Em busca de melhorar a eficiência do uso de fontes de fósforo (P) e viabilizar o aumento da absorção deste nutriente, objetivou-se com este trabalho determinar as mudanças promovidas por plantas de cobertura, associadas à fontes fosfatadas de solubilidade distintas, na colonização por fungos micorrízicos arbusculares (FMA), como também avaliar as mudanças promovidas na disponibilidade de frações de P no solo e na eficiência de uso do P pelas coberturas. O delineamento adotado foi de blocos ao acaso, em esquema fatorial 5x3, com quatro repetições. Foram utilizadas quatro plantas de cobertura: milheto (Pennisetum glaucum), braquiária (Brachiaria ruziziensis), guandú-anão (Cajanus cajan) e crotalária (Crotalária juncea), além do controle (pousio);Duas fontes de P: fosfato natural reativo Bayóvar e superfosfato simples, além de um tratamento controle (sem fosfato),. Avaliou-se a colonização micorrízica por FMA e densidade de esporos no solo em três épocas, correspondendo à estação chuvosa e seca de 2013 e a estação chuvosa de 2014. Avaliou-se também a produção de massa seca e o acúmulo de P pelas plantas. No final do segundo ano, analisou-se o fracionamento de P do solo. A colonização radicular foi mais influenciada nas épocas chuvosas. A presença das plantas de cobertura proporcionou maior colonização micorrízica e densidade de esporos na época chuvosa. As aplicações de fontes fosfatadas não influenciam a densidade dos esporos, enquanto que as plantas de cobertura, principalmente o guandú e a braquiária, apresentaram aumento no número de esporos. Apesar de não aumentar as frações lábeis do P no solo, a utilização de plantas de cobertura proporcionou maior ciclagem do nutriente. Os fosfatos não influenciaram a massa seca nem o acúmulo de P, sendo que houve efeitos das plantas de cobertura na massa seca e no acúmulo de P na parte aérea, com destaque para o milheto e a braquiária. / In order to improve the use efficiency of phosphorus sources and enable a higher absorption of this nutrient, this research aimed to determine the changes promoted by cover crops and phosphorus sources of different solubility in the colonization by arbuscular mycorrhizal fungi (AMF), as much as the availability of P fractions in the soil and the use efficiency of P by the cover crops. A complete randomized block design was adopted, in a 5x3 factorial scheme, with four replications. For the first factor were used four cover crops: millet (Pennisetum glaucum), brachiaria (Brachiaria ruziziensis), pigeon pea (Cajanus cajan) and sun hemp (Crotalaria juncea), including a control (fallow); for the second factor were used the reactive phosphate Bayovar and the simple superphosphate plus a control treatment (no phosphate). It was assessed the AMF colonization, the spore density in the soil in three different times, the rainy and dry seasons in 2013, and the rainy season in 2014. At the end of 2014, it was also evaluated the amount of the fractioned P in the soil. The root colonization was more influenced in rainy season. The presence of cover crops provided greater mycorrhizal colonization and spore density in the rainy season. The applications of phosphate sources did not influence the spores density. However, the cover crops, mainly pigeon pea and brachiaria, showed an increase in the number of spores. The use of cover crops did not increase the labile fractions of P in the soil, Nevertheless they provided greater cycling of this nutrient. Phosphates did not influence the dry matter or the accumulation of P. Interestingly, the dry matter and P accumulation in shoots was influenced by the kind of cover crops, being higher for millet and brachiaria.

Em busca de melhorar a eficiência do uso de fontes de fósforo (P) e viabilizar o aumento da absorção deste nutriente, objetivou-se com este trabalho determinar as mudanças promovidas por plantas de cobertura, associadas à fontes fosfatadas de solubilidade distintas, na colonização por fungos micorrízicos arbusculares (FMA), como também avaliar as mudanças promovidas na disponibilidade de frações de P no solo e na eficiência de uso do P pelas coberturas. O delineamento adotado foi de blocos ao acaso, em esquema fatorial 5x3, com quatro repetições. Foram utilizadas quatro plantas de cobertura: milheto (Pennisetum glaucum), braquiária (Brachiaria ruziziensis), guandú-anão (Cajanus cajan) e crotalária (Crotalária juncea), além do controle (pousio);Duas fontes de P: fosfato natural reativo Bayóvar e superfosfato simples, além de um tratamento controle (sem fosfato),. Avaliou-se a colonização micorrízica por FMA e densidade de esporos no solo em três épocas, correspondendo à estação chuvosa e seca de 2013 e a estação chuvosa de 2014. Avaliou-se também a produção de massa seca e o acúmulo de P pelas plantas. No final do segundo ano, analisou-se o fracionamento de P do solo. A colonização radicular foi mais influenciada nas épocas chuvosas. A presença das plantas de cobertura proporcionou maior colonização micorrízica e densidade de esporos na época chuvosa. As aplicações de fontes fosfatadas não influenciam a densidade dos esporos, enquanto que as plantas de cobertura, principalmente o guandú e a braquiária, apresentaram aumento no número de esporos. Apesar de não aumentar as frações lábeis do P no solo, a utilização de plantas de cobertura proporcionou maior ciclagem do nutriente. Os fosfatos não influenciaram a massa seca nem o acúmulo de P, sendo que houve efeitos das plantas de cobertura na massa seca e no acúmulo de P na parte aérea, com destaque para o milheto e a braquiária. / In order to improve the use efficiency of phosphorus sources and enable a higher absorption of this nutrient, this research aimed to determine the changes promoted by cover crops and phosphorus sources of different solubility in the colonization by arbuscular mycorrhizal fungi (AMF), as much as the availability of P fractions in the soil and the use efficiency of P by the cover crops. A complete randomized block design was adopted, in a 5x3 factorial scheme, with four replications. For the first factor were used four cover crops: millet (Pennisetum glaucum), brachiaria (Brachiaria ruziziensis), pigeon pea (Cajanus cajan) and sun hemp (Crotalaria juncea), including a control (fallow); for the second factor were used the reactive phosphate Bayovar and the simple superphosphate plus a control treatment (no phosphate). It was assessed the AMF colonization, the spore density in the soil in three different times, the rainy and dry seasons in 2013, and the rainy season in 2014. At the end of 2014, it was also evaluated the amount of the fractioned P in the soil. The root colonization was more influenced in rainy season. The presence of cover crops provided greater mycorrhizal colonization and spore density in the rainy season. The applications of phosphate sources did not influence the spores density. However, the cover crops, mainly pigeon pea and brachiaria, showed an increase in the number of spores. The use of cover crops did not increase the labile fractions of P in the soil, Nevertheless they provided greater cycling of this nutrient. Phosphates did not influence the dry matter or the accumulation of P. Interestingly, the dry matter and P accumulation in shoots was influenced by the kind of cover crops, being higher for millet and brachiaria.

Ce mémoire de validation des acquis de l’expérience (VAE) s’inscrit dans le cadre d’une demande d’accès au diplôme de doctorat. Il s’organise autour de trois parties. La première est un bilan de parcours, la deuxième est une analyse des activités de recherche et la troisième est un bilan des productions scientifiques. Autour de nombreux exemples, il structure une analyse des acquis et des compétences. Dans le premier chapitre, le bilan de parcours s’appuie sur une analyse chronologique et catégorielle des activités (travaux de recherche, animation scientifique, encadrement, enseignement, etc.) aussi bien en recherche publique que privée. Il rend compte de nombreuses évolutions sensibles : évolution du positionnement à la recherche, spécialisation progressive des sujets d’étude, internationalisation croissante des échanges scientifiques, structuration du réseau partenarial, management d’équipe…Dans le deuxième chapitre, plusieurs travaux scientifiques sont présentés portant sur l’amélioration de l’efficience d’utilisation du phosphore selon diverses approches (complexation, solubilisation bactérienne, voie de signalisation, vectorisation de principes actifs et modélisation de diffusion…). Ces sujets de recherche s’organisent autour de la compréhension des processus, des mécanismes d’actions et des domaines de validité des solutions à destination du milieu agricole. Enfin, dans le troisième chapitre, les types de productions scientifiques (publications, brevets, autorisations de mise sur le marché, posters, communications, rapports d’expertise…) rendent compte de la trans / This manuscript is part of a process of recognition of acquired experience. It is organized around three parts. The first part is an assessment of the course, the second part is an analysis of the research activities and the third part is a review of the scientific productions. Around many examples, it structures an analysis of skills and competencies. In the first chapter, the assessment of the course is based on a chronological and categorical analysis of activities (research work, scientific animation, supervision, teaching, etc.) in both public and private research. It reports on many significant developments: evolution of positioning to research, progressive specialization of the subjects of study, increasing internationalization of scientific exchanges, structuring of the partnership network, team management ...In the second chapter, several scientific works are presented on the improvement of the efficiency of use of phosphorus according to various approaches (complexation, bacterial solubilization, signaling pathway, vectorization of active principles and diffusion modeling ...). These research topics are organized around the understanding of processes, mechanisms of action and areas of validity of solutions for the agricultural community. Finally, in the third chapter, the types of scientific productions (publications, patents, marketing authorizations, posters, communications, expert reports ...) reflect the transdisciplinary of the work, reveal the importance of protection strategies. intellectual property and concretize the complementary nature of the laborato