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Agronomic performance of wild mustard in an intercropping with green beans.Phiri, Nathan. January 2005 (has links)
Wild mustard (Brassica spp.) is used as an edible wild leafy vegetable by indigenous people
in South Africa. The potential of wild leafy vegetables in agriculture is not well understood,
because there is generally no agronomic research on their production practices. The objective
of this study was to examine the performance of three wild mustard species (herein referred
to as I, K and M) over four cropping seasons in an intercropping system with green beans
(Phaseolus vulgaris L. cv. Imbali). The crops were grown with and without organic fertiliser
under dryland conditions at two sites (The University of KwaZulu-Natal Research Farm,
Ukulinga and in a rural area of Umbumbulu, KwaZulu-Natal within the farmers' locality)
during autumn, winter, spring and summer of 2004 to 2005. Plant development (leaf number,
plant height and fresh biomass) during the first six weeks after sowing and seed yield were
used to determine agronomic performance of each species. Nutrient status of the rhizosphere
soil was determined at 42 days after sowing for each species to determine what effect
growing the species would have on mineral availability. Wild mustard production
significantly (P < 0.01) performed better at Ukulinga than Umbumbulu. Polyculture was
beneficial for wild mustard leaf accumulation and green bean production as determined by
land equivalent ratios greater than one for all species combinations, regardless of fertiliser
application. Cool environmental conditions occurring in autumn and spring were more
favourable (P < 0.05) for wild mustard and green bean biomass accumulation than summer
and winter conditions. However, wild mustard seed yield was highest in winter compared
with autumn and spring, and there was no measurable seed production in summer. Soil
analysis results at 42 days after sowing showed an increase in P, K, Cu and Mg in the
rhizosphere of wild mustard without organic fertiliser. Polyculture improved Zn, Cu, Mn and
K in wild mustard leaf tissue. It is concluded that wild mustard can be grown as a leafy
vegetable throughout the year, but it requires cool environmental conditions to enhance seed
yield. Species M significantly yielded better biomass and seeds than species I and K during
all the seasons. However, species K performed the least in all aspects. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
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Temperatura e umidade de um solo franco arenoso cultivado com milho / Temperature and humidity of a sandy loam soil cultivated with maizeKnies, Alberto Eduardo 01 March 2010 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Water is a key factor for crop yields, and causes major fluctuations in productivity, especially for maize cultivated in southern Brazil. Mulching the soil surface, temperature and soil moisture are factors closely linked and, when handled properly, can provide the increases crop yields. The soil water conservation is an important aspect for more stable and sustainable agricultural production. The purpose of this study was to evaluate changes in water content and dynamics of the temperature in a soil cultivated with maize under different amounts of plant residue on the surface and water regimes. The experiment was conducted in the experimental area of Agricultural Engineering Department, Federal University of Santa Maria, RS, in the crop year 2009/10, inside a rainfall shelter. The experimental design was completely randomized, factorial, with five replications. Factor A consisted of three quantity of plant residue on the soil surface: 0 (zero), 3 and 6 Mg ha-1 of oat (Avena strigosa Schreb). Factor B consisted of two water regimes: with and without irrigation. The volumetric water content (cm3 water cm-3 soil) of soil was determined in the layers: 0-0.1, 0.1-0.25, 0.25-0.55 and 0.55 - 0.85 m, for a set FDR
(Frequency Domain Reflectometry). The soil temperature was measured by thermocouples, consisting of a copper wire and the other of constantan, which determined the soil temperature at depths of 0.03, 0.08, 0.15 and 0.30 m. The
morphological characteristics of maize plants, as leaf area and cumulative length of leaves were determined with the portable leaf area LI-COR 3000C. The lowest
cumulative losses of soil water in the 0-0.1 m were observed in the soil maintained with 6 Mg ha-1 crop residues on the surface, reaching 50% reduction to 100 mm of accumulated reference evapotranspiration (18 days after seeding) compared to bare soil. The use of crop residues on the soil surface did not produce significant changes
fenometric in maize plants during the evaluation period. The quantities of 3 and 6 Mg ha-1 crop residues oat deposited on the surface of the soil decreased the maximum
temperature and temperature range in the soil. / A água é um fator fundamental à produção das culturas, tendo papel importante nas flutuações de produtividade, principalmente para a cultura do milho no Sul do Brasil. A cobertura morta na superfície do solo, a temperatura e a umidade do solo são fatores intimamente interligados e, quando manejados adequadamente, podem propiciar incrementos à produção das culturas. A conservação da água no solo é um aspecto de relevância para uma produção agrícola mais estável e sustentável. A finalidade deste trabalho foi avaliar as variações no conteúdo de água
e na dinâmica da temperatura de um solo cultivado com milho sob diferentes quantidades de resíduo vegetal na superfície e regimes hídricos. O experimento foi realizado em área experimental do Departamento de Engenharia Rural da
Universidade Federal de Santa Maria, RS, no ano agrícola de 2009/10, no interior de uma cobertura móvel. O delineamento experimental utilizado foi o inteiramente casualizado, bifatorial, com cinco repetições. O fator A foi constituído de três quantidades de resíduo vegetal sobre a superfície do solo: 0 (zero), 3 e 6 Mg ha-1 de aveia preta (Avena strigosa Schreb). O fator B foi constituído de dois regimes hídricos: irrigado e não irrigado. O conteúdo volumétrico de água (cm3 água cm-3 solo) do solo foi determinado nas camadas de: 0-0,1; 0,1-0,25; 0,25-0,55 e 0,55-0,85 m, por um conjunto FDR (Reflectometria no Domínio de Freqüência). Para avaliação
da temperatura do solo, foram utilizados termopares, constituídos de um fio de cobre e de outro de constantan, os quais determinaram a temperatura do solo nas profundidades de 0,03; 0,08; 0,15 e 0,30 m. As características morfológicas das plantas de milho, como área foliar e comprimento acumulado das folhas, foram determinadas com medidor portátil de área foliar LI-COR 3000C. As menores perdas
acumuladas de água do solo na camada de 0-0,1 m foram observadas no solo mantido com 6 Mg ha-1 de resíduo vegetal na superfície, chegando a 50 % de redução aos 100 mm de evapotranspiração de referência acumulada (18 dias após a semeadura) comparado ao solo descoberto. A utilização de resíduos vegetais não proporcionou alterações fenométricas significativas nas plantas de milho durante o
período de avaliação. As quantidades de 3 e 6 Mg ha-1 de resíduos vegetais de aveia preta depositados sobre a superfície do solo diminuíram a temperatura máxima e a amplitude térmica no solo.
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Analyse des conflits et synergies entre services écosystémiques multiples en vergers de pommiers / Analyzing multiple ecosystem services in apple orchardsDemestihas, Constance 23 February 2017 (has links)
Le concept de « service écosystémique », en plein essor depuis la publication du Millenium Ecosystem Assessment en 2005, a permis de souligner l'importance des performances non-marchandes des écosystèmes. En arboriculture, assurer une bonne productivité tout en préservant les ressources naturelles et la santé humaine est aujourd’hui un défi majeur, qui peut être analysé sous l’angle des services écosystémiques. Quels sont ces services au sein d’un verger de pommiers ? Comment les analyser ? Quels sont les liens - conflits et synergies - entre services écosystémiques multiples et comment les systèmes de culture modifient-ils les profils de services multiples? Ce travail de thèse vise à répondre à ces questions avec une démarche novatrice combinant mesures expérimentales, modélisation et analyse statistique. Suite à une analyse bibliographique des services écosystémiques pouvant être délivrés dans des vergers, cinq services ont été sélectionnés. Il s’agit de la production de fruits, de la disponibilité de l’azote dans le sol, de la régulation du climat reposant sur la prévention de la dénitrification de l’azote et sur la séquestration du carbone, de la maintenance et de la régulation du cycle de l’eau y compris de sa qualité, et de la régulation des bioagresseurs. Conjointement à ces services nous avons considéré les nuisances environnementales dues aux pesticides. Pour chaque service nous avons identifié les fonctions écosystémiques sous-jacentes ainsi que les pratiques agricoles et les conditions pédoclimatiques ayant un impact sur ces fonctions. Les services et fonctions ont été décrits par un ou plusieurs indicateurs et quantifiés à l’aide de modèles dans les cas suivants : (i) neuf systèmes de culture réels sur deux dispositifs expérimentaux dans le sud-est de la France et (ii) 150 systèmes de culture fictifs conçus à partir de la combinaison de cinq leviers de pratiques et de leurs modalités, dans des conditions pédoclimatiques identiques. Les deux modèles utilisés ont été STICS, un modèle générique de simulation du fonctionnement du sol et des cultures sous l’influence des pratiques, qui a nécessité une paramétrisation et une évaluation sur pommier à partir de mesures expérimentales, et IPSIM, une plateforme de modélisation simulant les effets des pratiques et des conditions du milieu sur les dégâts aux cultures causés par les bioagresseurs. IPSIM a été paramétré sur pommier, sur la base d’une importante étude bibliographique et à dires d’experts. Les simulations des modèles ont fait l’objet d’analyses statistiques simples dans le cas des systèmes de culture réels, et d’analyses multivariées à deux tableaux (analyse en composantes principales avec variables instrumentales) pour les systèmes de culture fictifs. Pour les neufs systèmes de culture réels, 14 liens importants entre services écosystémiques ont été identifiés, notamment des conflits comme celui entre la prévention de la dénitrification ou de la lixiviation de l’azote et la disponibilité de l’azote dans le sol à court terme, et des synergies, comme celle entre l’humidité du sol ou la séquestration du carbone et la disponibilité de l’azote dans le sol à court terme. Ces liens entre services sont expliqués par les fonctions écosystémiques sous-jacentes. La comparaison de profils de services entre systèmes a mis en évidence l’impact de pratiques agricoles sur certains services. Ainsi, sur un même site, une forte densité de plantation augmente la production de fruits et la séquestration du carbone. La fertilisation exclusivement sous une forme organique diminue la production de fruits via un stress azoté mais diminue également la lixiviation. Par ailleurs, les profils de services sont fortement influencés par les caractéristiques pédoclimatiques de chaque site. Ces résultats confortent la nécessité d’une prise en compte explicite de l’interdépendance ‘pratiques x conditions du milieu’ pour analyser les services. / The concept of « ecosystem service », which has been used increasingly since the publication of the Millennium Ecosystem Assessment in 2005, has highlighted the importance of ecosystem’s non-marketed performances. In orchards, ensuring high productivity while preserving natural resources and human health has become a real challenge that could be analyzed with the concept of ecosystem service. Which ecosystem services are delivered in an apple orchard? How to analyze them? What are the relationships - conflicts or synergies – among multiple ecosystem services and how do cropping systems change multiple ecosystem service profiles? This PhD work aims at answering those questions with an innovative approach combining experimental measures, modeling and statistical analysis.Based on a literature review of ecosystem services in orchards, five services were selected: fruit production, nitrogen availability in soil, climate regulation based on the prevention of nitrogen denitrification and on carbon sequestration, maintenance and regulation of water cycle, including water quality, and pest control. We also considered the environmental disturbances caused by the use of pesticides. For each service, we identified the underlying ecosystem functions as well as the agricultural practices and soil and climate conditions affecting these functions. Services and functions were described by one or multiple indicators and quantified using models in the case of (i) nine existing cropping systems on two experimental sites in southeastern France differing in terms of soil and climate conditions, and (ii) 150 virtual cropping systems designed out of the combination of five major agricultural practice levers and their modalities, in identical soil and climate conditions. The two models used were STICS, a generic soil-crop simulation model under the influence of practices which required a parameterization and an evaluation on apple orchards based on experimental measures, and IPSIM, a generic modeling framework simulating the impacts of agricultural practices and local conditions on crop injuries caused by pests. IPSIM was parameterized on apple orchards, based on an important literature review and expert opinions. Model simulations were analyzed with simple statistics in the case of the nine existing cropping systems and with two-table multivariate analyses (principal component analysis with instrumental variables) for virtual cropping systems.Concerning the existing cropping systems, 14 important relationships were identified among ecosystem services, especially conflicts, like the one between nitrogen denitrification or leaching prevention and soil nitrogen availability on the short term, and synergies such as the one between soil humidity or carbon sequestration and nitrogen availability on the short term. These relationships are explained by the underlying ecosystem functions. Comparing service profiles among cropping systems highlighted the impacts of agricultural practices on some services. That way, on a same site, a high planting density increases fruit production and carbon sequestration. An exclusively organic fertilization decreases fruit production through nitrogen stress but also nitrogen leaching in drained water. Furthermore, service profiles are strongly influenced by the soil and climate conditions of each site. These results strengthen the need to explicitly consider the ‘agricultural practices x soil and climate conditions’ interdependence in order to analyze ecosystem services. The results obtained with the virtual cropping systems simulations confirmed those of the existing ones and gave precision on the impacts of fertilization, irrigation and pest control for codling moth, rosy apple aphid and apple scab on ecosystem functions and services.
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Grazing management in the communal rangelands of the Upper Thukela, Kwazulu-Natal.Tau, Mahlodi Solly. January 2005 (has links)
The grazing management project in the Okhombe ward of the Amazizi Tribal Authority
formed part of the National Department of Agriculture's LandCare program to address
communal natural resource management issues. Okhombe land is communal whereby
every member of the community is the legal owner of the rangeland with individual
ownership of stock with the chieftaincy playing a major role in land allocation. In order
to avoid critics of the past and address the top-down approach of the past interventions, a
participatory approach was conducted in the planning and implementation of the grazing
system. The service providers held a series of visioning workshops with the community
in an effort to better understand community resource use patterns, needs, constraints and
opportunities as part of the participatory approach. Issues identified by the community
were the need for fencing grazing camps, animal health improvement, subdivision of
rangeland and crop fields and the development of a rotational grazing system.
The main aims of this study were to develop a participatory grazing plan with the
community, develop and support institutional structures governing range management,
and build capacity of the community in range management. The effect of the current
grazing system on species composition was determined. In addition to these, the project
investigated the potential different fodder trees has on alleviating feed and nutritional
deficit, particularly during the dry winter months of the Upper Thukela.
Among the main achievements of this study was the development and strengthening of
local institutional structures and effective liaison by all structures with the Inkosi and the
tribal council. The community developed a rotational grazing plan, marked the camp
boundaries, produced digital maps and successfully built fence boundaries
(approximately 20 kms of fencing) to divide their land. The fence boundaries separated
the crop fields and rangeland, closed ward boundaries in the upland to prevent access by
cattle from neighbouring wards, and divided the land into three camps. Six crush pens
were constructed in each subward of the Okhombe ward. A communal herders fund
opened and fence construction improved crop yields due to a decrease in crop damage by
cattle.
Okhombe ward, located in the Highland Sourveld region of KwaZulu-Natal, experiences
feed and nutrition deficits to ruminants during winter. The prevailing species composition
in Okhombe was investigated as part of the grazing plan. The veld condition of the sites
ranged from poor (40.7%) in the bottomland to an averaged of 47.0% in upland sites. The
most distinctive feature of the rangeland in this area was the loss of highly palatable
Decreaser grass species (P <0.05), such as Themeda triandra in the bottom slopes «
1300 m) when compared to the upland (> 1800 m). The proportional abundance of
Decreaser species accounted for an averaged of 1.02% of the bottomland and an averaged
of 11.5% of the upland compared to the values of 49% in the benchmark (grassland in
optimal condition). The composition of the less palatable Increaser Il species was very
high at all elevations (1200 m -80.7%, 1400 m - 75.8% and 1700 m - 55.7%) when
compared to the low benchmark composition of 19%. The dominant grasses of the
bottom slopes were Increaser Il species, such as Eragrostis curvula, Eragrostis plana and
Sporobolus africanus and unpalatable Increaser III species such as Aristida junciformis.
A significant difference (P < 0.05) in the composition of Decreaser, Increaser I and
Increaser Il species was found between the bottom and slopes compared to the upland
region. However, the grass cover formed by these tufted species was generally high,
making it more resistant to physical degradation. The bottom slope ranged from
reasonable to excellent cover (16.9%), the middle slope ranged from reasonable (15.9%)
to a good cover of 18.1%, averaging 16.7% and a range of 16.1% to 17.9% for the upland
plateau.
In the agroforestry trial the potential of different fodder species for supplementing fodder
was examined. Leucaena leucocephala had the potential of being a suitable fodder tree
species for use in alley cropping (P < 0.05) compared to Morus alba and Acacia karroo.
Results from the partially intercropped treatments showed that L. leucocephala yield (665
kg ha-I) varied significantly (P < 0.05) from the A. karroo (378 kg ha-I) and M alba yield
(345 kg ha-I). Treatments that were fully intercropped varied, but no significant
difference (P > 0.05) were recorded. Morus alba produced the least yield of 345 kg ha-I,
A. karroo yielded 378 kg ha-1 and 1. leucocephala recorded the high of 664 kg ha-I.
Results from the second season showed similar trend in that 1. leucocephala yielded a
significant (P < 0.05) fodder production of 1715 kg ha-I in comparison to M. alba (1101
kg ha-I) and A karroo (1140 kg ha-I).
M alba yielded the least dry matter production (P < 0.05) but had high potential (P <
0.05) for addressing lack of firewood in rural areas. Morus alba yielded high fuel wood
production from both two seasons. There were no significant differences in fuel wood
yield (P > 0.05) from the partially intercropped M alba (507.9 kg ha-I) and 1.
leucocephala (455.0 kg ha-I) but the yield from both species varied significantly from the
A. karroo yield (103.kg ha-I). With regard to fully intercropped plots, fuel wood yield
from all tree species varied significantly, A karroo resulting in low yield (63 kg ha-I), 1.
leucocephala recorded 243 kg ha-l and M alba the highest yield of 444 kg ha-I. In the
second season, M. alba yielded an averaged fuel wood production of 728 kg ha-l and a
low of 439 kg ha-I from 1. leucocephala.
Acacia karroo, a slow growing indigenous tree, might be preferred by farmers due to its
less branches resulting in minimal light competition with crops. Leucaena leucocephala
tend to grow slowly in its initial establishment stage, but once roots become well
established, it grows fast and produces high quantity of fodder. The effect all fodder trees
had on crop yield was not negative during the trial period and further research on long
term effects of alley cropping is recommended. The conclusions drawn here were based
on tree growth and their likely impact in alley cropping.
Leucaena leucocephala was also recommended as a preferred species for rural ruminants
based on the forage quality study. The results showed high content of crude protein
(19.27%), low NDF content (50.38%) and very low tannin content (1.19%) from 1.
leucocephala compared to A. karroo with a high tannin content of 5.69%. Acacia karroo
had a crude protein content of 13.60%, NDF percentages of 44.16 and 34.64% of ADF
content. Morus alba also had a recommended chemical composition of 11.71% of CP,
42.86% of NDF, 36.96% of ADF and a low tannin content of 0.65%. L. leucocephala
foliage proven is readily degradable under different diet ranging within 24 hrs of intake
(P < 0.001) compared to other feeds. L. leucocephala had high dry matter loss degraded
from the rumen under Eragrostis hay diet with poor nutrients to high protein concentrates
diet. Under the Eragrostis hay diet for instance, L. leucocephala tend to degrade rapidly
with values of dry matter loss ranging from 32.2% to 39% at 4 hrs to 16 hrs, when
compared to low dry mater loss of 26% at 4 hrs to 31.33% at 16 hrs. Feeds such as M
alba tend to degrade slowly within 24 hrs of intake and rapidly degrades after the stated
period.
The ep content of maize stover was very low ranging from 1.60% in maize stalks to
2.63% in maize leaves. The fibre content in maize stover was very high when compared
to lower values in fodder samples. The NDF content ranged from 77.92% in maize leaves
to 81.60% in maize stalks. Maize leaves when compared to a combination of maize
leaves and maize stalks sole tend to degrade better within 24 hrs of intake. This was due
to low (P < 0.05) degradability rate of maize stalks compared to a combination of maize
stalks and leave and leaves sole and least NDF content in maize leaves might have
attributed to these results. Due to poor chemical compositions of these roughage samples,
the study recommended the establishment of fodder banks and agroforestry systems to
curb the nutrients deficit during winter.
In conclusion therefore, this study highlight that the sustainability of rural systems to
manage communal grazing land should be further explored. Most of the challenging
issues in communal range management are social in nature rather than technical concepts.
These include ways of improving social contributions from cattle to the community while
maintaining cultural values of the use of cattle. The interventions in communal range
management by service providers should understand the institutional arrangements within
a community and an attempt to strengthen such existing structures is recommended.
Further interventions by service providers in Okhombe ward should bring in the planning
discussions, experts from social sciences, to deal with understanding of community
dynamics. Complexities in communal range management involve dealing with non-stock
owners within project boundaries. Communities from neighbouring wards should not be
ignored and ways of improving communications and updating project details to them
should be formulated. Shortage of land and closing of ward boundaries to prevent access
to land by neighbouring wards is among community complexities to be explored.
Communities in rural lands do share land and in most cases boundaries are known but
invisible by an outsider to identify. It is important to strengthen and maintain every
success in communal lands as that may form core of the project. Successes on grazing
management by locals is far from being the improvement in veld but there are rather
various factors to the successes of grazing projects in rural areas. Examples of successes
based on Okhombe project are reduction in stock theft, improved in relationship between
community and locals institutions, a reduction in stock mortalities during winter and
improved animal health. Veld improvement is among successes but there are
accomplishments phases to fulfil before focusing on improvement of species
composition. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
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Alternatives agro-écologiques à l’usage d’intrants chimiques dans les bananeraies plantains : Le cas de deux régions de la Caraïbe : Guadeloupe et Haïti / Agroecological alternatives to the use of chemical inputs in banana plantains : The case of Caribbean regions : Guadeloupe and HaïtiDeloné, Brunise 01 October 2014 (has links)
La banane plantain (Musa paradisiaca) est l’aliment de base de millions de personnes dans le monde et sa culture génère des revenus permanents pour un grand nombre d’agriculteurs, dans des plantations de taille petite ou moyenne. Comme dans d’autres régions tropicales, la culture du plantain en Guadeloupe et en Haïti est soumise à de fortes contraintes parasitaires aussi bien telluriques (i.e. du sol : nématodes phytoparasites et charançon du bananier) qu’aériennes (Cercosporiose noire notamment). Les moyens de lutte conventionnels reposent sur l’usage de produits de synthèse dont les effets néfastes sur l’environnement (sols, eaux, animaux) comme sur la santé humaine ne sont plus supportables. Il est donc urgent de réfléchir à des solutions agro-écologiques permettant de rétablir les équilibres biologiques, de maintenir une bonne qualité des sols et une production optimale dans les systèmes de culture plantains. C’est le but de ce travail de thèse qui couple la réalisation d’un diagnostic agro-écologique dans des parcelles paysannes, et le test d’alternatives agro-écologiques en milieu semi-contrôlé. Pour ce faire, une typologie des systèmes de culture plantains a été réalisée à l’issue d’une enquête agro-environnementale dans les deux zones d’étude. Elle a permis de sélectionner 23 parcelles en Guadeloupe et 12 en Haïti dans lesquelles un diagnostic agro-écologique a été conduit. Sur la base de ce diagnostic et de la recherche d’alternatives agro-écologiques à l’usage des produits chimiques, une expérimentation au champ a été mise en place en Guadeloupe en station de recherche, permettant le test de trois pratiques culturales innovantes pour le plantain (seules et combinées), à savoir : i) l’introduction d’une plante de service Paspalum notatum pour la gestion des adventices et la réduction de l’utilisation d’herbicides ; ii) l’apport de vermicompost pour le contrôle des nématodes phytoparasites inféodés au bananier plantain et la fertilisation de celui-ci ; iii) l’utilisation de plants sains PIF (Plants Issus de Fragments de tiges) indemnes de nématodes et de larves de charançon du bananier. La typologie des systèmes de culture plantains révèle que : i) en Guadeloupe les précédents : jachère, ananas et banane plantain sont prédominants avec un niveau d’intensification faible (apports d’intrants chimiques faibles et peu fréquents) ou élevé (apports d’intrants chimiques élevés et plus fréquents) ; ii) en Haïti, les précédents : jachère, banane plantain et manioc prédominent avec un niveau d’intensification faible ou nul (apport d’intrants inexistant). Les résultats du diagnostic agro-écologique montrent que, i) lorsque le niveau d’intensification est faible, les bananeraies plantains pérennes et le précédent-ananas permettent de maintenir une bonne qualité du sol et une bonne régulation des parasites telluriques ; ii) lorsque le niveau d’intensification est fort, les populations d’ingénieurs du sol diminuent drastiquement, alors que le cortège parasitaire tellurique augmente sans que cela n’affecte l’obtention de bons niveaux de rendement instantannés (parcelles précédées d’ananas ou d’une jachère principalement) ; iii) en absence totale de fertilisation, il résulte une diminution de l’activité biologique du sol mais aussi du rendement du plantain, exacerbé par le choix des précédents-culturaux (manioc ou banane plantain) en lien avec les contraintes pédoclimatiques et la maladie des raies noires (Cercosporiose noire) causée par Mycosphaerella fijiensis, notamment au sein des parcelles Haïtiennes ; iv) la succession plantain/plantain est la plus pénalisante vis-à-vis de la culture du plantain, car quelque soit le niveau d’intensification, le rendement reste relativement faible, en lien avec une dégradation de l’état sanitaire, comparativement aux autres précédents. / Plantain (Musa paradisiaca) is the staple food of millions of people worldwide and its cropping generates ongoing revenues for many farmers who are planting small or medium size areas. As in other tropical regions, plantain cultivation in Guadeloupe and Haiti is under heavy parasitic constraints terrestrial (plant-parasitic nematodes and banana weevil) as well as aerial (black Sigatoka in particular). Conventional means of control based on the use of synthetic products which adverse effects on the environment (soil, water, animals ...) as on human health are not bearable any more. It is thus urgent to think about agroecological solutions allowing to restore the biological balances, to maintain good soil quality and optimal plantain cropping systems.This is the ultimate goal of this thesis which couples the realization of an agroecological diagnosis in peasants’ plots, and the test of agroecological alternatives in semi-controlled conditions. To do this, a typology of plantain cropping systems was carried out from an agrienvironmental survey in the two study areas. It allowed to select 23 plots in Guadeloupe and 12 in Haiti in which an agroecological diagnosis was implemented. Based on this diagnosis and the research of agroecological alternatives to the use of chemicals, a field experiment was set up in Guadeloupe, in an experimental station allowing the test of three innovative practices for plantain cultivation (alone and combined), namely : i) the introduction of a cover-crop Paspalum notatum for weed control while reducing the use of herbicides ; ii) the input of worms’ compost to control plant-parasitic nematodes specific to plantain and to fertilize it ; iii) the use of healthy “PIF” plants (plants issued from stem fragments) free from telluric pests (nematodes and weevil’s larvaes).The typology of plantains cropping systems shows: i) in Guadeloupe the previous crops are: fallow pineapple and plantain predominate with a low level of intensification (low and infrequent chemical inputs) or high (high and frequent chemical inputs); ii) in Haiti, the previous crops are: fallow, plantain and cassava predominate with a low level or no intensification at all (no inputs). The results of the agroecological analysis show that : i) when the level of intensification is low, perennial plantain and pineapple as previous crops help maintaining a good soil quality and a good regulation of the telluric pests ; ii) when the level of intensification is strong, the soil engineers drastically reduce, while the density of telluric parasites increases without affecting good levels of instantaneous yields (plots where the previous crop is pineapple or mostly fallow) ; iii) when the fertilization is totally missing, it decreases the biological activity of the soil furthermore the plantain yields, exacerbated by the choice of the previous crop (cassava or plantain), in connection with soils and climate constraints and the black Sigatoka caused by Mycosphaerella fijiensis, especially in the Haitian plots ; iv) the crop succession plantain/plantain is the most critical regarding the plantain’s cropping, because whatever the level of intensification, the yields remain relatively low in connection with a degradation of the health state, compared to other previous crops.The driving of an experiment in a research station shows that on the scale of one year, the three tested innovative practices allow maintaining a good soils quality. Healthy plants "PIF" have a better health state (absence of plant parasitic nematodes in the roots) which helps a significant increase of the yields. Cover-crop P. notatum helps the weeds and the soil pests control and favors the improvement of soil biological activity and plantain yields. Worms’ compost contributes to the maintenance of a better soils quality while allowing the regulation of the populations of plant-parasitic nematodes of the plantains.
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