Evaluation of Suitability of Some Soils in the Forest-Savanna Transition and the Guinea Savanna Zones of Ghana for Maize Production

Suitability of four soils located in the Forest-Transition zone and four others located in the Guinea Savanna zone of Ghana were evaluated for maize production using Soil Quality Index (SQI), Decision Support System for Agrotechnology Transfer (DSSAT) yield simulations and the Multi-Criteria Analysis (MCA).  Wenchi (Ferric Dystric Leptosol), Ejura (Haplic Lixisol), Damongo (Dystric Nitisol) and Lima series (Eutric Gleysol) were located in the Forest-Savanna Transition agro-ecological zone whereas Kpelesawgu (Eutric Plinthosol), Varempere (Ferric Luvisol), Mimi (Haplic Lixisol) and Kupela (Eutric Gleysol) series were located in the Guinea Savanna agro-ecological zone. The study sites in the Forest-Savanna zone were located in the Brong-Ahafo region whereas those in the Guinea Savanna zone were in the Northern region of Ghana. Properties used for the SQI rating included bulk density, pH, organic carbon, total nitrogen, available phosphorus, texture and water holding capacity. For the DSSAT, 1980 – 2010 weather variability impacts in addition to soil and management effects were used. The MCA evaluation included factors such as price, input and labour costs, distance to market, soil erosion and conservation factors. The three approaches gave different rankings of the soils for maize production. The SQI results rated the soils in the order: Wenchi > Damongo > Mimi > Ejura > Kupela > Lima > Varempere > Kpelesawgu. From the DSSAT simulations, the order was Varempere > Kpelesawgu > Damongo > Ejura > Kupela > Mimi > Lima > Wenchi. From the MCA, the rankings under different soil management options was in the order: Damongo > Mimi > Ejura > Wenchi > Lima > Varempere > Kupela > Kpelesawgu. Whereas both the SQI and the MCA ranked Kpelesawgu series as the least suitable for maize production, the DSSAT ranked it as the second most suitable. From the results, soils in the Forest-Savanna Transition zone were more suitable for maize production than those in the Guinea Savannah zone. Soils with negligible gravel content could generally be considered as more suitable for intensive maize production. Although the SQI and the DSSAT yield simulations gave less desirable outcomes than the MCA simulations, they should be considered as useful basis for evaluating and designing the MCA criteria

Mode of Biochar Application to Vertisols Influences Water Balance Components and Water Use Efficiency of Maize (Zea mays L.)

Vertisols belong to a group of soils with high fertility but poor physical properties of swelling when wet and shrinking and cracking when dry. The swelling inhibits infiltration, resulting in flooding, limiting the production of upland crops. Biochar (<BC) application has been shown to reduce the shrink-swell behaviour of Vertisols. However, the mode of biochar application to these soils may affect the effectiveness of the amendment. This study investigated the water relations and maize (Zea mays L.) growth under two BC application modes: (i) biochar applied into cracks that develop with drying, C, and (ii) biochar that was surface broadcast and incorporated into the topsoil, FM. A control treatment did not receive any BC amendment. Maize was grown on the BC-amended Vertisols using the two modes of application in a greenhouse under two seasonal water regimes of 610 and 450 mm. The results showed that the proportion of total water application lost to runoff was 37%, 49% and 53% for C, FM and control treatments, respectively. Both maize yield and Water Use Efficiency (WUE), for the C treatments were significantly (p < 0.05) higher than those for FM treatments. The maize yield under the C treatments was 19% over the control. Similarly, the WUE for the C treatments was 28% above the control treatment. It is concluded that the application of biochar into cracks is a more effective way of improving the water relations and upland crop productivity and WUE in Vertisols than the traditional surface incorporation

Location and Land use effects on Soil Carbon Accretion and Productivity in the Coastal Savanna Agro-ecological Zone of Ghana

Land use type, climate and soil properties are major determinants of soil carbon storage and productivity, especially in low-input agriculture. In this study, we investigated the interactions among these factors at four (4) locations, namely Accra Metropolis, Ga West, Ga East and Shai Osudoku, within the Coastal-Savannah agro-ecological zone of Ghana. The land use types were maize-based cropping, cassava-based cropping, woodlot/plantations and natural forests. The impact of these on soil productivity at a given location was assessed in terms of soil carbon stocks and a Soil Productivity Index (SPI). The SPI is a composite value derived from routine soil properties such as: soil texture, available water capacity, pH, cation exchange capacity, soil organic carbon, available P, exchangeable K, potentially mineralizable nitrogen, and basic cations, among others. Principal component analysis was used to select soil properties that were used to estimate SPI. The results showed that the locations differed with respect to rainfall regimes and soil types. Locations with slightly heavier soil texture and relatively higher rainfall regimes (Ga East and Shai Osudoku) had significantly higher soil carbon storage and SPI values than the lighter soil textured locations (Accra Metropolis and Ga West). With regards to land use, forest had significantly higher soil carbon storage and SPI than all the other land use types, irrespective of location. The order of soil carbon storage and SPI were: forest > woodlot/plantation > cassava > maize. It was observed that though the Accra Metropolis location hosted the oldest forest, soil carbon was still low, apparently due to the lighter soil texture. We concluded that the soil productivity restorative ability is an interactive effect of carbon management (land use), soil texture and other properties. This interaction hitherto has not been adequately investigated, especially in low-input agriculture

Smallholder farmers’ perception of climatic and socio-economic factors influencing livelihoods in the transition zone of Ghana

Background: The study analyzed smallholder farmers’ perception with regards to climatic and socio-economic changes influencing their agriculture livelihoods and coping strategies thereof in the transition zone of Ghana. Methods: We used semi-structured questionnaires for household survey involving 59 households and focus group discussions (n=60) for data collection in three communities. Results: Farming systems are influenced by high and extreme temperatures, delayed onsets of rain, short raining season as well as unpredictable raining seasons. Similarly, socioeconomic factors affecting the communities and their households’ livelihood included i) bad road network; ii) high prices of farm inputs; iii) prevalent crop pests and diseases and iv) absence of irrigation facilities. It was ascertained that though most farmers have not made conscious efforts to adapt strategies in their farming system to climate change and the social stressors, as expressed in ‘doing nothing or bearing losses’ and we are at the ‘mercy’ of the weather, there are hidden resilience mechanisms that can be harnessed to strengthen their adaptation capabilities. Women in the study area have adapted to the changes in the weather and safeguarded against post-harvest loss of cassava more effectively as compared to their male counterparts. Similarly, the prevailing group farming and maintenance structure (locally known as ‘Noboa’) strengthen the shared responsibility and reciprocity among migrant’ farmers. Conclusions: Though these agrarian communities have some coping strategies to overcome some climatic and socioeconomic challenges, their general adaptive capacity in terms of physical, financial and human assets are limited. This, therefore, calls for the capacity building of both men and women on best farming practices, adaptation strategies and piloting of irrigation systems to enhance their major livelihood but these must be complemented with good road network for ease of access to the market centres

Productivity of Soybean under Projected Climate Change in a Semi-Arid Region of West Africa: Sensitivity of Current Production System

The production of soybean is gaining more attention in West Africa. In light of projected changes in climate, there is a need to assess the potential impacts on yield productivity and variability among farmers. An evaluated GROPGRO module of the Decision Support System for Agro-technological Transfer (DSSAT) was used to simulate soybean productivity under both historical (1980–2009) and projected climate scenarios from multiple general circulation models (GCMs) under two representative concentration pathways (RCPs): 4.5 and 8.5. Agronomic data from 90 farms, as well as multiple soil profile data, were also used for the impact assessment. Climate change leads to a reduction (3% to 13.5% across GCMs and RCPs) in the productivity of soybean in Northern Ghana. However, elevated atmospheric carbon dioxide has the potential to offset the negative impact, resulting in increased (14.8% to 31.3% across GCMs and RCPs) productivity. The impact of climate change on yield varied widely amongst farms (with relative standard deviation (RSD) ranging between 17% and 35%) and across years (RSD of between 10% and 15%). Diversity in management practices, as well as differences in soils, explained the heterogeneity in impact among farms. Variability among farms was higher than that among years. The strategic management of cultural practices provides an option to enhance the resilience of soybean productivity among smallholder

Climate Change Impact and Variability on Cereal Productivity among Smallholder Farmers under Future Production Systems in West Africa

Agriculture inWest 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) wer

The Agricultural Model Intercomparison and Improvement Project (AgMIP): Integrated Regional Assessment Projects

The worldwide agricultural sector faces the significant challenge of increasing production to provide food security for a population projected to rise to nine billion by mid-century, while protecting the environment and the sustainable functioning of ecosystems. This challenge is compounded by the need to adapt to climate change by taking advantage of potential benefits, and by minimizing the potentially negative impacts, to agricultural production. The goals of Agricultural Model Intercomparison and Improvement Project (AgMIP) are to improve substantially the characterization of world food security under climate change and to enhance adaptation capacity in both developing and developed countries (www.agmip.org). To accomplish these goals, AgMIP organizes protocol-based intercomparisons of crop and economic models and ensemble projections to produce enhanced climate change assessments by the crop and economic modeling communities. These assessments focus on research related to climate change agricultural impacts and adaptation (Rosenzweig et al., 2012). This chapter describes the AgMIP regional integrated assessment projects in Sub-Saharan Africa and South Asia..

Climate Change Impacts on West African Agriculture: An Integrated Regional Assessment (CIWARA)

The West African Sub-Saharan region (Fig. 1) is home to some 300 million people, with at least 60% engaged in agricultural activity. Climate change is now recognized as a major constraint to development worldwide. While climate change primarily relates to the future, historical trends give evidence of climate change already occurring. Temperature increases of 1 to 1.5◦C have been observed over the last 30 years in West Africa (EPA Ghana, 2001; IPCC, 2007) and there are projections of further warming of the West African region in the foreseeable future (2040–2069; Fig. 2a). The impact of climate change on West African rainfall is less clear. The analysis of historical data over the last 30 years shows that, whereas some zones experienced increased rainfall by as much as 20% to 40%, other locations experienced a decline in annual rainfall by about 15%. Future projections suggest a drier western Sahel (e.g., Senegal) but a wetter eastern Sahel (e.g., Mali, Niger; Fig. 2b). The southern locations of WestAfrica (e.g., Ghana) are projected to experience no change or slight increases in annual rainfall (Hulme et al., 2001). Irrespective of whether these zones will be dryer or not, there is historical evidence of shifts in rainfall patterns with extreme events (i.e., droughts and floods) becoming more frequent (Adiku and Stone, 1995) and it is probable that this trend may persist into the future..

Perceived stressors of climate vulnerability across scales in the Savannah zone of Ghana: a participatory approach

Smallholder farmers in sub-Saharan Africa are confronted with climatic and non-climatic stressors. Research attention has focused on climatic stressors, such as rainfall variability, with few empirical studies exploring non-climatic stressors and how these interact with climatic stressors at multiple scales to affect food security and livelihoods. This focus on climatic factors restricts understanding of the combinations of stressors that exacerbate the vulnerability of farming households and hampers the development of holistic climate change adaptation policies. This study addresses this particular research gap by adopting a multi-scale approach to understand how climatic and non-climatic stressors vary, and interact, across three spatial scales (household, community and district levels) to influence livelihood vulnerability of smallholder farming households in the Savannah zone of northern Ghana. This study across three case study villages utilises a series of participatory tools including semi-structured interviews, key informant interviews and focus group discussions. The incidence, importance, severity and overall risk indices for stressors are calculated at the household, community, and district levels. Results show that climatic and non-climatic stressors were perceived differently; yet, there were a number of common stressors including lack of money, high cost of farm inputs, erratic rainfall, cattle destruction of crops, limited access to markets and lack of agricultural equipment that crossed all scales. Results indicate that the gender of respondents influenced the perception and severity assessment of stressors on rural livelihoods at the community level. Findings suggest a mismatch between local and district level priorities that have implications for policy and development of agricultural and related livelihoods in rural communities. Ghana’s climate change adaptation policies need to take a more holistic approach that integrates both climatic and non-climatic factors to ensure policy coherence between national climate adaptation plans and District development plans