Spatial distribution of microbial biomass in microaggregates of a silty-loam soil and the relation with the resistance of microorganisms to soil drying

Gestel, M Van; Merckx, Roel; Vlassak, K.

doi:10.1016/0038-0717(95)00192-1

Cited by 139 publications

(62 citation statements)

References 29 publications

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“…Several studies reported a higher microbial biomass in smaller size fractions (27,30,32,58). Our results clearly demonstrated that not only biomass, but also bacterial community structure, was significantly affected by particle size and that smaller size fractions host higher diversities of microbes than larger size particles.…”

Section: Discussionsupporting

confidence: 71%

“…Different methods have been applied to study the distribution of organic matter and microbes in the soil matrix, such as electron microscopy (15), repeated washing of soil aggregates (23), and techniques based on physical soil fractionation (6,27,58). Several studies have demonstrated that cell numbers and microbial biomass were most concentrated in the smaller size silt and clay fractions (27,30,32,58).…”

mentioning

confidence: 99%

“…Several studies have demonstrated that cell numbers and microbial biomass were most concentrated in the smaller size silt and clay fractions (27,30,32,58). Because the sizes of soil aggregates and soil pores correlate, microbial biomass is also mainly present in micropores (5 to 30 m) (3,22,36).…”

mentioning

confidence: 99%

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Microbial Population Structures in Soil Particle Size Fractions of a Long-Term Fertilizer Field Experiment

Sessitsch

Weilharter

Gerzabek

et al. 2001

Appl Environ Microbiol

609

344

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Soil structure depends on the association between mineral soil particles (sand, silt, and clay) and organic matter, in which aggregates of different size and stability are formed. Although the chemistry of organic materials, total microbial biomass, and different enzyme activities in different soil particle size fractions have been well studied, little information is available on the structure of microbial populations in microhabitats. In this study, topsoil samples of different fertilizer treatments of a long-term field experiment were analyzed. Size fractions of 200 to 63 m (fine sand fraction), 63 to 2 m (silt fraction), and 2 to 0.1 m (clay fraction) were obtained by a combination of low-energy sonication, wet sieving, and repeated centrifugation. Terminal restriction fragment length polymorphism analysis and cloning and sequencing of 16S rRNA genes were used to compare bacterial community structures in different particle size fractions. The microbial community structure was significantly affected by particle size, yielding higher diversity of microbes in small size fractions than in coarse size fractions. The higher biomass previously found in silt and clay fractions could be attributed to higher diversity rather than to better colonization of particular species. Low nutrient availability, protozoan grazing, and competition with fungal organisms may have been responsible for reduced diversities in larger size fractions. Furthermore, larger particle sizes were dominated by ␣-Proteobacteria, whereas high abundance and diversity of bacteria belonging to the Holophaga/Acidobacterium division were found in smaller size fractions. Although very contrasting organic amendments (green manure, animal manure, sewage sludge, and peat) were examined, our results demonstrated that the bacterial community structure was affected to a greater extent by the particle size fraction than by the kind of fertilizer applied. Therefore, our results demonstrate specific microbe-particle associations that are affected to only a small extent by external factors.

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Section: Discussionsupporting

confidence: 71%

mentioning

confidence: 99%

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Microbial Population Structures in Soil Particle Size Fractions of a Long-Term Fertilizer Field Experiment

Sessitsch

Weilharter

Gerzabek

et al. 2001

Appl Environ Microbiol

609

344

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“…This differential effect is related to the greater cation exchange capacity and surface area of 2:1 clay particles (Stotzky, 1966), which presumably confer greater protection against desiccation (Bitton et al, 1976;Bushby and Marshall, 1977) than 1:1 clays and oxides. Van Gestel et al (1996), however, suggested that clays do not provide protection against severe drying because water associated with clays is evaporated during drying events. Nevertheless, bacteria were protected in soil aggregates subjected to dry-wet cycles; whereas, fungi were not, presumably because they reside in larger pores and on the surfaces of the aggregates where they are more exposed to drying conditions .…”

Section: Protected Versus Unprotected Microbial Biomassmentioning

confidence: 99%

Bacterial and Fungal Contributions to Carbon Sequestration in Agroecosystems

Six

Frey

Thiet

et al. 2006

Soil Science Soc of Amer J

1,729

783

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“…This may be attributed to the higher ratio of soil porosity in loamy and clay soils making the conditions more favorable for the biological activities of the bacteria and plant roots, including the biochemical communications between the bacteria and the plant at the onset of symbiosis. Also Van Gestel et al (1996) reported that most of the bacterial populations (more than 50%) were located in the clay soil, in comparison with the sandy soil (only 7%).…”

Section: Genistein (Mm) Leafmentioning

confidence: 99%

Using signal molecule genistein to alleviate the stress of suboptimal root zone temperature on soybean-Bradyrhizobium symbiosis under different soil textures

Miransari

Smith

2008

TJPI

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Suboptimal root zone temperatures (RZTs) (below 258C) in Canada until July may adversely affect the secretion of interorganismal signal molecules such as genistein by soybean and hence, the soybean-Bradyrhizobium symbiosis. We also proposed for the first time that soil texture might play a role in these biochemical communications. Soybean plants, planted in undisturbed soil samples (with sandy, loamy and clay textures), collected from the field, were subjected to three different soil temperatures (14, 19 and 248C). Bradyrhizobium japonicum (strain 532C) inocula, preincubated with four levels of genistein (0, 5, 10 and 20 mM), were used to inoculate the plants. The experiment was conducted at the research greenhouse of Macdonald Campus, McGill University, Canada. The effects of genistein 5 and 20 mM on soybean nodulation and growth were significant at 148C. As genistein was more effective in loamy and clay soils, soil texture may also be a determining factor in the biochemical communications between B. japonicum and soybean.

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Spatial distribution of microbial biomass in microaggregates of a silty-loam soil and the relation with the resistance of microorganisms to soil drying

Cited by 139 publications

References 29 publications

Microbial Population Structures in Soil Particle Size Fractions of a Long-Term Fertilizer Field Experiment

Microbial Population Structures in Soil Particle Size Fractions of a Long-Term Fertilizer Field Experiment

Bacterial and Fungal Contributions to Carbon Sequestration in Agroecosystems

Using signal molecule genistein to alleviate the stress of suboptimal root zone temperature on soybean-Bradyrhizobium symbiosis under different soil textures

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