Dynamic composting optimization through C/N ratio variation as a startup parameter

Different organic wastes (waste of tomato leaves and stems, sheep manure, olive mill waste and melon waste) were mixed with different proportions for different C/N ratio to make better use of tomato waste as it constitutes the majority of horticultural waste in the Souss-Massa region (south-western of Morocco). The objective of this study was to evaluate the effect of C/N ratio on the physicochemical parameters during aerobic composting process (temperature, relative humidity, pH, EC...), and the quality of the compost. The effect of each produced compost was also tested by its incorporation at different rates into sandy soil. The four studied C/N ratios (treatments) were: C/N=25; C/N=30; C/N=35 and C/N=40. Results revealed that the treatment C/N=35 has resulted in the highest oxygen consumption and also, the longest thermophilic phase. Treatments C/N=25 and C/N=35 have reached optimal C/N ratios at the end of the process (respectively 11.88 and 14.71), while treatments C/N=30 and C/N=40 stood higher than 15 (respectively 17.93 and 18.84). Fulvic acid evolution remained constant for all treatments, whereas humic acid content has reached highest levels with C/N=25 and C/N=35 treatments. The effect of compost on seed germination test and phytotoxicity test showed that treatment C/N=35 has produced the most mature compost with the lowest phytotoxicity effect. The amendment of compost has reduced the pH, increased the EC, and enriched soil with organic matter as far as the rate of the amendment is increasing (10; 20 and 30Tonnes.ha-1). Compost of treatment C/N=40 has recorded the highest soil total organic matter content poorly decomposed during composting. However compost of treatment C/N=35 has resulted in the lowest soil total organic matter content, this is mainly due to the intense degradation of the compost during the composting process. The quality of the produced compost depends largely on the level of C/N startup ratio and also the quality of its constituents within the mixture

Claude Perissol. Dynamique des communautés bactériennes de la phyllosphère et de la litière de chêne vert (Quercus ilex L.). Approche des interrelations champignons-bactéries / Dynamics of bacterial communities on the phylloplane and the leaf litter of the evergreen oak (Quercus ilex L.). An approach to relationships between fungi and bacteria. Thèse de Doctorat (spécialité microbiologie) soutenue le 31 janvier 1992 à l’Université d’Aix-Marseille III

Perissol Claude. Claude Perissol. Dynamique des communautés bactériennes de la phyllosphère et de la litière de chêne vert (Quercus ilex L.). Approche des interrelations champignons-bactéries / Dynamics of bacterial communities on the phylloplane and the leaf litter of the evergreen oak (Quercus ilex L.). An approach to relationships between fungi and bacteria. Thèse de Doctorat (spécialité microbiologie) soutenue le 31 janvier 1992 à l’Université d’Aix-Marseille III. In: Ecologia mediterranea, tome 17,1991. pp. 175-176

Dynamique des communautes bacteriennes de la phyllosphere et de la litiere de chene vert (Quercus ilex L.). Approche des interrelations champignons-bacteries

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 81447 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Claude Perissol. Dynamique des communautés bactériennes de la phyllosphère et de la litière de chêne vert (Quercus ilex L.). Approche des interrelations champignons-bactéries / Dynamics of bacterial communities on the phylloplane and the leaf litter of the evergreen oak (Quercus ilex L.). An approach to relationships between fungi and bacteria. Thèse de Doctorat (spécialité microbiologie) soutenue le 31 janvier 1992 à l’Université d’Aix-Marseille III

Perissol Claude. Claude Perissol. Dynamique des communautés bactériennes de la phyllosphère et de la litière de chêne vert (Quercus ilex L.). Approche des interrelations champignons-bactéries / Dynamics of bacterial communities on the phylloplane and the leaf litter of the evergreen oak (Quercus ilex L.). An approach to relationships between fungi and bacteria. Thèse de Doctorat (spécialité microbiologie) soutenue le 31 janvier 1992 à l’Université d’Aix-Marseille III. In: Ecologia mediterranea, tome 17,1991. pp. 175-176

Co-compostage de boues de station d'épuration et de déchets verts (nouvelle méthodologie du suivi des transformations de la matière organique)

Afin d'éliminer et de valoriser les biodéchets, de nombreuses collectivités ont opté pour une plate-forme de compostage. Les exigences de qualité des composts nécessitent actuellement un nombre important de caractérisations physico-chimiques et biologiques. Nos objectifs ont donc été d'étudier les processus du compostage et de mettre au point une méthode simple et efficace de suivi de l'évolution chimique et biologique des composts. Notre étude a porté sur un compostage de six mois en andains constitués d'un mélange de boues de station d'épuration urbaines et de déchets verts broyés. Les composts ont été caractérisés par des paramètres physico-chimiques (analyses élémentaires, matières organiques, substances humiques et lignine. Résonance Magnétique Nucléaire 13C du solide) et biologiques (respiration, dénombrement des micro-organismes et changements des profils métaboliques des communautés microbiennes, activités enzymatiques) qui ont mis en évidence la minéralisation et l'humification de la matière organique. Une banque de données établie à partir de 432 composts a ensuite démontré l'efficacité de la Spectroscopie Proche InfraRouge (SPIR) pour distinguer les composts suivant leur maturité. Enfin, aucun paramètre n'étant utilisable seul, l'ensemble des informations a été synthétisé par ACP en un Indice global d'Evolution du Compostage (IEC) parfaitement calibré en SPIR par la méthode PLS et permettant une détermination simple et précise de la maturité. Cette alliance SPIR-IEC pourrait être appliquée à l'optimisation d'un nouveau procédé de compostage en réacteur en cours de développement.AIX-MARSEILLE3-BU Sc.St Jérô (130552102) / SudocSudocFranceF

Effets de l'épandage de boues de station d'épuration sur l'évolution des caractéristiques chimiques, microbiologiques et enzymatiques d'une litière de chêne-liège (Quercus suber L.) en milieu sylvo-pastoral

L'épandage de boues de station d'épuration en milieu sylvo-pastoral représente en France une nouvelle voie de valorisation de ces déchets. L'impact d'un tel épandage est étudié sur la décomposition d'une litière de chêne-liège (Quercus suber L.), prise pour modèle. Une expérimentation in situ a été réalisée sur une période de 14 mois à l'aide de la méthode d'échantillonnage des sacs de litière en comparant deux parcelles, témoin et épandue, dans le Massif des Maures (Var, France). La perturbation ainsi provoquée a été évaluée en analysant, d'une part l'évolution chimique de la litière en décomposition (analyses élémentaires, NIRS, RMN 13C) et, d'autre part, les microorganismes et les activités enzymatiques impliquées dans les cycles du carbone et du phosphore. Les résultats ont montré que l'apport de boues accélère les phénomènes se produisant au cours de la décomposition de la litière : une dégradation préférentielle des constituants cellulosiques et hémicellulosiques accompagnée d'un enrichissement relatif plus important en azote et en composés aromatiques. Cette accélération de la minéralisation de la matière organique est expliquée par la stimulation de l'activité microbienne. Celle-ci a été caractérisée par une augmentation significative des respirations (réelle et potentielle), de la plupart des effectifs microbiens étudiés et des activités enzymatiques : laccases, peroxydases, cellulases et phosphatases basiques. Cependant, bien que l'apport de boues influence l'activité microbienne, l'humidité des feuilles de la litière reste le facteur primordial dans l'évolution annuelle de cette activité.AIX-MARSEILLE3-BU Sc.St Jérô (130552102) / SudocSudocFranceF

Influence of plants on microbial activity in a vertical-downflow wetland system treating waste activated sludge with high organic matter concentrations

International audienceThe rhizosphere is a key zone for pollutant removal in treatment wetlands; therefore, studies on microbial activity may provide helpful information for a better understanding of purification processes. We studied microbial activity in a vertical-downflow constructed wetland system treating waste activated sludge with high organic matter concentrations, under Mediterranean climate. The aims of the work were to study the influence of (i) the presence of plants, (ii) the plant species (Phragmites australis Cav., Typha latifolia L., Iris pseudacorus L.), and (iii) the plant growth stage (plant senescence and plant fast growing stage) on total respiration rate and phosphatase activity in the substrate (intented here as the solid support on which the plants grow). The presence of plants had a positive influence on microbial activity, since substrate respiration and both acid and alkaline phosphatase activity were always higher in planted than in unplanted mesocosms. Among the three tested species, Phragmites was the one that most stimulated both substrate respiration rate and phosphatase activity, followed by Typha and Iris. These differences of microbial activity between mesocosms were corresponding to differences of removal efficiency. Substrate respiration and phosphatase activity were of similar magnitude at the two growth stages, while the stimulating effect of plants seemed to have been delayed and microbial activity showed higher fluctuations at plant fast growing stage than at plant senescence

Sporulation and physiological profiles of bacterial communities of three Mediterranean soils affected by drying-rewetting or freezing-thawing cycles

International audienceIn the global change context, the basal respiration (BR), the estimated number of bacterial spores (SP) and the community level physiological profiles (CLPPs) were investigated in three different Mediterranean soils following different hydric and thermic stress scenarios. The treatments consisted in an increasing number (1, 2, 4, and 7) of drying-rewetting (DRWc) or freezing-thawing cycles (FR) at 20, 40 or -20 degrees C. The results highlighted that the different soils responded differently to the same treatment and that the three variables considered were weakly related one to each another. In almost all soils and modalities, the BR increased significantly during the first cycles before decreasing during the last. With regards to SP, it appeared that, for a given soil, the capacity of microbial communities to sporulate and/or germinate can be considerably more influenced by the temperature rather than by the hydric stress. Finally, the CLPPs literally collapsed with the treatment at 40 degrees C, irrespective of the soil considered. This suggested a progressive replacement of the catabolically diversified original bacterial communities by another showing lower functional diversities

Effects of drying-rewetting or freezing thawing cycles on enzymatic activities of different Mediterranean soils

International audienceThe aim of this study was to determine the impact of climatic stress scenarios on soil microbial functions. To this end, three Mediterranean soils (south exposed soil, S; north exposed soil, N; soil from riparian forest, R) were sampled and subjected to climatic stress events consisting of an increasing number of drying-rewetting (DRWc) or freezing thawing (FFc) cycles (1, 2, 4, and 7 cycles) at 20, 20, and 40 degrees C. The microbial functions considered were: fluorescein diacetate hydrolase (FDAse), lipase, acid phosphomonoesterase (PhA), and beta-glucosidase (beta-glu). Results showed that the soils had different enzymatic patterns, the S soil being less active than the two others. Considering the climatic stresses, the repeated effects of hydric and thermic stresses resulted, in most cases, in enzymatic activity decreases. The soils with colder and moister conditions (i.e. R and N soils) had globally more vulnerable enzyme activities to DRWc, a phenomenon which was amplified by increased temperatures, 40 degrees C being the more deleterious temperature. On the contrary, the S soil appeared more resistant to climatic stresses and, in some cases, certain enzyme activities, namely beta-glu and PhA, were unaffected by the various treatments. gamma-irradiation was also used to assess the biotic and abiotic parts in soil FDAse response to stresses. Results showed that in soils devoid of active microbial biomass, the FDAse activity was very sensitive to DRWc at high temperature (40 degrees C), activity losses ranging from 90 to 95%. Moreover, comparison with unsterilized soils indicated that microbial communities were able to reload efficiently this activity between stresses. (C) 2015 Elsevier Ltd. All rights reserved