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Dilys S MacCarthy
Soil and Irrigation Research Centre, School of Agriculture, College of Basic and Applied Science (CBAS), University of Ghana, P.O. Box LG 68 Accra, Ghana

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Journal article
Published: 06 May 2021 in Sustainability
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Agriculture in West Africa is constrained by several yield-limiting factors, such as poor soil fertility, erratic rainfall distributions and low input systems. Projected changes in climate, thus, pose a threat since crop production is mainly rain-fed. The impact of climate change and its variation on the productivity of cereals in smallholder settings under future production systems in Navrongo, Ghana and Nioro du Rip, Senegal was assessed in this study. Data on management practices obtained from household surveys and projected agricultural development pathways (through stakeholder engagements), soil data, weather data (historical: 1980–2009 and five General Circulation Models; mid-century time slice 2040–2069 for two Representative Concentration Pathways; 4.5 and 8.5) were used for the impact assessment, employing a crop simulation model. Ensemble maize yield changes under the sustainable agricultural development pathway (SDP) were −13 and −16%, while under the unsustainable development pathway (USDP), yield changes were −19 and −20% in Navrongo and Nioro du Rip, respectively. The impact on sorghum and millet were lower than that on maize. Variations in climate change impact among smallholders were high with relative standard deviations (RSD) of between 14% and 60% across the cereals with variability being higher under the USDP, except for millet. Agricultural production systems with higher intensification but with less emphasis on soil conservation (USDP) will be more negatively impacted by climate change compared to relatively sustainable ones (SDP).

ACS Style

Dilys MacCarthy; Myriam Adam; Bright Freduah; Benedicta Fosu-Mensah; Peter Ampim; Mouhamed Ly; Pierre Traore; Samuel Adiku. Climate Change Impact and Variability on Cereal Productivity among Smallholder Farmers under Future Production Systems in West Africa. Sustainability 2021, 13, 5191 .

AMA Style

Dilys MacCarthy, Myriam Adam, Bright Freduah, Benedicta Fosu-Mensah, Peter Ampim, Mouhamed Ly, Pierre Traore, Samuel Adiku. Climate Change Impact and Variability on Cereal Productivity among Smallholder Farmers under Future Production Systems in West Africa. Sustainability. 2021; 13 (9):5191.

Chicago/Turabian Style

Dilys MacCarthy; Myriam Adam; Bright Freduah; Benedicta Fosu-Mensah; Peter Ampim; Mouhamed Ly; Pierre Traore; Samuel Adiku. 2021. "Climate Change Impact and Variability on Cereal Productivity among Smallholder Farmers under Future Production Systems in West Africa." Sustainability 13, no. 9: 5191.

Journal article
Published: 28 April 2021 in Sustainability
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Changes in land cover (LC) can lead to environmental challenges, but few studies have investigated LC changes at a country wide scale in Ghana. Tracking LC changes at such a scale overtime is relevant for devising solutions to emerging issues. This study examined LC changes in Ghana for the past almost two and half decades covering 1995–2019 to highlight significant changes and opportunities for sustainable development. The study used land cover data for six selected years (1995, 2000, 2005, 2010, 2015, and 2019) obtained from the European Space Agency. The data was analyzed using R, ArcGIS Pro and Microsoft Excel 365 ProPlus. The original data was reclassified into eight LC categories, namely: agriculture, bare area, built-up, forest, grassland, other vegetation, waterbody, and wetland. On average, the results revealed 0.7%, 131.7%, 23.3%, 46.9%, and 11.2% increases for agriculture, built-up, forest, waterbody, and wetland, respectively, across the nation. However, losses were observed for bare area (92.8%), grassland (51.1%), and other vegetation (41%) LCs overall. Notably, agricultural land use increased up to 2015 and decreased subsequently but this did not affect production of the major staple foods. These findings reveal the importance of LC monitoring and the need for strategic efforts to address the causes of undesirable change.

ACS Style

Peter Ampim; Michael Ogbe; Eric Obeng; Edwin Akley; Dilys MacCarthy. Land Cover Changes in Ghana over the Past 24 Years. Sustainability 2021, 13, 4951 .

AMA Style

Peter Ampim, Michael Ogbe, Eric Obeng, Edwin Akley, Dilys MacCarthy. Land Cover Changes in Ghana over the Past 24 Years. Sustainability. 2021; 13 (9):4951.

Chicago/Turabian Style

Peter Ampim; Michael Ogbe; Eric Obeng; Edwin Akley; Dilys MacCarthy. 2021. "Land Cover Changes in Ghana over the Past 24 Years." Sustainability 13, no. 9: 4951.

Journal article
Published: 24 March 2021 in Ecological Modelling
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The harsh environmental conditions and poor management of agricultural fields in many parts of the tropics lead to rapid soil degradation and low crop yields, once native lands are converted to agriculture. The assessment and management of degraded fields is constrained by the low resource availability to support field data collection. Crop simulation models offer tools for assessing the degradation problem and support improved management decisions. Though a host of comprehensive crop models have been published, their wide-scale application in the tropics, especially as decision support tools continues to lag, largely due to the types and fine-scale data requirements for model execution, which are often lacking in the tropical regions. In this paper, we present a simple modelling framework that is capable of simulating the impact of soil degradation on maize yields using field-scale agriculture data. The major departure of this new modelling framework is the description of erosion in terms of soil depth loss instead of soil mass loss. The framework, which was developed from an assembly of relevant theory and equations in the published literature is designed to address the data paucity challenges often encountered in many tropical regions. The model was programmed in Excel and tested against published observed maize yields for situations where the maize was grown on simulated eroded soils of varying severity and nitrogen application rates. The model simulated well the decline in maize yields with increased erosion severity and varying nitrogen application rates (R2 = 0.79, nRMSE = 28% and Willmott d-index = 0.95). It is concluded that the model, though simple, provided a framework for assessing maize yield response to varied soil degradation conditions.

ACS Style

Samuel G.K. Adiku; Dilys S. MacCarthy; Samuel K. Kumahor. A conceptual modelling framework for simulating the impact of soil degradation on maize yield in data-sparse regions of the tropics. Ecological Modelling 2021, 448, 109525 .

AMA Style

Samuel G.K. Adiku, Dilys S. MacCarthy, Samuel K. Kumahor. A conceptual modelling framework for simulating the impact of soil degradation on maize yield in data-sparse regions of the tropics. Ecological Modelling. 2021; 448 ():109525.

Chicago/Turabian Style

Samuel G.K. Adiku; Dilys S. MacCarthy; Samuel K. Kumahor. 2021. "A conceptual modelling framework for simulating the impact of soil degradation on maize yield in data-sparse regions of the tropics." Ecological Modelling 448, no. : 109525.

Primary research article
Published: 06 July 2020 in Global Change Biology
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Smallholder farmers in sub‐Saharan Africa (SSA) currently grow rainfed maize with limited inputs including fertilizer. Climate change may exacerbate current production constraints. Crop models can help quantify the potential impact of climate change on maize yields, but a comprehensive multi‐model assessment of simulation accuracy and uncertainty in these low‐input systems is currently lacking. We evaluated the impact of varying [CO2], temperature and rainfall conditions on maize yield, for different nitrogen (N) inputs (0, 80, 160 kg N ha‐1) for five environments in SSA, including cool sub‐humid Ethiopia, cool semi‐arid Rwanda, hot sub‐humid Ghana and hot semi‐arid Mali and Benin using an ensemble of 25 maize models. Models were calibrated with measured grain yield, plant biomass, plant N, leaf area index, harvest index and in‐season soil water content from two‐year experiments in each country to assess their ability to simulate observed yield. Simulated responses to climate change factors were explored and compared between models. Calibrated models reproduced measured grain yield variations well with average rRMSE of 26%, although uncertainty in model prediction was substantial (CV = 28%). Model ensembles gave greater accuracy than any model taken at random. Nitrogen fertilization controlled the response to variations in [CO2], temperature and rainfall. Without N fertilizer input, maize (i) benefited less from an increase in atmospheric [CO2], (ii) was less affected by higher temperature or decreasing rainfall and (iii) was more affected by increased rainfall because N leaching was more critical. The model inter‐comparison revealed that simulation of daily soil N supply and N leaching plays a crucial role in simulating climate change impacts for low‐input systems. Climate change and N input interactions have strong implications for the design of robust adaptation practices across SSA, because the impact of climate change will be modified if farmers intensify maize production with more mineral fertilizer.

ACS Style

Gatien N. Falconnier; Marc Corbeels; Kenneth J. Boote; François Affholder; Myriam Adam; Dilys S. MacCarthy; Alex C. Ruane; Claas Nendel; Anthony M. Whitbread; Éric Justes; Lajpat R. Ahuja; Folorunso M. Akinseye; Isaac N. Alou; Kokou A. Amouzou; Saseendran S. Anapalli; Christian Baron; Bruno Basso; Frédéric Baudron; Patrick Bertuzzi; Andrew J. Challinor; Yi Chen; Delphine Deryng; Maha Elsayed; Babacar Faye; Thomas Gaiser; Marcelo Galdos; Sebastian Gayler; Edward Gerardeaux; Michel Giner; Brian Grant; Gerrit Hoogenboom; Esther S. Ibrahim; Bahareh Kamali; Kurt Christian Kersebaum; Soo‐Hyung Kim; M Van Der Laan; Louise Leroux; Jon I. Lizaso; Bernardo Maestrini; Elizabeth A. Meier; Fasil Mequanint; Alain Ndoli; Cheryl H. Porter; Eckart Priesack; Dominique Ripoche; Tesfaye S. Sida; Upendra Singh; Ward N. Smith; Amit Srivastava; Sumit Sinha; Fulu Tao; Peter J. Thorburn; Dennis Timlin; Bouba Traore; Tracy Twine; Heidi Webber. Modelling climate change impacts on maize yields under low nitrogen input conditions in sub‐Saharan Africa. Global Change Biology 2020, 26, 5942 -5964.

AMA Style

Gatien N. Falconnier, Marc Corbeels, Kenneth J. Boote, François Affholder, Myriam Adam, Dilys S. MacCarthy, Alex C. Ruane, Claas Nendel, Anthony M. Whitbread, Éric Justes, Lajpat R. Ahuja, Folorunso M. Akinseye, Isaac N. Alou, Kokou A. Amouzou, Saseendran S. Anapalli, Christian Baron, Bruno Basso, Frédéric Baudron, Patrick Bertuzzi, Andrew J. Challinor, Yi Chen, Delphine Deryng, Maha Elsayed, Babacar Faye, Thomas Gaiser, Marcelo Galdos, Sebastian Gayler, Edward Gerardeaux, Michel Giner, Brian Grant, Gerrit Hoogenboom, Esther S. Ibrahim, Bahareh Kamali, Kurt Christian Kersebaum, Soo‐Hyung Kim, M Van Der Laan, Louise Leroux, Jon I. Lizaso, Bernardo Maestrini, Elizabeth A. Meier, Fasil Mequanint, Alain Ndoli, Cheryl H. Porter, Eckart Priesack, Dominique Ripoche, Tesfaye S. Sida, Upendra Singh, Ward N. Smith, Amit Srivastava, Sumit Sinha, Fulu Tao, Peter J. Thorburn, Dennis Timlin, Bouba Traore, Tracy Twine, Heidi Webber. Modelling climate change impacts on maize yields under low nitrogen input conditions in sub‐Saharan Africa. Global Change Biology. 2020; 26 (10):5942-5964.

Chicago/Turabian Style

Gatien N. Falconnier; Marc Corbeels; Kenneth J. Boote; François Affholder; Myriam Adam; Dilys S. MacCarthy; Alex C. Ruane; Claas Nendel; Anthony M. Whitbread; Éric Justes; Lajpat R. Ahuja; Folorunso M. Akinseye; Isaac N. Alou; Kokou A. Amouzou; Saseendran S. Anapalli; Christian Baron; Bruno Basso; Frédéric Baudron; Patrick Bertuzzi; Andrew J. Challinor; Yi Chen; Delphine Deryng; Maha Elsayed; Babacar Faye; Thomas Gaiser; Marcelo Galdos; Sebastian Gayler; Edward Gerardeaux; Michel Giner; Brian Grant; Gerrit Hoogenboom; Esther S. Ibrahim; Bahareh Kamali; Kurt Christian Kersebaum; Soo‐Hyung Kim; M Van Der Laan; Louise Leroux; Jon I. Lizaso; Bernardo Maestrini; Elizabeth A. Meier; Fasil Mequanint; Alain Ndoli; Cheryl H. Porter; Eckart Priesack; Dominique Ripoche; Tesfaye S. Sida; Upendra Singh; Ward N. Smith; Amit Srivastava; Sumit Sinha; Fulu Tao; Peter J. Thorburn; Dennis Timlin; Bouba Traore; Tracy Twine; Heidi Webber. 2020. "Modelling climate change impacts on maize yields under low nitrogen input conditions in sub‐Saharan Africa." Global Change Biology 26, no. 10: 5942-5964.

Journal article
Published: 25 June 2020 in Agronomy
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The efficiency of mineral fertilizer use in most soils in Sub-saharan Africa is low. Prominent among the reasons for this is low soil carbon stock. In this study, we hypothesized that in the short term, combined use of biochar and inorganic fertilizer in irrigated rice (Oryza sativa var KRC Baika) cropping systems will increase soil organic carbon storage, N recovery and agronomic efficiency of N use (above world average of 55% and 20 kg grain·kg−1·N respectively) and improved economic returns compared to the sole use of inorganic fertilizer. A two-year (4‒cropping cycles) field trial was, thus, conducted on a Vertisol. The experiments were designed as split–plot with two (0 and 10 t·ha−1) biochar and four (0, 45, 90, 120 kg·ha−1·N) nitrogen application rates. Additionally, the effect of biochar on the chemical properties of the soil was investigated using standard protocols. Biochar application improved the soil organic carbon storage in the topsoil. There were significant interactions between the application of biochar and nitrogen fertilizer on yield parameters. Introducing biochar significantly increased root volume and nutrient (N, P and K) uptake, resulting in increased grain and straw yield. Grain yields under biochar amended plots were higher than sole fertilizer amended plots in 14 out of 16 instances (cropping cycles x N rates). The increase in grain yield was between 12 to 29% across N rates. Biochar amendment also enhanced agronomic N use and apparent N recovery efficiencies in 3 out of the 4 cropping cycles. Gross margin indicated that biochar application under irrigated rice cropping systems is economically feasible in all cropping cycles and N rates. However, the value cost ratio of biochar application was higher than for sole inorganic fertilizer in three out of the four cropping cycles (each cropping cycle has three N rates). The soil organic carbon storage of biochar amended soil increased by 17% under unfertilized condition and by 32% under fertilized condition. To enable the promotion and efficient use of the biochar technology in enhancing productivity and profitability in irrigated rice, extension officers and farmers will need to be trained on how to char the rice husk to reduce emissions prior to upscaling the technology to farmers.

ACS Style

Dilys S. MacCarthy; Eric Darko; Eric K. Nartey; Samuel G. K. Adiku; Abigail Tettey. Integrating Biochar and Inorganic Fertilizer Improves Productivity and Profitability of Irrigated Rice in Ghana, West Africa. Agronomy 2020, 10, 904 .

AMA Style

Dilys S. MacCarthy, Eric Darko, Eric K. Nartey, Samuel G. K. Adiku, Abigail Tettey. Integrating Biochar and Inorganic Fertilizer Improves Productivity and Profitability of Irrigated Rice in Ghana, West Africa. Agronomy. 2020; 10 (6):904.

Chicago/Turabian Style

Dilys S. MacCarthy; Eric Darko; Eric K. Nartey; Samuel G. K. Adiku; Abigail Tettey. 2020. "Integrating Biochar and Inorganic Fertilizer Improves Productivity and Profitability of Irrigated Rice in Ghana, West Africa." Agronomy 10, no. 6: 904.

Journal article
Published: 15 October 2019 in Agronomy
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Climate change is estimated to exacerbate existing challenges faced by smallholder farmers in Sub-Sahara Africa. However, limited studies quantify the extent of variation in climate change impact under these systems at the local scale. The Decision Support System for Agro-technological Transfer (DSSAT) was used to quantify variation in climate change impacts on maize yield under current agricultural practices in semi-arid regions of Senegal (Nioro du Rip) and Ghana (Navrongo and Tamale). Multi-benchmark climate models (Mid-Century, 2040–2069 for two Representative Concentration Pathways, RCP4.5 and RCP8.5), and multiple soil and management information from agronomic surveys were used as input for DSSAT. The average impact of climate scenarios on grain yield among farms ranged between −9% and −39% across sites. Substantial variation in climate response exists across farms in the same farming zone with relative standard deviations from 8% to 117% at Nioro du Rip, 13% to 64% in Navrongo and 9% to 37% in Tamale across climate models. Variations in fertilizer application, planting dates and soil types explained the variation in the impact among farms. This study provides insight into the complexities of the impact of climate scenarios on maize yield and the need for better representation of heterogeneous farming systems for optimized outcomes in adaptation and resilience planning in smallholder systems.

ACS Style

Bright S. Freduah; Dilys S. MacCarthy; Myriam Adam; Mouhamed Ly; Alex C. Ruane; Eric C. Timpong-Jones; Pierre S. Traore; Kenneth J. Boote; Cheryl Porter; Samuel G. K. Adiku. Sensitivity of Maize Yield in Smallholder Systems to Climate Scenarios in Semi-Arid Regions of West Africa: Accounting for Variability in Farm Management Practices. Agronomy 2019, 9, 639 .

AMA Style

Bright S. Freduah, Dilys S. MacCarthy, Myriam Adam, Mouhamed Ly, Alex C. Ruane, Eric C. Timpong-Jones, Pierre S. Traore, Kenneth J. Boote, Cheryl Porter, Samuel G. K. Adiku. Sensitivity of Maize Yield in Smallholder Systems to Climate Scenarios in Semi-Arid Regions of West Africa: Accounting for Variability in Farm Management Practices. Agronomy. 2019; 9 (10):639.

Chicago/Turabian Style

Bright S. Freduah; Dilys S. MacCarthy; Myriam Adam; Mouhamed Ly; Alex C. Ruane; Eric C. Timpong-Jones; Pierre S. Traore; Kenneth J. Boote; Cheryl Porter; Samuel G. K. Adiku. 2019. "Sensitivity of Maize Yield in Smallholder Systems to Climate Scenarios in Semi-Arid Regions of West Africa: Accounting for Variability in Farm Management Practices." Agronomy 9, no. 10: 639.

Articles
Published: 03 October 2019 in Communications in Soil Science and Plant Analysis
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The interactive effect of biochar, cattle manure and nitrogen (N) fertilizer on the dynamics of carbon (C) mineralization and stabilization was investigated in a sandy soil amended with three sole biochar (0, 20 or 40 t ha−1) or manure (0, 13 or 26 t ha−1) and four combined biochar-manure levels (20 or 40 t ha−1 biochar plus 13 or 26 t ha−1 manure) with or without N fertilizer (0 or 90 kg ha−1) and CO2-C evolution measured over 54-d incubation period. Biochar application, solely or combined with manure resulted in lower applied C mineralized (ACM), indicating C sequestration in the soils. Negative attributable effect (AE) of co-application of biochar and manure on C mineralization was observed relative to the sole treatments. Both ACM and AE were negatively correlated with C/N ratio and mineral N content of the soil-mixtures (r ≥ – 0.573; p ≤ 0.01), indicating microbial N limitation. The double first-order exponential model described CO2-C efflux very well and indicated that ≥94% of C applied was apportioned to stable C pools with slower mineralization rate constant and longer half-life. Cumulative C mineralized and modeled C pools were positively correlated with each other (r ≥ 0.853; p ≤ 0.001) and with readily oxidizable C of soil-amendment mixtures (r ≥ 0.861; p ≤ 0.001). The results suggested that co-application of biochar and manure can promote initial rapid mineralization to release plant nutrients but sequester larger amounts of applied C in refractive C pool, resulting in larger C sequestration in sandy soils.

ACS Style

Daniel E. Dodor; Yahaya J. Amanor; Abena Asamoah-Bediako; Dilys S. MacCarthy; Delali B.K. Dovie. Kinetics of Carbon Mineralization and Sequestration of Sole and/or Co-amended Biochar and Cattle Manure in a Sandy Soil. Communications in Soil Science and Plant Analysis 2019, 50, 2593 -2609.

AMA Style

Daniel E. Dodor, Yahaya J. Amanor, Abena Asamoah-Bediako, Dilys S. MacCarthy, Delali B.K. Dovie. Kinetics of Carbon Mineralization and Sequestration of Sole and/or Co-amended Biochar and Cattle Manure in a Sandy Soil. Communications in Soil Science and Plant Analysis. 2019; 50 (20):2593-2609.

Chicago/Turabian Style

Daniel E. Dodor; Yahaya J. Amanor; Abena Asamoah-Bediako; Dilys S. MacCarthy; Delali B.K. Dovie. 2019. "Kinetics of Carbon Mineralization and Sequestration of Sole and/or Co-amended Biochar and Cattle Manure in a Sandy Soil." Communications in Soil Science and Plant Analysis 50, no. 20: 2593-2609.

Research article
Published: 05 April 2018 in Applied and Environmental Soil Science
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The emission of greenhouse gases (GHGs) results in global warming and climate change. The extent to which developing countries contribute to GHG emissions is not well known. This study reports findings on the effects of different land-use systems on GHG emissions (CO2 in this case) from two locations in the southern zone of Ghana, West Africa. Site one (located at Kpong) contained a heavy clay soil while site two (located at Legon) contained a light-textured sandy soil. Land-use systems include cattle kraals, natural forests, cultivated maize fields, and rice paddy fields at site one, and natural forest, woodlots, and cultivated soya bean fields at site two. CO2 emissions were measured using the gas entrapment method (PVC chambers). Trapping solutions were changed every 12–48 h and measurement lasted 9 to 15 days depending on the site. We found that, for the same land-use, CO2 emissions were higher on the clay soil (Kpong) than the sandy soil (Legon). In the clay soil environment, the highest average CO2 emission was observed from the cattle kraal (256.7 mg·m−2·h−1), followed by the forest (146.0 mg·m−2·h−1) and rice paddy (140.6 mg·m−2·h−1) field. The lowest average emission was observed for maize cropped land (112.0 mg·m−2·h−1). In the sandy soil environment, the highest average CO2 emission was observed from soya cropped land (52.5 mg·m−2·h−1), followed by the forest (47.4 mg·m−2·h−1) and woodlot (33.7 mg·m−2·h−1). Several factors influenced CO2 emissions from the different land-use systems. These include the inherent properties of the soils such as texture, temperature, and moisture content, which influenced CO2 production through their effect on soil microbial activity and root respiration. Practices that reduce CO2 emissions are likely to promote carbon sequestration, which will consequently maintain or increase crop productivity and thereby improve global or regional food security.

ACS Style

Dilys Sefakor MacCarthy; Robert B. Zougmoré; Pierre Bienvenu Irénikatché Akponikpè; Eric Koomson; Patrice Savadogo; Samuel Godfried Kwasi Adiku. Assessment of Greenhouse Gas Emissions from Different Land-Use Systems: A Case Study of CO2 in the Southern Zone of Ghana. Applied and Environmental Soil Science 2018, 2018, 1 -12.

AMA Style

Dilys Sefakor MacCarthy, Robert B. Zougmoré, Pierre Bienvenu Irénikatché Akponikpè, Eric Koomson, Patrice Savadogo, Samuel Godfried Kwasi Adiku. Assessment of Greenhouse Gas Emissions from Different Land-Use Systems: A Case Study of CO2 in the Southern Zone of Ghana. Applied and Environmental Soil Science. 2018; 2018 ():1-12.

Chicago/Turabian Style

Dilys Sefakor MacCarthy; Robert B. Zougmoré; Pierre Bienvenu Irénikatché Akponikpè; Eric Koomson; Patrice Savadogo; Samuel Godfried Kwasi Adiku. 2018. "Assessment of Greenhouse Gas Emissions from Different Land-Use Systems: A Case Study of CO2 in the Southern Zone of Ghana." Applied and Environmental Soil Science 2018, no. : 1-12.

Chapter
Published: 04 April 2018 in Improving the Profitability, Sustainability and Efficiency of Nutrients Through Site Specific Fertilizer Recommendations in West Africa Agro-Ecosystems
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Recommendations and decisions of crop management in sub-Saharan Africa (SSA) are often based on traditional field experimentation. This usually ignores the variability of production factors in space and time, and hence invalidates such decisions and recommendations outside of the experimental sites. Yet, the use of alternative or complementary decision support approaches such as crop modelling is limited. In this paper, we reviewed the state of the use of crop modelling in informing site specific fertilizer recommendations in some countries in SSA. Even though nitrogen fertilizer recommendations in most countries across Africa are blanket, the limited employment of models show that optimum nitrogen application should be differentiated according to soil types, management and climate. A number of studies reported on increased fertilizer use efficiency and reduced crop production risks with the use of Decision Support Tools (DST). The review also showed that the gross limitation of the use of models as agricultural decision-making tools in SSA could be attributed to factors such as low capacity due to limited training opportunities, and the general lack of support from national governments for model development and application for policy formulation. Proposals identified to overcome these limitations include (1) introduction of the science of DST in the curricula at the tertiary level, (2) encouragement and support for the adoption of model use by governmental and non-governmental organizations as additional tools for decision making and (3) simplifying DSTs to facilitate their use by non-scientific audience to scale uptake and use for farm management.

ACS Style

Dilys S. MacCarthy; Job Kihara; Patricia Masikati; Samuel G. K. Adiku. Decision Support Tools for Site-Specific Fertilizer Recommendations and Agricultural Planning in Selected Countries in Sub-Sahara Africa. Improving the Profitability, Sustainability and Efficiency of Nutrients Through Site Specific Fertilizer Recommendations in West Africa Agro-Ecosystems 2018, 265 -289.

AMA Style

Dilys S. MacCarthy, Job Kihara, Patricia Masikati, Samuel G. K. Adiku. Decision Support Tools for Site-Specific Fertilizer Recommendations and Agricultural Planning in Selected Countries in Sub-Sahara Africa. Improving the Profitability, Sustainability and Efficiency of Nutrients Through Site Specific Fertilizer Recommendations in West Africa Agro-Ecosystems. 2018; ():265-289.

Chicago/Turabian Style

Dilys S. MacCarthy; Job Kihara; Patricia Masikati; Samuel G. K. Adiku. 2018. "Decision Support Tools for Site-Specific Fertilizer Recommendations and Agricultural Planning in Selected Countries in Sub-Sahara Africa." Improving the Profitability, Sustainability and Efficiency of Nutrients Through Site Specific Fertilizer Recommendations in West Africa Agro-Ecosystems , no. : 265-289.

Original articles
Published: 02 April 2018 in International Journal of Vegetable Science
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Smallholder vegetable farmers involved in agricultural production are confronted with numerous challenges which can adversely affect performance. Farmers would prefer to adopt the most profitable vegetable production systems. A cost-benefit analysis of integrated crop management (ICM) and conventional method (CM) systems for vegetable production was conducted. Primary data were solicited from 120 vegetable farmers using questionnaires. Descriptive statistics were used to describe levels of awareness and extent to which farmers understood use of the ICM system. A cash flow projection was done on a 0.4 ha size of land for 5 years. Net present value (NPV) and cost-benefit ratio (CBR) analyses were performed for farmers operating under the ICM and CM production systems. The NPV analysis indicated production of vegetables under both systems was viable. The incremental NPV for cabbage (Brassica oleracea var. capitata L.) and onion (Allium cepa L.) production, and the whole farm enterprise were all positive, indicating the ICM system was more financially viable than the CM system. The NPV increase was GHS 2563.58 (GHS is Ghanaian currency, 1$US = 3.5 GHS in January 2015 when data were collected) for cabbage and GHS 3949.43 for onion, and of the whole farm enterprise, i.e., combined cabbage and onion production, was GHS 6162.75. The CBR analysis indicated that vegetable production under the two systems was viable, confirming results of the NPV analyses. The CBR for cabbage production was 1.58 for the CM and 2.08 for the ICM systems; the CBR for onion production was 2.69 for the CM and 4.36 for the ICM systems. The CBR for whole farm enterprise was 2.42 for the CM and 3.93 for the ICM systems. Sensitivity analyses, under the assumption of a 5% reduction in yield and a 10% cost over-run, indicated positive NPVs for both production systems for cabbage and onion production, and the whole farm enterprise. The NPVs from use of the ICM system were higher than under the CM system. Overall, vegetable production is profitable under both the ICM and CM systems, and awareness is a factor influencing practice of the ICM system.

ACS Style

John K.M. Kuwornu; Eugenia Oduro; Ditchfield P.K. Amegashie; Ken O. Fening; Macarius Yangyouru; Dilys MacCarthy; Christiana Amoatey; Avishek Datta. Cost-Benefit Analysis of Conventional and Integrated Crop Management for Vegetable Production. International Journal of Vegetable Science 2018, 24, 597 -611.

AMA Style

John K.M. Kuwornu, Eugenia Oduro, Ditchfield P.K. Amegashie, Ken O. Fening, Macarius Yangyouru, Dilys MacCarthy, Christiana Amoatey, Avishek Datta. Cost-Benefit Analysis of Conventional and Integrated Crop Management for Vegetable Production. International Journal of Vegetable Science. 2018; 24 (6):597-611.

Chicago/Turabian Style

John K.M. Kuwornu; Eugenia Oduro; Ditchfield P.K. Amegashie; Ken O. Fening; Macarius Yangyouru; Dilys MacCarthy; Christiana Amoatey; Avishek Datta. 2018. "Cost-Benefit Analysis of Conventional and Integrated Crop Management for Vegetable Production." International Journal of Vegetable Science 24, no. 6: 597-611.

Journal article
Published: 19 October 2017 in South African Journal of Plant and Soil
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The yield gap and variability in maize under smallholder systems in two agroecologies in northern Ghana were evaluated using a decision support system for agrotechnology transfer (DSSAT). The model was used to assess (1) the potential yield of maize (YPOT), (2) water-limited exploitable maize yield (YWEX), (3) nitrogen-limited yield (YNI), (4) farmer practice maize yield (YCFP) and (5) proposed enhanced nutrient use yield (enhanced farmer practice; YEFP). Effect of supplementary irrigation was also assessed on YCFP and YEFP conditions. Yield gaps were determined as the difference between YPOT and YCFP or YEFP on the one hand, and between YWEX and YCFP or YEFP on the other hand. The yield gap based on potential yield ranged from 59% to 75% under CFP and narrowed to between 29% and 59% under EFP. With water-limited exploitable yields, the yield gap ranged from 53% to 65% under CFP, reducing to between 22% and 42% under EFP. The use of supplementary irrigation further reduced the yield gap. Improved fertiliser use and supplementary irrigation have the potential to increase yield and hence reduce the yield gap if effective policies and institutional structures are in place to provide farmers with credit facilities and farm inputs.

ACS Style

Dilys S MacCarthy; Samuel G Adiku; Bright S Freduah; Alpha Y Kamara; Stephen Narh; Alhassan L Abdulai. Evaluating maize yield variability and gaps in two agroecologies in northern Ghana using a crop simulation model. South African Journal of Plant and Soil 2017, 35, 137 -147.

AMA Style

Dilys S MacCarthy, Samuel G Adiku, Bright S Freduah, Alpha Y Kamara, Stephen Narh, Alhassan L Abdulai. Evaluating maize yield variability and gaps in two agroecologies in northern Ghana using a crop simulation model. South African Journal of Plant and Soil. 2017; 35 (2):137-147.

Chicago/Turabian Style

Dilys S MacCarthy; Samuel G Adiku; Bright S Freduah; Alpha Y Kamara; Stephen Narh; Alhassan L Abdulai. 2017. "Evaluating maize yield variability and gaps in two agroecologies in northern Ghana using a crop simulation model." South African Journal of Plant and Soil 35, no. 2: 137-147.

Original article
Published: 29 August 2017 in Nutrient Cycling in Agroecosystems
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Recommendations and decisions of crop management in sub-Saharan Africa (SSA) are often based on traditional field experimentation. This usually ignores the variability of production factors in space and time, and hence invalidates such decisions and recommendations outside of the experimental sites. Yet, the use of alternative or complementary decision support approaches such as crop modelling is limited. In this paper, we reviewed the state of the use of crop modelling in informing site specific fertilizer recommendations in some countries in SSA. Even though nitrogen fertilizer recommendations in most countries across Africa are blanket, the limited employment of models show that optimum nitrogen application should be differentiated according to soil types, management and climate. A number of studies reported on increased fertilizer use efficiency and reduced crop production risks with the use of decision support tools (DST). The review also showed that the gross limitation of the use of models as agricultural decision-making tools in SSA could be attributed to factors such as low capacity due to limited training opportunities, and the general lack of support from national governments for model development and application for policy formulation. Proposals identified to overcome these limitations include (1) introduction of the science of DST in the curricula at the tertiary level, (2) encouragement and support for the adoption of model use by governmental and non-governmental organizations as additional tools for decision making and (3) simplifying DSTs to facilitate their use by non-scientific audience to scale uptake and use for farm management.

ACS Style

Dilys S. MacCarthy; Job Kihara; Patricia Masikati; Samuel G. K. Adiku. Decision support tools for site-specific fertilizer recommendations and agricultural planning in selected countries in sub-Sahara Africa. Nutrient Cycling in Agroecosystems 2017, 110, 343 -359.

AMA Style

Dilys S. MacCarthy, Job Kihara, Patricia Masikati, Samuel G. K. Adiku. Decision support tools for site-specific fertilizer recommendations and agricultural planning in selected countries in sub-Sahara Africa. Nutrient Cycling in Agroecosystems. 2017; 110 (3):343-359.

Chicago/Turabian Style

Dilys S. MacCarthy; Job Kihara; Patricia Masikati; Samuel G. K. Adiku. 2017. "Decision support tools for site-specific fertilizer recommendations and agricultural planning in selected countries in sub-Sahara Africa." Nutrient Cycling in Agroecosystems 110, no. 3: 343-359.

Original research article
Published: 26 January 2017 in Frontiers in Plant Science
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Maize (Zea mays) has traditionally been a major cereal staple in southern Ghana. Through breeding and other crop improvement efforts, the zone of cultivation of maize has now extended to the northern regions of Ghana which, hitherto, were the home to sorghum and millet as the major cereals. Maize yield in the northern Ghana is hampered by three major biophysical constraints, namely, poor soil fertility, low soil water storage capacity and climate variability. In this study we used the DSSAT crop model to assess integrated water and soil management strategies that combined the pre-season El-Niño-Southern Oscillation (ENSO)-based weather forecasting in selecting optimal planting time, at four locations in the northern regions of Ghana. It could be shown that the optimum planting date for a given year was predictable based on February-to-April (FMA) Sea Surface Temperature (SST) anomaly for the locations with R2 ranging from 0.52 to 0.71. For three out of four locations, the ENSO-predicted optimum planting dates resulted in significantly higher maize yields than the conventional farmer selected planting dates. In Wa for instance, early optimum planting dates were associated with La Nina and El Niño (Julian Days 130 – 150) whereas late planting was associated with the Neutral ENSO phase. It was also observed that the addition of manure and fertilizer improved soil water and nitrogen use efficiency, respectively, and minimized yield variability, especially when combined with weather forecast. The use of ENSO-based targeted planting date choice together with modest fertilizer and manure application has the potential to improve maize yields and also ensure sustainable maize production in parts of northern Ghana.

ACS Style

Dilys S. MacCarthy; Samuel G. K. Adiku; Bright S. Freduah; Francis Gbefo; Alpha Y. Kamara. Using CERES-Maize and ENSO as Decision Support Tools to Evaluate Climate-Sensitive Farm Management Practices for Maize Production in the Northern Regions of Ghana. Frontiers in Plant Science 2017, 8, 31 .

AMA Style

Dilys S. MacCarthy, Samuel G. K. Adiku, Bright S. Freduah, Francis Gbefo, Alpha Y. Kamara. Using CERES-Maize and ENSO as Decision Support Tools to Evaluate Climate-Sensitive Farm Management Practices for Maize Production in the Northern Regions of Ghana. Frontiers in Plant Science. 2017; 8 ():31.

Chicago/Turabian Style

Dilys S. MacCarthy; Samuel G. K. Adiku; Bright S. Freduah; Francis Gbefo; Alpha Y. Kamara. 2017. "Using CERES-Maize and ENSO as Decision Support Tools to Evaluate Climate-Sensitive Farm Management Practices for Maize Production in the Northern Regions of Ghana." Frontiers in Plant Science 8, no. : 31.

Journal article
Published: 24 May 2015 in Nutrient Cycling in Agroecosystems
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This study set out to (1) calibrate and evaluate the performance of APSIM in simulating maize response to N, P and residue management and (2) identify strategies to reduce instability in crop production, and increase the efficiency of mineral fertilizer use. The response of maize to inorganic nitrogen (N) and phosphorus (P) additions were determined in the coastal savannah agro-ecology in the main rainy and secondary rainy seasons, of 2008 and 2009. Field experiments were set-up in a randomized complete block design with different levels of N (0–120 kg N ha−1) and P (0–30 kg P2O5 ha−1) mineral fertilizer. The APSIM model adequately simulated agroecosystem dynamics, resulting in the following RMSE values: anthesis (1.2 days), maturity (2.0 days), maximum LAI (0.18 m2m−2) total-biomass (543 kg ha−1), grain yield (318 kg ha−1), N uptake (12.6 kg ha−1), P uptake (2.2 kg ha−1) and in-season soil water content (0.01 mm). A long-term simulation study (30 years) showed that probabilities of obtaining higher yields were higher in the main growing season than in the secondary growing season. The efficiency of mineral N fertilizer use was also higher in the main growing season. The use of 40 kg N ha−1 mineral N fertilizer in both seasons was more efficient than using 80 kg N ha−1. The variability in the efficiency of mineral fertilizer use was higher in the secondary growing (44–96 %) than in the main growing season (27–48 %). Retaining crop residues yielded higher stability in grain production and increased the minimum grain yield production significantly. Applying 40 kg N ha−1 and 30 kg P2O5 ha−1 mineral fertilizer with crop residue retention will reduce the uncertainty in maize production, particularly in the secondary growing seasons which are characterized by prolonged drought spells. This study suggests that resource-poor farmers will be better off prioritizing the main growing season for rainfed maize production and applying a moderate amount (40 kg N ha−1) of N fertilizer rather than the 90 kg N ha−1 currently recommended for the coastal savannah of Ghana in the secondary growing season because of the higher instability in yields associated with N fertilizer use in this season.

ACS Style

D. S. MacCarthy; P. B. I. Akponikpe; S. Narh; R. Tegbe. Modeling the effect of seasonal climate variability on the efficiency of mineral fertilization on maize in the coastal savannah of Ghana. Nutrient Cycling in Agroecosystems 2015, 102, 45 -64.

AMA Style

D. S. MacCarthy, P. B. I. Akponikpe, S. Narh, R. Tegbe. Modeling the effect of seasonal climate variability on the efficiency of mineral fertilization on maize in the coastal savannah of Ghana. Nutrient Cycling in Agroecosystems. 2015; 102 (1):45-64.

Chicago/Turabian Style

D. S. MacCarthy; P. B. I. Akponikpe; S. Narh; R. Tegbe. 2015. "Modeling the effect of seasonal climate variability on the efficiency of mineral fertilization on maize in the coastal savannah of Ghana." Nutrient Cycling in Agroecosystems 102, no. 1: 45-64.

Journal article
Published: 10 September 2010 in Field Crops Research
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The CERES-sorghum module of the Decision Support System for Agro-Technological Transfer (DSSAT) model was calibrated for sorghum (Sorghum bicolor (L.) Moench) using data from sorghum grown with adequate waterand nitrogen and evaluated with data from several N rates trials in Navrongo, Ghana with an overall modified internal efficiency of 0.63. The use of mineral N fertilizer was found to be profitable with economically optimal rates of 40 and 80 kg N ha−1 for more intensively managed homestead fields and less intensively managed bush fields respectively. Agronomic N use efficiency varied from 21 to 37 kg grain kg−1 N for the homestead fields and from 15 to 49 kg grain kg−1 N in the bush fields. Simulated grain yield for homestead fields at 40 kg N ha−1 application was equal to yield for bush fields at 80 kg N ha−1. Water use efficiency generally increased with increased mineral N rate and was greater for the homestead fields compared with the bush fields. Grain yield per unit of cumulative evapo-transpiration (simulated) was consistently higher compared with yield per unit of cumulative precipitation for the season, probably because of runoff and deep percolation. In the simulation experiment, grain yield variability was less with mineral N application and under higher soil fertility (organic matter) condition. Application of mineral N reduced variability in yield from a CV of 37 to 11% in the bush farm and from 17 to 7% in the homestead fields. The use of mineral fertilizer and encouraging practices that retain organic matter to the soil provide a more sustainable system for ensuring crop production and hence food securit

ACS Style

Dilys S. MacCarthy; Paul L.G. Vlek; A. Bationo; R. Tabo; M. Fosu. Modeling nutrient and water productivity of sorghum in smallholder farming systems in a semi-arid region of Ghana. Field Crops Research 2010, 118, 251 -258.

AMA Style

Dilys S. MacCarthy, Paul L.G. Vlek, A. Bationo, R. Tabo, M. Fosu. Modeling nutrient and water productivity of sorghum in smallholder farming systems in a semi-arid region of Ghana. Field Crops Research. 2010; 118 (3):251-258.

Chicago/Turabian Style

Dilys S. MacCarthy; Paul L.G. Vlek; A. Bationo; R. Tabo; M. Fosu. 2010. "Modeling nutrient and water productivity of sorghum in smallholder farming systems in a semi-arid region of Ghana." Field Crops Research 118, no. 3: 251-258.

Journal article
Published: 03 August 2009 in Field Crops Research
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The cropping systems model APSIM (Agricultural Production Systems sIMulator) was applied to assess the response of sorghum grain yield to inorganic fertilizers applications and residue retention in diverse farmers’ management systems (homestead fields and bush farms). The model was parameterized using data collected from experiments under optimum growth conditions (limited water or nutrient stress). Independent data from field experiments with three levels of P and four levels of N fertilizers conducted at two different locations and soils were used to evaluate the model. Soil water and fertility parameters measured were used for simulations while same starting conditions were assumed for unmeasured parameters for all trials. APSIM predicted the grain yield response of sorghum to both N and P applications with an overall modified internal coefficient of efficiency of 0.64. Following model parameterization, a long-term simulation study was conducted using a stochastic weather data derived from historical weather data to assess the effects of crop residue management on grain production. A gradual decline in sorghum grain yield was simulated over the 30-year simulation period in both the homestead fields and the bush farms, with yields being much lower in the latter under farmers’ management practices. Half the amount of mineral N fertilizer used in the bush farms was needed in the homestead fields to produce the average grain yields produced on the bush farm with full fertilization, if crop residues were returned to the fields in the homestead. Year-to-year variability in grain yield was consistently higher with the removal of crop residues, irrespective of management systems. APSIM was responsive to both organic and inorganic fertilizer applications in the study area and also highlighted the essential role of crop residues and inorganic fertilizer in influencing the temporal sorghum grain production and hence the impact of farmers’ management practices on food security. This was evident in the rapid decline in soil organic carbon (SOC) accompanied by a decline in grain yield over the 30 years of cropping. The use of inorganic fertilizer and retention of crop residues (SOC) are critical for attaining food security in the study area.

ACS Style

Dilys S. MacCarthy; Rolf Sommer; Paul L.G. Vlek. Modeling the impacts of contrasting nutrient and residue management practices on grain yield of sorghum (Sorghum bicolor (L.) Moench) in a semi-arid region of Ghana using APSIM. Field Crops Research 2009, 113, 105 -115.

AMA Style

Dilys S. MacCarthy, Rolf Sommer, Paul L.G. Vlek. Modeling the impacts of contrasting nutrient and residue management practices on grain yield of sorghum (Sorghum bicolor (L.) Moench) in a semi-arid region of Ghana using APSIM. Field Crops Research. 2009; 113 (2):105-115.

Chicago/Turabian Style

Dilys S. MacCarthy; Rolf Sommer; Paul L.G. Vlek. 2009. "Modeling the impacts of contrasting nutrient and residue management practices on grain yield of sorghum (Sorghum bicolor (L.) Moench) in a semi-arid region of Ghana using APSIM." Field Crops Research 113, no. 2: 105-115.