Pub Date : 2009-09-07DOI: 10.4314/WAJAE.V12I1.45770
Buri Mohammed Moro, I. Nuhu, Wakatsuki Toshiyuki
Nutrient input and output balances are very essential for maintaining balances in not only soil nutrient management but also in preventing pollution and waste through excess use. A study was undertaken to determine the optimum levels of the major elements (N, P, K) required for optimum lowland rice yields under the “sawah” system within the Biem and Dwinyan watersheds of the Ashanti Region, Ghana. Results show that the sites suffer multinutrient (N, P, K) deficiencies, with N and P being more pronounced. Mineral fertilizer positively and significantly affected rice paddy grain yield. The addition of 30 kg/ha each of N, P2O5 and K2O increased mean paddy grain yield by 71%, 51% and 56%, respectively. The application of higher rates of N (> 90 kg/ha) did not reflect in yield improvement and, therefore, was not economically beneficial. Optimum grain yield was observed at 60 kg P2O5/ha and 60 kg K2O/ha. Site significantly affected grain yield only in the first year. Maximum economic grain yields were observed from the rates 90-60-90 and 90-90-60 kg/ha N - P2O5 - K2O, respectively. From the results obtained, 90-60-60 kg/ha N- P2O5 - K2O is recommended for these areas.
{"title":"Determining Optimum Rates of Mineral Fertilizers for Economic Rice Grain Yields under the \"Sawah\" System in Ghana","authors":"Buri Mohammed Moro, I. Nuhu, Wakatsuki Toshiyuki","doi":"10.4314/WAJAE.V12I1.45770","DOIUrl":"https://doi.org/10.4314/WAJAE.V12I1.45770","url":null,"abstract":"Nutrient input and output balances are very essential for maintaining balances in not only soil nutrient management but also in preventing pollution and waste through excess use. A study was undertaken to determine the optimum levels of the major elements (N, P, K) required for optimum lowland rice yields under the “sawah” system within the Biem and Dwinyan watersheds of the Ashanti Region, Ghana. Results show that the sites suffer multinutrient (N, P, K) deficiencies, with N and P being more pronounced. Mineral fertilizer positively and significantly affected rice paddy grain yield. The addition of 30 kg/ha each of N, P2O5 and K2O increased mean paddy grain yield by 71%, 51% and 56%, respectively. The application of higher rates of N (> 90 kg/ha) did not reflect in yield improvement and, therefore, was not economically beneficial. Optimum grain yield was observed at 60 kg P2O5/ha and 60 kg K2O/ha. Site significantly affected grain yield only in the first year. Maximum economic grain yields were observed from the rates 90-60-90 and 90-90-60 kg/ha N - P2O5 - K2O, respectively. From the results obtained, 90-60-60 kg/ha N- P2O5 - K2O is recommended for these areas.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"12 1","pages":"19-31"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V12I1.45770","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-07DOI: 10.4314/WAJAE.V11I1.45732
J. Yaro
The relationships between peasant livelihoods and land degradation in the Gia-Kajelo community were examined in a wider context of the man-environment relations in the African savanna. The relationship has to be looked at in a wider dimension involving conceptual frameworks that incorporate contemporary understanding of rural livelihoods, institutional dynamics, resource diversity, environmental variability and macro level influences on local socio-politicoeconomic landscapes. Investigating these relationship should move from the biased technocratic objective assessment of virgin lands and so-called mapping of human impacts to studies identifying the environment as an arena for synergistic interaction between ‘man’ and ‘nature’. Based on the later approach results showed that all wealth groups experienced land degradation on their fields, reflecting the type of land investments made and mediated by levels of access to resources and opportunities. Being poor reduced the ability of most people to invest in land improvement, but being rich did not automatically lead to good environmental health
{"title":"Peasant livelihoods and land degradation: Evidence from a participatory assessment in the Gia-Kajelo community in Northern Ghana","authors":"J. Yaro","doi":"10.4314/WAJAE.V11I1.45732","DOIUrl":"https://doi.org/10.4314/WAJAE.V11I1.45732","url":null,"abstract":"The relationships between peasant livelihoods and land degradation in the Gia-Kajelo community were examined in a wider context of the man-environment relations in the African savanna. The relationship has to be looked at in a wider dimension involving conceptual frameworks that incorporate contemporary understanding of rural livelihoods, institutional dynamics, resource diversity, environmental variability and macro level influences on local socio-politicoeconomic landscapes. Investigating these relationship should move from the biased technocratic objective assessment of virgin lands and so-called mapping of human impacts to studies identifying the environment as an arena for synergistic interaction between ‘man’ and ‘nature’. Based on the later approach results showed that all wealth groups experienced land degradation on their fields, reflecting the type of land investments made and mediated by levels of access to resources and opportunities. Being poor reduced the ability of most people to invest in land improvement, but being rich did not automatically lead to good environmental health","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"11 1","pages":"109-128"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V11I1.45732","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-07DOI: 10.4314/WAJAE.V11I1.45729
Bk Kortatsi
Reconnaissance hydrochemical survey of 56 wells was conducted in the Wassa West District with the objective of providing baseline data for the establishment of groundwater quality monitoring stations. The data acquired is used in this paper to assess the quality of groundwater in the District. Groundwaters are mainly mildly aggressive with pH values in the range 4.5–6.9. However, a few of the boreholes show strong acidic character (pH range 3.7–4.0). The conductivity values are in the range 37–780 mS cm-1 with a mean 246.4 mS cm-1 suggesting the groundwaters are generally fresh and have short residence time. The groundwaters are moderately hard to very hard with only 40% of the samples representing soft waters. Groundwater quality is excellent with respect to major ions (Ca2+, Mg2+, Na+, HCO3 -, SO4 2-, Cl-) as they fall below their respective WHO guideline limits for water potability. Uncharacteristic of mining areas, trace metals loading of the groundwaters are generally low. All except aluminum, arsenic, barium, iron, manganese, mercury and nickel have concentrations well below the WHO guideline limits for water potability. Aluminum (0.0–2.5 mg l-1), iron (0.0–18.3 mg l-1) and manganese (0.0–2.41 mg l-1) are higher than WHO guideline limits of 0.2 mg l-1, 0.3 mg l-1 and 0.5 mg l-1 in more than 20%, 40% and 25% of the wells, respectively, and, therefore, pose significant aesthetic quality problems to groundwater quality. Mercury concentration exceeds the WHO guideline limit of 0.001 mg l-1 in all the wells during the rainy season and, thus, poses the greatest physiological threat for groundwater usage for drinking purposes in the District. Arsenic and barium exceeded the WHO guideline limit in less than 5% of the wells. Aesthetic problems can be eliminated using iron removal plants or aerators. These will induce the co-precipitation of trace metals with ferric oxyhydroxide. Limiting mercury usage in mining will curtail physiological problems.
{"title":"Groundwater quality in the Wassa West District of the Western Region of Ghana","authors":"Bk Kortatsi","doi":"10.4314/WAJAE.V11I1.45729","DOIUrl":"https://doi.org/10.4314/WAJAE.V11I1.45729","url":null,"abstract":"Reconnaissance hydrochemical survey of 56 wells was conducted in the Wassa West District with the objective of providing baseline data for the establishment of groundwater quality monitoring stations. The data acquired is used in this paper to assess the quality of groundwater in the District. Groundwaters are mainly mildly aggressive with pH values in the range 4.5–6.9. However, a few of the boreholes show strong acidic character (pH range 3.7–4.0). The conductivity values are in the range 37–780 mS cm-1 with a mean 246.4 mS cm-1 suggesting the groundwaters are generally fresh and have short residence time. The groundwaters are moderately hard to very hard with only 40% of the samples representing soft waters. Groundwater quality is excellent with respect to major ions (Ca2+, Mg2+, Na+, HCO3 -, SO4 2-, Cl-) as they fall below their respective WHO guideline limits for water potability. Uncharacteristic of mining areas, trace metals loading of the groundwaters are generally low. All except aluminum, arsenic, barium, iron, manganese, mercury and nickel have concentrations well below the WHO guideline limits for water potability. Aluminum (0.0–2.5 mg l-1), iron (0.0–18.3 mg l-1) and manganese (0.0–2.41 mg l-1) are higher than WHO guideline limits of 0.2 mg l-1, 0.3 mg l-1 and 0.5 mg l-1 in more than 20%, 40% and 25% of the wells, respectively, and, therefore, pose significant aesthetic quality problems to groundwater quality. Mercury concentration exceeds the WHO guideline limit of 0.001 mg l-1 in all the wells during the rainy season and, thus, poses the greatest physiological threat for groundwater usage for drinking purposes in the District. Arsenic and barium exceeded the WHO guideline limit in less than 5% of the wells. Aesthetic problems can be eliminated using iron removal plants or aerators. These will induce the co-precipitation of trace metals with ferric oxyhydroxide. Limiting mercury usage in mining will curtail physiological problems.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"11 1","pages":"25-40"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V11I1.45729","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-07DOI: 10.4314/WAJAE.V11I1.45719
TM Akabzaa, B. Banoeng-Yakubo, J. Seyire
Surface and groundwater samples within the catchment area of the Obuasi mine were analysed to assess the impact of mining activities on water resources. The concentration of Fe, Mn, Cu, Zn, Pb, Cd, Hg, As and selected major ions in water samples were analysed to assess their role in the contamination of both surface and ground water. The mineralogical composition of various mine spoil and rock samples was investigated by microprobe analysis to ascertain the possible sources of the metals in drainage and ground water. The hydrochemical analytical study, using standard methods, shows that streams in the study area have higher trace and major ions loading than ground water with iron and arsenic concentrations ranging from 0.025 mg/l to 17.19 mg/l and indication of mixed waters from a variety of sources. The microprobe results showed that waste rocks and related mine spoil contain a variety of Fe, Cu, As, Sb, Zn and co-bearing sulphides with strong compositional variations, and account for the augmented levels of these metals in drainage proximal to mining and processing facilities. The probe results did not show Hg in mine spoil, and very high Hg values observed in the vicinity of areas of intense illegal smallscale mining are attributed to the use of this chemical by miners in gold amalgamation
{"title":"Impact of mining activities on water resources in the vicinity of the Obuasi mine","authors":"TM Akabzaa, B. Banoeng-Yakubo, J. Seyire","doi":"10.4314/WAJAE.V11I1.45719","DOIUrl":"https://doi.org/10.4314/WAJAE.V11I1.45719","url":null,"abstract":"Surface and groundwater samples within the catchment area of the Obuasi mine were analysed to assess the impact of mining activities on water resources. The concentration of Fe, Mn, Cu, Zn, Pb, Cd, Hg, As and selected major ions in water samples were analysed to assess their role in the contamination of both surface and ground water. The mineralogical composition of various mine spoil and rock samples was investigated by microprobe analysis to ascertain the possible sources of the metals in drainage and ground water. The hydrochemical analytical study, using standard methods, shows that streams in the study area have higher trace and major ions loading than ground water with iron and arsenic concentrations ranging from 0.025 mg/l to 17.19 mg/l and indication of mixed waters from a variety of sources. The microprobe results showed that waste rocks and related mine spoil contain a variety of Fe, Cu, As, Sb, Zn and co-bearing sulphides with strong compositional variations, and account for the augmented levels of these metals in drainage proximal to mining and processing facilities. The probe results did not show Hg in mine spoil, and very high Hg values observed in the vicinity of areas of intense illegal smallscale mining are attributed to the use of this chemical by miners in gold amalgamation","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"11 1","pages":"129-139"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V11I1.45719","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-07DOI: 10.4314/WAJAE.V12I1.45767
I. Omoniyi, A. Agbon
A comparative racial study of Sarotherodon melanotheron (Ruppell) from brackish and fresh water habitats both in south-western Nigeria using morphometric and meristic characters to determine variations showed that they were phenotypically separable populations of the same species. The results revealed significant differences (P < 0.05) in body depth, caudal peduncle depth, number of gill rakers and scales on the lateral line which were suggested to have occurred as a result of difference in the temperature, salinity and substratum in the two water bodies. The results also implied that fresh water broodstock could be preferable to the brackish population for breeding programmes.
{"title":"Morphometric Variations in Sarotherodon melanotheron (Pisces: Cichlidae) from Brackish and Fresh Water Habitats in South-western Nigeria","authors":"I. Omoniyi, A. Agbon","doi":"10.4314/WAJAE.V12I1.45767","DOIUrl":"https://doi.org/10.4314/WAJAE.V12I1.45767","url":null,"abstract":"A comparative racial study of Sarotherodon melanotheron (Ruppell) from brackish and fresh water habitats both in south-western Nigeria using morphometric and meristic characters to determine variations showed that they were phenotypically separable populations of the same species. The results revealed significant differences (P < 0.05) in body depth, caudal peduncle depth, number of gill rakers and scales on the lateral line which were suggested to have occurred as a result of difference in the temperature, salinity and substratum in the two water bodies. The results also implied that fresh water broodstock could be preferable to the brackish population for breeding programmes.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V12I1.45767","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-07DOI: 10.4314/WAJAE.V11I1.45725
I. Ewa-Oboho, O. Oladimej
Quantitative surveys of the intertidal macro-fauna were conducted during September-October 1998 along transects established at various locations along the Nigeria coastline, following the rupture of a 24-inch pipeline at Idoho, off the Gulf of Guinea, southeastern Nigeria on 12 January 1998. Samples were taken within impacted areas and at control unpolluted sites approximately 5 km to the east of the Idoho off-shore platform. Spilled oil moved rapidly ashore and into river mouths, and estuaries and their mangals shortly after the spills. Biomass of macrofauna in the impacted areas tended to decrease with level of oiling, as the mean abundance decreased rapidly to about 50% of that found on the control unpolluted sites. Edible gastropod, mainly species of Tympanotomus fuscatus, and the brachyuran decapod, Uca tangeri, typically consumed by coastal inhabitants, had reduction in mean densities (up to 62%) in the oiled Bonny, Brass, Lagos and Forcados than in the non-oiled areas of Imo, Andoni and Cross River, showing partial recovery of the environment from the debacle after 9 months. The ecological implications of these findings are discussed.
{"title":"Studies on the short-term fffects of the mobil Idoho oil Spill on the Littoral Biota of Southeastern Nigeria","authors":"I. Ewa-Oboho, O. Oladimej","doi":"10.4314/WAJAE.V11I1.45725","DOIUrl":"https://doi.org/10.4314/WAJAE.V11I1.45725","url":null,"abstract":"Quantitative surveys of the intertidal macro-fauna were conducted during September-October 1998 along transects established at various locations along the Nigeria coastline, following the rupture of a 24-inch pipeline at Idoho, off the Gulf of Guinea, southeastern Nigeria on 12 January 1998. Samples were taken within impacted areas and at control unpolluted sites approximately 5 km to the east of the Idoho off-shore platform. Spilled oil moved rapidly ashore and into river mouths, and estuaries and their mangals shortly after the spills. Biomass of macrofauna in the impacted areas tended to decrease with level of oiling, as the mean abundance decreased rapidly to about 50% of that found on the control unpolluted sites. Edible gastropod, mainly species of Tympanotomus fuscatus, and the brachyuran decapod, Uca tangeri, typically consumed by coastal inhabitants, had reduction in mean densities (up to 62%) in the oiled Bonny, Brass, Lagos and Forcados than in the non-oiled areas of Imo, Andoni and Cross River, showing partial recovery of the environment from the debacle after 9 months. The ecological implications of these findings are discussed.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"11 1","pages":"51-63"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V11I1.45725","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-07DOI: 10.4314/WAJAE.V12I1.45749
M. Glover‐Amengor, F. Tetteh
Lindane is listed among the Prior Informed Consent (PIC) pesticides, and agricultural uses of lindane have been banned in 52 countries due to its hazardous nature. However, lindane is still widely used in vegetable cultivation in Ghana. The effect of increasing rates of application of lindane (156.0, 244.0 and 312.0 g ha-1), unden (propoxur) (125.0, 187.5 and 250.0 g ha-1), dithane and karate (166.6, 209.8 and 333.3 g ha-1) on garden eggs, okro and tomatoes was studied to find out if it has any advantage that makes its use attractive to farmers despite its ban. Yields of garden eggs were suppressed by all the rates of lindane applied. In tomatoes, lower rates of lindane increased yields whereas the higher rates suppressed yields lower than the control. In okro yields were higher than the control at all levels of lindane applied though yield increments were low. Unden application had the highest effect on garden egg yields followed by tomatoes and least on okro. In the garden egg and tomato treatments, increasing concentration of unden resulted in decreasing yields though yields were higher on the control plots. The optimum unden rate for garden egg and tomato was U20 (i.e. 125.0 g ha-1). Increasing rates of unden on okro did not have any significant effect. Pesticide application had a higher effect on fungal population (50-70% reduction) than on bacterial population in the soil (23.0–38.4% reduction). Dithane suppressed bacteria most whereas karate suppressed fungal population most. Lower levels of chloride residues in tomato fruits corresponded to lower rates of lindane application. Lindane did not have any advantage over the other pesticides as it caused the least increase in yield. It is recommend that farmers are educated on the adverse effects of lindane use, and government enforces the restriction on lindane importation and use in agriculture.
林丹被列为事先知情同意(PIC)农药之一，由于其危险性，林丹已在52个国家被禁止在农业上使用。然而，林丹在加纳的蔬菜种植中仍被广泛使用。研究了林丹(156.0、244.0和312.0 g公顷-1)、残杀威(125.0、187.5和250.0 g公顷-1)、乙烷和空手道(166.6、209.8和333.3 g公顷-1)增加施用量对花园鸡蛋、黑豆和西红柿的影响，以确定它是否有任何优势，使其在被禁止的情况下仍能吸引农民使用。林丹施用量对园蛋产量均有抑制作用。在番茄中，低剂量林丹增加了产量，而高剂量林丹抑制的产量低于对照。施用林丹的各个水平的okro产量均高于对照，但增产幅度不大。施肥对果园鸡蛋产量影响最大，其次是番茄，对秋葵产量影响最小。在果园鸡蛋和番茄处理中，尽管对照地产量较高，但氮肥浓度的增加导致产量下降。果园鸡蛋和番茄的最佳羽化率为U20(即125.0 g ha-1)。增加赤潮对赤潮的影响不显著。施用农药对土壤真菌数量(减少50 ~ 70%)的影响大于对土壤细菌数量(减少23.0 ~ 38.4%)的影响。乙烷对细菌的抑制作用最大，空手道对真菌的抑制作用最大。番茄果实中氯残留水平较低，与林丹施用量较低相对应。与其他农药相比，林丹没有任何优势，因为它对产量的增加作用最小。建议对农民进行有关林丹使用的不良影响的教育，并建议政府对林丹在农业中的进口和使用实施限制。
{"title":"Effect of pesticide application rate on yield of vegetables and soil microbial communities","authors":"M. Glover‐Amengor, F. Tetteh","doi":"10.4314/WAJAE.V12I1.45749","DOIUrl":"https://doi.org/10.4314/WAJAE.V12I1.45749","url":null,"abstract":"Lindane is listed among the Prior Informed Consent (PIC) pesticides, and agricultural uses of lindane have been banned in 52 countries due to its hazardous nature. However, lindane is still widely used in vegetable cultivation in Ghana. The effect of increasing rates of application of lindane (156.0, 244.0 and 312.0 g ha-1), unden (propoxur) (125.0, 187.5 and 250.0 g ha-1), dithane and karate (166.6, 209.8 and 333.3 g ha-1) on garden eggs, okro and tomatoes was studied to find out if it has any advantage that makes its use attractive to farmers despite its ban. Yields of garden eggs were suppressed by all the rates of lindane applied. In tomatoes, lower rates of lindane increased yields whereas the higher rates suppressed yields lower than the control. In okro yields were higher than the control at all levels of lindane applied though yield increments were low. Unden application had the highest effect on garden egg yields followed by tomatoes and least on okro. In the garden egg and tomato treatments, increasing concentration of unden resulted in decreasing yields though yields were higher on the control plots. The optimum unden rate for garden egg and tomato was U20 (i.e. 125.0 g ha-1). Increasing rates of unden on okro did not have any significant effect. Pesticide application had a higher effect on fungal population (50-70% reduction) than on bacterial population in the soil (23.0–38.4% reduction). Dithane suppressed bacteria most whereas karate suppressed fungal population most. Lower levels of chloride residues in tomato fruits corresponded to lower rates of lindane application. Lindane did not have any advantage over the other pesticides as it caused the least increase in yield. It is recommend that farmers are educated on the adverse effects of lindane use, and government enforces the restriction on lindane importation and use in agriculture.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"12 1","pages":"41-47"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V12I1.45749","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-07DOI: 10.4314/WAJAE.V12I1.45779
E. Attua
Fallow ecosystems provide a significant carbon stock that can be quantified for inclusion in the accounts of global carbon budgets. Process and statistical models of productivity, though useful, are often technically rigid as the conditions for their application are not easy to satisfy. Multiple regression techniques have been applied to study some biophysical phenomena but yet to be applied to carbon stock estimation. Using ecological data from 28 sampling locations, the study applied the stepwise multiple regression technique to identify ecological variables that would explain carbon stock of fallow vegetation, aged between 3 and 8 years. The procedure generated three predictive regression models. The full model, could explain nearly 98% of variability of carbon stock (R 2 = .979), using cationexchange capacity and total nitrogen content of soil and leaf area index as the three predictor variables. Sampling inaccuracies could have contributed to the error component of models and sample size increase has been suggested for reduction of such errors. The advantage of the method is its simplicity. The paper suggests that the derived models be validated before broad application. Also, the cost-effectiveness of the approach should be tested against other approaches.
{"title":"Using multiple linear regression techniques to quantify carbon stocks of fallow vegetation in the tropics","authors":"E. Attua","doi":"10.4314/WAJAE.V12I1.45779","DOIUrl":"https://doi.org/10.4314/WAJAE.V12I1.45779","url":null,"abstract":"Fallow ecosystems provide a significant carbon stock that can be quantified for inclusion in the accounts of global carbon budgets. Process and statistical models of productivity, though useful, are often technically rigid as the conditions for their application are not easy to satisfy. Multiple regression techniques have been applied to study some biophysical phenomena but yet to be applied to carbon stock estimation. Using ecological data from 28 sampling locations, the study applied the stepwise multiple regression technique to identify ecological variables that would explain carbon stock of fallow vegetation, aged between 3 and 8 years. The procedure generated three predictive regression models. The full model, could explain nearly 98% of variability of carbon stock (R 2 = .979), using cationexchange capacity and total nitrogen content of soil and leaf area index as the three predictor variables. Sampling inaccuracies could have contributed to the error component of models and sample size increase has been suggested for reduction of such errors. The advantage of the method is its simplicity. The paper suggests that the derived models be validated before broad application. Also, the cost-effectiveness of the approach should be tested against other approaches.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V12I1.45779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70685048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-04DOI: 10.4314/WAJAE.V10I1.45693
I. Ewa-Oboho, N. Abby-Kalio
The carapace length-weight relationship in juvenile Brachyura (crabs) was studied theoretically to assess the relevance of the allometric factor and the validity of the condition factor as these factors are often not determined because most fishery investigations are conducted for adult population. The allometric factor appears to be the main parameter in the equation: W = aLb (where W = weight, a is a constant and L = carapace length). Parameters a (also called the condition factor K, known as the ponderal index) and k = 103 W/L3 were found to be of less significance and they were closely related to b. The theoretical value of b = 3 was found to be rarely met in crab fishery studies; rather much wider range was observed. It was, therefore, recommended that the assumed theoretical value of b = 3 would not be applied in all ichthiofauna surveys as it is generally commonly done by fishery scientists. The present analytical studies has opened a new approach to the elucidation of the biological significance of the allometric factor b, through the theories of tractal geometry (where b is seen as a fractal dimension equivalent and salutatory ontogeny where b is a critical point in the early life history of crabs.
{"title":"Theoretical basis of allometric relationships in juvenile brachyura: Data from a West African mangrove swamp crab population","authors":"I. Ewa-Oboho, N. Abby-Kalio","doi":"10.4314/WAJAE.V10I1.45693","DOIUrl":"https://doi.org/10.4314/WAJAE.V10I1.45693","url":null,"abstract":"The carapace length-weight relationship in juvenile Brachyura (crabs) was studied theoretically to assess the relevance of the allometric factor and the validity of the condition factor as these factors are often not determined because most fishery investigations are conducted for adult population. The allometric factor appears to be the main parameter in the equation: W = aLb (where W = weight, a is a constant and L = carapace length). Parameters a (also called the condition factor K, known as the ponderal index) and k = 103 W/L3 were found to be of less significance and they were closely related to b. The theoretical value of b = 3 was found to be rarely met in crab fishery studies; rather much wider range was observed. It was, therefore, recommended that the assumed theoretical value of b = 3 would not be applied in all ichthiofauna surveys as it is generally commonly done by fishery scientists. The present analytical studies has opened a new approach to the elucidation of the biological significance of the allometric factor b, through the theories of tractal geometry (where b is seen as a fractal dimension equivalent and salutatory ontogeny where b is a critical point in the early life history of crabs.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"12 1","pages":"35-45"},"PeriodicalIF":0.0,"publicationDate":"2009-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V10I1.45693","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70683959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-04DOI: 10.4314/WAJAE.V10I1.45691
I. Asante, A. Dixon
Ninety-eight cassava accessions were grown in augmented randomized complete block design to screen for superior clones with desirable traits. The desirable traits were root number (RTNO), fresh root yield (FYLD), harvest index (HI), dry matter (DM), cyanide potential (CNP), mean plant height (MPHT) and level of branching (LOBR). Three standard varieties were used, namely 30572, 91/01730 and 91/023227. Acessions that were superior to the standard types in more than one trait were 92/0681, 92/02325; 92/0455, 88/02555; Alice Local and 88/02555. These accessions could be selected and put into crossing blocks to combine the traits into one genotype. The present results show that augmented designs are efficient in the identification of superior cassava genotypes with desirable traits.
{"title":"Field screening of cassava (Manihot esculenta Crantz) germplasm for desirable traits by the use of augmented design","authors":"I. Asante, A. Dixon","doi":"10.4314/WAJAE.V10I1.45691","DOIUrl":"https://doi.org/10.4314/WAJAE.V10I1.45691","url":null,"abstract":"Ninety-eight cassava accessions were grown in augmented randomized complete block design to screen for superior clones with desirable traits. The desirable traits were root number (RTNO), fresh root yield (FYLD), harvest index (HI), dry matter (DM), cyanide potential (CNP), mean plant height (MPHT) and level of branching (LOBR). Three standard varieties were used, namely 30572, 91/01730 and 91/023227. Acessions that were superior to the standard types in more than one trait were 92/0681, 92/02325; 92/0455, 88/02555; Alice Local and 88/02555. These accessions could be selected and put into crossing blocks to combine the traits into one genotype. The present results show that augmented designs are efficient in the identification of superior cassava genotypes with desirable traits.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"10 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2009-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V10I1.45691","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70683908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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