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Articles 211 - 240 of 443

Full-Text Articles in Agricultural Science

Cowpea (Vigna Unguiculata L. Walp) Hosts Several Widespread Bradyrhizobial Root Nodule Symbionts Across Contrasting Agro-Ecological Production Areas In Kenya, Samuel Mathu Ndungu, Monika M. Messmer, Dominik Ziegler, Hannes A. Gamper, Éva Mészáros, Moses Thuita, Bernard Vanlauwe, Emmanuel Frossard, Cécile Thonar Jul 2018

Cowpea (Vigna Unguiculata L. Walp) Hosts Several Widespread Bradyrhizobial Root Nodule Symbionts Across Contrasting Agro-Ecological Production Areas In Kenya, Samuel Mathu Ndungu, Monika M. Messmer, Dominik Ziegler, Hannes A. Gamper, Éva Mészáros, Moses Thuita, Bernard Vanlauwe, Emmanuel Frossard, Cécile Thonar

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Cowpea (Vigna unguiculata L. Walp.) is an important African food legume suitable for dry regions. It is the main legume in two contrasting agro-ecological regions of Kenya as an important component of crop rotations because of its relative tolerance to unpredictable drought events. This study was carried out in an effort to establish a collection of bacterial root nodule symbionts and determine their relationship to physicochemical soil parameters as well as any geographical distributional patterns. Bradyrhizobium spp. were found to be widespread in this study and several different types could be identified at each site. Unique but rare symbionts were …

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Integrated Soil Fertility Management Sequences For Reducing Climate Risk In Smallholder Crop Production Systems In Southern Africa, Hatirarami Nezomba, Florence Mtambanengwe, Jairos Rurinda, Paul Mapfumo Jul 2018

Integrated Soil Fertility Management Sequences For Reducing Climate Risk In Smallholder Crop Production Systems In Southern Africa, Hatirarami Nezomba, Florence Mtambanengwe, Jairos Rurinda, Paul Mapfumo

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Climate change, increased climate variability and poor soil fertility are major bio-physical constraints to cropping on smallholder farms in southern Africa. We used the Agricultural Production Systems sIMulator (APSIM) to assess maize yield response to integrated soil fertility management (ISFM) rotational sequences of low-quality organic resources, nitrogen-fixing green manure and grain legumes, and mineral fertilizers under baseline (1960–2005) and projected (2040–2069) climates. APSIM was also employed to evaluate the response of maize yield to the ISFM sequences under a combination of a changing climate, and typical sowing dates and mineral fertilizer application rates for smallholder households of varying resource endowment. …

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Sustainable Intensification Through Rotations With Grain Legumes In Sub-Saharan Africa: A Review, A. C. Franke, G. J. Van Den Brand, B. Vanlauwe, K. E. Giller Jul 2018

Sustainable Intensification Through Rotations With Grain Legumes In Sub-Saharan Africa: A Review, A. C. Franke, G. J. Van Den Brand, B. Vanlauwe, K. E. Giller

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We conducted a systematic review of literature on the residual effects of grain legumes in cereal-based systems of sub-Saharan Africa (SSA) to quantify the magnitude and variability of rotational effects, to explore the importance of environmental and management factors in determining variability and to evaluate the evidence of the different mechanisms that explain rotational effects. We retrieved 44 unique publications providing 199 observations comparing continuous cereal performance with that of a grain legume-cereal rotation. The overall mean yield increase of 0.49 t grain ha−1, equal to an increase of 41% of the continuous cereal yield, is highly significant, but the …

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Women’S Empowerment In Agriculture And Agricultural Productivity: Evidence From Rural Maize Farmer Households In Western Kenya, Gracious M. Diiro, Greg Seymour, Menale Kassie, Geoffrey Muricho, Beatrice Wambui Muriithi May 2018

Women’S Empowerment In Agriculture And Agricultural Productivity: Evidence From Rural Maize Farmer Households In Western Kenya, Gracious M. Diiro, Greg Seymour, Menale Kassie, Geoffrey Muricho, Beatrice Wambui Muriithi

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This paper documents a positive relationship between maize productivity in western Kenya and women’s empowerment in agriculture, measured using indicators derived from the abbreviated version of the Women’s Empowerment in Agriculture Index. Applying a cross-sectional instrumental-variable regression method to a data set of 707 maize farm households from western Kenya, we find that women’s empowerment in agriculture significantly increases maize productivity. Although all indicators of women’s empowerment significantly increase productivity, there is no significant association between the women’s workload (amount of time spent working) and maize productivity. Furthermore, the results show heter-ogenous effects with respect to women’s empowerment on maize …

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Effect Of Trichoderma Spp. And Purpureocillium Lilacinum On Meloidogyne Javanica In Commercial Pineapple Production In Kenya, Agnes W. Kiriga, Solveig Haukeland, George M. Kariuki, Danny L. Coyne, Nikolai V. Beek Apr 2018

Effect Of Trichoderma Spp. And Purpureocillium Lilacinum On Meloidogyne Javanica In Commercial Pineapple Production In Kenya, Agnes W. Kiriga, Solveig Haukeland, George M. Kariuki, Danny L. Coyne, Nikolai V. Beek

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Plant-parasitic nematodes, in particular Meloidogyne species, cause significant yield reduction in commercial pineapple, Ananas comosus, worldwide. The efficacy of three Trichoderma isolates (Trichoderma asperellum M2RT4, T. atroviride F5S21, Trichoderma sp. MK4) and two isolates of Purpureocillium lilacinum (KLF2 and MR2) were evaluated against Meloidogyne javanica, using rooted pineapple crowns in a pot experiment under greenhouse conditions. All the three Trichoderma isolates successfully colonized pineapple root endophytically. The application of two isolates of Trichoderma (T. asperellum M2RT4 and Trichoderma sp. MK4) and the two isolates of P. lilacinum significantly reduced nematode egg and egg mass production reducing root galling damage by …

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A Climate-Adapted Push-Pull System Effectively Controls Fall Armyworm, Spodoptera Frugiperda (J E Smith), In Maize In East Africa, Charles A.O. Midega, Jimmy O. Pittchar, John A. Pickett, Girma W. Hailu, Zeyaur R. Khan Mar 2018

A Climate-Adapted Push-Pull System Effectively Controls Fall Armyworm, Spodoptera Frugiperda (J E Smith), In Maize In East Africa, Charles A.O. Midega, Jimmy O. Pittchar, John A. Pickett, Girma W. Hailu, Zeyaur R. Khan

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Fall armyworm, Spodoptera frugiperda (J E Smith), an economically important pest native to tropical and sub-tropical America has recently invaded Africa, causing substantial damage to maize and other crops. We evaluated functionality of a companion cropping system, ‘climate-adapted push-pull’, developed for control of cereal stemborers in drier agro-ecologies, as an added tool for the management of fall armyworm. The technology comprises intercropping maize with drought-tolerant greenleaf desmodium, Desmodium intortum (Mill.) Urb., and planting Brachiaria cv Mulato II as a border crop around this intercrop. Protection to maize is provided by semiochemicals that are emitted by the intercrop that repel (push) …

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Reducing Losses But Failing To Sequester Carbon In Soils – The Case Of Conservation Agriculture And Integrated Soil Fertility Management In The Humid Tropical Agro-Ecosystem Of Western Kenya, Rolf Sommer, Birthe Katharina Paul, John Mukalama, Job Kihara Feb 2018

Reducing Losses But Failing To Sequester Carbon In Soils – The Case Of Conservation Agriculture And Integrated Soil Fertility Management In The Humid Tropical Agro-Ecosystem Of Western Kenya, Rolf Sommer, Birthe Katharina Paul, John Mukalama, Job Kihara

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Agriculture is a global contributor to greenhouse gas emissions, causing climate change. Soil organic carbon (SOC) sequestration is seen as a pathway to climate change mitigation. But, long-term data on the actual contribution of tropical soils to SOC sequestration are largely absent. To contribute to filling this knowledge gap, we measured SOC in the top 15 cm over 12 years in two agronomic long-term trials in Western Kenya. These trials include various levels – from absence to full adoption – of two widely promoted sustainable agricultural management practices: Integrated Soil Fertility Management (ISFM; i.e. improved varieties, mineral fertilizer and organic …

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Impact Of Improved Maize Adoption On Household Food Security Of Maize Producing Smallholder Farmers In Ethiopia, Moti Jaleta, Menale Kassie, Paswel Marenya, Chilot Yirga, Olaf Erenstein Feb 2018

Impact Of Improved Maize Adoption On Household Food Security Of Maize Producing Smallholder Farmers In Ethiopia, Moti Jaleta, Menale Kassie, Paswel Marenya, Chilot Yirga, Olaf Erenstein

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In recent years, maize has gained prominence as an important staple crop in Ethiopia second only to teff in terms of acreage. Most of this is grown by semi-subsistence farm households whose livelihoods are tied to crop production and some livestock keeping. Therefore, an important policy question concerns the impact that the reported maize revolution has had on household food security. This paper answers that question by examining the empirical regularities that explain the adoption of improved maize varieties (IMVs) and how this has impacted household food security in a sample of 2327 maize producing households in 39 districts of …

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Lepidopteran Stem Borer Species Abundance And Associated Damages On Irrigated Kilombero Low Land Rice Ecosystem In Tanzania, Bonaventure January, Gration M. Rwegasira, Tadele Tefera Jan 2018

Lepidopteran Stem Borer Species Abundance And Associated Damages On Irrigated Kilombero Low Land Rice Ecosystem In Tanzania, Bonaventure January, Gration M. Rwegasira, Tadele Tefera

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Background: Rice stem borers are among the most biotic stresses of economic importance in agriculture. Little was known about stem borer problem in Tanzania prior to this study. Understanding stem borer abundance and damages would help to design appropriate stem borer integrated pest management strategy in rice. This study was aimed at investigating rice stem borer’s species abundance and their associated damages in irrigated lowland rice ecosystem in Kilombero Tanzania. Materials and Methods: Field survey study on rice stem borer abundance and incidences were conducted in farmer’s fields on selected rice varieties at varied growth stages in Kilombero district under …

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An Assessment Of Effectiveness Of Participatory Video And Drama In Enhancing Learning Of “Climate-Smart” Push-Pull Technology: A Case Study Of Butere And Vihiga Farmers In Western Kenya, Wakesho George, Pittchar Jimmy, Midega Charles, Khan Zeyaur Jan 2018

An Assessment Of Effectiveness Of Participatory Video And Drama In Enhancing Learning Of “Climate-Smart” Push-Pull Technology: A Case Study Of Butere And Vihiga Farmers In Western Kenya, Wakesho George, Pittchar Jimmy, Midega Charles, Khan Zeyaur

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This study assessed the effectiveness of participatory video and drama in enhancing learning of climate-smart pushpull technology in western Kenya. A total of 80 farmers who had no knowledge of push pull technology were exposed to participatory drama and video that had been developed by farmers who are adopting push pull technology. Validated questionnaires were used for data collection where sampled non push pull farmers were interviewed before and after exposure to push pull knowledge using participatory video and drama. Data obtained was analyzed using chi square at 0.05 confidence level set a priori and also presented using frequency tables, …

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Farmers’ Perception And Control Practices Against The Invasive Red Spider Mite (Tetranychus Evansi Baker & Pritchard) In Benin, G. Y. Azandémè-Hounmalon, H. D. Affognon, F. Assogba-Komlan, M. Tamò, K. K.M. Fiaboe, S. Kreiter, T. Martin Jan 2018

Farmers’ Perception And Control Practices Against The Invasive Red Spider Mite (Tetranychus Evansi Baker & Pritchard) In Benin, G. Y. Azandémè-Hounmalon, H. D. Affognon, F. Assogba-Komlan, M. Tamò, K. K.M. Fiaboe, S. Kreiter, T. Martin

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Tetranychus evansi (Acari: Tetranychidae), is an important pest of solanaceous plants in Benin where it damages tomato (Solanum lycopersicum L.; Solanaceae), African eggplant (S. macrocarpon L.; Solanaceae), purple amaranth (Amaranthus cruentus L.; Amaranthaceae). The objective of the present study was to evaluate the intensity of T. evansi damage and impact of farmers’ control practices in Benin. Two surveys were conducted between 2013 and 2016. The first survey revealed Tetranychus evansi as the only mite, causing production losses of 65% for African eggplant, 56% for tomato and 25% for purple amaranth. To protect the infested crops, growers sprayed various synthetic pesticides …

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Push-Pull Farming System Controls Fall Armyworm: Lessons From Africa, Zeyaur R. Khan, Jimmy O. Pittchar, Charles A.O. Midega, John A. Pickett Jan 2018

Push-Pull Farming System Controls Fall Armyworm: Lessons From Africa, Zeyaur R. Khan, Jimmy O. Pittchar, Charles A.O. Midega, John A. Pickett

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Fall armyworm (FAW) Spodoptera frugiperda invaded Africa, with the first detections being reported in Central and Western Africa in early 2016, and now affects at least 40 countries in Africa, causing up to total crop loss amounting to over $6.2 billion p.a. FAW is an invasive polyphagous pest that causes damage to economically important crops and has recently been reported in the Indian sub-continent. Effective control of FAW through use of synthetic chemical pesticides and genetically modified crops such as Bt maize faces challenges including improper use, unaffordability by smallholder farmers and development of resistance by the pest. Additionally, dispersal …

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Relationship Between New Farming Practices And Chemical Use And The Consumption Of Giant Cricket (Brachytrupes Membranaceus Drury, 1770), F. O. Miantsia, F. Meutchieye, S. Niassy Jan 2018

Relationship Between New Farming Practices And Chemical Use And The Consumption Of Giant Cricket (Brachytrupes Membranaceus Drury, 1770), F. O. Miantsia, F. Meutchieye, S. Niassy

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The current work is aimed at generating information on giant crickets and the impact of commonly used pesticides on the natural population of these crickets. Data was collected based on interviews and complemented with field observations. Out of 319 respondents surveyed, 290 were aware of the use of the giant cricket as a food source, and 161 were active consumers. Regarding the availability of the giant cricket, respondents reported that the crickets' populations were diminishing because of farming practices. About 219 persons reported that commonly used herbicides harm giant crickets at different stages. This could be attributed to the scarcity …

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Parasitic Nematode Meloidogyne Incognita Interactions With Different Capsicum Annum Cultivars Reveal The Chemical Constituents Modulating Root Herbivory, Ruth Kihika, Lucy K. Murungi, Danny Coyne, Margaret Ng'ang'a, Ahmed Hassanali, Peter E.A. Teal, Baldwyn Torto Dec 2017

Parasitic Nematode Meloidogyne Incognita Interactions With Different Capsicum Annum Cultivars Reveal The Chemical Constituents Modulating Root Herbivory, Ruth Kihika, Lucy K. Murungi, Danny Coyne, Margaret Ng'ang'a, Ahmed Hassanali, Peter E.A. Teal, Baldwyn Torto

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Plant volatile signatures are often used as cues by herbivores to locate their preferred hosts. Here, we report on the volatile organic compounds used by the subterranean root-knot nematode (RKN) Meloidogyne incognita for host location. We compared responses of infective second stage juveniles (J2s) to root volatiles of three cultivars and one accession of the solanaceous plant, Capsicum annum against moist sand in dual choice assays. J2s were more attracted to the three cultivars than to the accession, relative to controls. GC/MS analysis of the volatiles identified common constituents in each plant, five of which were identified as α-pinene, limonene, …

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Identification Of Kairomones Of Second Instar Nymphs Of The Variegated Coffee Bug Antestiopsis Thunbergii (Heteroptera: Pentatomidae), Teresiah N. Njihia, Baldwyn Torto, Lucy K. Murungi, Janet Irungu, Dickson M. Mwenda, Régis Babin Dec 2017

Identification Of Kairomones Of Second Instar Nymphs Of The Variegated Coffee Bug Antestiopsis Thunbergii (Heteroptera: Pentatomidae), Teresiah N. Njihia, Baldwyn Torto, Lucy K. Murungi, Janet Irungu, Dickson M. Mwenda, Régis Babin

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The variegated coffee bug Antestiopsis thunbergii Gmelin is a key pest of Coffea arabica in East Africa. Although the bug feeds on various parts of the coffee plant, it has a strong preference for mature green berries which are essential for the bug to complete its life cycle, reproduce and enhance its longevity. To locate mature green coffee berries, we hypothesized that second instar nymphs, which are the most mobile and active feeding immature stage of the bug, must rely on key volatile compounds emitted by the host for recognition. We tested this hypothesis using behavioral and electrophysiological assays and …

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Strong Spatial-Temporal Patterns In Maize Yield Response To Nutrient Additions In African Smallholder Farms, Samuel Njoroge, Antonius G.T. Schut, Ken E. Giller, Shamie Zingore Dec 2017

Strong Spatial-Temporal Patterns In Maize Yield Response To Nutrient Additions In African Smallholder Farms, Samuel Njoroge, Antonius G.T. Schut, Ken E. Giller, Shamie Zingore

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Large variability in crop responses to macronutrient application at various spatial scales present challenges for developing effective fertilizer recommendations for crop production in smallholder farming systems of sub-Saharan Africa. We assessed maize yield responses to nitrogen (N), phosphorus (P) and potassium (K) application and evaluated relationships between crop responses to N, P and K application and soil analysis data. Nutrient omission trials were conducted on 23 farms located in Sidindi, Western Kenya, selected to be representative of the main soil and management factors in maize based systems in Siaya County. Treatments included a control and PK, NK, NP and NPK …

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Welwitschianalol A And B, Two Cyclohexene Derivatives And Other Insecticidal Constituents Of Caesalpinia Welwitschiana (Oliv.) Brenan, Flaure Rosette Ehawa Essoung, Brice Mittérant Mba'ning, Wilber Lwande, Silvère Augustin Ngouela, Etienne Tsamo, Sumesh Chander Chhabra, Ahmed Hassanali, Russell John Cox Dec 2017

Welwitschianalol A And B, Two Cyclohexene Derivatives And Other Insecticidal Constituents Of Caesalpinia Welwitschiana (Oliv.) Brenan, Flaure Rosette Ehawa Essoung, Brice Mittérant Mba'ning, Wilber Lwande, Silvère Augustin Ngouela, Etienne Tsamo, Sumesh Chander Chhabra, Ahmed Hassanali, Russell John Cox

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Crude methanol extract of the leaves of Caesalpinia welwitschiana was found to possess moderate larvicidal activity against second-instar larvae of Tuta absoluta Meyrick. Bioassay-guided fractionation of this extract led to the isolation of two oxygenated cyclohexene derivatives, welwitschianalol A (1, (1α,2β)-2-acetoxy-1-hydroxy-1- benzoyloxymethylcyclohex-5-ene) and B (2, (1α,2β)-2- benzoyloxy −1-cinnamoyloxymethyl-1-hydroxycyclohex-5-ene), together with eight known compounds, comprising bonducellin, dipteryxic acid, 3′-hydroxygenkwarin, afzelin, quercitrin, myricitrin, methyl gallate and gallic acid. The structures of the unknown compounds as well as those of the known ones were elucidated based on their MS, 1D and 2D NMR spectra, and in the case of known compounds, by comparison …

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The Cotesia Sesamiae Story: Insight Into Host-Range Evolution In A Hymenoptera Parasitoid And Implication For Its Use In Biological Control Programs, L. Kaiser, S. Dupas, A. Branca, E. A. Herniou, C. W. Clarke, C. Capdevielle Dulac, J. Obonyo, R. Benoist, J. Gauthier, P. A. Calatayud, J. F. Silvain, B. P. Le Ru Dec 2017

The Cotesia Sesamiae Story: Insight Into Host-Range Evolution In A Hymenoptera Parasitoid And Implication For Its Use In Biological Control Programs, L. Kaiser, S. Dupas, A. Branca, E. A. Herniou, C. W. Clarke, C. Capdevielle Dulac, J. Obonyo, R. Benoist, J. Gauthier, P. A. Calatayud, J. F. Silvain, B. P. Le Ru

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This review covers nearly 20 years of studies on the ecology, physiology and genetics of the Hymenoptera Cotesia sesamiae, an African parasitoid of Lepidoptera that reduces populations of common maize borers in East and South Africa. The first part of the review presents studies based on sampling of C. sesamiae from maize crops in Kenya. From this agrosystem including one host plant and three main host borer species, studies revealed two genetically differentiated populations of C. sesamiae species adapted to their local host community, and showed that their differentiation involved the joint evolution of virulence genes and sensory mechanisms of …

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Predicting Minimum Tillage Adoption Among Smallholder Farmers Using Micro-Level And Policy Variables, Paswel P. Marenya, Menale Kassie, Moti Jaleta, Dil Bahadur Rahut, Olaf Erenstein Dec 2017

Predicting Minimum Tillage Adoption Among Smallholder Farmers Using Micro-Level And Policy Variables, Paswel P. Marenya, Menale Kassie, Moti Jaleta, Dil Bahadur Rahut, Olaf Erenstein

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Minimum tillage combined with mulching (MTM) is critical to conservation agriculture, yet its use by smallholder farmers raises challenging questions regarding adoption, diffusion and scaling at farm level. In this paper, we used probit regression and post-estimation simulations to identify the key micro (farm specific) and macro (country specific) factors as predictors of MTM adoption in four countries spanning a north-south gradient in eastern and southern Africa (ESA): Ethiopia, Kenya, Tanzania and Malawi. We found that farmers’ access to markets and social capital empirically predicted MTM adoption. Policies that increased fertilizer subsidies and extension-staff-to-farmer ratios had similar effects, even if …

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Profitability Of Diammonium Phosphate Use In Bush And Climbing Bean-Maize Rotations In Smallholder Farms Of Central Burundi, Marie Chantal Niyuhire, Pieter Pypers, Bernard Vanlauwe, Generose Nziguheba, Dries Roobroeck, Roel Merckx Oct 2017

Profitability Of Diammonium Phosphate Use In Bush And Climbing Bean-Maize Rotations In Smallholder Farms Of Central Burundi, Marie Chantal Niyuhire, Pieter Pypers, Bernard Vanlauwe, Generose Nziguheba, Dries Roobroeck, Roel Merckx

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Soil fertility decline is a major constraint to bean (Phaseolus vulgaris L.) and maize (Zea mays) production in the Central Highlands of Burundi. Nutrient sources, specifically fertilizers, are paramount to increasing the production in the regions. Hence, improving fertilizer use efficiency is considered as a key factor towards sustainable intensification. The use of grain legumes with low harvest indices, such as climbing beans, are assumed to improve soil fertility and fertilizer use efficiency. This study compares the rotational effects of bush and climbing bean varieties on maize and evaluates the profitability of diammonium phosphate (DAP, 18–46-0) fertilizer in the bean-maize …

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Organic Farming Provides Improved Management Of Plant Parasitic Nematodes In Maize And Bean Cropping Systems, Janet G. Atandi, Solveig Haukeland, George M. Kariuki, Danny L. Coyne, Edward N. Karanja, Martha W. Musyoka, Komi K.M. Fiaboe, David Bautze, Noah Adamtey Sep 2017

Organic Farming Provides Improved Management Of Plant Parasitic Nematodes In Maize And Bean Cropping Systems, Janet G. Atandi, Solveig Haukeland, George M. Kariuki, Danny L. Coyne, Edward N. Karanja, Martha W. Musyoka, Komi K.M. Fiaboe, David Bautze, Noah Adamtey

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Intensification of agriculture, combined with poor agronomic practices have increased the incidence of plant parasitic nematodes (PPN) and other soil pathogens in East Africa, which consequently affects crop productivity in small holder farms. The objective of the study was to assess the effectiveness of farming systems in management of PPN and to recommend the best practice to farmers. Therefore, two field trials were established, one in farmer fields and one on-station, using maize (Zea mays L.), intercropped with beans (Phaseolus vulgaris L.) and in rotation with beans as a sole crop. Organic farming (that received compost, Tithonia diversifolia and neem …

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An Assessment Of The Magnitudes And Factors Associated With Postharvest Losses In Off-Farm Grain Stores In Kenya, Joseph K. Mwangi, Christopher M. Mutungi, Soul Kifouly G. Midingoyi, Abdul K. Faraj, Hippolyte D. Affognon Sep 2017

An Assessment Of The Magnitudes And Factors Associated With Postharvest Losses In Off-Farm Grain Stores In Kenya, Joseph K. Mwangi, Christopher M. Mutungi, Soul Kifouly G. Midingoyi, Abdul K. Faraj, Hippolyte D. Affognon

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Off-farm grain storage is an important postharvest undertaking by government, traders and processors in Kenya. A survey was conducted in 2014/2015 to assess the kinds and magnitudes of perceived losses experienced in off-farm stores, and the factors associated with them. Store supervisors or key personnel charged with grain storage in 39 public and 74 private stores, spread across the six maize growing agro-ecological zones, were interviewed using a structured questionnaire. Total perceived losses averaged 17.6± 2.3%, and were attributed to insects (7.2± 1.0%), molds (5.7± 2.1%), moisture loss (3.4± 0.5%), rodents (2.0± 0.5%), spillage (0.50 ± 0.0%) and birds (0.10± …

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Mapping Leaf Nitrogen And Carbon Concentrations Of Intact And Fragmented Indigenous Forest Ecosystems Using Empirical Modeling Techniques And Worldview-2 Data, Galal Omer, Onisimo Mutanga, Elfatih M. Abdel-Rahman, Kabir Peerbhay, Elhadi Adam Sep 2017

Mapping Leaf Nitrogen And Carbon Concentrations Of Intact And Fragmented Indigenous Forest Ecosystems Using Empirical Modeling Techniques And Worldview-2 Data, Galal Omer, Onisimo Mutanga, Elfatih M. Abdel-Rahman, Kabir Peerbhay, Elhadi Adam

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Forest nitrogen (N) and carbon (C) are among the most important biochemical components of tree organic matter, and the estimation of their concentrations can help to monitor the nutrient uptake processes and health of forest trees. Traditionally, these tree biochemical components are estimated using costly, labour intensive, time-consuming and subjective analytical protocols. The use of very high spatial resolution multispectral data and advanced machine learning regression algorithms such as support vector machines (SVM) and artificial neural networks (ANN) provide an opportunity to accurately estimate foliar N and C concentrations over intact and fragmented forest ecosystems. In the present study, the …

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Quality Of Charcoal Produced Using Micro Gasification And How The New Cook Stove Works In Rural Kenya, Mary Njenga, Yahia Mahmoud, Ruth Mendum, Miyuki Iiyama, Ramni Jamnadass, Kristina Roing De Nowina, Cecilia Sundberg Aug 2017

Quality Of Charcoal Produced Using Micro Gasification And How The New Cook Stove Works In Rural Kenya, Mary Njenga, Yahia Mahmoud, Ruth Mendum, Miyuki Iiyama, Ramni Jamnadass, Kristina Roing De Nowina, Cecilia Sundberg

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Wood based energy is the main source of cooking and heating fuel in Sub-Saharan Africa. Its use rises as the population increases. Inefficient cook stoves result in fuel wastage and health issues associated with smoke in the kitchen. As users are poor women, they tend not to be consulted on cook stove development, hence the need for participatory development of efficient woodfuel cooking systems. This paper presents the findings of a study carried out in Embu, Kenya to assess energy use efficiency and concentrations of carbon monoxide and fine particulate matter from charcoal produced using gasifier cook stoves, compared to …

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Drought-Tolerant Desmodium Species Effectively Suppress Parasitic Striga Weed And Improve Cereal Grain Yields In Western Kenya, Charles A.O. Midega, Charles J. Wasonga, Antony M. Hooper, John A. Pickett, Zeyaur R. Khan Aug 2017

Drought-Tolerant Desmodium Species Effectively Suppress Parasitic Striga Weed And Improve Cereal Grain Yields In Western Kenya, Charles A.O. Midega, Charles J. Wasonga, Antony M. Hooper, John A. Pickett, Zeyaur R. Khan

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The parasitic weed Striga hermonthica Benth. (Orobanchaceae), commonly known as striga, is an increasingly important constraint to cereal production in sub-Saharan Africa (SSA), often resulting in total yield losses in maize (Zea mays L.) and substantial losses in sorghum (Sorghum bicolor (L.) Moench). This is further aggravated by soil degradation and drought conditions that are gradually becoming widespread in SSA. Forage legumes in the genus Desmodium (Fabaceae), mainly D. uncinatum and D. intortum, effectively control striga and improve crop productivity in SSA. However, negative effects of climate change such as drought stress is affecting the functioning of these systems. There …

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Application Of Secondary Nutrients And Micronutrients Increases Crop Yields In Sub-Saharan Africa, Job Kihara, Gudeta Weldesemayat Sileshi, Generose Nziguheba, Michael Kinyua, Shamie Zingore, Rolf Sommer Aug 2017

Application Of Secondary Nutrients And Micronutrients Increases Crop Yields In Sub-Saharan Africa, Job Kihara, Gudeta Weldesemayat Sileshi, Generose Nziguheba, Michael Kinyua, Shamie Zingore, Rolf Sommer

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Secondary and micronutrients are important in enhancing crop productivity; yet, they are hardly studied in sub-Sahara Africa. In this region, the main focus has been on macronutrients but there is emerging though scattered evidence of crop productivity limitations by the secondary and micronutrients. Elsewhere, widespread deficiencies of these nutrients are associated with stagnation of yields. Here, we undertake a meta-analysis using 40 articles reporting crop response to secondary and micronutrients to (1) determine the productivity increase of crops and nutrient use efficiency associated with these nutrients, and (2) provide synthesis of responses to secondary nutrients and micronutrients in sub-Sahara Africa. …

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Why Organic Resources And Current Fertilizer Formulations In Southern Africa Cannot Sustain Maize Productivity: Evidence From A Long-Term Experiment In Zimbabwe, Tongai J. Mtangadura, Florence Mtambanengwe, Hatirarami Nezomba, Jairos Rurinda, Paul Mapfumo Aug 2017

Why Organic Resources And Current Fertilizer Formulations In Southern Africa Cannot Sustain Maize Productivity: Evidence From A Long-Term Experiment In Zimbabwe, Tongai J. Mtangadura, Florence Mtambanengwe, Hatirarami Nezomba, Jairos Rurinda, Paul Mapfumo

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Sustainability of maize-based cropping systems is a major challenge for southern Africa, yet the demand for maize as staple food and animal feed in the region continues to increase. A study was conducted on a sandy clay loam (220 g clay kg-1 soil) at Domboshawa in Zimbabwe to investigate the long-term effects of organic resource quality and application rate, and nitrogen (N) fertilization on soil chemical properties and maize (Zea mays L.) productivity. Crotalaria juncea (high quality), Calliandra calothyrsus (medium quality), cattle manure (variable quality), maize stover and Pinus patula sawdust (both low quality) were incorporated into soil at 4.0 …

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Screening Napier Grass Accessions For Resistance To Napier Grass Stunt Disease Using The Loop-Mediated Isothermal Amplification Of Dna (Lamp), N. I.E. Wamalwa, C. A.O. Midega, S. Ajanga, N. E. Omukunda, F. N. Muyekho, G. O. Asudi, M. Mulaa, R. K. Zeyaur Aug 2017

Screening Napier Grass Accessions For Resistance To Napier Grass Stunt Disease Using The Loop-Mediated Isothermal Amplification Of Dna (Lamp), N. I.E. Wamalwa, C. A.O. Midega, S. Ajanga, N. E. Omukunda, F. N. Muyekho, G. O. Asudi, M. Mulaa, R. K. Zeyaur

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Napier grass stunt (NGS) disease is a major threat to Napier grass cultivation and the smallholder dairy industry in East and Central Africa. The disease is caused by a phytoplasma, which is transmitted by the leafhopper Maiestas banda (Kramer) (Hemiptera: Cicadellidae). The current study was conducted to identify among 65 Napier grass accessions that could be resistant to NGS disease using the loop-mediated isothermal amplification of DNA (LAMP). The accessions were caged with NGS phytoplasma-infected Napier grass as inoculum source and M. banda as the vector. All Napier grass accessions were subjected to phytoplasma testing thereafter 18 phytoplasma negative and …

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The Yield Gap: Closing The Gap By Widening The Approach, Katherine A. Snyder, Sriyanie Miththapala, Rolf Sommer, Juliet Braslow Jul 2017

The Yield Gap: Closing The Gap By Widening The Approach, Katherine A. Snyder, Sriyanie Miththapala, Rolf Sommer, Juliet Braslow

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The yield gap has arisen again as a focus for agricultural research to ensure food security and economic growth for farmers around the world. To examine this renewed interest, we carried out a review of key literature in the field of yield gap analysis to identify important gaps in research and analysis. In so doing, both the complexities in yield gap studies emerged along with some significant omissions. Much of the literature and research on the yield gap has been framed by larger concerns and initiatives to raise agricultural productivity. This focus has led to an emphasis on technical solutions …

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Advances In Crop Insect Modelling Methods—Towards A Whole System Approach, Henri E.Z. Tonnang, Bisseleua D.B. Hervé, Lisa Biber-Freudenberger, Daisy Salifu, Sevgan Subramanian, Valentine B. Ngowi, Ritter Y.A. Guimapi, Bruce Anani, Francois M.M. Kakmeni, Hippolyte Affognon, Saliou Niassy, Tobias Landmann, Frank T. Ndjomatchoua, Sansao A. Pedro, Tino Johansson, Chrysantus M. Tanga, Paulin Nana, Komi M. Fiaboe, Samira F. Mohamed, Nguya K. Maniania, Sunday Ekesi, Christian Borgemeister Jun 2017

Advances In Crop Insect Modelling Methods—Towards A Whole System Approach, Henri E.Z. Tonnang, Bisseleua D.B. Hervé, Lisa Biber-Freudenberger, Daisy Salifu, Sevgan Subramanian, Valentine B. Ngowi, Ritter Y.A. Guimapi, Bruce Anani, Francois M.M. Kakmeni, Hippolyte Affognon, Saliou Niassy, Tobias Landmann, Frank T. Ndjomatchoua, Sansao A. Pedro, Tino Johansson, Chrysantus M. Tanga, Paulin Nana, Komi M. Fiaboe, Samira F. Mohamed, Nguya K. Maniania, Sunday Ekesi, Christian Borgemeister

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A wide range of insects affect crop production and cause considerable yield losses. Difficulties reside on the development and adaptation of adequate strategies to predict insect pests for their timely management to ensure enhanced agricultural production. Several conceptual modelling frameworks have been proposed, and the choice of an approach depends largely on the objective of the model and the availability of data. This paper presents a summary of decades of advances in insect population dynamics, phenology models, distribution and risk mapping. Existing challenges on the modelling of insects are listed; followed by innovations in the field. New approaches include artificial …

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