drivers to ageing and sequestration of these biochars and that these forces act at different scales but driven by time.
