The effect of nitrate-nitrogen supply on bacteria and bacterial-feeding fauna in the rhizosphere of different grass species

Griffiths, Bryan S.; Welschen, Rob; Arendonk, J. J. C. M. Van; Lambers, Hans

doi:10.1007/bf00317793

Cited by 73 publications

(31 citation statements)

References 31 publications

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“…The stimulation of bacterial feeding nematodes rather than Protozoa in N treatments 1 week before ear emergence corresponds to earlier findings in barley rhizosphere soil (Griffiths 1990;Griffiths et al 1992). However, Protozoa, but not bacterial feeding nematodes were stimulated in NP treatments at this stage.…”

Section: Discussionsupporting

confidence: 64%

“…14 C labelling has shown increased relative allocation of photoassimilated C to soil and higher microbial growth in the rhizosphere in response to high compared to low soil N status (Merckx et al 1987;Liljeroth et al 1990), and Griffiths et al (1992) found a stimulation of rhizosphere nematodes in Namended treatments. Contrary to these findings, a higher relative C allocation belowground was found at low soil N (Johansson 1992) or P (Saggar et al 1997).…”

Section: Introductionmentioning

confidence: 97%

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Aphid effects on rhizosphere microorganisms and microfauna depend more on barley growth phase than on soil fertilization

2004

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This paper gives the first reports on aphid effects on rhizosphere organisms as influenced by soil nutrient status and plant development. Barley plants grown in pots fertilized with N but without P (N), with N and P (NP), or not fertilized (0) were sampled in the early growth phase (day 25), 1 week before and 1 week after spike emergence. Aphids were added 16 days before sampling was carried out. In a separate experiment belowground respiration was measured on N and NP fertilized plant-soil systems with aphid treatments comparable to the first experiment. Aphids reduced numbers of rhizosphere bacteria and fungal feeding nematodes 1 week before spike emergence. Before spike emergence, aphids reduced belowground respiration in NP treatments. These findings strongly indicate that aphids reduced allocation of photoassimilates to roots and deposition of root exudates in the growth phase of the plant. Contrary to this, 1 week after spike emergence numbers of bacteria, fungal feeding nematodes and Protozoa were higher in rhizospheres of plants subjected to aphids probably because aphids enhanced root mortality and root decomposition. Protozoa and bacterial feeding nematodes were stimulated at different experimental conditions with nematodes being the dominant bacterial grazers at N fertilization and Protozoa in the NP treatment before spike emergence.

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Section: Discussionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 97%

Aphid effects on rhizosphere microorganisms and microfauna depend more on barley growth phase than on soil fertilization

2004

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“…Extrinsic factors such as nutrient availability (Bosatta and Berendse, 1984;De Angelis, 1992;Moore et al, 1993), pH (Wardle, 1998) and the amount of detritus in a system (De Angelis et al, 1989) may also drive resistance and resilience. In soil systems, many of these potential driving factors can be altered by plant community composition, including the composition and structure of the soil microbial community (Griffiths et al, 1992;Wardle and Nicholson, 1996), and the chemical properties of the soil (Gastine et al, 2003;Hooper and Vitousek, 1998;Tilman and Wedin, 1991). It is therefore reasonable to predict that the presence of different plant species may result in soil communities with different abilities to resist and recover from disturbances.…”

Section: Introductionmentioning

confidence: 98%

Plant Species Composition Effects on Belowground Properties and the Resistance and Resilience of the Soil Microflora to a Drying Disturbance

Orwin

Wardle

2005

Plant Soil

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We hypothesised that plant species composition and richness would affect soil chemical and microbial community properties, and that these in turn would affect soil microbial resistance and resilience to an experimentally imposed drying disturbance. We performed a container experiment that manipulated the composition and species richness of common pasture plant species (Trifolium repens, Lolium perenne, and Plantago lanceolata) by growing them in monoculture, and in all the possible two and three-way combinations, along with an unplanted control soil. Experimental units were harvested at four different times over a 16-month period to determine the effect of plant community development and seasonal changes in temperature and moisture on belowground properties. Results showed that plant species composition influenced soil chemistry, soil microbial community properties and soil microbial resistance and resilience. Soil from planted treatments generally showed reduced soil microbial resistance to drying compared to unplanted control soils. Soils from under T. repens showed a higher resistance and resilience than the soils from under P. lanceolata, and a higher resistance than soils from under L. perenne. We suggest that differences across soils in either resource limitation or soil microbial community structure may be responsible for these results. Plant species richness rarely affected soil microbial community properties or soil microbial resistance and resilience, despite having some significant effects on plant community biomass and soil nitrogen contents in some harvests. The effect that treatments had for most variables differed between harvests, suggesting that results can be altered by the stage of plant community development or by extrinsic environmental factors that varied with harvest timing. These results in combination show that soil microbial resistance and resilience was affected by plant community composition, and the time of measurement, but was largely unrelated to plant species richness.

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“…Microbial biomass has been shown to correlate with aboveground primary production (Wardle 1992;Zak et al 1994;Wardle and Barker 1997), and to be responsive to those aboveground trophic interactions, such as herbivory, that aect root exudation (reviewed by Bardgett et al 1998). Since soil microbes are consumed by microbivorous animals, changes in microbial biomass and production can be re¯ected in the biomasses of upper trophic groups of soil food webs (Sohlenius 1990;Christensen et al 1992;Griths et al 1992;Parmelee et al 1993;Griths 1994). Mikola and SetaÈ laÈ (1998b) found that in simple heterotrophic food webs containing microbes and nematodes, increased microbial production led to increases in the biomass of microbes and microbivores, and to a marginal increase in the biomass of top predators (i.e., consumers of microbivores).…”

Section: Introductionmentioning

confidence: 98%

Effects of microbivore species composition and basal resource enrichment on trophic-level biomasses in an experimental microbial-based soil food web

Mikola

1998

Oecologia

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Previous theoretical and empirical evidence suggests that species composition within trophic levels may profoundly affect the response of trophic-level biomasses to enhanced basal resources. To test whether species composition of microbivorous nematodes has such an effect in microbial-based soil food webs, I created three microcosm food webs, consisting of bacteria, fungi, bacterial-feeding nematodes (Acrobeloides tricornus, Caenorhabditis elegans), fungal-feeding nematodes (Aphelenchus avenae, Aphelenchoides sp.) and a predatory nematode (Prionchulus punctatus). The food webs differed in species composition at the second trophic level: food web A included A. tricornus and Aph. avenae, food web B included C. elegans and Aphelenchoides sp., and food web AB included all four species. I increased basal resources by adding glucose to half of the replicates of each food web, and sampled microcosms destructively four times during a 22-week experiment to estimate the biomass of organisms at each trophic level. Microbivore species composition significantly affected bacterivore and fungivore biomass but not bacterial, fungal or predator biomass. Greatest bacterivore and fungivore biomass was found in food web A, intermediate biomass in food web AB, and smallest biomass in food web B. Basal resource addition increased the biomass of microbes and microbivores but did not affect predator biomass. Importantly, microbivore species composition did not significantly modify the effect of additional resources on trophic-level biomasses. The presence of a competitor reduced the biomass of A. tricornus and Aph. avenae, in that the biomass of these species was less in food web AB than in food web A, whereas the biomass of C. elegans and Aphelenchoides sp. was not affected by their potential competitors. The biomass of Aph. avenae increased with additional resources in the absence of the competitor only, while the biomass of A. tricornus and Aphelenchoides sp. increased also in the presence of their competitors. The results imply that microbivore species composition may determine the second-level biomass in simple microbe-nematode food webs, but may not significantly affect biomass at other levels or modify the response of trophic-level biomasses to enhanced basal resources. The study also shows that even if the role of predation in a food web is diminished, the positive response of organisms to increased resource availability may still be hindered by competition.

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The effect of nitrate-nitrogen supply on bacteria and bacterial-feeding fauna in the rhizosphere of different grass species

Cited by 73 publications

References 31 publications

Aphid effects on rhizosphere microorganisms and microfauna depend more on barley growth phase than on soil fertilization

Aphid effects on rhizosphere microorganisms and microfauna depend more on barley growth phase than on soil fertilization

Plant Species Composition Effects on Belowground Properties and the Resistance and Resilience of the Soil Microflora to a Drying Disturbance

Effects of microbivore species composition and basal resource enrichment on trophic-level biomasses in an experimental microbial-based soil food web

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