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Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Understanding poverty-related diseases in Cameroon from a salutogenic perspective
    Makoge, Valerie - \ 2017
    Wageningen University. Promotor(en): M.A. Koelen, co-promotor(en): H. Maat; H.W. Vaandrager. - Wageningen : Wageningen University - ISBN 9789463434515 - 193
    armoede - kameroen - malaria - tyfus - acquired immune deficiency syndrome - hiv-infecties - cholera - tuberculose - diarree - gezondheidsgedrag - gezondheidsvoorzieningen - spanningen - poverty - cameroon - malaria - typhoid - acquired immune deficiency syndrome - hiv infections - cholera - tuberculosis - diarrhoea - health behaviour - health services - stresses

    Poverty-related diseases (PRDs) assume poverty as a determinant in catching disease and an obstacle for cure and recovery. In Cameroon, over 48 % of the population lives below the poverty line. This dissertation starts from the premise that the relation between poverty and disease is mediated by a person’s capacity to cope with the challenges posed by the natural and social environment. The central problem addressed is that in (inter)national health promotion, disease eradication is overemphasized whereas strengthening the capacity of people to cope with harsh conditions is disregarded. Research efforts show a similar division in emphasis, resulting in a limited understanding of the way people deal with health challenges in conditions of poverty. This dissertation is based on the salutogenic model of health that emphasizes the combined effects of (natural) disease conditions, mental conditions and social factors as determinants of health. This implies an emphasis on health as a positive strategy to deal with stressors and also an emphasis on the agency of people to respond to challenges that hamper their health and wellbeing. The study is carried out among two different groups of people in Cameroon. These are workers including dependants of workers of the Cameroon Development Corporation (CDC) and students from the universities of Buea and Yaoundé. The overall aim of this dissertation is to understand how conditions of poverty impact the health of people and how they manage these challenges. Specifically, the study aims to unravel the interlinkages between poverty and health by creating a deeper understanding of the social and material dynamics which enable people’s capacity to preserve health, anticipate health risks, and mitigate or recover from stressors such as PRDs. The main research question addressed is: What factors underlie the maintenance of good health and overcoming stressors in the face of PRDs in Cameroon?

    Different research methods were used to collect data. Interviews were carried out with respondents from both groups addressing PRDs, other stressors and coping strategies. General surveys were carried out to identify perceptions as well as health behaviour patterns across the two groups. Standardised surveys were carried out to measure individual factors such as sense of coherence, resilience, self-efficacy, subjective well-being and self-rated health. Results presented in different empirical chapters of the thesis each respond to a specific research question. In Chapters 2 and 3 are presented surveys with 272 students and 237 camp-dwellers respectively. Perceptions, attributed causes of, and responses towards PRDs are explored as well as motivations for given responses to health challenges. In chapter 4, a qualitative study with 21 camp-dwellers and 21 students is presented in which the dynamics of health-seeking behaviour is highlighted. In this chapter also, factors which are influential in seeking formal healthcare are indicated. Chapter 5 elaborates on what people experience as stressors and the mechanisms they put in place to cope with the stressors. In this chapter, not only is the diversity of stressors outlined for both groups, but also presented are the different identified coping mechanisms put in place by respondents. Chapter 6 which is the last empirical chapter presents coping with PRDs through an analysis of individual, demographic and environmental factors.

    Based on the studies carried out, this thesis concludes that the two groups investigated are very aware of what PRDs are and can differentiate them from common diseases. Major PRDs listed by the two groups of respondents were malaria, cholera and diarrhoea. This classification is different from what is considered major PRDs by (inter)national health bodies such as the World Health Organisation and the Ministry of Public Health in Cameroon. Also, organisations such as CDC and Universities, offer limited contributions towards better health for camp-dwellers and students respectively. This is experienced relative to the living conditions, quality of the healthcare system and poor work or study conditions. That notwithstanding, people play an active role in maintaining their health through diverse coping mechanisms. Coping was most strongly related to enabling individual factors such as sense of coherence and subjective health, perceptions of effective strategies to respond to diseases as well as social factors such as the meaningful activities in the social groups to which they belong. The results presented in this thesis are intended to contribute to sustainable and effective response strategies towards PRDs.

    Understanding the diverse roles of soil organic matter in the cereal - Striga hermontica interaction
    Ayongwa, G.C. - \ 2011
    Wageningen University. Promotor(en): Thomas Kuijper, co-promotor(en): Tjeerd-Jan Stomph. - S.l. : s.n. - ISBN 9789085858430 - 131
    striga hermonthica - sorghum bicolor - parasitaire onkruiden - organisch bodemmateriaal - bodemvruchtbaarheid - experimenteel veldonderzoek - stikstof - mineralisatie - beperkingen - gewasproductie - kameroen - nigeria - striga hermonthica - sorghum bicolor - parasitic weeds - soil organic matter - soil fertility - field experimentation - nitrogen - mineralization - constraints - crop production - cameroon - nigeria

    Keywords: Striga hermonthica, Sorghum bicolor, soil fertility, organic matter, N-mineralisation, farmers’ priority, production constraints, intensification.

    The problem of the parasitic weed striga (Striga hermonthica (Del.) Benth.) has worsened for African farmers, in conjunction with degrading soil fertility. An analysis of the striga problem showed that scientists, policy makers and farmers conceptualise striga differently. Whether striga is viewed as a weed or a symptom of degraded soils raises two questions: Should farmers control striga, even when the impact on yields would be negligible? Or should fertility enhancement, leading to higher yields, be their focus, even when not accompanied by an immediate reduction in striga? This study seeks to understand how organic matter inputs affect nutrient dynamics, sorghum (Sorghum bicolor [L.] Moench) production and striga abundance.
    Surveys in northern Cameroon showed that striga infestation increased over the past two decades. Increased land pressure led to reduced fallow periods and enhanced cereal (mono-) cropping. Reduced access to fertiliser and manure hampered options to improve soil fertility. Yields from farmers’ fields did not correlate with striga incidence, confirming farmers’ prioritisation of soil fertility, weeds, and labour as production constraints, rather than striga. The entry point to tackle low yields and the worsening of the striga situation should follow farmers’ priority of alleviating low soil fertility.
    Whether and how soil fertility improvement, through organic matter, enhances agricultural productivity and reduces striga, was investigated in field experiments. Organic matter amendments significantly depressed striga seed survival, with the strongest effect achieved at higher quality; presumably due to higher microbial activity. Organic matter enhanced soil water retention and soil temperature but without effects on striga seed survival. Organic matter did not affect soil ethylene concentrations. The effect of organic matter amendments was directly related to N mineralisation, both for better cereal growth and reduced striga survival. The organic matter amendments and use of fallow, as applied here, however, may not be practicable for the resource-poor farmer.
    Increasing N-fertilisation increased sorghum root N mass concentration, which resulted in a lower striga seed germination. That relationship was linear up to a root N mass concentration of 19.5 mg g-1 where seed germination was close to but always still above 0%.
    In a broader framework of the research findings, the ultimate solution for farm productivity for Africa is in sustainable farm intensification by investing in soil fertility. However, the prevailing land tenure system and limited access to fertiliser and organic matter need to be overcome. A new conceptual model is proposed, indicating how changes in both cereal yield and striga infestation over time co-vary with changes in soil fertility. The implication of this model is that recovery of soil fertility should be the priority. The challenge to agronomists remains to consider how to make farm intensification rewarding and attainable for resource-poor farmers. In areas where striga is an obstacle, an integrated scheme for the intensification of cereal cropping should start with integrated soil fertility management. Crop rotation and intercropping with selected non-host leguminous crops are essential ingredients.

    Dangerous assumptions : the agroecology and ethnobiology of traditional polyculture cassava systems in rural Cameroon and implications of green revolution technologies for sustainability, food security, and rural welfare
    Nchang Ntumngia, R. - \ 2010
    Wageningen University. Promotor(en): Patricia Howard, co-promotor(en): Lisa Price. - [S.l : S.n. - ISBN 9789085858423 - 392
    ontwikkelingsstudies - plattelandsontwikkeling - plattelandsvrouwen - bedrijfssystemen - teeltsystemen - meervoudige teelt - cassave - groene revolutie - duurzaamheid (sustainability) - voedselzekerheid - rurale welzijnszorg - kameroen - franssprekend afrika - ontwikkelingslanden - centraal-afrika - acs-landen - hoogopbrengende rassen - etnobotanie - agro-ecologie - middelen van bestaan - development studies - rural development - rural women - farming systems - cropping systems - multiple cropping - cassava - green revolution - sustainability - food security - rural welfare - cameroon - francophone africa - developing countries - central africa - acp countries - high yielding varieties - ethnobotany - agroecology - livelihoods
    The Alliance for a New Green Revolution in Africa and African government and
    CGIAR programmes oriented toward improving cassava production through intensification
    and the use of external inputs have the ultimate goals to improve food production, promote
    market integration, and increase incomes of small farm households. Essentially, AGRA’s
    arguments, which are either implicit or explicit in the policies and programmes of the Government
    of Cameroon and of several CGIAR institutes that the Government collaborates
    with, are that traditional farming systems and practices suffer from low productivity and are
    unsustainable. African soils are naturally poor, farmers use little or no fertiliser, and the
    fallow periods that, in the past, provided for nutrient recycling, are declining due to population
    pressure, leading farmers to mine the soil, which results in declining crop yields. Further,
    farmers’ local varieties are low yielding and are highly susceptible to pests and diseases
    compared to improved, high-yielding varieties (HYVs). Across Africa, per capita food
    production is declining, and families live in poverty and hunger. Population pressure is increasing,
    farmers are poor and thus in need of additional income and, if given the opportunity,
    they will seek to maximise their income from crops sales, which they in turn will
    reinvest in agriculture, given the right incentives. Farm households are food insecure and,
    by increasing their output and sales, they will become food secure.
    This dissertation challenges these underlying assumptions and questions the underlying
    parameters individually and as a whole by examining traditional and more commercial
    smallholder cassava agroecological systems and households in two study sites in rural
    Cameroon (where conditions are theoretically quite positive for the acceptance of such
    technologies) from agroecological, ethnobiological, economic, and cultural perspectives.
    The objective is to understand the implications of policies and programmes that promote
    Green Revolution-type technologies and market integration for the productivity and sustainability
    of such agroecological systems, for the conservation of crop genetic resources,
    and for the livelihoods, income, and food and nutritional security of smallholder farm
    households. The intention is to critically examine the assumptions and underlying parameters
    posited by AGRA, and to reformulate these on the basis of the findings to provide a
    more adequate framework for approaching and assessing agricultural innovations in the
    African context.
    The following questions orient the research: Are African farming systems, and
    farmers, characterised by attributes that AGRA ascribes to them? Are such farmers likely to
    accept the technologies that AGRA is promoting? Are AGRA technologies and strategies
    likely to lead to more sustainable, higher yielding farming systems? Are they likely to
    translate into greater market integration, higher incomes, greater food security, and renewed
    investment in agricultural intensification for small farm households? Are there trade-offs
    that farmers and their households and communities have to confront in adopting such technologies
    and, if so, how might these influence their strategies and responses to programmes
    that promote Green Revolution-type intensification of the ‘old’ or ‘new’ varieties?
    Findings presented in this dissertation show that Koudandeng and Malende farmers
    have barely accepted Green Revolution technologies and modern farming strategies and
    systems (including monoculture). The analysis of the findings proposes reasons for this,
    and attempts to explain farmers’ and households’ production systems and strategies from an
    emic (farmers’) perspective. It is argued that, if African farmers do not accept the Green

    Revolution-type technologies, or accept them only on their own terms and in accordance
    with the outcomes that they themselves desire that differ significantly from what governments
    and researchers and donors anticipate, then this may be attributable at least in part to
    the fact that the strategies and technologies that are promoted are based on erroneous assumptions,
    not least about the key parameters that define the performance of real African
    farming systems and real African farming households. These parameters are grouped under
    two main categories - agroecological and socio-economic – which, in AGRA’s discourse,
    are treated as if they were unrelated. There is thus an absence of attention to the relations
    between the agroecological (or what can be termed environmental, or ‘nature’), and the
    socioeconomic (or what can be termed ‘culture’), which in turn leads to an inattention to
    the diversity of cultures and agroecologies across Africa – its biocultural diversity – that
    permits blanket recommendations to be made on the basis of over-generalised and oversimplified
    When emphasising the need to give greater consideration to the relations between
    culture and nature – that is, to the diversity of African cultures, agroecologies, and socioeconomic
    systems and relations, and to the relations between culture, agroecology, and socioeconomics
    - this dissertation proposes three different interacting sets of analytical parameters
    that must be considered if insights into real African agriculture and real African farm
    households are to emerge. Two of these sets of parameters emerge from a critique of
    AGRA’s parameters and a third arises out of a framework for assessing the acceptability of
    crop varieties that has its foundations in ethnobiology.
    This comparative research, which was carried out between 2002 and 2008, involved
    a total of 206 farmers in two different villages in two regions in the South of Cameroon.
    The methods for collecting and analysing data were both quantitative and qualitative, and
    were drawn from sociology, anthropology, and ethnobiology (cognitive anthropology).
    Qualitative data collection methods included a review of grey and published literature, as
    well as ethnographic interviewing and participant observation. Quantitative methods included
    four closed question surveys and cognitive ethnobiological elicitation (freelisting
    and triads testing). Qualitative interview data were coded and analysed narratively (description,
    explanation, interpretation, quotations) using Microsoft Word. The small household
    sample size that was used did not permit the use of sophisticated statistical analyses according
    to population sub-samples, which limited the analysis of survey data to that which
    would be done using descriptive statistics, such as proportions, percentages, and frequencies.
    Regression analysis was done sparingly. Cultural consensus analysis, proximities
    analysis, multidimensional scaling, quadratic assessment product, cluster analysis, and
    property fitting regression were used to analyse the ethnobiological data that was collected.
    The general conclusions of this dissertation assert that traditional African polyculture
    systems and their genetic diversity (crop species and varieties) are often environmentally
    sustainable, able to meet income and food needs of rural households and communities,
    and fulfil multiple cultural needs relating to identity, foodways, spirituality, and social reciprocity.
    The assumptions behind the promotion of AGRA-type technologies are reductionist;
    they do not take into consideration the complexities of African agriculture and livelihoods,
    or the interrelation between farmers’ social and cultural norms, resource access, and
    livelihood strategies, and how they carry out agriculture (e.g. spatial and temporal configurations,
    cropping patterns, crop and varietal choices, cultural practices). Across most of
    Africa, smallholders and their agroecosystems are firmly embedded in ethnic and tribal
    communities that adhere more or less strongly to cultural norms, beliefs, and kinship or

    lineage-based social relations. Their agricultural knowledge and practices are often based
    largely on local knowledge and resources. Such ‘traditional’ agricultural systems generally
    represent a long-term adaptation between culture and nature, where both have co-evolved
    over time. Farmers’ knowledge and practices are embedded in social relations where many
    modes of subsistence are characterised by forms of communalism that are relatively egalitarian,
    which tends to ensure that resources are distributed in such a way that people have
    sufficient means to meet socially defined, as well as biological needs. Unsustainable practices
    and inegalitarian social relations that may accompany the adoption of Green Revolution
    technologies and greater market integration are likely to be mal-adaptive over the long
    The assumptions underlying the ‘New Green Revolution for Africa’ drastically
    over-simplify traditional African farming systems and ignore their diversity and thus do not
    hold everywhere in Africa which, it is argued, may represent yet another threat to the integrity
    of traditional African cultures, agroecological systems, and biological diversity. Eight
    major critiques of this over-simplification and the resultant dangerous consequences for
    African farm households include: i) the inappropriateness (technical and practical limitations)
    of the recommendations for integrated soil fertility management practices and fertiliser
    use for most African contexts; ii) the lack of consideration for farm households’ social
    constraints: differential access to income, land, and labour, and investments in other livelihood
    activities that compete with investments in agricultural inputs, which consequently
    may have implications for soil fertility management; iii) the lack of attention to the pests
    and diseases of most significance to farmers; iv) the relative inattention to the need to develop
    varieties that conform with local foodways and food processing and storage conditions;
    v) the implications of mass production of the reduction of crop diversity and varietal
    diversity for food security and nutrition and the consequences for human health; vi) the
    lack of serious consideration of farmers’ knowledge and practices in crop breeding strategies
    and the lack of precise methodologies for effectively and systematically accessing and
    document farmers’ varietal knowledge, perceptions, and preferences and relating these to
    farmer behaviour when accepting crop varieties; vii) the improbability that prices for mass
    produced HYVs will increase income and investments in inputs; and viii) the consequences
    of conversion to monoculture for livelihood and food security that are entailed in widescale
    acceptance of AGRA-type recommendations.
    Based on these critiques, the major policy recommendation emphasised in this dissertation
    is to give greater consideration to real African farming systems and real African
    farmers and how and why they function as they do, which, it is argued, must serve as the
    point of departure for agricultural policies and programmes across the region if these are to
    succeed in supporting such farmers, their communities, and their nations. Farmers’ culture,
    social relations, knowledge, practices, and experiences that remain, in the ‘New’ Green
    Revolution, as in the ‘Old’, a black box, should be newly considered in policies and research
    and development as positive points of departure for increasing food security in Africa.

    Soil macrofauna community structure along a gradient of land use intensification in the humid forest zone of southern Cameroon.
    Madong à Birang, - \ 2004
    Wageningen University. Promotor(en): Lijbert Brussaard, co-promotor(en): W.A.M. Didden; S. Hauser. - Wageningen : S.n. - ISBN 9789085040316 - 200
    bodemfauna - bodeminvertebraten - aardwormen - formicidae - isoptera - zwerflandbouw - landgebruik - bossen - humide klimaatzones - kameroen - macrofauna - soil fauna - soil invertebrates - earthworms - formicidae - isoptera - shifting cultivation - land use - forests - humid zones - cameroon - macrofauna
    The impact of land use systems on soil macrofauna community structures is described as well as their relationships with the vegetation and soil parameters in the humid forest zone of southernCameroon. 36 Earthworm species were found. A completely different earthworm assemblage was found at high LUI while low and medium LUI blocks had species in common in the various functional groups. Earthworm surface casting decreased when fallow plots were converted to cultivated fields. This reduction depended on the type of fallow. 223 Termite species were recorded.There was no significant effect of LUI but in contrast, a strong effect of LUS on termite species richness and abundance. 80 Ant species were found. LUI and LUS had striking effects on ant communities with highest richness in the low LUI block. Ant species assemblages were location specific.Soil macrofaunal species richness was more responsive to soil and vegetation parameters than macrofaunal abundances.The knowledge gathered on the present state of earthworm, termite and ant communities and the effects of land use change on these macrofauna in southernCameroonconstitutes the baseline information necessary for the design and /or implementation of measures of conservation in which farmers should play a pivotal role.
    Plant diversity in a central African rain forest, implications for biodiversity conservation in Cameroon
    Tchouto, M.G.P. - \ 2004
    Wageningen University. Promotor(en): Jos van der Maesen; A.M. Cleef, co-promotor(en): Fred de Boer. - Wageningen : S.n. - ISBN 9789051130683 - 210
    vegetatie - biodiversiteit - soortendiversiteit - tropische regenbossen - natuurbescherming - bosecologie - kameroen - centraal-afrika - vegetation - biodiversity - species diversity - tropical rain forests - nature conservation - forest ecology - cameroon - central africa
    Slash and burn agriculture in the humid forest zone of southern Cameroon
    Kanmegne, J. - \ 2004
    Wageningen University. Promotor(en): Lijbert Brussaard; E.M.A. Smaling. - Wageningen : s.n. - ISBN 9789051130706 - 184
    inga edulis - zwerflandbouw - gewasopbrengst - wormhoopjes - landgebruik - verbeterde braak - ontbossing - voedingsstoffen - humide klimaatzones - bossen - kameroen - inga edulis - shifting cultivation - crop yield - worm casts - land use - improved fallow - deforestation - nutrients - humid zones - forests - cameroon
    Keywords: crop yields, earthworm cast, Inga edulis , land use, nutrient flows, nutrient stocks, nutrient management, slash and burn

    A field study was conducted on acid soils in the humid forest zone of Southern Cameroon, to characterize the traditional slash-and-burn land uses, assess the major effects of land use change on soil nutrient stocks, flows, and soil biological quality, and to explore alternatives for sustainable land management. The typical land use chronosequence in the area after forest felling includes essep (cucumber-based), banana, and afup (groundnut/cassava-based), and is interrupted by short (after banana) and long (after afup) fallows. Moreover, farmers have cocoa farms where many shade trees are kept. Yield declines in farmers' fields were attributed to diseases and weed infestation (56%) and soil properties (44%).  Burning is practiced prior to essep, and prior to afup. It reduces the weed seed-bank, cleans the field and improves short-term soil fertility, but, together with changing land use, it strongly reduces standing biomass, carbon and nutrient stocks in the vegetation. The forest carbon stock decreased from 199 Mg.ha -1 to 102 Mg.ha -1 in essep , and to 64 Mg.ha -1 in banana farm. Nutrient stocks showed the same trend, but Chromolaena short fallow, that followed banana, recovered most of the P. The cocoa plantation had 53 % of the carbon stocks of the original forest. Soil carbon stock was less affected than vegetation stocks.Burning increased P, K, Ca and Mg available stocks in essep and afup . Lowest 'system' C and N occurred in afup , which is followed by a long fallow to restore soil fertility. The nutrient balance at farm level was strongly negative, i.e., -72.6 kg N, -4.8 kg P and -38.2 kg K ha -1 yr -1 , showing its 'no external input' character, where food and wood are derived from natural stocks. Major losseswere dueto burning, leaching and the non-recycling of farm residues. Only the cocoa farm had a positive nutrient balance: +9.6 kg N, +1.4 kg P and +7.6 kg K ha -1 .yr -1 , as burning is absent, leachingmodest,and deep capture by shade trees providing inputs to the productive system. Simple scenarios showed that recycling farm residues is able to redress the P and K balance, and avoiding burning could even turn the entire nutrient balance positive. Burning also negatively affected earthworm density and casting activities. Up to 95% loss in density was recorded, and casting activity was inhibited during 14 and 19 months in land use systems following afup and essep respectively. Inga fallow proved to favour rapid and intensive casting just as the forest ecosystem. Total cast production was: 5.9 Mg.ha -1 in afup , 3.2 Mg.ha -1 in forest and Inga , and 2.9 Mg.ha -1 in essep after two years, but although the casts were richer in nutrients than the topsoil, the nutrients recycled from casts alone were insufficient for sustained crop production.   Inga edulis was found to be a suitable planted fallow, providing several benefits to farmers and follow-up crops.   Inga fallows produce more biomass (between 44.5 and 62 Mg ha -1 ), and accumulate more C and N than natural fallow. Maize following Inga fallow yielded 800 to 2200 kg.ha -1, against a mere 200-400 kg.ha -1 after natural fallow.  Burning Inga residues gave ngon (cucumber) productionof 300 kg.ha -1 ,which is similar to yields obtained in essep following natural forest. Mulching instead of burning, however, only gave50 kg.ha -1. An innovative on-farm approach was used in the development and implementation of planted fallows, ensuring highadoption. Inga edulis planted fallow can play a leading role among strategies to fight the gradual process of land degradation in the land use chronosequence, providing wood and fruits, and mimicking the natural forest to a considerable extent.
    De drieweg interactie tussen sorghum, Striga hermonthica en arbusculaire mycorrhiza schimmels
    Lendzemo, V.W. - \ 2004
    Gewasbescherming 35 (2004)6. - ISSN 0166-6495 - p. 319 - 322.
    striga hermonthica - striga - mycorrhizae - sorghum bicolor - sorghum - planteninteractie - onkruidbiologie - kameroen - striga hermonthica - striga - mycorrhizas - sorghum bicolor - sorghum - plant interaction - weed biology - cameroon
    Striga hermonthica is a major biological constraint to cereal production in Africa. The intricate association between this phytoparasite and the cereal host makes management difficult. Damage to the host begins before Striga comes out of the soil. Also, infestation correlates negatively with soil fertility. Arbuscular mycorrrhizal (AM) fungi have a variety of ecological functions ranging from improved uptake of immobile nutrients, protection of host from pathogens, to soil aggregation. The question whether these beneficial micro-organisms could play a role within the Striga-cereal (patho)system was addressed. Inoculating Striga-infested sorghum with AM fungi in pots or in the field resulted in a significant reduction in the performance of Striga in terms of numbers attached to the roots, relative time of emergence, numbers emerged and dry weight of Striga shoots at sorghum harvest. AM effects on Striga were more pronounced with the Striga-tolerant S-35 sorghum cultivar compared to effects with the Striga-sensitive CK60B. Inoculation with AM fungi compensated for damage by Striga in the S-35 cultivar. This compensation was independent of AM inoculum density and was not affected by P application. Germination of preconditioned Striga seeds after exposure to root exudates from sorghum colonized by AM fungi was significantly reduced, with effects more prominent with exudates from S-35 plants. AM fungi have the potential to affect Striga during germination, attachment, emergence, and possibly subsequent growth and development. It is important to understand the kind of management practices that farmers can apply to enhance mycorrhizal performance in an integrated management system
    The tripartite interaction between sorghum, Striga hermonthica, and arbuscular mycorrhizal fungi
    Lendzemo, V.W. - \ 2004
    Wageningen : Wageningen University and Research Centre (Tropical resource management papers 55) - ISBN 9789067547543 - 112
    striga hermonthica - striga - mycorrhizae - sorghum bicolor - sorghum - planteninteractie - onkruidbiologie - kameroen - striga hermonthica - striga - mycorrhizas - sorghum bicolor - sorghum - plant interaction - weed biology - cameroon
    The tripartite interaction between sorghum, Striga hermonthica, and arbuscular mycorrhizal fungi
    Lendzemo, V.W. - \ 2004
    Wageningen University. Promotor(en): Martin Kropff, co-promotor(en): Thomas Kuijper. - [S.l.] : S.n. - ISBN 9789085040309 - 112
    striga hermonthica - striga - mycorrhizae - sorghum bicolor - sorghum - planteninteractie - onkruidbiologie - kameroen - striga hermonthica - striga - mycorrhizas - sorghum bicolor - sorghum - plant interaction - weed biology - cameroon
    Striga hermonthica is a major biological constraint to cereal production inAfrica. The intricate association between this phytoparasite and the cereal host makes management difficult. Damage to the host begins before Striga comes out of the soil. Also, infestation correlates negatively with soil fertility. Arbuscular mycorrrhizal (AM) fungi have a variety of ecological functions ranging from improved uptake of immobile nutrients, protection of host from pathogens, to soil aggregation. The question whether these beneficial micro-organisms could play a role within the Striga -cereal (patho)systemwas addressed. Inoculating Striga -infested sorghum with AM fungi in pots or in the field resulted in a significant reduction in the performance of Striga in terms of numbers attached to the roots, relative time of emergence, numbers emerged and dry weight of Striga shoots at sorghum harvest. AM effects on Striga were more pronounced with the Striga -tolerant S-35 sorghum cultivar compared to effects with the Striga -sensitive CK60B. Inoculation with AM fungi compensated for damage by Striga in the S-35 cultivar. This compensation was independent of AM inoculum density and was not affected by P application. Germination of preconditioned Striga seeds after exposure to root exudates from sorghum colonized by AM fungi was significantly reduced, with effects more prominent with exudates from S-35 plants. AM fungi have the potential to affect Striga during germination, attachment, emergence, and possibly subsequent growth and development. It is important to understand the kind of management practices that farmers can apply to enhance mycorrhizal performance in an integrated management system.
    Immigration: a potential time bomb under the integration of Conservation and Development
    Scholte, P. - \ 2003
    Ambio 32 (2003)1. - ISSN 0044-7447 - p. 58 - 64.
    natuurbescherming - stroomvlakten - herstel - wildbescherming - kameroen - projecten - internationale samenwerking - nederland - nature conservation - wildlife conservation - floodplains - rehabilitation - projects - international cooperation - netherlands - cameroon - africa - biodiversity - management - parks
    Integrated Conservation and Development Projects (ICDPs) aim to stimulate conservation without the previous negative experiences for local people, but pay little attention to their long-term impact such as immigration. The rehabilitation of the Logone floodplain in North Cameroon, the core activity of the Waza-Logone ICDP, has led to a 34% increase of sedentary fishermen and a multiple number of temporary fishermen. Whereas livestock pressure tripled, kob antelopes, a key floodplain species, have not increased, reducing their competitiveness. The virtual disappearance of wildlife in nearby Kalamaloue National Park (NP), due to advanced human encroachment forms, is therefore a bleak perspective for Waza NP. Examples from the Central African Republic (CAR), Galapagos, Nigeria and Zimbabwe also showed that in open-access systems, improvement in living standards (development) may stimulate immigration, jeopardizing the stability necessary in protected areas (conservation). Most ICDPs lack demographic monitoring, masking its possible immigration risk. To counter the immigration risk in Waza, a policy was formulated based on local stakeholder categorization and subsequent privileges, resulting in the voluntarily displacement of a village out of Waza NP. It is further recommended that ICDPs should be involved in regional land-use planning and discourage development activities that stimulate immigration.
    Studies in Begoniaceae: VII
    Wilde, J.J.F.E. de - \ 2002
    Leiden : Backhuys (Wageningen University papers 2001-2) - 271
    begoniaceae - begonia - taxonomische revisies - taxonomie - voortplanting - geografische verdeling - plantenecologie - identificatie - determinatietabellen - plantenmorfologie - nieuwe soorten - gabon - kameroen - begoniaceae - begonia - taxonomic revisions - taxonomy - reproduction - geographical distribution - plant ecology - identification - keys - plant morphology - new species - gabon - cameroon
    Sustainable Management of African Rain Forest Part I: Workshops
    Foahom, B. ; Jonkers, W.B.J. ; Nkwi, P.N. ; Schmidt, P. ; Tchatat, M. - \ 2001
    Wageningen : The Tropenbos Foundation - ISBN 9789051130478 - 274
    regenbossen - bosbedrijfsvoering - duurzaamheid (sustainability) - landgebruiksplanning - plattelandsgemeenschappen - participatie - biodiversiteit - houtteelt - zwerflandbouw - houtkap - kameroen - rain forests - forest management - sustainability - land use planning - rural communities - participation - biodiversity - silviculture - shifting cultivation - logging - cameroon
    Sustainable Management of African Rain Forest. Part II: Symposium
    Jonkers, W.B.J. ; Foahom, B. ; Schmidt, P. - \ 2001
    Wageningen : The Tropenbos Foundation - ISBN 9789051130515 - 159
    regenbossen - bosbedrijfsvoering - duurzaamheid (sustainability) - landgebruiksplanning - plattelandsgemeenschappen - participatie - biodiversiteit - houtteelt - zwerflandbouw - houtkap - kameroen - rain forests - forest management - sustainability - land use planning - rural communities - participation - biodiversity - silviculture - shifting cultivation - logging - cameroon
    Biophysical suitability classification of forest land in the Bipindi - Akom II - Lolodorf region, South Cameroon
    Hazeu, G.W. ; Gemerden, B.S. van; Hommel, P.W.F.M. ; Kekem, A.J. van - \ 2000
    Wageningen : Alterra (Tropenbos-Cameroon Doc 4) - 130
    landschapsecologie - tropische regenbossen - landevaluatie - landgebruik - natuurbescherming - bosbouw - landbouw - kameroen - bosproducten anders dan hout - landscape ecology - tropical rain forests - land evaluation - land use - nature conservation - forestry - agriculture - cameroon - non-wood forest products
    The social dimension of rainforest management in Cameroon : Issues for co-management
    Berg, J. van den; Biesbrouck, K. - \ 2000
    Kribi : The Tropenbos-Cameroon Programme - ISBN 9789051130430 - 99
    bosbedrijfsvoering - bosbouw - tropische regenbossen - bedrijfsvoering - regenbossen - gemeenschappen - bosbestanden - bosproducten - wetgeving - participatie - plaatselijke bevolking - kameroen - forest management - forestry - tropical rain forests - management - rain forests - communities - forest resources - forest products - legislation - participation - local population - cameroon
    TROPFOMS, a decision support model for sustainabele management of south Cameroon's rainforests
    Eba'a Atyi, R. - \ 2000
    Agricultural University. Promotor(en): A. van Maaren; W.B.J. Jonkers. - S.l. : S.n. - ISBN 9789058081940 - 203
    tropische regenbossen - oerbossen - bosbedrijfsvoering - duurzaamheid (sustainability) - bosbestanden - houtkap - conservering - kameroen - beslissingsondersteunende systemen - tropical rain forests - virgin forests - forest management - sustainability - forest resources - logging - conservation - cameroon - decision support systems

    Natural forests play an important role in the economy of Cameroon, at both the national and local levels. Unfortunately, there is still a general sense that in Cameroon, like in most tropical countries, forests are not managed in a sustainable way. The poor forest management practices, which still prevail in Cameroon, result from both an inadequate institutional context and insufficient scientific and technical knowledge. For the last few decades important research efforts have been made in tropical forestry. However, these efforts concentrate mostly on developing silvicultural systems and more and more on predicting growth and yield of forest stands. Research on supporting decision-making for forest has been negligible in tropical forestry. The research presented here confronts the problem of how to assist decision-making in tropical forest management using the best available scientific information gathered in different disciplines. The specific objectives of the research were:

    1. To design a system for supporting decision-making with respect to the management of tropical forests.
    2. To assess the effects of different management options on the economic returns of the logging enterprise as well as on the structure of the forest at steady state.
    3. To provide insights into the trade off between income generation through sustainable timber harvesting and the use of the forest by the local population on the one hand, and between income generation through sustainable timber production and nature conservation on the other hand.
    4. To derive recommendations for conversion of the current forest at the Tropenbos Cameroon Programme (TCP) research site into a steady state forest.
    5. To suggest and evaluate adaptations of existing strategies aimed at sustainable management of the tropical moist forest in south Cameroon.

    A methodological tool was developed to support decision making with respect to tropical forest management. The system was given the acronym of TROPFOMS (TROPical Forest Management support System). The management items to which TROPFOMS provides support for decision making include:

    The target steady state growing stock characteristics, mainly the structure in terms of number of trees per size class to be found both before and after harvest and the species composition of the stand

    1. The appropriate cutting cycle for timber harvest,
    2. The amount of wood to be harvested at the end of each cutting cycle,
    3. The expected length of the conversion period and the expected levels of harvest during that period
    4. The multiple use of the forest through an analysis of the trade off between alternative land use types
    5. Consequences of changes in management parameters.

    TROPFOMS consists of four modules including a mathematical programming module, a growth and yield module, and economic module and a constraint definition module. TROPFOMS was developed using mostly quantitative techniques and methods such as transition matrices, cluster analysis, logistic regression analysis, mathematical programming and stumpage prices derivation. The outcomes show that the optimal cutting cycle is about 30 years, for a harvest of 13.4 m 3/ha for the species currently commercialized in south Cameroon. In addition it would require about 120 year to convert the current forest of the Tropenbos Cameroon research site to a regulated forest. TROPFOMS has shown a great deal of sensitivity to hypotheses concerning growth and yield and timber value. Research needs for the improvement of the outcomes of TROPFOMS include: Costs and returns of silvicultural operations, relationships between growth and yield and density of forest stands, reproductive maturity of different tree species, logging efficiency, costs and damage, the utilization of the forest by local population, royalties.

    Diversity and dynamics of mycorrhizal associations in tropical rain forests with different disturbance regimes in South Cameroon
    Onguene, N.A. - \ 2000
    Agricultural University. Promotor(en): L. Brussaard; T.W. Kuyper. - S.l. : S.n. - ISBN 9789058082930 - 167
    mycorrhizae - mycorrhizaschimmels - ectomycorrhiza - vesiculair-arbusculaire mycorrhizae - symbiose - bosecologie - regenbossen - tropische regenbossen - bosbedrijfsvoering - bosschade - entstofdichtheid - kameroen - mycorrhizas - mycorrhizal fungi - ectomycorrhizas - vesicular arbuscular mycorrhizas - symbiosis - forest ecology - rain forests - tropical rain forests - forest management - forest damage - inoculum density - cameroon

    The present study documents the occurrence of mycorrhizal associations in the rain forests of south Cameroon. All species investigated are mycorrhizal. Most timber species form arbuscular mycorrhiza, but some timber species, which usually occur in clumps, form ectomycorrhiza. Species diversity of ectomycorrhizal fungi in the undisturbed rain forest is substantial, with more than 125 species having been recorded. Inoculum potential of arbuscular mycorrhizal and ectomycorrhizal fungi is high in the undisturbed rain forest. The shifting cultivation cycle increases inoculum potential of arbuscular mycorrhizal fungi, but lowers inoculum potential of ectomycorrhizal fungi to various extent.

    On sites of forestry practices (skid trails, landings) inoculum potential of arbuscular mycorrhizal and ectomycorrhizal fungi is very substantially reduced and recovery rates are low. Mycorrhizal colonisation and seedling growth are positively correlated with mycorrhiza inoculum potential. Inoculum potential of arbuscular mycorrhizal fungi and performance of seedlings of arbuscular mycorrhizal trees can be boosted after inoculum addition. Both inoculum quantity and inoculum quality are important criteria for inoculation practices. Ectomycorrhizal inoculum potential cannot be increased through inoculum addition and management of the intact ectomycorrhizal network is necessary for maintenance of the ectomycorrhizal tree species.

    Key words : Arbuscular mycorrhiza, ectomycorrhiza, disturbance, rain forest, diversity, inoculum potential, Cameroon, forestry practices

    Impact of land use change on the hydrology and erosion of rain forest land in South Cameroon
    Waterloo, M.J. ; Ntonga, J.C. ; Dolman, A.J. ; Ayangma, A.B. - \ 1997
    Wageningen : DLO Winand Staring Centre - 89
    ruimtelijke ordening - landgebruik - zonering - bodem - erosie - bosbouw - bodembescherming - waterbescherming - hydrologie - beheer van waterbekkens - bodemwaterbalans - kameroen - physical planning - land use - zoning - soil - erosion - forestry - soil conservation - water conservation - hydrology - watershed management - soil water balance - cameroon
    Rainfall, water, sediment yields and evaporation were quantified in three catchment areas with undisturbed rain forest, selectively logged forest, and forest with shifting cultivation respectively. Despite a considerable regional variation in rainfall(1700-2300 mm/a), annual evaporation rates were similar (1209-1314 mm/a). The impact of land use practices on water yield is negligible compared to the effect of rainfall. The sediment yield increased from 56 kg per ha per year for undisturbed forest to 105 kg per ha per year for forest with agriculture and to 564 kg per ha per year for selective logging. The simulated soil erosion increased by more than 1000 kg/ha when skid tracks were constructed on slopes exceeding 10°.
    The biology and management of wild helmeted guineafowl (Numida meleagris galeata Pallas) in the Waza region of North Cameroon
    Njiforti, H.L. - \ 1997
    Agricultural University. Promotor(en): H.H.T. Prins; H.A. Udo de Haes. - Maroua : Njiforti - ISBN 9789054857365 - 132
    numida - parelhoenders - wildbescherming - populatie-ecologie - nestelen - maatschappelijke betrokkenheid - kameroen - numida - guineafowls - wildlife conservation - population ecology - nesting - community involvement - cameroon

    Criticisms have arisen with respect to the way protected areas in Africa are being managed in a top-down fashion, with the state as the sole owner. Such an approach has failed in a number of protected areas because of encroachment (mainly poaching and habitat destruction), socioeconomic instability, and conflicts of interests with local communities. The long-term conservation of wildlife and the future of many protected areas in Africa today requires a review of present management strategies. In the general introduction (Chapter 1), some of the major problems of protected areas of Africa in general and of Cameroon in particular are discussed.

    One of the major problems facing the managers of protected areas is poaching of wildlife by both local communities and outsiders. 'Bushmeat' (meat from wild animals) is a major source of animal proteins in most parts of Africa. In the two Northern provinces of Cameroon, meat from wildlife is widely consumed. The North African Porcupine ( Hystrix cristata ) and the guineafowl ( Numida meleagris ) top the list among the wildlife species that are consumed (Chapter 2). Since wildlife utilisation by local communities cannot be completely stopped, it is important that some way be found to make such use sustainable. A good sustainable use scheme may also be a way of getting local communities involved in nature and wildlife conservation. Such a scheme could take the form of a regulated hunting arrangement for villages in the area adjacent to protected areas. However, if local communities are to be legally authorised to exploit any natural resources, the exploitation must be sustainable. For the exploitation to be sustainable, there must be a good management strategy based on sound ecological knowledge of the resources.

    The guineafowl was chosen as a species that could possibly be exploited by local communities around the Waza National Park of North Cameroon. The biology of this bird was investigated from 1991 to 1995 to establish an ecological basis for such exploitation. Censuses in and around the Waza National Park showed that the population density of guineafowl in this area could be up to 216±108 birds/km 2. This density varies with habitat type, year, and level of human activity (Chapter 3). Investigation of the diet of this bird from crop content analysis (Chapter 4) showed that it is omnivorous. It feeds on a wide
    variety of plant seeds, roots and insects, but especially on the rhizomes of Stylochiton lancifolius (a plant) and on termites (an insect). A study of the breeding performance of the guineafowl inside the National Park (Chapter 5) showed that the annual rainfall plays an important role in its annual breeding success. Nest abandonment, predation of both eggs and guineafowl hens, trampling by elephants and floods were found to be principal causes of nest losses, but play a lesser role in the total breeding success.

    An investigation of mortality and mortality factors (Chapter 6) showed that the annual mortality rate varied slightly with sex, age and year. A multifactorial analysis of population parameters showed that variations in annual breeding success resulting from variation in annual rainfall could explain most of the population density changes in the region. Hence annual rainfall can be used to estimate annual production and possible harvesting strategy for the Waza guineafowl population.

    Studies on the home range size, emigration, and social organisation (Chapter 7) showed that the home range size varied with season (rainy and dry season). Group size varied with month, being largest between March and April and smallest in August. Young birds and birds in large groups had a higher tendency to emigrate. Information from previous chapters is used to develop a model for predicting annual guineafowl productivity and assess the possible magnitude of harvesting quota for the Waza region (Chapter 8). In the last chapter (Chapter 9), information from a socioeconomic survey in the Waza region and those from other chapters are used to propose a hunting zone for the management of hunting of guineafowl by villagers. A possible set-up of an organisation for running this hunting zone is also proposed.

    The environmental situation in Bamenda, Cameroon : results of a workshop on 30 September 1994
    Hart, T.M. 't; Langeveld, J.W.M. - \ 1995
    Wageningen : IBN-DLO (IBN research report 95/5) - 22
    milieu - mens - milieueffect - sociologie - watervoorziening - afvalwaterbehandeling - gezondheidstechniek - stedelijke gebieden - hygiëne - afval - vuilnis - afvalverwijdering - huisvuilverwijdering - verzamelen - overheidsbeleid - milieubeleid - milieuwetgeving - luchtverontreiniging - bodemverontreiniging - waterverontreiniging - kameroen - menselijke invloed - milieuhygiëne - environment - man - environmental impact - sociology - water supply - waste water treatment - public health engineering - urban areas - hygiene - wastes - refuse - waste disposal - municipal refuse disposal - collection - government policy - environmental policy - environmental legislation - air pollution - soil pollution - water pollution - cameroon - human impact - environmental hygiene
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