Samuel Gameda

International Maize and Wheat Improvement Center | CIMMYT

Agronomic biofortification, encompassing the use of mineral and organic nutrient resources to improve micronutrient concentration in staple crops, is a potential strategy to promote production and access of micronutrient-dense foods at farm-level. However, the heterogeneity of smallholder farming landscapes presents challenges on implementing agron...

The dataset comprises primary data for the concentration of 29 mineral micronutrients in cereal grains and up to 84 soil chemistry properties from GeoNutrition project surveys in Ethiopia and Malawi. The work provided insights on geospatial variation in the micronutrient concentration in staple crops, and the potential influencing soil factors. In...

Abstract Dietary zinc (Zn) deficiency is widespread globally, and in particular among people in sub-Saharan Africa (SSA). In Malawi, dietary sources of Zn are dominated by maize and spatially dependent variation in grain Zn concentration, which will affect dietary Zn intake, has been reported at distances of up to ~ 100 km. The aim of this study wa...

Micronutrient deficiencies (MNDs) remain widespread among people in sub-Saharan Africa1–5, where access to sufficient food from plant and animal sources that is rich in micronutrients (vitamins and minerals) is limited due to socioeconomic and geographical reasons4–6. Here we report the micronutrient composition (calcium, iron, selenium and zinc) o...

Human zinc deficiency is a global public health problem. Many African soils are zinc deficient (ZnD), indicating fertilizers could increase crop yields and grain Zn levels, thereby increasing Zn in the food supply and alleviating human Zn deficiency. To analyze associations among soil Zn, human Zn deficiency, and child nutritional status, we combin...

Grain and soil were sampled across a large part of Amhara, Ethiopia in a study motivated by prior evidence of selenium (Se) deficiency in the Region's population. The grain samples (teff, Eragrostis tef, and wheat, Triticum aestivum) were analysed for concentration of Se and the soils were analysed for various properties, including Se concentration...

Zinc deficiency is a major public health problem in Ethiopia and other African countries, affecting nutrition and health outcomes particularly in young children and women of reproductive age, but some widely-used interventions such as food fortification can be less effective in reaching rural populations. Recent soil fertility mapping initiatives h...

Zinc is an essential element in human nutrition but is frequently found to be deficient in children’s diets. In Sub-­‐Saharan Africa (SSA), 50% of children under five are zinc deficient. Zinc deficiencies in children are known to result in significant stunting, wasting, being underweight, and compromising immune systems leading to illness. An in-­‐...

Land cover changes (LCCs) play an important role in the climate system. Research over recent decades highlights the impacts of these changes on atmospheric temperature, humidity, cloud cover, circulation, and precipitation. These impacts range from the local- and regional-scale to sub-continental and global-scale. It has been found that the impacts...

The Canadian agricultural sector is facing the impacts of climate change. Future scenarios of agroclimatic change provide information for assessing climate change impacts and developing adaptation strategies. The goal of this study was to derive and compare agroclimatic indices based on current and projected future climate scenarios and to discuss...

Agriculture is one of the activities with the highest degree of edaphoclimatic risk exposure in Ethiopia. The survival of 80The analysis showed that for most of the medium small farmers it is absolutely necessary the use of risk management tools to mitigate or prevent the consequences. A case that has been very interesting is the use of index insur...

This work is devoted to bridging the gap between large‐area, economically driven macromodels such as the Canadian Regional Agriculture Model (CRAM) and small‐area biophysically based process models used in environmental assessments through the development of a Land Use Allocation Model (LUAM). LUAM is designed to enable environmental assessments of...

It is theoretically interesting for climate change detection and practically important for agricultural producers to know whether climate change has influenced agroclimatic conditions and, if so, what the potential impacts are. We present analyses on statistical differences in means and variances of agroclimatic indices between three 30-year period...

Agriculture in Ethiopia is one of first priority since close to 10 In this context, the Ethiopian crop production faces to the following soil management challenges: lack of updated soil data, macro and micro nutrient depletion, acid-ity, salinity and soil surface erosion and crusting. One of the biggest issues is the loss of arable land, above 137...

Stochastic weather generators have been used in the development of climate scenarios which are input to agricultural simulation models that assess the climate impacts on crop growth and production. The synthetic data generated by a stochastic weather generator only mimic the observed weather data, thus discrepancies between the synthetic and the ob...

Trends in soil temperature are important, but rarely reported, indicators of climate change. On the basis of the soil temperature data from 30 climate stations across Canada during 1958–2008, trends in soil temperatures at 5, 10, 20, 50, 100, and 150 cm depths were analyzed, together with atmospheric variables, such as air temperature, precipitatio...

Stochastic weather generators have been used extensively in the development of climate scenarios, especially at the daily or shorter time scales, for the use as climate input to agricultural simulation models that evaluate the climate impacts on crop yields. Because generated synthetic weather data mimic the observed weather data, discrepancies bet...

Xu, H., De Jong, R., Gameda, S. and Qian, B. 2010. Development and evaluation of a Canadian agricultural ecodistrict climate database. Can. J. Soil Sci. 90: 373-385. Spatially representative climate data are required input in various agricultural and environmental modelling studies. An agricultural ecodistrict climate database for Canada was develo...

Stochastic weather generators are widely used for developing local climate scenarios from large-scale climate change scenarios simulated by GCMs. We used AAFC-WG, a stochastic weather generator developed at Agriculture and Agri-Food Canada (AAFC), to develop daily climate scenarios for the time period 2040-2069 for the agricultural regions of Canad...

Human activities have modified the environment for thousands of years. Significant population increase, migration, and accelerated socioeconomic activities have intensified these environmental changes over the last several centuries. The climate impacts of these changes have been found in local, regional, and global trends in modern atmospheric tem...

Under the threat of global warming it is important to determine the impact that future changes in climate may have on the environment and to what extent any adverse effects can be mitigated. In this study we assessed the impact that climate change scenarios may have on soil carbon stocks in Canada and examined the potential for agricultural managem...

Water use by spring wheat and soil water contents at meteorological stations on the Canadian prairies were simulated with the Versatile Soil Moisture Budget model for different crop growth stages. Six water-related agroclimatic indices at five growth stages (seeding-emergence, emergence-jointing, jointing-heading, heading-soft dough and soft dough-...

International initiatives such as the United Nations Framework Convention on Climate Change and the Kyoto Protocol require that countries conduct national inventories of their greenhouse gas emissions. The primary objective of the present study was to apply a country-specific (Tier II) methodology at the regional (~150 000 ha) scale to estimate dir...

Stochastic weather generators are widely used for generating synthetic weather data, and constitute one of the techniques for developing local climate scenarios from large-scale climate changes simulated by global climate models. Since climate change impact models may be more sensitive to changes in climate extremes than to changes in climate means...

The Canadian Prairies have undergone important land use changes over the past 150 years. Beginning in the early 20th century, a significant portion of agricultural land was under summerfallow primarily to conserve soil moisture. The area under fallow grew to over 11 Mha, which constitute about 25% of Canada's cultivated land, and mostly remained at...

Global warming associated with anthropogenic greenhouse gas emissions is of great concern due to its potential threat to ecological systems, including threats to agricultural production systems. In turn, land surface changes associated with agricultural practices may have an influence on local, regional and even global climate. Such effects may hav...

There is a need to know how well stochastic weather generators can produce daily climate scenarios for climate change impact studies. In this study, 2 stochastic weather generators (LARS-WG and AAFC-WG) were assessed, based on an experiment with historical daily climate data. The experiment was conducted for 3 stations in Canada, using 1911-1940 as...

In this paper, relationships between agroclimatic indices and average yields of grain corn (Zea mays L.), soybeans (Glycine max L. Merr.) and barley (Hordeum vulgare L.) in field trials conducted in eastern Canada are explored and then used to estimate potential impacts of climate change scenarios on anticipated average yields and total production...

Two weather generators-LARS-WG, developed at Long Ashton Research Station (UK), and AAFC-WG, developed at Agriculture and Agri-Food Canada-were compared in order to gauge their capabilities of reproducing probability distributions, means and variances of observed daily precipitation, maximum temperature and minimum temperature for diverse Canadian...

Accurate estimates of the impact of crop management practices on soil organic carbon (SOC) changes are most likely made using process-based models, such as CENTURY. However, quick, first approximations of SOC changes can be made if measurements of grain yield, grain-to-straw, and straw-to-root ratios are available, and if efficiencies of conversion...

Statistics on annual crop production for the Canadian prairies, Canada's largest agricultural region, were summarized by crop, soil zone, and province for the period 1976-1998. A brief discussion, demonstrating how these data can be used by agronomists and policy analysts to derive other information of interest to society (e.g., how much raw materi...

Efforts are underway at Agriculture and Agri-Food Canada (AAFC) to develop an integrated, nationally applicable, socioeconomic/biophysical modeling capability in order to predict the environmental impacts of policy and program scenarios. This paper outlines our Decision Support System (DSS), which integrates the IROWCN (Indicator of the Risk of Wat...

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In 1990, primary agriculture contributed 10% of the anthropogenic greenhouse gas emissions in Canada while the whole agriculture and agri-food sector contributed 15%. By 2010, greenhouse gas emissions from primary agriculture are expected to have increased by about 8 Tg CO 2 equivalent. In order to examine the potential of this sector to reduce its...

A large number and variety of indicator programs are currently being developed or are in place. In most cases these programs are aimed at evaluating sustainability, environmental impact(s), or land management in agriculture, forestry, and conservation. Literature on indicators is rapidly increasing, and it is often difficult and time-consuming to i...

Local knowledge as obtained from questionnaires and interviews were valuable for addressing gaps in information requirements for sustainability assessment. The role of indicators, identified by agricultural producers in conducting FESLM-based sustainability assessments, are discussed. Preliminary indications are that producer decision-making charac...

In a previous study, we investigated the effect of additions of 10, 15, and 20% water (on a weight basis) to snow at an initial temperature of −11°C on the energy required for compaction. Water-addition of 10% significantly reduced the amount of energy required to compact snow. Here, we describe the compressive characteristics of snow at water-addi...

The Framework for Evaluation of Sustainable Land Management (FESLM) was used to assess the sustainability of two land-use systems in the Canadian Prairies. The FESLM provided a means of identifying the factors impacting on sustainability, the processes by which these factors operate and interact, and the indicators and thresholds by which they coul...

The long-term effects of a single incidence of compactive loads of 12 and 20 Mg per axle on a clay soil are evaluated. Changes in soil bulk density and crop performance under monocultural row production were monitored over the 7 year period following loading. Soil bulk densities were significantly increased by the initial high axle load compaction....

The effect of annual compactive loads of 10 and 18 Mg per axle on soil structure and crop yields were compared with effects of loads limited to 5 Mg per axle. Chemical conditioning and subsoiling were also applied to determine their alleviating effects. Significant topsoil and subsoil compaction resulted from both loading levels. Maximum dry bulk d...

Soil profile characteristics were determined in plots subjected to annual compaction, subsoiling and chemical conditioning. Treatments significantly affected profile characteristics. Ped size, ped type and rooting depth exhibited the greatest differences after treatment. Soil structure in compacted plots consisted of medium- to coarse-sized, angula...

There is an abundant supply of snow in cold countries for nearly half of the year. Apart from recreational purposes, very little use is made of it. However, it can provide an opportunity for novel use in pre-cooling, refrigeration and air-conditioning. The main drawback to using snow is its low density. Efficient compaction methods can greatly impr...

Detailed soil profile descriptions were made to assess the residual effect of compaction and tillage treatments applied 10 yr ago on a Ste-Rosalie clay. The treatments applied consisted of five passes at a contact pressure of 61.8 kPa with no tillage, 15 passes of 61.8 kPa with chiselling, moldboard plowing, no tillage, subsoiling, and a control. T...

A 3-year study on the effect of annual compaction by heavy axle loads was conducted in a loam soil. Each year, loads of 10 and 20 t/axle were applied at two soil moisture contents. The resulting changes in soil bulk density to a depth of 0. 6 m and crop response were monitored during each growing season. The loam soil was able to sustain cumulative...

A 3-year investigation was carried out on the effect of annual compaction by 10- and 20-t axle−1 loads applied at 2 soil moisture contents on bulk densities and on corn (Zea mays L.) yields in a clay soil. Maximum bulk densities, and the depth at which they occurred, increased with each annual loading. Only the 20-t axle−1 loading increased soil de...

The recovery of clay soil from a single incidence of heavy axle load compaction was investigated. Loads of 10 and 20 t axle−1 were applied before and after a rainfall event in May, 1982. Grain corn (Zea mays L.) was then grown for three consecutive seasons and changes in bulk density to a depth of 0.6 m and crop yields were monitored. Differences b...

Studies were carried out to determine the natural alleviation of compaction induced by heavy axle loads in a loam soil. 10 and 20 t/axle were applied at two soil moisture contents in May, 1982, following which soil density changes and crop growth and yields were monitored for three growing seasons. Initial soil density changes were minimal due to a...

Field calibration of a single and dual probe gamma ray density gauge was carried out in three soil textures. Relationships were established between gauge determined dry densities and core determined values. In all soils tested, the dual probe correlated better with core measurements than did the single probe gauge. Differences between core sampled...

An experiment was set up to study the effect of high axle loads on subsoil compaction and corn production in two soil textures. Treatments of 10 and 20 t/axle were applied at two soil moisture contents. Resulting changes in soil physical characteristics as compared to a control were measured to a depth of 0.60 m. Topsoil and subsoil dry density lev...

The deposition of iron ochre in drains and around outlets has been associated with the continual reduction in the efficacity of an experimental drainage system. Ochre formation was primarily due to the action of the microorganism Gallionella and Sphaerotilus. The highest amount of ochre deposition took place at groundwater temperatures between 10 a...