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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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    Integratie van de productie van tomaat en algen in kassen
    Sapounas, A. - \ 2013
    algenteelt - tomaten - groenteteelt - meervoudige teelt - glastuinbouw - haalbaarheidsstudies - economische haalbaarheid - biobased economy - modellen - algae culture - tomatoes - vegetable growing - multiple cropping - greenhouse horticulture - feasibility studies - economic viability - biobased economy - models
    Poster met onderzoeksinformatie. Het doel van deze studie is om de productiviteit en de economische haalbaarheid van de combinatie van tomaten en algen productie in een Nederlandse kas te beoordelen. Hiertoe is een model ontwikkeld.
    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
    assumptions.
    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
    run.
    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.



    Diversiteit voor stabiliteit : handreiking voor inpassing van diversiteit binnen productieperceel ter onderdrukking van ziekten en plagen in akkerbouw en vollegrondsgroenteteelt
    Zuilichem, J.A.A. van - \ 2006
    Lelystad : PPO Akkerbouw, Groene Ruimte en Vollegrondsgroenten (PPO nr. 346) - 58
    teeltsystemen - meervoudige teelt - biodiversiteit - akkerbouw - groenteteelt - plantenplagen - plantenziekten - aardappelen - daucus - brassica oleracea var. gemmifera - preien - penen - vollegrondsteelt - agrobiodiversiteit - cropping systems - multiple cropping - biodiversity - arable farming - vegetable growing - plant pests - plant diseases - potatoes - daucus - brassica oleracea var. gemmifera - leeks - carrots - outdoor cropping - agro-biodiversity
    A deskstudy to find the most suitable culture methods for diversification within and between vegetables and arable crops grown at the same field at the same time to reduce pests and diseases.
    Multifunctionele beplantingen van ontwerp naar realisatie; verslag van ervaringen met en onderzoek naar de combinatie van multiproductieve beplantingen met gras en vee
    Oosterbaan, A. ; Berg, C.A. van den; Valk, H. - \ 2004
    Wageningen : Alterra (Alterra-rapport 837) - 44
    meervoudige teelt - teeltsystemen - productiefuncties - dierhouderij - ontwerp - haalbaarheidsstudies - projectbeoordeling - achterhoek - multiple cropping - cropping systems - production functions - animal husbandry - design - feasibility studies - project appraisal - achterhoek
    In het kader van Meervoudig Duurzaam Landgebruik zijn in de omgeving van Winterswijk op verschillende typen bedrijven proefsgewijs `multifunctionele beplantingen¿ aangelegd. Onderzoek is gericht op geschikte boomsoorten, plantafstanden, grasbeheermethoden, invloed van de bomen op de samenstelling en voederwaarde van het gras, vruchtproductie, oogst, afzet en op mogelijkheden voor recreatie-inkomsten. Het concept lijkt goed te passen op extensieve landbouwbedrijven.
    De haalbaarheid van multifunctionele teelt van energiegewassen en bio-energieproductie in Hardenberg.
    Elbersen, H.W. ; Meeusen-van Onna, M.J.G. ; Breteler, H. ; Kasper, G.J. ; Kasper, H. ; Wintjes, A. - \ 2001
    Wageningen : ATO - 91
    bio-energie - gewassen - biomassa - meervoudige teelt - teelt - nederland - brandstofgewassen - haalbaarheidsstudies - biobased economy - economische aspecten - bioenergy - crops - biomass - multiple cropping - cultivation - netherlands - fuel crops - feasibility studies - biobased economy - economic aspects
    Het doel van deze studie was het opstellen van twee verschillende ketens voor de productie van energie uit biomassa (teelt en residuen) in Hardenberg en het verschaffen van inzicht in de technische, economische, maatschappelijke, landschappelijke en bestuurlijke haalbaarheid van deze ketens. Het uitgangspunt is dat energieteelt eerder haalbaar is in Nederland wanneer energieteelt multifunctioneel plaatsvindt. Er zijn twee bio-energieketens, die op een groot aantal punten van elkaar verschillen, beoordeeld op hun haalbaarheid.
    Biological control of cotton aphid (Aphis gossypii Glover) in cotton (inter)cropping systems in China : a simulation study
    Xia, J. - \ 1997
    Agricultural University. Promotor(en): R. Rabbinge, co-promotor(en): W. van der Werf. - S.l. : Xia - ISBN 9789054857136 - 173
    biologische bestrijding - insecten - nuttige insecten - katoen - Aphididae - Coccinellidae - gemengde teelt - tussenteelt - meervoudige teelt - tussenplanting - computersimulatie - simulatie - simulatiemodellen - China - Aphis gossypii - Coccinella septempunctata - biological control - insects - beneficial insects - cotton - Aphididae - Coccinellidae - mixed cropping - intercropping - multiple cropping - interplanting - computer simulation - simulation - simulation models - China - Aphis gossypii - Coccinella septempunctata

    Cotton aphid ( Aphis gossypii Glover) is the key insect pest of seedling cotton ( Gossypium hirsutum L. ) in China, particularly in the North China cotton region. The resulting annual losses amount to 10-15% of the attainable yield. Sole reliance on insecticides against the cotton aphid in the past four decades has brought about a rapid development of insecticide resistance, serious outbreaks of key pests, resurgence of secondary pests, and risk for man and environment. Biological control of the cotton aphid by naturally-occurring seven-spot beetle ( Coccinella septempunctata L .) is the first priority for integrated pest management in cotton to avoid early season application of insecticides and lay a foundation for biological control of aphids and other pests during the season. Augmentation of the seven-spot beetle by intercropping cotton with wheat is the most commonly used approach for cotton aphid biological control. Disadvantages of intercropping are decreased fiber and seed quality, increased outbreaks of cotton bollworm ( Helicoverpa armigera Hubner) and verticillium wilt ( Verticillium dahliae Kleb.), and difficulties with mechanization. There is, therefore, a demand for developing more sociologically, economically and ecologically sound cotton-wheat intercropping systems. Systems research provides an appropriate framework to analyse biological control systems and prototype promising biological control strategies. The objective of this study is (1) to better understand and quantify the major processes in C. septempunctata-A. gossypii system in cotton monoculture and cotton-wheat intercrop; (2) to develop simulation models of the dynamics of the coccinellid- aphid system in both cotton cropping systems by integrating process-level knowledge; and (3) to use the models to obtain insight in the dynamic behavior of the system and explore intercropping strategies that are not only favorable for biological control but also advantageous with respect to labor requirement, fiber and seed quality, and suppression of the cotton bollworm and verticillium wilt by cultural practices.

    A major factor affecting A. gossypii population growth is temperature. Life table parameters of the cotton aphid were determined at 10, 15, 20, 25, 30 and 35 ± 0.5°C in the laboratory (Chapter 2). The relationship of temperature with the developmental rate of each life stage (the reciprocal of the stage duration) was described using Logan curves. The relationship of temperature with the relative mortality rate of each prereproductive stage and each adult age class was described using parabolas. The relationship of temperature with the mean reproductive rate of each adult age class was described using the Weibull model. Development of A. gossypii was fastest at 30°C, with a pre-reproductive period of 4.6 d. The greatest survival from birth to adult (81 %) was obtained at 25°C. Fecundity was maximum at 25°C , with a total fecundity of 28.3 nymphs per female and a mean reproductive rate of 3.1 nymphs per female per day. Threshold temperatures for development of the first to fourth instar and the adult were 8.2, 8.0, 7.2, 6.2 and 7.9°C, respectively; and the thermal constants were 24.2, 23.7, 23.0, 25.5 and 168.8 degree-days (D°), respectively. A. gossypii obtained its greatest intrinsic rate of increase (0.386 d -1) at 25°C. High relative rate of population increase at 25°C resulted in a daily population increase of 47% and a doubling time of 1.8 d, illustrating the tremendous growth capacity of A. gossypii under favorable conditions. Comparison to similar records from other crops indicates a relatively high heat tolerance of A. gossypii on cotton in North China. The data gathered are used to construct a simulation model of A. gossypii population dynamics in cotton.

    Temperature and food quantity are two major factors affecting C. septempunctata population growth. Life history parameters of the seven-spot beetle feeding on A. gossypii were determined in two experiments in the laboratory (Chapter 3). The first experiment addressed the effect of five temperatures (15, 20, 25, 30 and 35 ± 0.5°C) on the beetle bionomics, while the second one addressed the effect of food quantity on the beetle bionomics at a temperature of 25°C. The relationship between temperature and the developmental rate of each life stage was described with Logan curves. The relationship of temperature with the relative mortality rate of each pre-oviposition stage and each adult age class was described with parabolas. The relationship between temperature and the mean oviposition rate of each adult age class was described with the Weibull model. C.septempunctata developed most rapidly at 35°C, with a preimaginal period of 10.8 d. The highest survival from egg to adult (47%) was obtained at 25°C. Oviposition was greatest at 25°C, with a total oviposition of 287.4 eggs per female and a mean oviposition rate of 22.4 eggs per female per day. Threshold temperatures for development of eggs, larvae, pupae and adults ranged from 10.9 to 13.9°C, with 12.6°C for the entire life span; and thermal constants were 42.0, 103.7, 63.6 and 302.9 D°, respectively. Over the range of prey densities tested, a 3.54-fold increase in prey density resulted in a 2-fold reduction in larval development time and a 3-fold increase in larval survival. A 2-fold increase in prey density led to a 2-fold increase in total oviposition and the mean oviposition rate. The data gathered are used to construct a simulation model of C.septempunctata population dynamics in cotton.

    Functional responses of five foraging stages of C. septempunctata on three sizegroups of A. gossypii (mixed first and second nymphs, mixed third and fourth nymphs, and adults) at five temperatures (15, 20, 25, 30 and 35 ± 0.5°C) were determined in the laboratory (Chapter 4). All functional responses were of type 11 and were adequately described by Rogers' random predator equation. The search rate increased linearly from 15 to 35°C with a factor of 3-8. The handling rate showed a curvilinear relation to temperature and was lowest at 15°C. There was a considerable variation in the latter response curves in different predator-prey stage combinations. In some predator-size- groupsprey interactions, handling rate increased consistently with temperature, while in other combinations, the relationship had a maximum at an intermediate temperature. Search rate increased with 50-100% from one larval predator instar to the next but decreased from the fourth instar to the adult predator. There was only moderate difference in search rate between prey size-groups for the same predator stage (< 50% between extremes). Handling rate increased with 50-100% from one predator stage to the next, but it was somewhat similar in the fourth instar and adult predators. Handling rate towards early instar, late instar and adult prey varied with a ratio of about 3:2:1. The functional responses are incorporated in the simulation model of C.septempunctata-A. gossypii population interaction and dynamics in cotton.

    In Chapter 5, a simulation model of the temporal dynamics of the coccinellid-aphid system in cotton monoculture was developed by integrating process-level knowledge. Six submodels were distinguished: cotton aphid, seven-spot beetle, predator-prey interaction, parasitism, cotton plant, and abiotic factors. The model was tested and evaluated at three levels of the system complexity: laboratory, field cage and open field. At each level of complexity, processes were added to the model, based on discrepancies between "original model" behaviors and observations, and additional experimentation. Processes included in the model at the laboratory level were temperature-dependent development, survival and reproduction of both insects; and prey density, prey size-group and temperature- dependent predation. Adaptations for the field cage level were density dependence of wing induction and reproduction of A . gossypii, extrapolation of the functional response from single stage interaction in experimental arenas in the laboratory to multiple stage interactions on plants, and a higher mortality for C . septempunctata than observed in the laboratory. Adaptations for the open field level were immigration rates of both insects; time- dependent parasitization of alate immigrants by Allothrombium, apterous aphids by hymenopterous parasitoids and seven-spot beetle pupae by Tetrastichus coccinellae Kurjumov; prey density-dependent departure rate of seven-spot beetle adults; prey density and prey size-group dependent predation by Propylaea japonica (Thungberg); and accumulated (D°)-driven cotton canopy growth. The simulated and observed data were in reasonable agreement at all levels, though discrepancies increased with the level of scale. Simulations at the open field level show that C. septempunctata plays a key role in controlling A. gossypii in cotton monoculture, but its numbers increase too late to guarantee a sufficient biological control. Predation by P . japonica and parasitism by Allothrombium and hymenopterous parasitoids play only a minor role. Variations in temperature or immigration of alate A. gossypii alone can not explain between-season differences in aphid population dynamics. Immigrating numbers of seven- spot beetle adults is the key factor.

    Based on the model of Chapter 5, a simulation model of the spatio-temporal dynamics of the coccinellid-aphid system in cotton-wheat intercropping was developed in Chapter 6. Six submodels were distinguished: temporal dynamics of A. gossypii populations, temporal dynamics of C.septempunctata populations on wheat, seven-spot beetle dispersal from wheat into cotton, predator-prey interaction on cotton, cotton plant, and abiotic factors. In addition to the processes common in cotton monoculture and cotton-wheat intercrop, processes related to the cotton-wheat intercrop were experimentally characterized and included: (a) immigration of alate aphids into intercropped cotton and seven-spot beetle adults into intercropped wheat; (b) prey density-dependent emigration of seven-spot beetle adults from ripening wheat by flight; (c) prey density-dependent dispersal of foraging predators from wheat into cotton by walking; (d) time-dependent parasitization in apterous aphids and seven-spot beetle pupae; and (e) accumulated (D°)-driven cotton canopy growth. Dispersal of foraging seven-spot beetles from wheat into cotton was modelled as a diffusion process. There was satisfactory correspondence between the simulated and observed data. Simulations show that the low abundance of the cotton aphid in the current cotton-wheat intercropping system is due to a combined effect of increased predation and parasitism, and decreased aphid immigration, of which predation by the seven-spot beetle is the most important. Current cotton-wheat intercropping has an "overcapacity" for biological control. Simulations indicate that effective biological control can still be achieved when the immigration rate of alate aphids is increased by a factor 4, and the proportion of the seven-spot beetle foraging on cotton and the parasitization of apterous aphid are decreased by 40%. These results suggest that it is possible to increase distance from wheat to cotton strips in the current intercropping system and maintain effective biological control of the cotton aphid.

    Based on models developed and insights gained in this study, a promising strategy of cotton-wheat strip cropping was proposed, which would be not only favorable for A. gossypii biological control but also advantageous with respect to labor requirement, fiber and seed quality, and suppression of the cotton bollworm and verticillium wilt by cultural practices. For its validation, field work is required. More research is needed to determine the effect of distance from wheat to cotton strips on immigration of alate aphids into cotton and dispersal of major predators from wheat into cotton. With these parameters included in the model of Chapter 6, the promising strategy of cotton-wheat strip cropping can be identified and tested on a large scale. Observations should be also made for effectiveness and profitability of the proposed strategy for further improvement and development of cotton cropping systems in North China.

    Mengteelt van populieren met suikerbieten, snijmaos en gras. Deel 2 en 3: Groei en opbrengst van bomen en landbouwgewassen in mengteelt en verzamelde data van mengteeltonderzoek
    Bervaes, J.C.A.M. ; Dik, E.J. ; Edelenbosch, N.H. ; Everts, H. ; Schans, D.A. van der; Westerdijk, C.E. - \ 1995
    Wageningen [etc.] : IBN-DLO [etc.]
    bosbouw - meervoudig landgebruik - gemengde teelt - agroforestry - tussenteelt - meervoudige teelt - tussenplanting - bomen - graslanden - beta vulgaris - suikerbieten - zea mays - maïs - kosten-batenanalyse - nederland - forestry - multiple land use - mixed cropping - agroforestry - intercropping - multiple cropping - interplanting - trees - grasslands - beta vulgaris - sugarbeet - zea mays - maize - cost benefit analysis - netherlands
    Woody plants in agro-ecosystems of semi-arid regions
    Breman, H. ; Kessler, J.J. - \ 1995
    Springer Verlag (Advanced Series in Agricultural Sciences ) - ISBN 9783642792090
    bosbouw - agroforestry - ecologie - gewassen - landbouw - fenologie - acclimatisatie - gemengde teelt - tussenteelt - meervoudige teelt - tussenplanting - bedrijfssystemen - relaties - steppen - pampa's - semi-aride klimaatzones - agro-ecosystemen - forestry - ecology - crops - agriculture - phenology - acclimatization - mixed cropping - intercropping - multiple cropping - interplanting - farming systems - relationships - steppes - pampas - semiarid zones - agroecosystems
    A quantitative analysis of the role of woody plants in semi-arid regions, focusing on the Sahel and Sudan zones in West-Africa, is given for the assessment of their benefits in agro-sylvopastoral land-use systems with productive and sustainability objectives.
    Compatibility, persistence and productivity of grass-legume mixtures for sustainable animal production in the Atlantic Zone of Costa Rica
    Ibrahim, M.A. - \ 1994
    Agricultural University. Promotor(en): L. 't Mannetje. - S.l. : Ibrahim - ISBN 9789054852278 - 129
    weiden - fabaceae - gemengde teelt - tussenteelt - meervoudige teelt - tussenplanting - vleesvee - begrazing - costa rica - voedergrassen - pastures - fabaceae - mixed cropping - intercropping - multiple cropping - interplanting - beef cattle - grazing - costa rica - fodder grasses

    The main objective of this study was to identify compatible and persistent grass-legume mixtures of high feeding value for forage improvement in the Atlantic Zone of Costa Rica. The study was conducted between September 1989 and October 1992 at LA)s Diamantes research station, Guápiles, Costa Rica. The treatments consisted of a factorial of three legumes (Centrosema macrocarpum(Cm) CIAT 5713, Stylosanthes guianensis (Sg) CIAT 184 and Arachis pintoi (Ap) CIAT 17434), two grasses (Brachiaria brizantha (Bb) CIAT 6780 and Brachiaria humidicola (Bh) CIAT 6339) and two stocking rates (1.75 (LSR) and 3.00 (HSR) AU/ha). Measurements were made on dry matter yields and botanical composition, legume persistence, nutritive value, liveweight gain (LWG) and soil fertility, carbon storage and soil compaction.

    Dry matter yields were high in all mixtures in particular at the LSR and with Bb. Cm and Sg failed to persist during the 2.5 years of grazing while Ap was persistent, especially at the HSR. Ap proved to be too aggressive for Bh. Ap was more or less stable with Bb and it performed better at the HSR. Bh mixtures were invaded with unpalatable weeds while those of Bb were practically weed free.

    Nutritive value of the mixtures was adequate for high beef production. LWG on Bb + Ap at the HSR was 937 kg/ha/year which was six times that reported for native pastures in the region and 459 kg higher than that of the monoculture of Bb.

    Soil organic matter and total organic carbon were similar to those measured under primary forest and there was no evidence of high degree of soil compaction. From the results it is concluded that Ap was the most persistent legume studied and the mixture of Bb + Ap at the HSR was the most suitable combination for forage improvement in this region.

    Analysis of yield advantage in mixed cropping
    Ranganathan, R. - \ 1993
    Agricultural University. Promotor(en): C.T. de Wit, co-promotor(en): C.K. Ong. - S.l. : Ranganathan - ISBN 9789054850335 - 93
    gemengde teelt - tussenteelt - meervoudige teelt - tussenplanting - oogsttoename - oogstverliezen - opbrengsten - mixed cropping - intercropping - multiple cropping - interplanting - yield increases - yield losses - yields

    It has long been recognized that mixed cropping can give yield advantages over sole cropping, but methods that can identify such yield benefits are still being developed. This thesis presents a method that combines physiological and economic principles in the evaluation of yield advantage. A production possibility frontier, drawn from economics literature, represents the maximum yield combinations that can be obtained from intercropping. Inter- and intra-specific competition for resources determine yield in mixed cropping. Production possibility frontiers have been derived using such a priori knowledge of the processes underlying mixed cropping, thereby facilitating economic and agronomic analyses of yield advantage. The analytical procedure used in such analyses is illustrated for various crop mixtures.

    The assumption underlying the derivation of a production possibility frontier is the hyperbolic relationship between yield and plant density. This assumption cannot always be made for marketable yield. Per-plant marketable yield and total dry matter relationships are explored and used to derive production possibility frontiers.

    When annuals are cropped with perennials, the strongly competitive perennial often dominates, effecting a significant yield reduction in the annual. Management seeks to alter the competitive relationships of the perennial and annual towards a more equitable distribution of resources. A strategy for managing the perennial, on the basis of its competitive strength, by relating yield loss in the annual to the relative leaf area of the perennial in the mixture is described.

    Field experiments with groundnut ( Arachis hypogaea ) intercropped with perennial pigeonpea ( Cajanus cajan ) and the analysis of yield advantage from this cropping system are discussed.

    Low-external-input alternatives to shifting cultivation in S. Sumatera : brief description of an Indonesian - Dutch project on environment and development
    Noordwijk, M. van; Guritno, B. - \ 1992
    Haren (Gr.) : DLO-Instituut voor Bodemvruchtbaarheid (Nota / DLO-Instituut voor Bodemvruchtbaarheid 251) - 24
    alternatieve landbouw - tussenteelt - tussenplanting - gemengde teelt - meervoudige teelt - biologische landbouw - zwerflandbouw - zelfvoorzieningslandbouw - sumatra - alternative farming - intercropping - interplanting - mixed cropping - multiple cropping - organic farming - shifting cultivation - subsistence farming
    Woody species in auxiliary roles : live stakes in yam cultivation
    Budelman, A. - \ 1991
    Agricultural University. Promotor(en): M. Flach; R.A.A. Oldeman. - S.l. : Budelman - 151
    gemengde teelt - tussenteelt - meervoudige teelt - tussenplanting - dioscorea - yams - bosbouw - bomen - cultuurmethoden - agroforestry - mixed cropping - intercropping - multiple cropping - interplanting - dioscorea - yams - forestry - trees - cultural methods - agroforestry

    Het opnemen van houtige overblijvende plantesoorten in éénjarige teeltsystemen wordt momenteel gepropageerd als een mogelijkheid om de duurzaamheid van seizoensgebonden gewasproduktie te vergroten. Deze ontwikkeling is van belang voor landbouwsystemen in gebieden waar de natuurlijke vruchtbaarheid laag is, het klimaat bodemerosie sterk bevordert en de landbouwondersteunende infrastructuur onbetrouwbaar is, met name wat betreft de aanvoer en prijs van inputs en vermarkting van de produktie. Een dergelijke combinatie van omstandigheden treffen we niet zelden aan in landen in de tropen.

    Ten grondslag aan het opnemen van overblijvende plantesoorten ligt het idee dat de permanent aanwezige biomassa (boven- en ondergronds) en de afgeleide strooisellaag bijdragen tot het behoud van de kwaliteit van de omgeving waar de gewasproduktie plaatsvindt. Wezenlijke aspecten daarbij zijn het vermijden van verliezen van voedingsstoffen door uitloging en oppervlakte-erosie, het behoud van de bodemstructuur en de tijdelijke opslag van voedingsstoffen in de biomassa.

    In dit boek worden informatie uit de literatuur en resultaten van veldonderzoek samengebracht, met betrekking tot het gebruik van drie houtige leguminosen (Leucaena leucocephala, Gliricidia sepium en Flemingia macrophylla) in de teelt van het voedingsgewas yam (Dioscorea alata). In de studie spelen de houtige soorten een hulprol; zij produceren mulch-materiaal en bieden steun aan het klimmend hoofdgewas.

    In Deel II van het boek wordt in twee artikelen ingegaan op de bladproduktie van de hulpgewassen en wordt beschreven hoe de nutriëntensamenstelling van het blad zich in de loop van de tijd ontwikkelt.

    In Deel III wordt aan de hand van een viertal artikelen een beschrijving gegeven van de afbraak van de bladsoorten wanneer deze gebruikt worden als mulch, en de gevolgen voor temperatuur en vochtgehalte in de bovenste bodemlaag, het opkomen van onkruiden en het vrijkomen van voedingsstoffen.

    In Deel IV, bestaande uit twee artikelen, wordt de interactie tussen hulpgewas en hoofdgewas verkend, en de problemen aangaande de interpretatie van gegevens verkregen uit veldproeven beschreven.

    De artikelen zijn samengevat in Deel I en worden daar voorzien van een algemene achtergrond waartegen de resultaten van het onderzoek geplaatst moeten worden. Op grond van dit overzicht worden aanbevelingen voor verder onderzoek geformuleerd.

    Mixed cropping of groundnuts and maize in East Java
    Hoof, W.C.H. van - \ 1987
    Agricultural University. Promotor(en): M. Flach; G.H. de Bruijn. - Renkum : Van Hoof - 156
    Arachis hypogaea - aardnoten - tussenteelt - tussenplanting - Java - maïs - gemengde teelt - meervoudige teelt - Zea mays - Arachis hypogaea - groundnuts - intercropping - interplanting - Java - maize - mixed cropping - multiple cropping - Zea mays
    Mixed cropping of groundnuts and maize in East Java was studied by means of a survey of farming practice and by field experiments. The influence of different sowing times and plant density of maize on the development and yield of groundnuts and maize were the main topics in this thesis. Plant arrangement, light use efficiency, and economic aspects were also investigated.

    The normal farming practice in East Java for mixed cropping of groundnuts and maize was to sow the crops simultaneously at the end of the rainy season. The average plant densities used were: 190,000 plants per hectare (167,000-214,000) for groundnuts (95% of the plant density of the sole crop) and 40,000 plants per hectare (31,000-50,000) for maize (53% of the sole crop density). Average yields were 1140 kg/ha of groundnuts (80% of the sole crop yield) and 900 kg/ha of maize (43% of the sole maize yield). The average LER of the mixed crops was 1.23, which means a 23% higher productivity than the sole crops of groundnuts and maize.

    In the field experiments, the density of groundnuts was 160,000 plants per hectare, and the density of sole maize was 125,000 plants per hectare (80 x 20 cm, 2 plants per hill). In each of the experiments 3 to 7, the plant density of maize in the mixed crops was varied. in experiments 1 and 2 , however, the maize density was 83,000 plants per hectare (80 x 30 cm, 2 plants per hill), both in sole and mixed crops.

    In experiments 1 and 2, the sowing date of maize (sown at 100% density) in the mixed crop was varied. Later sown maize plants were less developed and gave lower yields than simultaneouslysown maize. Groundnuts in the mixed crops showed a better development and yield when maize was sown later, but not as good as sole groundnuts.

    In experiment 2, the sole crop yields were much higher, and the response to a delay in sowing time of the maize was much stronger than in experiment 1. The higher yield was due to better nutrient availability and freedom from water stress in the beginning of the growing period.
    The most equal yield distribution between groundnuts and maize in mixed crops was reached when maize was sown about 10 days later than groundnuts.

    In experiments 3 to 5 the plant density of maize in the mixed crop was varied, with maize sown 10 days later than the groundnuts. At higher plant densities, the development and yield of the groundnut crop and of the individual maize plants was less than at lower maize densities.
    When maize was sown 10 days later than the groundnuts (100% density), maximum maize yields in mixed crops were obtained at maize densities between 80% and 150% of the sole crop density, but the highest LER values for the mixed crop were reached with slightly lower maize densities between 70% and 100%. This was higher than the usual maize density in farmers' fields of about 50% in mixed crops with simultaneously- sown groundnuts and maize.

    The effect of the arrangement of maize plants in mixed crops was small compared with the effect of plant density. only at extremely high maize densities, plant arrangement had a substantial effect (experiment 5).

    The interaction of sowing time effect and plant density effect, studied in experiments 6 and 7, showed that the longer the delay in sowing time of the maize, the higher the plant density of maize had to be, to reach maximum LER values for the mixed crop.

    The higher productivity of the mixed crops compared to sole maize can be explained by the higher percentage of intercepted light (67% against 43%), and compared to sole groundnuts by the better utilization of the intercepted light (1.0% against 0.6%).

    The revenues from the mixed crops were much higher than from sole maize and only slightly lower than from sole groundnuts. Delaying the sowing of maize in the mixed crop resulted in higher revenues. A change in the price ratio between groundnuts and maize from 4:1 to 2:1 would result in higher revenues for the mixed crop than for each of the sole crops (chapter g).

    In mixed crops, a higher share of the work was done by women (57%) than in sole groundnuts (53%) and sole maize (27%). A 10-day delay in the sowing time of maize resulted in a better spreading of the labour demand over the growing period.

    Sowing maize 10 days later than groundnuts at a density of 75% of the normal sole crop density can be an improvement of the normal farming practice to sow maize at 50% density simultaneously with the groundnuts. In mixed crops with 10 days delay in sowing time of maize and 70% to 100% maize density, the marketable yield was 1070 kg/ha of groundnuts and 1840 kg/ha of maize, averaged over the 7 field experiments. The groundnut yield in the experiments was similar to that in the farmers' practice with simultaneous sowing and 50% maize density, and the maize yield was twice as high.

    In experiment 2, with its high fertility level and its adequate water supply, the LAI of sole maize was higher than 4, and sole maize yield was over 4 tons per hectare. In mixed crops with LAI values of maize higher than 4, the shading of the groundnut crop is too heavy, and no yield advantage can be expected from the mixed crop compared to the sole maize crop. Relay cropping can be a proper practice of intensive crop production when high yield levels are obtained with sole crops. Mixed crops are more secure than sole crops in situations of marginal farming, low soil fertility, unreliable water supply and low input level. Improvements in mixed cropping techniques are a cheap way to increase the food production in East Java.

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