Alpha Yaya Kamara

Alpha Yaya Kamara
Consultative Group on International Agricultural Research | CGIAR

B.Sc, M.Sc, PhD

About

200
Publications
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Publications

Publications (200)
Preprint
AimsImproper nutrient management reduces yield and affects the nutrient status of crops. This study aimed at diagnosing nutrient limitation in maize.MethodsA three-year multi-location (348 sites) nutrient experiments were conducted in randomized blocked design to analyse nutrient limitations for maize production under conventional fertilizer recomm...
Article
Full-text available
Absence of site-specific nutrient recommendation and high spatial variability of soil fertility are major factors affecting maize response to applied nutrients in Nigeria. In this study, we assessed maize response to applied nutrients and nutrient use efficiency in different management zones, for designing site-specific nutrient management recommen...
Article
Full-text available
Spatially explicit information on soil variability is relevant for agronomic decisions; however, such information is limited in the northern Guinea savanna (NGS) agroecological zone of Nigeria. This study was conducted to delineate soil nutrient management zones (MZs), based on spatial variability of soils in the smallholder maize-based farming sys...
Article
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Soybean production is limited by poor soil fertility and unstable rainfall due to climate variability in the Nigeria savannas. There is a decline in the amount and duration of rainfall as one moves from the south to north of the savanna zones. The use of adapted soybean varieties and optimum sowing windows are avenues to increase productivity in th...
Chapter
The agricultural landscape in Sub-Sahara Africa is dominated by smallholders and characterized by high heterogeneity due to high variation in soil, crop varieties, and land management practices. As a consequence, crop yields vary considerably in space and time. This study aimed at developing a production domain for different maize varieties in nort...
Chapter
The Decision Support Systems for Agro‐Technological Transfer (DSSAT) was calibrated, evaluated for three maturity duration maize ( Zea mays L.) varieties, and used to provide decision support for maize production in northern Ghana. Multi location N fertilizer trials were conducted in northern Ghana for three different maturity duration maize variet...
Article
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Selection of appropriate sowing density is an important yield enhancing management decision in maize (Zea mays L.) production particularly in rainfed conditions. This study aimed at evaluating the optimum stand densities (OSDs) of 10 recently released maize varieties under different crop management decisions and environments. Ten maize varieties of...
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Knowledge of the genetic structure and diversity of germplasm collections is crucial for sustainable genetic improvement through hybridization programs and rapid adaptation to changing breeding objectives. The objective of this study was to determine the genetic diversity and population structure of 281 International Institute of Tropical Agricultu...
Article
The study was conducted to compare two main sources of cowpea seed, Community Based Seed Producers (CBSP) and Licensed Seed Producers (LSP) for physical purity indices. From each seed source in every state, 15 seed samples of between 2 to 3 kg were collected for seed quality analysis. The collected seed samples were bulked according to variety, sta...
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Field studies were conducted to assess the adaptability of Provitamin-A rich maize hybrids across farmer locations in Sudan (SS), Northern Guinea (NGS) and Southern Guinea Savannas (SGS). Six intermediate maturing maize hybrids, one Improved and one Local Check were laid out in a randomized complete block design and the treatments replicated 4 time...
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Low nutrient use efficiency in maize as a result of imbalanced nutrition has been reported to drastically reduce yield. We implemented a nutrient omission experiment to assess the effect of nutrient application on maize yield and nutritional balance. Maize ear leaves were analyzed for nutrients, to identify nutrient balance status using the Diagnos...
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The Decision Support System for Agricultural Technology Transfer (DSSAT) was used to quantify the impact of climate change on maize yield and the potential benefits of the use of drought-tolerant maize variety over non-drought tolerant variety in savanna ecological zones of Nigeria. Projections of maize yields were estimated for three locations rep...
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The Agricultural Production Systems Simulator (APSIM) model was calibrated and validated and used to identify the optimum planting windows for two contrasting maize varieties for three agro-ecologies in the Nigeria savannas. The model was run for 11 planting windows starting from June 1 and repeated every 7 days until 16 August using long-term hist...
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In this study, the CERES-Maize model was calibrated and evaluated using data from 60 farmers’ fields across Sudan (SS) and Northern Guinea (NGS) Savannas of Nigeria in 2016 and 2017 rainy seasons. The trials consisted of 10 maize varieties sown at three different sowing densities (2.6, 5.3, and 6.6 plants m ⁻² ) across farmers’ field with contrasti...
Chapter
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Limited access to and low use of quality seed of improved varieties rank among the topmost causes of persistently low cowpea yields in Nigeria. This paper presents experiences under the Tropical Legume III (TL III) project in facilitating the access of smallholder farmers to seeds of improved cowpea varieties through the establishment of innovation...
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This paper assessed the application of the Agricultural Production Systems sIMulator (APSIM)–maize module as a decision support tool for optimizing nitrogen application to determine yield and net return of maize production under current agricultural practices in the Nigeria savannas. The model was calibrated for two maize varieties using data from...
Article
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The rapid assessment of maize yields in a smallholder farming system is important for understanding its spatial and temporal variability and for timely agronomic decision-support. We assessed the predictability of maize grain yield using unmanned aerial/air vehicle (UAV)-derived vegetation indices (VI) with (out) biophysical variables on smallholde...
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Site-specific nutrient management can reduce soil degradation and crop production risks related to undesirable timing, amount, and type of fertilizer application. This study was conducted to understand the spatial variability of soil properties and delineate spatially homogenous nutrient management zones (MZs) in the maize belt region of Nigeria. S...
Article
Striga hermonthica infestation causes significant losses of maize yield in the Nigerian savannas and several technologies have been developed and promoted to control Striga in maize. However, since no single technology has been found to be effective against Striga, integrated management is needed to achieve satisfactory and sustainable Striga contr...
Preprint
Full-text available
Rapid assessment of maize yields in smallholder farming system is important to understand its spatial and temporal variability and for timely agronomic decision-support. Imageries acquired with unmanned air vehicles (UAV) offer opportunity to assess agronomic variables at field scale, however, it is not clear if this can be translated into reliable...
Article
Full-text available
Establishing balanced nutrient requirements for maize (Zea mays L.) in the Northern Nigerian Savanna is paramount to develop site-specific fertilizer recommendations to increase maize yield, profits of farmers and avoid negative environmental impacts of fertilizer use. The model QUEFTS (QUantitative Evaluation of Fertility of Tropical Soils) was us...
Article
Full-text available
An experiment was conducted to examine the performance of pearl millet under different nitrogen (N) fertilizer rates in two locations in the semiarid zone of Nigeria. The objective was to evaluate the effects of different N rates on pearl millet yields, water- and nitrogen-use efficiency, and profitability. Grain yield increased by 23, 26, 32, 32,...
Article
Full-text available
Striga hermonthica infestation causes significant losses of maize yield in the Nigerian savannas and several technologies have been developed and promoted to control Striga in maize. However, since no single technology has been found to be effective against Striga, integrated management is needed to achieve satisfactory and sustainable Striga contr...
Preprint
Full-text available
Low soil nitrogen status of savanna soils in Nigeria contributes to the persistent Striga hermonthica (Del.) Benth. infestation that limits maize production. The application of nitrogen fertilizer to Striga-resistant hybrids may reduce Striga infection and increase grain yields. This study assessed the performance of maize hybrids at low (30 kg ha-...
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When properly calibrated and evaluated, dynamic crop simulation models can provide insights into the different components of genotype by environment interactions (GEIs). Modelled outputs could be used to complement data from multi-environment trials. Field experiments were conducted in the rainy and dry seasons of 2015 and 2016 across four location...
Book
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The Guide to Cowpea Production in West Africa is intended to guide farmers, extension personnel, students of agriculture in higher institutions, and researchers in Nigeria, Mali, Burkina Faso, Niger, Ghana, and other countries in West Africa to use improved varieties and complementary production practices to increase productivity
Book
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Importance of soybean in the global economy Soybean is among the major industrial and food crops grown in every continent. The crop can be successfully grown in many States in Nigeria using low agricultural input and cultivation has expanded as a result of its nutritive and economic importance and diverse domestic uses. It is also a prime source of...
Book
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Production and importance of maize in Nigeria Maize is a major cereal and one of the most important food crops in Nigeria. Its genetic plasticity has made it the most widely cultivated crop in the country from the wet evergreen climate of the forest zone to the dry ecology of the Sudan savanna. Being photoperiod insensitive, it can be grown any tim...
Book
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The importance of cowpea Cowpea (Vigna unguiculata L. Walp.) is an important grain legume, a major staple food crop for household nutrition in sub-Saharan Africa, especially in the dry savanna regions of Nigeria. It plays an important role in human nutrition, food security, and income generation for both farmers and food vendors in the region. The...
Book
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Rice is one of the major staple foods in Nigeria, consumed across all geopolitical zones and socioeconomic classes. Rice consumption is increasing rapidly in Nigeria because of the shift in consumer preference towards rice, increasing population growth, increased income levels, and rapid urbanization. It is commonly boiled and eaten with stew or ve...
Article
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Several maize (Zea mays L.) hybrids have been developed and commercialized in the Nigeria savannas, but limited informationis available on how they perform at plant densities higher than the recommended density of 53,333 plants ha-1. Therefore, field trials were conducted in northern Nigeria in 2015 and 2016 at two locations with contrasting rainfa...
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Growing drought tolerant maize at adequate N rate is a good trend in maize production to mitigate the effect of climate change in Rainforest agro-ecology of Nigeria. This study evaluated the performance of two extra-early maturing maize cultivars (2004 TZEE-W STR, 2009 TZEE-W STR) and two early maturing maize cultivars (2004 TZE-W POP DT STR C4, EV...
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The Crop Environment Resource Synthesis (CERES)-Maize model in Decision Support System for Agricultural Technology Transfer (DSSAT) was calibrated and evaluated with experimental data for simulation of response of two intermediate-maturing maize varieties to different sowing dates in the Nigerian savannas. The calibration experiments involved 14 co...
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Leaf area index (LAI) plays an important role in radiation capture, crop growth and yield formation. However, there is limited quantitative data on the influence of poultry manure (PM) and NPK fertilizer rate (NPK) on LAI, as estimated directly. Using a split-plot design with three replications, a field experiment was conducted to determine the eff...
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In sub-Saharan Africa, there is considerable spatial and temporal variability in relations between nutrient application and crop yield, due to varying inherent soil nutrients supply, soil moisture, crop management and germplasm. This variability affects fertilizer use efficiency and crop productivity. Therefore, development of decision systems that...
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Use of small doses of imazapyr and pyrithiobac for seed coatings of imazapyr-resistant maize hybrids (IR-Maize) offers an effective means to control Striga hermonthica. Field trials were conducted in Bauchi and Kano States of Nigeria in 2014 and 2015 under heavy Striga infestation to evaluate the potential effectiveness of herbicide coated hybrids...
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Background and Objective: In order to address the inadequacy of the current blanket fertilizer recommendation in the Guinea Savanna of Nigeria, the effect of other nutrients in addition to N, P and K in limiting maize productivity must be assessed. This study aimed to quantify the effects of the addition of secondary macronutrients and micronutrien...
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The Agricultural Production Systems simulator (APSIM) model was calibrated and evaluated using two improved sorghum varieties conducted in an experiment designed in a randomized complete block, 2014–2016 at two research stations in Nigeria. The results show that the model replicated the observed yield accounting for yield differences and variations...
Article
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Drought, infestation of cereal crops by the parasitic weed Striga hermonthica , and poor soil fertility are the major constraints to maize production by smallholder farmers in the Sudan savannas of northern Nigeria. Four innovation platforms (IPs) were therefore established in 2008 in the Sudan savanna (SS) agroecological zone of northern Nigeria t...
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There are several hurdles to ensure sustainable seed production and consistent flow of improved legume varieties in sub‐Saharan Africa (SSA) and South Asia (SA). The unreliable demand, autogamous nature of most of the grain legumes, and slow variety replacement rate by smallholder farmers do not provide strong incentive for private seed companies t...
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Full-text available
Cercospora leaf spot (CLS) caused by Pseudocercospora cruenta (Sacc.) is an important disease affecting cowpea production in Nigeria. Understanding the genetic nature of CLS is an important step in developing an effective breeding strategy. This study investigated the inheritance of CLS disease in cowpea under natural epiphytotic field condition in...
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This study undertakes an ex‐ante evaluation of the effects of alternative technology and policy options on soybean supply and demand in sub‐Saharan Africa (SSA) to 2050. Current soybean consumption in SSA is dominated by cooking oil followed by soybean cake used as animal feed. Due to weak processing sectors and low soybean yields, the region is cu...
Preprint
Full-text available
Establishing balanced nutrient requirements for maize (Zea mays L.) in the Northern Nigerian Savanna is paramount to develop site-specific fertilizer recommendations to increase maize yield, profits of farmers and avoid negative environmental impacts of fertilizer use. The model QUEFTS (QUantitative Evaluation of Fertility of Tropical Soils) was us...
Article
Full-text available
A field experiment was conducted during 2014 and 2016 rainy season at Tudun Wada, Kano and Shika, Zaria in the Northern Guinea Savanna of Nigeria in order to study the physiological responses of maize hybrids under low nitrogen. The experiment consisted of two nitrogen levels 0 and 120 N kg ha ⁻¹ as main plot and 8 drought-tolerant maize hybrids an...
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Most crop simulation models require the use of Genotype Specific Parameters (GSPs) which provide the Genotype component of G×E×M interactions. Estimation of GSPs is the most difficult aspect of most modelling exercises because it requires expensive and time-consuming field experiments. GSPs could also be estimated using multi-year and multi locatio...
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Formal public sector soybean breeding in Africa spans over four decades, and it was initiated by the International Institute of Tropical Agricultural (IITA). As the demand of soybean continues to outstrip production, strategic projects such the Tropical Legume (TL) were initiated, in which the main goal was to enhance the productivity of soybean in...
Article
Full-text available
Low planting densities and use of unimproved varieties contribute to the low yields of pearl millet (Pennisetum glaucum L.) in Nigeria. Field experiments were conducted during the 2013 and 2014 growing seasons, to evaluate the response of pearl millet varieties to varying plant hill population in semi-arid environments of Nigeria. Year, variety and...
Article
Full-text available
Performance under sub-optimal nitrogen (N) conditions, of early maturing maize cultivars bred for tolerance to drought and Striga parasitism in the Nigerian savanna is not known. This study evaluated the tolerance of selected early maturing drought and Striga-tolerant maize cultivars to low N conditions in Northern Nigeria. The cultivars were evalu...
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In order to ensure sustainability of maize production in short-season environments of Nigeria, the Sudan savanna taskforce of Kano–Katsina–Maradi (KKM) Pilot Learning Site promoted short-season maize varieties in 2008 via Innovation Platforms (IPs). In the light of the promoted varieties, we evaluated the adoption and net benefits (productivity and...
Preprint
Full-text available
To close the nutrient-related yield gaps in maize, balanced nutrition using primary and secondary macronutrients as well as micronutrients is recommended. Multi-nutrient diagnostic field trials were conducted in Guinea Savanna of Nigeria to assess the interactive effects of macronutrients and micronutrients on maize grain yields, nutrient uptake as...