Response of grain legumes to phosphorus application in the guinea savanna agro-ecological zones of Ghana

Article purchased; Published online: 05 April 2018Grain legumes (cowpea, peanut, and soybean) play important roles in household food and income security in smallholder farming systems in the Guinea Savanna agro-ecological zones of Ghana. However, yields are low, rarely exceeding 600 kg ha−1, prompting the need to evaluate responses of grain legumes to P fertilizer applications for two seasons. Conducting P studies is critical to help farmers adopt economic-based recommendations. Treatments evaluated in 2015 for the three crops were (i) farmers’ practice (no input and planted by farmer); (ii) control (no input and planted by researcher), and (iii) triple super phosphate (TSP) fertilizer. However, for soybean, an additional two treatments (inoculant only and inoculant plus TSP fertilizer) were included. In 2016, the treatments were the same, except on-farm demonstrations were not conducted on cowpea. The demonstrations were laid out in a Randomized Complete Block Design with each demonstration representing a replicate within a region. On average, P-fertilizer application increased yields by 296; 527, and 390 kg ha−1 for cowpea, peanut, and soybean grains, respectively. On average over the two seasons, P-fertilizer increased yield by 9.85; 13.00, and 17.56 per kg ha−1 kg−1 P applied for cowpea, soybean, and peanut, respectively, and these applications were cost effective. Peanut showed little response to P in the Upper East Region compared with a greater response in the Northern and Upper West Regions, suggesting that benefits from P-fertilizer for peanut may be location-specific. On average, rhizobium inoculation increased grain yield by 157 kg ha−1 across the three regions and significantly positive effects of inoculation were observed in both seasons. Our results show that substantial increases in grain legume yield may be achieved by applying P fertilizers, but farmers cannot afford them because of their relatively high cost. Planting adapted and improved varieties and using rhizobium inoculants may provide the most economically viable and low risk options for increasing yields of grain legumes in the savanna agro-ecological zones of Ghan

CARIAA Working Paper no. 2

Includes abstract in FrenchAn optimal institutional framework for climate change adaptation is sometimes impeded by the nature of research, which focuses on a small number of contexts. This report synthesizes findings from a number of participatory action research (PAR) projects conducted as part of the Climate Change Adaptation in Africa (CCAA) program, for example: local informal institutions play a key role in enabling and/or constraining adaptation; coordination among and between institutions is essential; a well-coordinated institutional framework should take into account the three main chains of connection (horizontal coordination at the national level; horizontal coordination at the local level; and vertical coordination between national and local institutions)

Legume-maize rotation or relay? Options for ecological intensification of smallholder farms in the Guinea Savanna of northern Ghana

Article purchasedSoil nutrient constraints coupled with erratic rainfall have led to poor crop yields and occasionally to crop failure in sole cropping in the Guinea savanna of West Africa. We explored different maize-grain legume diversification and intensification options that can contribute to mitigating risks of crop failure, increase crop productivity under different soil fertility levels, while improving soil fertility due to biological N2-fixation by the legume. There were four relay patterns with cowpea sown first and maize sown at least 2 weeks after sowing (WAS) cowpea; two relay patterns with maize sown first and cowpea sown at least 3 WAS maize in different spatial arrangements. These were compared with groundnut-maize, soybean–maize, fallow-maize and continuous maize rotations in fields high, medium and poor in fertility at a site each in the southern (SGS) and northern (NGS) Guinea savanna of northern Ghana. Legumes grown in the poorly fertile fields relied more on N2-fixation for growth leading to generally larger net N inputs to the soil. Crop yields declined with decreasing soil fertility and were larger in the SGS than in the NGS due to more favourable rainfall and soil fertility. Spatial arrangements of relay intercrops did not have any significant impact on maize and legume grain yields. Sowing maize first followed by a cowpea relay resulted in 0.18–0.26 t ha−1 reduction in cowpea grain yield relative to cowpea sown from the onset. Relaying maize into cowpea led to a 0.29–0.64 t ha−1 reduction in maize grain yield relative to maize sown from the onset in the SGS. In the NGS, a decline of 0.66 and 0.82 t ha−1 in maize grain yield relative to maize sown from the onset was observed due to less rainfall received by the relay maize. Groundnut and soybean induced 0.38–1.01 t ha−1 more grain yield of a subsequent maize relative to continuous maize, and 1.17–1.71 t ha−1 more yield relative to relay maize across both sites. Accumulated crop yields over both years suggest that sowing maize first followed by cowpea relay is a promising ecological intensification option besides the more common legume–maize rotation in the Guinea savanna, as it was comparable with soybean–maize rotation and more productive than the other treatments

Soyabean response to rhizobium inoculation across sub-Saharan Africa: Patterns of variation and the role of promiscuity

Article purchased; Published online: 7 Sept 2017Improving bacterial nitrogen fixation in grain legumes is central to sustainable intensification of agriculture in sub-Saharan Africa. In the case of soyabean, two main approaches have been pursued: first, promiscuous varieties were developed to form effective symbiosis with locally abundant nitrogen fixing bacteria. Second, inoculation with elite bacterial strains is being promoted. Analyses of the success of these approaches in tropical smallholder systems are scarce. It is unclear how current promiscuous and non-promiscuous soyabean varieties perform in inoculated and uninoculated fields, and the extent of variation in inoculation response across regions and environmental conditions remains to be determined. We present an analysis of on-farm yields and inoculation responses across ten countries in Sub Saharan Africa, including both promiscuous and non-promiscuous varieties. By combining data from a core set of replicated on-farm trials with that from a large number of farmer-managed try-outs, we study the potential for inoculation to increase yields in both variety types and evaluate the magnitude and variability of response. Average yields were estimated to be 1343 and 1227 kg/ha with and without inoculation respectively. Inoculation response varied widely between trials and locations, with no clear spatial patterns at larger scales and without evidence that this variation could be explained by yield constraints or environmental conditions. On average, specific varieties had similar uninoculated yields, while responding more strongly to inoculation. Side-by side comparisons revealed that stronger responses were observed at sites where promiscuous varieties had superior uninoculated yields, suggesting the availability of compatible, effective bacteria as a yield limiting factor and as a determinant of the magnitude of inoculation response

Looking back and moving forward: 50 years of soil and soil fertility management research in sub-Saharan Africa

Article purchased; Published online: 02 Nov 2017Low and declining soil fertility has been recognized for a long time as a major impediment to intensifying agriculture in sub-Saharan Africa (SSA). Consequently, from the inception of international agricultural research, centres operating in SSA have had a research programme focusing on soil and soil fertility management, including the International Institute of Tropical Agriculture (IITA). The scope, content, and approaches of soil and soil fertility management research have changed over the past decades in response to lessons learnt and internal and external drivers and this paper uses IITA as a case study to document and analyse the consequences of strategic decisions taken on technology development, validation, and ultimately uptake by smallholder farmers in SSA. After an initial section describing the external environment within which soil and soil fertility management research is operating, various dimensions of this research area are covered: (i) ‘strategic research’, ‘Research for Development’, partnerships, and balancing acts, (ii) changing role of characterization due to the expansion in geographical scope and shift from soils to farms and livelihoods, (iii) technology development: changes in vision, content, and scale of intervention, (iv) technology validation and delivery to farming communities, and (v) impact and feedback to the technology development and validation process. Each of the above sections follows a chronological approach, covering the last five decades (from the late 1960s till today). The paper ends with a number of lessons learnt which could be considered for future initiatives aiming at developing and delivering improved soil and soil fertility management practices to smallholder farming communities in SSA

A new phosphorus fertilizer blend enhances grain legume yield and profitability in northern part of Ghana

Low concentrations of phosphorus limit grain legumes’ yield in the northern part of Ghana. Smallholder farmers could benefit from P-fertilizer blends to improve yield. This study evaluated the responses of soybean, cowpea and groundnut to P-fertilizer blends and their profitability in researcher-managed and farmer-managed trials in Northern, Upper West, and Upper East regions. The experiment was set up in a cross-factorial arranged in randomized complete block design with four replications. The treatments were two types of P-fertilizer blends (triple superphosphate and new yaraLegume applied at 30 kg P ha−1), a control and three varieties each of soybean (TGX 1835-10E, TGX 1789-8E and TGX 1834-5E), cowpea (Padituya, Wang-Kae and Kirkhouse), and groundnut (Samnut 23, Samnut 22 and Yenyawwaso). P-fertilizer blends increased grain yield of grain legumes in researcher-managed trials. In the researcher-managed trials, P-fertilizer blends doubled the nodulation of soybean varieties but did not influence the nodulation of cowpea and groundnut. P-fertilizer blends increased P-agronomic efficiency over control; however, the different P-fertilizer blends had similar P-use efficiencies. In farmer-managed trials, only the yield of groundnuts varied with the different P-fertilizer blends in the Upper West region, suggesting that P utilization may be location-specific for groundnuts. P-fertilizer blends increased the grain yield of soybean and cowpea varieties in the Northern and Upper West regions but not the Upper East region. The interaction between soybean and cowpea varieties and P-fertilizer blends was not significant. P-fertilizer blends recorded a higher value cost ratios (VCRs) that can offset uncertainties in price fluctuations. The high VCRs indicated that P-fertilizer blends were profitable and could be used to improve the livelihoods of smallholder grain legume farmers. The study demonstrated that grain legumes responded to P-fertilizer blends and are profitable. However, the non-responsive nature of the Upper East soils needs to be investigated to make P-fertilizer blends profitable in the region

Innovation platforms and institutional change: the case of small-scale palm oil processing in Ghana

Oil palm is an important industrial, livelihood and food crop in Ghana. Smallholders produce the bulk of the palm fruits and small-scale processors, mainly women, produce most of the crude palm oil. Poor practices lead to a high proportion of free fatty acids in the crude palm oil and the processors thus cannot access remunerative national and international markets. Exploratory and diagnostic studies identified the absence of rules and regulations governing processing as a major factor. An innovation platform was convened and facilitated to remove the identified institutional constraints. Based on event tracing, this paper reports a study of the effects of the innovation platform's interventions and how these were achieved. Institutional entrepreneurs are shown to play important roles: they mobilised resources such as expertise, knowledge, access to information and high-level political power to influence small-scale processors to adopt alternative practices. The institutional changes observed are shown to arise in cooperation between traditional authorities (chiefs), the district legislature and authorities at the national level, who together institutionalised the experimental actions and processes taken in the study area. The institutional elements they most affected were: rules and regulations, the legitimacy of new practices and organisational arrangements, co-generation of knowledge, material resources, and the strategic and communication skills of key actors

Intercropping and crop rotations in cassava cultivation: a production systems approach

Publication date: 31 July 201

Platforms for institutional change: assessing the potential of livelihood enhancement groups as community entry points in Zambia

Published online: 10 Aug 2017To address the livelihood problems faced by the poor and vulnerable in Northern Province of Zambia, a novel collective action approach called livelihoods enhancement groups (LEGs) was used as a platform for facilitating research on development initiatives to generate change. Using focus group discussions and key informant interviews, this article assesses the potential of using the LEGs approach in generating change. The livelihood changes observed arose with the LEG as a platform through which different knowledge nodes interacted. Livelihood areas that LEGs affected included crop production, livestock production, nutrition, and access to credit. Afin de discuter des problèmes de subsistance auxquels sont confrontées les personnes pauvres et vulnérables dans la Province Septentrionale de la Zambie, une nouvelle approche d'action collective appelée Livelihoods Enhancement Groups, ou LEGs, (Groupes d'amélioration des moyens de subsistance) a été utilisée en tant que plateforme de recherche sur des initiatives de développement visant à générer du changement. Basé sur des groupes de discussion thématique et des entretiens avec des informateurs clés, cet article évalue le potentiel de cette approche pour générer du changement. Les changements observés dans les moyens de substitution ont augmenté avec l'approche LEG en tant que plateforme d'interactions entre différents noyaux de connaissance. Les domaines de subsistance impactés incluent la production agricole, l'élevage du bétail, la nutrition et l'accès au crédit. Para abordar los problemas vinculados a los medios de vida enfrentados por la población empobrecida y vulnerable de la Provincia del Norte de Zambia, se impulsó un novedoso enfoque de acción colectiva llamado “grupos destinados al mejoramiento de los medios de vida” (leg por sus siglas en inglés); se trata de una plataforma encaminada a facilitar la investigación de aquellas iniciativas de desarrollo orientadas a generar cambios. A partir de discusiones realizadas en varios grupos de enfoque y de entrevistas con informantes clave, el presente artículo evalúa la posibilidad de usar el enfoque de leg para promover la generación de cambios. En este sentido, se constata que los cambios que tuvieron lugar en los medios de vida surgieron tras el uso de los leg como plataforma en la que interactuaron diversos nodos de información. Éstos incidieron en varias áreas vinculadas a los medios de vida, por ejemplo, la producción de cultivos, la cría de ganado, la nutrición y el acceso a créditos