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Papers by isabelle barois
European Journal of Soil Biology, 2000
The moment the soil enters into contact with an earthworm, both superficially and intemally, phys... more The moment the soil enters into contact with an earthworm, both superficially and intemally, physicochemical and biological changes take place. The drilosphere represents the whole soil volume under earthworm influence. Thus it includes the body surfaces, the gut and all the internal features of the worm that are in contact with the ingested soil, as well as the external structures (casts, burrows, middens) created by earthworm activities. The extent of the drilosphere and its particular characteristics depend on the species and ecological categories of the earthworm community present as well as the spatial and temporal scale of interest. Spatially, the drilosphere can interact with other soil functional domains and lead to significant changes in the litter system or detritusphere (generally decreasing litter stocks) and the rhizosphere (affecting both root biomass and density), the two main sources of organic matter (OM) additions to the soil, as well as in the aggregatusphere and the porosphere. Drilosphere effects on microbial activity and OM decomposition can be completely different (and opposite) depending on the spatio-temporal scale of observation. At the level of the gut, microbial activity is dramatically stimulated in a matter of a few hours via a mutualistic digestion system. In this process, water and soluble-C in the form of intestinal mucus (the Kiss) produced by the earthworm (Prince Charming) awakens the dormant microflora (Sleeping Beauties), thereby increasing decomposition of the stable forms of soil OM ingested. During gut passage populations of other organisms (e.g. protozoa, nematodes, fungi) may decline with digestion, although these organisms probably form a minor component of the earthworm's energy needs. In the casts and on the burrow walls, the abundant nutrient resources for soil microflora continue the priming effect of the gut, increasing over a short time period mineralization rates and plant nutrient bio-availability. However as castings, particularly of the 'compacting group', and burrow walls begin to dry and stabilize with age (days to weeks), OM decomposition, nutrient mineralization and microbial activity decrease, often reaching levels lower than uningested soil due to 'protection'. Finally at the scale of years to decades and soil profile, it,appears that the drilosphere can exert an important regulation on OM incorporation and tumover rates, and soil C stocks. O 2000 Editions scientifiques et médicales Elsevier SAS I ~~~~~~~~~~ I drilosphere / earthworms / soil properties / microorganisms / organic matter dynamics
Emirates Journal of Food and Agriculture
Description or the subject: Spent mushroom substrate (SMS) is a by-product of the mushroom cultiv... more Description or the subject: Spent mushroom substrate (SMS) is a by-product of the mushroom cultivation industry. Mexico produces more than 350 thousand tons of SMS annually. Attempts have been made to use SMS as a soil amendment, among other applications, with some success. However, leaching from the SMS can discard into groundwater and potentially lead to eutrophication in discharge areas. These problems can be overcome by bioconversion of the waste. Objectives: Thus, the present study aimed to apply composting and vermicomposting methods on a pilot scale, to convert SMS into a highly enriched substrate suitable for soil amendment and horticulture. Method: For this purpose, 800 kg (fresh weight) of SMS was processed by each of the above-mentioned bioconversion methods for 120 days. The physicochemical properties of the initial material (SMS) and the compost and vermicompost obtained at the end of the two processes were analyzed by measuring pH, electrical conductivity, organic matt...
Scope of the journal. The primary intention of the journal is to stimulate wide interdisciplinary... more Scope of the journal. The primary intention of the journal is to stimulate wide interdisciplinary cooperation and understanding among workers in the different fields of pedology. Therefore, the journal tries to bring together papers from the entire field of soil research, rather than to emphasize any one subdiscipline. Interdisciplinary work should preferably be focused on occurrence and dynamic characterization in space and time of soils in the field. Publication information. Geoderma (ISSN O01 6-7061). For 1998 volumes 81-86 are scheduled for publication. Subscription prices are available upon request from the publisher. Subscriptions are accepted on a prepaid basis only and are entered on a calendar year basis. Issues are sent by surface mail except to the following countries where air delivery via SAL is ensured: Argentina, Australia, Brazil, Canada, Hong Kong, India, Israel, Japan, Malaysia, Mexico, New Zealand, Pakistan, PR China, Singapore, South Africa, South Korea, Taiwan, ...
Plant and Soil, 1995
Most soil invertebrates and roots have developed strong interactions with micro-organisms to expl... more Most soil invertebrates and roots have developed strong interactions with micro-organisms to exploit the organic and mineral resources of soil. Micro-fauna are mainly predators of microorganisms whereas larger organisms interact with micro-organisms through the “external rumen” or facultative endosymbiotic digestive systems. Mobilisation of nutrient and organic resources through mutualism with soil microflora seems to be all the more efficient as
l Departamento Biologra de Suelos, Instituto de Ecologra A.c., Xalapa, Mexico; 2Laboratoire d'... more l Departamento Biologra de Suelos, Instituto de Ecologra A.c., Xalapa, Mexico; 2Laboratoire d'Ecologie des Sols Tropicaux, IRD, Bondy, France; 31nstituto de Ecologra y systematica, La Habana, Cuba; 4School of Ufe Sciences, Sambalpur University, Sambalpur, India; 5 Universidad Complutense, Madrid, Spain; 6Universite de Bukaru, Republique de Congo Democratique; 7 Laboratoire B.O.s. T., IRD, Fort-de-France, Martinique; 81RD, Brasilia D.F., Brazil
Soil Biology and Biochemistry, 1986
Soil ingested by Pontoscolex corethrurus Milller, a geophagous tropical earthworm, was transforme... more Soil ingested by Pontoscolex corethrurus Milller, a geophagous tropical earthworm, was transformed considerably during passage through the digestive tract. Readily-assimilable water-soluble compounds (mucus) with a high energy content represented 16 and 12.7% of the dry mass of soil in the anterior and posterior intestine respectively but comprised only 0.12% of the control soil and 0.43% of the fresh casts. Water content increased from 35% in the soil to 149% in the anterior part of the gut; it was 122% in the terminal part and 99% in the fresh casts. Ingested soil of pH 4.6 was neutralized in the anterior part of the gut (pH 6.8); the pH decreased to 6.0 in the posterior part and declined to 4.8 in the casts. These physicochemical modifications and the intense mixing within the gizzard and gut stimulated an increase in the respiratory activity of the microflora ranging from 1.37 fold in the anterior part of the gut to 7.30-fold in the posterior part and declining to 1.69-fold in the casts. Thus, the microbial activity is first strongly stimulated by more favourable physical conditions and it increases as intestinal mucus is expended. The microflora appears to become more able to digest the more complex organic matter of the soil for the benefit of the earthworm. A mutualistic relationship is proposed between microflora and earthworms for the exploitation of the complex organic matter of tropical soils.
European Journal of Soil Biology, 2000
The moment the soil enters into contact with an earthworm, both superficially and intemally, phys... more The moment the soil enters into contact with an earthworm, both superficially and intemally, physicochemical and biological changes take place. The drilosphere represents the whole soil volume under earthworm influence. Thus it includes the body surfaces, the gut and all the internal features of the worm that are in contact with the ingested soil, as well as the external structures (casts, burrows, middens) created by earthworm activities. The extent of the drilosphere and its particular characteristics depend on the species and ecological categories of the earthworm community present as well as the spatial and temporal scale of interest. Spatially, the drilosphere can interact with other soil functional domains and lead to significant changes in the litter system or detritusphere (generally decreasing litter stocks) and the rhizosphere (affecting both root biomass and density), the two main sources of organic matter (OM) additions to the soil, as well as in the aggregatusphere and the porosphere. Drilosphere effects on microbial activity and OM decomposition can be completely different (and opposite) depending on the spatio-temporal scale of observation. At the level of the gut, microbial activity is dramatically stimulated in a matter of a few hours via a mutualistic digestion system. In this process, water and soluble-C in the form of intestinal mucus (the Kiss) produced by the earthworm (Prince Charming) awakens the dormant microflora (Sleeping Beauties), thereby increasing decomposition of the stable forms of soil OM ingested. During gut passage populations of other organisms (e.g. protozoa, nematodes, fungi) may decline with digestion, although these organisms probably form a minor component of the earthworm's energy needs. In the casts and on the burrow walls, the abundant nutrient resources for soil microflora continue the priming effect of the gut, increasing over a short time period mineralization rates and plant nutrient bio-availability. However as castings, particularly of the 'compacting group', and burrow walls begin to dry and stabilize with age (days to weeks), OM decomposition, nutrient mineralization and microbial activity decrease, often reaching levels lower than uningested soil due to 'protection'. Finally at the scale of years to decades and soil profile, it,appears that the drilosphere can exert an important regulation on OM incorporation and tumover rates, and soil C stocks. O 2000 Editions scientifiques et médicales Elsevier SAS I ~~~~~~~~~~ I drilosphere / earthworms / soil properties / microorganisms / organic matter dynamics
Emirates Journal of Food and Agriculture
Description or the subject: Spent mushroom substrate (SMS) is a by-product of the mushroom cultiv... more Description or the subject: Spent mushroom substrate (SMS) is a by-product of the mushroom cultivation industry. Mexico produces more than 350 thousand tons of SMS annually. Attempts have been made to use SMS as a soil amendment, among other applications, with some success. However, leaching from the SMS can discard into groundwater and potentially lead to eutrophication in discharge areas. These problems can be overcome by bioconversion of the waste. Objectives: Thus, the present study aimed to apply composting and vermicomposting methods on a pilot scale, to convert SMS into a highly enriched substrate suitable for soil amendment and horticulture. Method: For this purpose, 800 kg (fresh weight) of SMS was processed by each of the above-mentioned bioconversion methods for 120 days. The physicochemical properties of the initial material (SMS) and the compost and vermicompost obtained at the end of the two processes were analyzed by measuring pH, electrical conductivity, organic matt...
Scope of the journal. The primary intention of the journal is to stimulate wide interdisciplinary... more Scope of the journal. The primary intention of the journal is to stimulate wide interdisciplinary cooperation and understanding among workers in the different fields of pedology. Therefore, the journal tries to bring together papers from the entire field of soil research, rather than to emphasize any one subdiscipline. Interdisciplinary work should preferably be focused on occurrence and dynamic characterization in space and time of soils in the field. Publication information. Geoderma (ISSN O01 6-7061). For 1998 volumes 81-86 are scheduled for publication. Subscription prices are available upon request from the publisher. Subscriptions are accepted on a prepaid basis only and are entered on a calendar year basis. Issues are sent by surface mail except to the following countries where air delivery via SAL is ensured: Argentina, Australia, Brazil, Canada, Hong Kong, India, Israel, Japan, Malaysia, Mexico, New Zealand, Pakistan, PR China, Singapore, South Africa, South Korea, Taiwan, ...
Plant and Soil, 1995
Most soil invertebrates and roots have developed strong interactions with micro-organisms to expl... more Most soil invertebrates and roots have developed strong interactions with micro-organisms to exploit the organic and mineral resources of soil. Micro-fauna are mainly predators of microorganisms whereas larger organisms interact with micro-organisms through the “external rumen” or facultative endosymbiotic digestive systems. Mobilisation of nutrient and organic resources through mutualism with soil microflora seems to be all the more efficient as
l Departamento Biologra de Suelos, Instituto de Ecologra A.c., Xalapa, Mexico; 2Laboratoire d'... more l Departamento Biologra de Suelos, Instituto de Ecologra A.c., Xalapa, Mexico; 2Laboratoire d'Ecologie des Sols Tropicaux, IRD, Bondy, France; 31nstituto de Ecologra y systematica, La Habana, Cuba; 4School of Ufe Sciences, Sambalpur University, Sambalpur, India; 5 Universidad Complutense, Madrid, Spain; 6Universite de Bukaru, Republique de Congo Democratique; 7 Laboratoire B.O.s. T., IRD, Fort-de-France, Martinique; 81RD, Brasilia D.F., Brazil
Soil Biology and Biochemistry, 1986
Soil ingested by Pontoscolex corethrurus Milller, a geophagous tropical earthworm, was transforme... more Soil ingested by Pontoscolex corethrurus Milller, a geophagous tropical earthworm, was transformed considerably during passage through the digestive tract. Readily-assimilable water-soluble compounds (mucus) with a high energy content represented 16 and 12.7% of the dry mass of soil in the anterior and posterior intestine respectively but comprised only 0.12% of the control soil and 0.43% of the fresh casts. Water content increased from 35% in the soil to 149% in the anterior part of the gut; it was 122% in the terminal part and 99% in the fresh casts. Ingested soil of pH 4.6 was neutralized in the anterior part of the gut (pH 6.8); the pH decreased to 6.0 in the posterior part and declined to 4.8 in the casts. These physicochemical modifications and the intense mixing within the gizzard and gut stimulated an increase in the respiratory activity of the microflora ranging from 1.37 fold in the anterior part of the gut to 7.30-fold in the posterior part and declining to 1.69-fold in the casts. Thus, the microbial activity is first strongly stimulated by more favourable physical conditions and it increases as intestinal mucus is expended. The microflora appears to become more able to digest the more complex organic matter of the soil for the benefit of the earthworm. A mutualistic relationship is proposed between microflora and earthworms for the exploitation of the complex organic matter of tropical soils.