CSIR Soil Research Institute

Accra, Ghana

CSIR Soil Research Institute

Accra, Ghana
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Okebalama C.B.,University of Nigeria | Okebalama C.B.,Kwame Nkrumah University Of Science And Technology | Safo E.Y.,Kwame Nkrumah University Of Science And Technology | Yeboah E.,CSIR Soil Research Institute | And 3 more authors.
Tropicultura | Year: 2016

In most parts of West Africa, poverty contributes immensely to poor fertilizer adoption by smallholder farmers. Fertilizer adoption could be improved with micro-dosing technology. A socio-economic survey was conducted in the semi-deciduous forest zone of Ghana to assess the extent of fertilizer use and management among maize and cowpea smallholder farmers. Oral interview with structured questionnaire was used to interview one hundred farmers each at two locations. The results showed that farmers are aware of the use of fertilizer to increase crop yield. About 65% and 80% of maize and cowpea farmers respectively, identified high cost of fertilizer as a major constraint to fertilizer utilization. Consequently, only 32% maize farmers and 19% cowpea farmers were fertilizer users. In addition, the choice of fertilizer type to use was dependent on the type available on the market. As such, NPK 15:15:15 was mostly used for both maize and cowpea crops. Also, fertilizer application rate was mainly determined by the quantity farmer can purchase. On average, fertilizer application rate for maize and cowpea crops were 18.45 kg/ha and 9.05 kg/ha, respectively. The prevalent fertilizer application method on maize was mostly by point/side placement while ring application was largely used for cowpea. Awareness of fertilizer micro-dosing among the farmers was only 10%. Since the quantity of fertilizer used by the farmers as well as the fertilizer application methods were comparable to fertilizer micro-dosing, dissemination of micro-dosing technology to these farmers could promote fertilizer use and management among smallholder farmers, and ultimately sustain maize and cowpea production.

Hengl T.,Wageningen University | Leenaars J.G.B.,Wageningen University | Shepherd K.D.,International Center for Research in Agroforestry | Walsh M.G.,Columbia University | And 9 more authors.
Nutrient Cycling in Agroecosystems | Year: 2017

Spatial predictions of soil macro and micro-nutrient content across Sub-Saharan Africa at 250 m spatial resolution and for 0–30 cm depth interval are presented. Predictions were produced for 15 target nutrients: organic carbon (C) and total (organic) nitrogen (N), total phosphorus (P), and extractable—phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), sodium (Na), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), aluminum (Al) and boron (B). Model training was performed using soil samples from ca. 59,000 locations (a compilation of soil samples from the AfSIS, EthioSIS, One Acre Fund, VitalSigns and legacy soil data) and an extensive stack of remote sensing covariates in addition to landform, lithologic and land cover maps. An ensemble model was then created for each nutrient from two machine learning algorithms—random forest and gradient boosting, as implemented in R packages ranger and xgboost—and then used to generate predictions in a fully-optimized computing system. Cross-validation revealed that apart from S, P and B, significant models can be produced for most targeted nutrients (R-square between 40–85%). Further comparison with OFRA field trial database shows that soil nutrients are indeed critical for agricultural development, with Mn, Zn, Al, B and Na, appearing as the most important nutrients for predicting crop yield. A limiting factor for mapping nutrients using the existing point data in Africa appears to be (1) the high spatial clustering of sampling locations, and (2) missing more detailed parent material/geological maps. Logical steps towards improving prediction accuracies include: further collection of input (training) point samples, further harmonization of measurement methods, addition of more detailed covariates specific to Africa, and implementation of a full spatio-temporal statistical modeling framework. © 2017 The Author(s)

PubMed | KNUST, Ghana Atomic Energy Commission, University for Development Studies, University of Ghana and 3 more.
Type: Journal Article | Journal: International journal of environmental research and public health | Year: 2016

A human health risk assessment of artisanal miners exposed to toxic metals in water bodies and sediments in the PresteaHuni Valley District of Ghana was carried out in this study, in line with US EPA risk assessment guidelines. A total of 70 water and 30 sediment samples were collected from surface water bodies in areas impacted by the operations of artisanal small-scale gold mines in the study area and analyzed for physico-chemical parameters such as pH, TDS, conductivity, turbidity as well as metals and metalloids such as As, Cd, Hg and Pb at CSIR-Water Research Institute using standard methods for the examination of wastewater as outlined by American Water Works Association (AWWA). The mean concentrations of As, Cd, Hg and Pb in water samples ranged from 15 g/L to 325 g/L (As), 0.17 g/L to 340 g/L (Cd), 0.17 g/L to 122 g/L (Pb) and 132 g/L to 866 g/L (Hg), respectively. These measured concentrations of arsenic (As), mercury (Hg), cadmium (Cd) and lead (Pb) were used as input parameters to calculate the cancer and non-cancer health risks from exposure to these metals in surface water bodies and sediments based on an occupational exposure scenario using central tendency exposure (CTE) and reasonable maximum exposure (RME) parameters. The results of the non-cancer human health risk assessment for small-scale miners working around river Anikoko expressed in terms of hazard quotients based on CTE parameters are as follows: 0.04 (Cd), 1.45 (Pb), 4.60 (Hg) and 1.98 (As); while cancer health risk faced by ASGM miners in Dumase exposed to As in River Mansi via oral ingestion of water is 3.1 10(-3). The hazard quotient results obtained from this study in most cases were above the HQ guidance value of 1.0, furthermore the cancer health risk results were found to be higher than the USEPA guidance value of 1 10(-4) to 1 10(-6). These findings call for case-control epidemiological studies to establish the relationship between exposure to the aforementioned toxic chemicals and diseases associated with them as identified in other studies conducted in different countries as basis for developing policy interventions to address the issue of ASGM mine workers safety in Ghana.

Snoeck D.,CIRAD - Agricultural Research for Development | Afrifa A.A.,CRIG | Ofori-Frimpong K.,CRIG | Boateng E.,CSIR Soil Research Institute | Abekoe M.K.,University of Ghana
West African Journal of Applied Ecology | Year: 2010

The intensely weathered nature of soils used for cocoa production in Ghana, and the long history of nutrient depletion due to the absence of fertilization in this farming system have resulted in increased incidence of soil nutrient deficiencies in cocoa farms. The paper discusses the use of a soil diagnostic model combined with geographic information systems (GIS) to convert the current blanket fertilizer recommendations (0 N - 165 P2O5 -200 K2O kg ha-1) into a more effective recommendation that accounts for local land resources and the actual nutrient requirements of cocoa trees. A digital map of cocoa nutrient requirements was created based on climatic and soil groups/associations data. The results showed that about 95% of the areas suitable for cocoa production are developed on only seven soil groups and four sub-groups (FAO classification). As inputs, 201 soil chemical analytic data were linked to land units to compute cocoa fertilizer formulae and doses. The number of fertilizer formulae was reduced to 32 using a fuzzy classification. Six fertilizer formulae would be sufficient to cover fertilizer recommendations for 52% of the cocoa growing areas, while 16 fertilizer formulae will cover 90% of the cocoa area. The current blanket fertilizer formula is only suitable for 6% of the cocoa growing areas in Ghana. In western Ghana, where rainfall is over 1800 mm, the climatic influence is predominant and high leaching of soils is probably responsible for greater needs for P, than for K, Ca, and Mg. In eastern Ghana, where soils have high exchangeable cation levels and base saturation, soil diagnostic method suggested application of N fertilizers. This integrated method could provide precision agriculture techniques for cocoa farmers in Ghana, and beyond, in order to sustain yields on cocoa farms.

Boateng E.,CSIR Soil Research Institute | Yangyuoru M.,University of Ghana | Breuning-Madsen H.,Copenhagen University | MacCarthy D.S.,University of Ghana
West African Journal of Applied Ecology | Year: 2013

The presence of coarse fragments can have profound impact on soil moisture retention characteristics. The study was conducted to assess the effects of coarse fragments on the moisture retention characteristics of 16 soil series, developed over five different parent materials in the Densu basin. Soil profiles were excavated at five locations, to depths within 1.5 m in the field. Undisturbed soil core samples and disturbed samples were taken in triplicates from the major genetic horizons of each soil type within the effective root depth of 1 m. Coarse fragments content of soil more than 2 mm was measured on mass basis by sieving through a 2-mm mesh. Soil moisture retention was determined using the pressure plate apparatus at suctions of pF 1 (1.0 kPa), pF 2 (10.0 kPa), pF 2.5 (33.0 kPa) and pF 3 (100.0 kPa) for the undisturbed and pF 4.2 (1500 kPa) for the disturbed samples. The volumetric moisture content between field capacity (FC) pF 2.5 (33.0 kPa) and permanent wilting pointing (PWP) pF 4.2 (1500.0 kPa) was used to evaluate the available water content (AWC) by volume and then converted to root zone available water capacity (RZAWC) in millimetres (mm) assuming an effective root depth of 1 m within the basin. Results showed that soils formed over granite and its associations have high percentage of coarse fragments while soils developed over phyllites and its associations have high clay percentage. Soil organic matter was high in the topsoil of all profiles, ranging from 0.81 to 4.44% compared with the horizons below, and the bulk density of the topsoils were less than the limiting value of 1.6 Mg m-3. Site-specific moisture retention characteristics of the various soil series have been delineated. It was evident from the analyses that soils containing high clay content gave high RZAWC values compared with soils with high coarse fragments. Most of the topsoils of the profiles gave high RZAWC values compared with sub-layers with high amounts of coarse fragments. Critical water for plants establishment within the basin in the surface layer was quite favourable.

Armah F.A.,University Of Cape Coast | Ason B.,CSIR Soil Research Institute | Luginaah I.,University of Western Ontario | Essandoh P.K.,University Of Cape Coast
Journal of Ecology and Field Biology | Year: 2012

This study conducted a comparative analysis of benthic macroinvertebrate communities in the Fosu and Benya lagoons in Ghana, based on the anthropogenic effect on the two lagoons. Salinity, oxygen, temperature, conductivity, turbidity and pH were measured, invertebrate richness and species densities were determined. The AZTI Marine Biotic Index (AMBI) and multivariate statistics were used to determine the different responses of fauna to pollution. The fauna were categorized into five ecological groups based on the degree of tolerance of the different species to pollution: disturbancesensitive species; disturbance-indifferent species, disturbance-tolerant species, second-order opportunistic species; and first-order opportunistic species. The Fosu Lagoon supported more pollution tolerant species, whereas the Benya Lagoon had more species that were sensitive to organic enrichment under relatively unpolluted conditions. Chironomus sp., which is adapted to virtually anoxic conditions, was the most abundant in the Fosu Lagoon whereas Nemertea sp. was the most abundant in the Benya Lagoon. The numerical and relative abundance (%) of all 7 taxa in the Fosu Lagoon was 1,359 and 92.35%, respectively. The numerical and relative abundance (%) of all 34 taxa in the Benya Lagoon was 2,459 and 87.52%, respectively. Expectedly, the level of dissolved oxygen in the less saline Fosu Lagoon was higher than that in the more saline Benya Lagoon. The reduced photoperiod and photosynthetic activities of aquatic plants might account for this trend. There is a need to implement comprehensive monitoring and management initiatives for sustaining the ecological health of coastal lagoons in Ghana in order to support the many people that depend upon these ecosystems for their livelihood. © The Ecological Society of Korea.

Okebalama C.B.,University of Nigeria | Okebalama C.B.,Kwame Nkrumah University Of Science And Technology | Safo E.Y.,Kwame Nkrumah University Of Science And Technology | Yeboah E.,CSIR Soil Research Institute | And 2 more authors.
Soil Science Society of America Journal | Year: 2016

High fertilizer costs pose a challenge in smallholder farming; optimizing fertilizer recommendations that are affordable to resource-poor farmers could increase crop yield and income. The study aimed to determining the yield and economic effects of N-P-K fertilizer microdosing on maize (Zea mays L.) crops on Gleyic Plinthic Acrisol (GPA) and Plinthic Acrisol (PA) in the semideciduous rainforest zone of Ghana using a split-plot randomized complete block design with three replications. The field trial included two cropping systems (continuous maize cropping [CMC] and cowpea [Vigna unguiculata (L.) Walp.]-maize rotation [CMR]) as main plots with four treatments (N0P0K0, N0P20K20, N0P40K20, and N20P40K20) and the recommended fertilizer rate (N90P60K60) as subplots. Fertilizer treatment effects on maize stover and grain yields were assessed. The microdose treatments increased maize yields by 32 to 99% across cropping systems and soil types. Maize grain yield increase was higher on the GPA than on the PA. The N90P60K60 and N20P40K20 treatments resulted in higher grain and stover yields than the other treatments across cropping systems and soil types. Among the treatments maximum grain yield increases of 76 and 99% were obtained with N20P40K20 on the PA and the GPA, respectively, under CMC. Under CMR, grain yield increased by 46% with N0P40K20 (PA) and 74% with N0P20K20 (GPA). The largest net return was obtained with N20P40K20 under CMC across both soil types and with N0P20K20 (GPA) and N0P40K20 (PA) under CMR. These fertilizer microdoses can be considered appropriate for increasing maize yield and the income of smallholder farmers. © Soil Science Society of America.

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