The increased soil organic phosphorus (P) mineralization observed under trees compared to pasture has been attributed to the contrasting mycorrhizal associations of the two systems but to date, little work has been conducted comparing P dynamics under different tree species with contrasting mycorrhizal associations. This study investigated rhizosphere P dynamics and P acquisition of three tree species with contrasting mycorrhizal associations (ectomycorrhizal Pinus radiata, arbuscular mycorrhizal Cupressus macrocarpa and tripartite Ecualyptus nitens) using a combination of field and controlled environment studies. Short-term field studies revealed greater acid phosphomonoesterase activity and therefore greater potential organic P mineralization under radiata pine and eucalypt compared with macrocarpa, which correlated with ectomycorrhizal colonization. Related field work revealed that the presence of pasture understory and litter had a significant impact on P dynamics. Pasture acts to increase phosphatase activity and microbial activity within the soil but with a litter layer, the increased activities are mainly above the soil in the overlying litter. A glasshouse study investigated the separate influence of mycorrhizal hyphae and roots and results showed that ectomycorrhizal fungi associated with radiata pine and eucalypt stimulated microbial activity and increased rhizosphere phosphatase activity with a concomitant decline in soil organic P. Macrocarpa and eucalypt roots exuded higher concentrations of low molecular weight organic anions compared with radiata pine which stimulated microbial activity, increased rhizosphere phosphatase activity and decreased soil organic P. A series of experiments were then conducted to further investigate the precise role of mycorrhizae in P dynamics and results showed that ectomycorrhizal colonization increased rhizosphere acid phosphomonoesterase to a greater extent than arbuscular mycorrhizae. Fluorescent staining revealed that the mycorrhizae associated with all three species had similar phosphatase production capacities. The ability of the three species to utilize organic P was investigated in two exhaustive pot experiments. Radiata pine was shown to be the best adapted to utilize organic P, especially in soils with high relative organic P contents. Eucalypt appeared to enhance soil organic P mineralization but did not take up the released inorganic P, while macrocarpa caused limited organic P mineralization compared with radiata pine and eucalypt. This work shows that ectomycorrhizal trees are best adapted to utilize organic P through increased rhizosphere phosphatase activity and stimulated microbial activity. Root exudation of LMWOAs is of higher relative importance to arbuscular mycorrhizal trees to increase microbial activity and consequently phosphatase activities when fewer hyphae are in the rhizosphere are present to produce them.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.

Made available in DSpace on 2015-03-26T13:51:52Z (GMT). No. of bitstreams: 1 texto completo.pdf: 649442 bytes, checksum: 480c7019b7f152a1aa0ec2308fbde07e (MD5) Previous issue date: 2006-03-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Epidendrum secundum and Zygopetalum mackaii, native from State Park of Serra do Brigadeiro, Minas Gerais State, Brazil, were studied to characterize the structure of mycorrhizae and associated mycorrhizal fungi. From August/2004 to July/2005, roots were collected from four different areas. A total of 28 isolates were obtained, all belonging to genus Epulorhiza, which were separated in three groups according their morphological and cultural characteristics. In both orchid species, mycorrhizae were tolipophagic, and colonizing all extension of the root system, presenting intact and degraded pelotons. Root colonization occurs mainly through root hairs and sometimes via epidermic cells, while cortex colonization occurs, mainly, via passage cells of the exodermis. Cortex colonization occurs by cell-to cell, and pelotons occupy all cellular space. Peloton degradation starts by hypha deformation, followed by a uniform reduction of peloton volume. Colonization intensity was higher in the dry season. The species growing on rocks showed higher colonization frequency and higher mycotrophic activity. This is the first report on the mycorrhizal association of Z. mackaii. Isolated fungi in this study show high potential to be used in commercial propagation of this orchid species. / Epidendrum secundum e Zygopetalum mackaii, nativas do Parque Estadual Serra do Brigadeiro (MG), foram estudadas com objetivo de caracterizar a associação micorrízica e os fungos micorrízicos associado a estas plantas. Durante o período de agosto/2004 a julho/2005, foram realizadas coletas do sistema radicular dessas espécies crescendo em quatro áreas com características distintas. Obtiveram-se o total de 28 isolados fúngicos, todos pertencentes ao gênero Epulorhiza, os quais foram divididos em três grupos, de acordo com as características culturais e morfológicas. A micorriza encontrada foi o tolipofágico, sendo observado pelotons intactos e degradados em toda a extensão do sistema radicular das espécies estudadas. A infecção da raiz ocorre via pêlo radicular ou células epidérmicas, enquanto a colonização do córtex é, principalmente, via célula de passagem da exoderme. A colonização no córtex ocorre via célula-célula, sendo todo o espaço celular ocupado pela estrutura fúngica, os pelotons. O estádio de degradação inicia-se pela deformação do peloton, seguida da redução uniforme de seu volume. A intensidade de colonização foi maior nos períodos de seca. As espécies crescidas diretamente sobre rochas apresentaram maior freqüência de colonização e maior atividade micotrófica. Este é o primeiro relato sobre o isolamento e caracterização de fungos micorrízicos em Z. mackaii. Os fungos isolados neste trabalho apresentam um grande potencial para serem utilizados na propagação comercial destas orquídeas.

Made available in DSpace on 2014-08-20T13:25:43Z (GMT). No. of bitstreams: 1 Dissertacao_Manoel_Ribeiro_Holanda_Neto.pdf: 1116819 bytes, checksum: dc8fb2273ba993e46e43090911a68a5d (MD5) Previous issue date: 2011-04-08 / The city of Candiota/RS has the largest coal mine in Brazil, with 38% of the entire national product extracted from open-pit mines. The inadequate disposal process of tailings from mining leads to loss of soil, surface water and changes in physical, chemical and biological attributes. The restoration degraded areas involves a set of actions that provide the functionality to restore ecosystem. The Revegetation is an important step in recovery of these soils which aims the landscaping the area, erosion control and restoration of physical, chemical and biological soil properties. This work aimed to evaluate the effect of different cropping systems on chemical and microbiological attributes of a constructed soil after the coal extraction. In an area of coal mining of the, located in Candiota, RS. The experimental design was composed by randomized blocks with four replications, with the following treatments of crops: T1 - Capim Vaqueiro (Cynodon dactilon (L.) Pers.); T2 - Braquiária (Brachiaria brizantha (Hochst.) Stapf); T3 - Capim Tanzânia (Panicum maximum Jacq); T4 - Braquiária humidícula (Brachiaria humidicola (Rendle) Schweickt); T5 - Hemártria (Hemarthria altissima (Poir.) Stapf & C. E. Hubbard); T6 - Grama Tifton (Cynodon dactilon (L.) Pers.); T7 - Capim Vaqueiro+Grama Tifton; T8 - Capim Vaqueiro+Hemártria; T9 - Braquiária brizantha+Grama Tifton; T10 - Braquiária brizantha+Hemártria; T11 - Capim Tanzânia+Grama Tifton; T12 - Capim Tanzânia+Hemártria; T13 - Braquiária humidícula+Grama Tifton; T14 - Braquiária humidícula+Hemártria, and T15 (SC) constructed soil without vegetation. Soil samples (0-0,05m) were collected in september of 2009 to determine chemical and microbiological attributes. The results were compared between treatments using analysis of variance and Tukey Test at 5% significance and a comparison of each treatment with control (T15) was made using the Dunnett Test at 5% of probability. It was observed that the addition of fertilizer and lime for the cultivation of crops increased the pH values, electrical conductivity, calcium, magnesium, potassium, phosphorous, manganese, zinc, copper, and exchangeable sodium, the organic carbon and soil basal respiration for crop cultivation, when compared to non-vegetated constructed soil These results suggest that all cultures tested may be promising in the recovery area over time. The treatments Hemártria and Braquiária humidícula+Hemártria showed the higher contents of microbial biomass carbon in constructed soil. The crops studied, in general, promoted an increased in mycorrhizal colonization and sporulation and also AMFs species when compared with non-vegetated constructed soil, reducing the impact caused by interference of mining. / A cidade de Candiota/RS possui a maior jazida de carvão do Brasil, com 38% de todo o produto nacional extraído a céu aberto. O processo de deposição inadequada dos rejeitos da mineração leva a perdas de solo, à contaminação das águas superficiais e do lençol freático e a alterações nos atributos físicos, químicos e biológicos. A recuperação destas áreas degradadas envolve um conjunto de ações, que proporcionam o restabelecimento da funcionalidade do solo no ecossistema. A revegetação é uma importante etapa na recuperação destes solos, que visa à recuperação paisagística da área, controle dos processos erosivos e restabelecimento das propriedades físicas, químicas e biológicas. O presente trabalho objetivou avaliar o efeito de diferentes sistemas de cultivo sobre a biomassa microbiana, a respiração basal e a colonização, densidade de esporos e diversidade de fungos micorrízicos de um solo construído e vegetado com gramíneas, após mineração de carvão mineral, em uma área pertencente à Companhia Riograndense de Mineração no município de Candiota RS. O delineamento experimental foi constituído por casualização por blocos com quatro repetições, com as seguintes espécies implantadas em 2007: T1 - Capim Vaqueiro (Cynodon dactilon (L.) Pers.); T2 - Braquiária (Brachiaria brizantha (Hochst.) Stapf); T3 - Capim Tanzânia (Panicum maximum Jacq); T4 - Braquiária humidícula (Brachiaria humidicola (Rendle) Schweickt); T5 - Hemártria (Hemarthria altissima (Poir.) Stapf & C. E. Hubbard); T6 - Grama Tifton (Cynodon dactilon (L.) Pers.); T7 - Capim Vaqueiro+Grama Tifton; T8 - Capim Vaqueiro+Hemártria; T9 - Braquiária brizantha+Grama Tifton; T10 - Braquiária brizantha+Hemártria; T11 - Capim Tanzânia+Grama Tifton; T12 - Capim Tanzânia+Hemártria; T13 - Braquiária humidícula+Grama Tifton; T14 - Braquiária humidícula+Hemártria, e T15 (SC) - solo construído sem vegetação. A coleta de amostras de solos foi realizada em 2009, para as determinações de atributos químicos e microbiológicos, na profundidade de 0 a 0,05m. Os resultados foram submetidos à análise de variância, sendo a comparação entre tratamentos cultivados feitos pelo teste de Tukey a 5% e a comparação de cada tratamento com a testemunha T15 utilizando o teste de Dunnett a 5%. Observou-se que a adição de corretivo e as adubações das culturas aumentaram os valores de pH, condutividade elétrica, cálcio, magnésio, potássio, fósforo, manganês, zinco, cobre e sódio trocável, o carbono orgânico total e a respiração basal do solo quando comparados ao solo construído não vegetado. Os maiores teores de carbono da biomassa microbiana no solo constatados nos cultivos com hemártria e braquiária humidícula+hemártria, indicam possíveis alternativas para a recuperação da área em estudo. A colonização micorrízica do solo construído da área minerada é aumentada com o cultivo de hemártria e capim vaqueiro + hemártria. Os cultivos de um modo geral, promoveram um aumento da esporulação micorrízica. As espécies de fungos micorrízicos arbusculares encontradas na área de estudo foram: Acaulospora mellea, Entrophospora infrequens, Glomus clarum, Glomus macrocarpum, Glomus tortuosum, Glomus sp., Glomus clavisporum, Glomus dominikii, Glomus etunicatum, Glomus lamellosum, Gigaspora sp., e Scutellospora sp. com maior predomínio das espécies Glomus macrocarpum e Glomus tortuosum, indicando uma possível especificidade das espécies vegetais com a comunidade de FMAs.

Made available in DSpace on 2016-04-26T19:39:29Z (GMT). No. of bitstreams: 1 2006-Luciano Lopes Reis.pdf: 1765828 bytes, checksum: e031c34734485e7d84bd20e5fcc0d59b (MD5) Previous issue date: 2006-02-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This study had as objective to monitor the process of environmental reclamation of tanks filled with residues from bauxite washings, vegetated by hydro-sowing legume trees species inoculated with rhizobia, and asbuscular mycorrhizal fungi. Nutrient fertilizers, without nitrogen, were added at the mixture at sowing. Later it was planted a mixture of native tree species seedlings, with a high proportion of N2-fixing legumes, in an experiment with additional increasing levels of fertilizers and liming, except for nitrogen. The deposits of sterile bauxite subsoil, vegetated with the mix of native species, with high proportion of legumes capable of N2 fixation and mineral fertilization, were evaluated at different periods of time, for the chemical and biological attributes of soil and plants. Samples of soil, leaves, litter, and soil invertebrates fauna were taken in 2002, 2003 and 2004, to measure nutrient availability in soil; foliar nutrient level of indicator plants; soil microbial biomass and activity; soil fauna activity, diversity and ecological indexes; and evaluation of vegetal coverage of the SP1 residue tank. The results of foliar analyses indicated that even at the highest level of fertilizer and lime additions in the SP1 residue tank were not sufficient to meet the adequate plant nutrition requirements, indicating the need of higher input of nutrients. By using multivariate statistical analyses of the data, it was possible to distribute the studied systems along Cartesian axis, where the native forest area, used as testimony, and old vegetated mining sites (planted in 1984, 1992 and 1994) were clustered together; while the most recent vegetated mining sites and the tanks filled with residues formed a distant cluster. Among the index attributes studied Al+3, total C, total N, K, soil pH, microbial carbon and respiration; and Ca and Mg from litter were the principal factors determining the ordering and distinction between reclamation sites. The reclamation methodology used in the residue tank SP1, which combined the hydro-sowing with application of low solubility fertilizers, using a mix of seeds from medium cycle legume trees inoculated and with mycorrhizae, with later planting of native seedlings and manual dispersion of seeds, showed to be an important technique to stimulate natural vegetation growth. Also, the technique resulted in a high capacity of addition of decidual material, and the legume tree Acacia holosericea showed the best capacity for soil coverage and input of nutrients. / Com o objetivo de monitorar o processo de recupera??o ambiental de tanques de dep?sito de rejeito da lavagem da bauxita, revegetados atrav?s da hidrossemeadura de leguminosas fixadoras de N2 e com adi??o de fungos micorrizicos, mais aporte de nutrientes. Posteriormente, foi feito o plantio de mudas nativas em experimento de n?veis de aduba??o e calagem, sem aplica??o de nitrog?nio. Os dep?sitos de subsolo est?ril em bauxita revegetados com mistura de esp?cies nativas, com grande propor??o de leguminosas fixadoras de N2 e aduba??o mineral na cova, avaliados em diferentes idades, foram utilizados atributos qu?micos e biol?gicos do solo e planta. Foram realizadas coletas de solo, de folhas, de serapilheira e da fauna de invertebrados do solo, nos anos de 2002, 2003 e 2004, para determina??o da disponibilidade de nutrientes no solo; dos teores foliares de nutrientes das plantas indicadoras; da biomassa e atividade microbiana; da atividade, diversidade de grupos e ?ndices ecol?gicos da comunidade da fauna do solo; e avalia??o da cobertura vegetal do tanque de rejeito SP1. Os resultados da an?lise foliar das esp?cies indicadoras e de disponibilidade de nutrientes no solo indicaram que nem os maiores n?veis de aduba??o e calagem utilizados no experimento do tanque de rejeito SP1 foram suficientes para permitir uma adequada nutri??o ?s plantas, indicando a necessidade de novos aportes de nutrientes. Atrav?s da aplica??o de ferramentas de estat?stica multivariada aos dados, foi poss?vel ordenar os sistemas estudados ao longo de eixos cartesianos, onde a ?rea de mata nativa, usada como testemunha, e reflorestamentos sobre res?duos de minera??o com maior idade (realizados nos anos de 1984, 1992 e 1994) se ordenam pr?ximos uns dos outros, enquanto que os reflorestamentos sobre est?ril mais recentes e ?reas dos tanques de rejeito se ordenam distantes destes, formando grupamentos entre si. Dentre os atributos indicadores utilizados, o Al+3, C total, N total, K e pH do solo; a respira??o e carbono microbiano; e o Ca e Mg da serapilheira foram os mais determinantes para o ordenamento e distin??o entre os sistemas em recupera??o. A metodologia de recupera??o utilizada no tanque de rejeito SP1 que combinou a pr?tica da hidrossemeadura com aplica??o de formas de adubos pouco sol?veis, utiliza??o de coquetel de sementes de leguminosas arb?reas de ciclo m?dio inoculadas e micorrizadas, posterior plantio de mudas nativas e lan?amento manual de sementes, mostrou-se como importante t?cnica propulsora da regenera??o natural. A t?cnica tamb?m resultou em elevada capacidade de aporte de material decidual, sendo a leguminosa arb?rea Acacia holosericea, a esp?cie que apresentou melhor capacidade de cobertura do solo e aporte de nutrientes.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-06-20T16:10:30Z No. of bitstreams: 1 2010 - Cristiane Alves Foga?a.pdf: 2979226 bytes, checksum: 16723accb45fe9477013bff730b4755d (MD5) / Made available in DSpace on 2017-06-20T16:10:30Z (GMT). No. of bitstreams: 1 2010 - Cristiane Alves Foga?a.pdf: 2979226 bytes, checksum: 16723accb45fe9477013bff730b4755d (MD5) Previous issue date: 2010-03-04 / Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do RJ, FAPERJ, Brasil. / The present study aimed to evaluate some limiting factors to the growth of Toona ciliata M. Roem. var. australis (Australian red cedar). In chapter I, it was evaluated the growth of Toona ciliata seedlings inoculated with arbuscular mycorrhizae fungi (FMAs), Acaulospora laevis, A. morrowiae, Entrophospora colombiana, E. contigua, Gigaspora margarita, Glomus clarum, Scutellospora calospora, S. gilmorei, S. heterogama e S. pellucida. In chapter II, it was evaluated the contents and accumulations of nutrients in Australian red cedar seedlings, submitted the complete solution, diluted solution 1/2 and 1/4. In chapter III, it was verified the symptoms of macronutrients deficiency, nutrients contents and accumulations in the Australian red cedar plants submitted the complete solution with omission of N, P, K, Ca and Mg. Chapter IV, it was observed the reply of the species the aluminum presence, using treatments with complete solution diluted the 1/4 with addition of 0, 5 and 20 mg. L-1 de Al. Between AMF tested, A. morrowiae, E. contigua e S. pellucida were most efficient in promoting the accumulation of dry weight of aerial part, development of the area leaf and phosphorous content on leaf in Toona ciliata seedlings, beyond presenting the biggest densities of esporos.50 cm-3 of substrate. And the biggest incidence of mycorrhizae settling in Toona ciliata seedlings was gotten with the species S. pellucida. The behavior of the species in reply to the use of nutritional solutions complete and diluted 1/2 and 1/4, showed that the biggest increment in height, diameter and dry weight had occurred in plants submitted at diluted solution the 1/4. The macronutrients contents and accumulations in Australian red cedar plants presented the following decreasing order: N > K > Ca > P > Mg. With regard to nutritional deficiency it verified that the omission of K was the one that more affected the development of the plant in height. The limitation in the increment stem diameter of the plants occurred in all the treatments, with exception of the complete solution. The production of total weight dry of the plants was affected in all the treatments with omission of nutrients, in according the following decreasing order: Complete Solution > - P > - Mg > - N > - K > - Ca. The initial growth of Toona ciliata seedlings was affected by the omission of all the macronutrients, having been the similar symptoms with the symptoms of other species of the same family. The immediate damages most intense and had been observed in the omission of K and Ca. Thus, the Toona ciliata species demonstrated to be demanding in macronutrients in the following decreasing order: K > N > Mg > Ca > P. The reply of the species the aluminum presence demonstrated that the growth, nutrient content and accumulation in Australian red cedar plants were stimulated in the presence of 5mg.L-1 of aluminum. The addition of 20 mg.L-1 de Al reduced the growth of the plants and macronutrients accumulation, in the following decreasing order: Ca > Mg > N > P > K. The visual symptoms of fitotoxicity had been typical to this element, beyound of the leaf with intense green coloration progressing for the yellow; the leaves oldest had progressed for yellow-brown, the edges to the limb center; and curving of new leaves. / O presente trabalho teve como objetivo avaliar alguns fatores limitantes ao crescimento de Toona ciliata M. Roem. var. australis (cedro-australiano). No cap?tulo I, avaliou-se o crescimento de mudas de cedro-australiano inoculadas com fungos micorr?zicos arbusculares (FMAs), Acaulospora laevis, A. morrowiae, Entrophospora colombiana, E. contigua, Gigaspora margarita, Glomus clarum, Scutellospora calospora, S. gilmorei, S. heterogama e S. pellucida. No cap?tulo II, foram avaliados os teores e ac?mulos de nutrientes em mudas de cedro-australiano, submetidas ? solu??o nutritiva de Hoagland & Arnon modificada, completa, dilu?da a 1/2 e a 1/4 de for?a i?nica. No cap?tulo III, verificou-se os sintomas de defici?ncia de macronutrientes, teores e ac?mulos de nutrientes nas plantas de cedroaustraliano crescidas em solu??o nutritiva com omiss?o de N, P, K, Ca e Mg. No Cap?tulo IV, observou-se a resposta da esp?cie estudada na presen?a de alum?nio, empregando tratamentos com solu??o nutritiva dilu?da a 1/4 com adi??o de 5 e 20 mg.L-1 de Al, al?m de uma testemunha Entre os fungos micorr?zicos arbusculares testados, A. morrowiae, E. contigua e S. pellucida foram os mais eficientes em promover o ac?mulo de mat?ria seca da parte a?rea, desenvolvimento da ?rea foliar e teor de f?sforo foliar em mudas de Toona ciliata, al?m de apresentarem as maiores densidades de esporos por 50 cm3 de substrato. A maior coloniza??o micorr?zica em mudas de Toona ciliata foi obtida com a esp?cie f?ngica S. pellucida. O comportamento da esp?cie em resposta ao emprego de solu??es nutritivas completas, dilu?da a 1/2 e 1/4, mostrou que o maior incremento em altura, di?metro e mat?ria seca ocorreram em plantas submetidas ? solu??o dilu?da a 1/4. Os teores e ac?mulos de macronutrientes em plantas de cedro-australiano seguiram a seguinte ordem decrescente: N > K > Ca > P > Mg. Com rela??o ? defici?ncia nutricional, verificou-se que a omiss?o de K foi a que mais afetou o crescimento em altura. A limita??o no crescimento em di?metro do coleto das plantas ocorreu em todos os tratamentos, com exce??o da solu??o de Hoagland & Arnon. A produ??o de massa seca total das plantas foi afetada em todos os tratamentos com omiss?o de nutrientes, obedecendo ? seguinte ordem decrescente: Completo> -P > -Mg > -N > -K > -Ca. O crescimento inicial de mudas de Toona ciliata ? afetado pela omiss?o de todos os macronutrientes, sendo os sintomas semelhantes com os sintomas de outras esp?cies da mesma fam?lia. Os danos mais intensos e imediatos foram observados na omiss?o de K e Ca. Assim, a esp?cie Toona ciliata demonstrou ser exigente em macronutrientes na seguinte ordem decrescente: K > N > Mg > Ca > P. A resposta da esp?cie ? presen?a de alum?nio demonstrou que o crescimento, teor e ac?mulo de nutrientes em plantas de cedro-australiano foram estimulados na presen?a de 5mg.L-1 de alum?nio. A adi??o de 20 mg.L-1 de Al reduziu o crescimento das plantas e o ac?mulo de macronutrientes, na seguinte ordem decrescente: Ca > Mg > N > P > K. Os sintomas visuais de fitotoxidez associados ? dose de 20 mg.L-1 de Al foram t?picos da toxidez a este elemento, al?m das folhas apresentarem colora??o verde intensa progredindo para o amarelecimento; com a acentua??o dos sintomas, as folhas mais velhas progrediram para amarelo-castanho, dos bordos para o centro do limbo e enrolamento ou encurvamento de folhas novas.

L’ingénierie agroécologique vise à produire des savoirs actionnables, pour concevoir des systèmes de cultures économiquement et écologiquement performants, par la valorisation de régulations naturelles. Notre problématique est centrée sur la santé des cultures, et plus particulièrement sur la bactérie phytopathogène Ralstonia solanacearum, agent du flétrissement bactérien alors qu’une souche extrêmement agressive menace la production de tomates en plein champ en Martinique. La nécessité d’explorer et de développer des alternatives aux méthodes conventionnelles de protection des plantes (variétés résistantes, pesticides), actuellement inefficaces, invite à la mise en œuvre d’une démarche de conception innovante. Nos travaux montrent que la mobilisation d’une barrière rhizosphérique est une stratégie de régulation biologique alternative. Différents processus y contribuent, telle que la mycorhization, symbiose entre racines et champignons mycorhiziens à arbuscules, présents dans la plupart des sols. Nous montrons que la mobilisation de réseaux de mycorhizes indigènes à partir d’un sol agricole permet une mycorhization précoce de la tomate. De plus, l’association de plantes aux propriétés mycorhizotrophes et assainissantes en conditions contrôlées montre des effets bioprotecteurs partiels et ouvre de nouvelles perspectives de combinaisons entre processus. Ces combinaisons sont mobilisables par des leviers d’actions multi-scalaires. Nous avons produit une grille d’analyse générique de ces leviers d’action pour la conception, par des trajectoires d’innovation multidirectionnelles, de « systèmes de culture bioprotégés ». Dans le contexte agricole martiniquais, une démarche d’apprentissage permet en effet l’émergence d’une dynamique de co-conception de systèmes de cultures recourant aux plantes mycorhizotrophes. Nos travaux proposent des outils pour une exploration collective de nouvelles stratégies de gestion durable de la santé des cultures. / Agroecological engineering aims to produce actionable knowledge to design economically and environmentally efficient cropping systems, based on the exploitation of natural regulation mechanisms. Our issue is centered on crop health, especially on the plant pathogenic bacterium Ralstonia solanacearum (bacterial wilt agent), of which an extremely aggressive strain threatens field tomato production in Martinique. The need to explore and develop alternatives to conventional methods of plant protection (resistant varieties, pesticides), ineffective in our case, calls for the implementation of an innovative design approach. Our work shows that the protection of the roots via the formation of a self-sustaining rhizospheric barrier may be an alternative biological control strategy. Different processes contribute, such as mycorrhizal symbiosis between roots and arbuscular mycorrhizal fungi, which are present in most soils. We show that the mobilization of indigenous mycorrhizal networks from an agricultural soil allows early mycorrhization of tomatoes. In addition, the association of plants with mycorrhizal and sanitizing properties in controlled conditions showed partial bioprotective effects and opens up new prospects for combinations between processes. These combinations may be exploited in various ways. We produced a generic analysis grid of key levers to design "healthy cropping systems " through multi-directional innovation trajectories. In Martinique's agricultural context, a learning process allows the emergence of a dynamic co-design of cropping systems using mycorrhizal plants. Our work thus provides tools for collective exploration of new sustainable management strategies for crop health.

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