Can Plants Stimulate Soil Microbes and Their Own Nutrient Supply? Evidence from a Grazing Tolerant Grass

Hamilton, E. William; Frank, Douglas A.

doi:10.2307/2679923

Cited by 151 publications

(187 citation statements)

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“…Inorganic N in the rhizospherein relation to date (Fig. 7) was similar to levels in other studies where grasses did increase rhizodeposition following defoliation (Hamilton and Frank 2001;Hamilton et al 2008). Furthermore, extractable N was lower in our study (*2-4 lN g dry soil -1 ) than in shortgrass steppe during the growing season (*10 lN g dry soil -1 ; McCulley et al 2009), suggesting low soil N availability in our study.…”

Section: Rhizosphere Responses To Defoliationsupporting

confidence: 80%

“…Such a short-term (1-to 2-day) pulse in microbial activity and biomass has the potential to increase soil N mineralization (several days to a week following defoliation), thereby enhancing N uptake and regrowth by the plant (Hamilton and Frank 2001). However, the magnitude and direction of herbivore effects on rhizosphere process can vary with plant species identity and defoliation intensity (e.g., Guitian and Bardgett 2000;Mikola et al 2001;Mikola and Kytoviita 2002;Dilkes et al 2004;Fu and Cheng 2004).…”

Section: Introductionmentioning

confidence: 96%

“…Some grazing-tolerant grass species have been shown to increase C inputs to the soil immediately following defoliation, which in turn stimulates microbial activity within the rhizosphere of the plant (Mawdsley and Bardgett 1997;Hamilton and Frank 2001;Paterson et al 2003;Henry et al 2008). Such a short-term (1-to 2-day) pulse in microbial activity and biomass has the potential to increase soil N mineralization (several days to a week following defoliation), thereby enhancing N uptake and regrowth by the plant (Hamilton and Frank 2001).…”

Section: Introductionmentioning

confidence: 97%

“…Soil N availability can strongly influence plant regrowth following defoliation, such that increasing [CO 2 ] could potentially limit aboveground plant regrowth and N concentration following defoliation (Morgan et al 2001). Feedbacks between grazed grasses and soil microbial communities represent one way that plants could influence soil N availability following defoliation (Bardgett et al 1998;Hamilton and Frank 2001;Bardgett and Wardle 2003), but little is known about how rhizosphere processes may respond to both grazing and climate change.…”

Section: Introductionmentioning

confidence: 99%

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Rhizosphere interactions, carbon allocation, and nitrogen acquisition of two perennial North American grasses in response to defoliation and elevated atmospheric CO2

et al. 2010

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Carbon allocation and N acquisition by plants following defoliation may be linked through plant-microbe interactions in the rhizosphere. Plant C allocation patterns and rhizosphere interactions can also be affected by rising atmospheric CO(2) concentrations, which in turn could influence plant and microbial responses to defoliation. We studied two widespread perennial grasses native to rangelands of western North America to test whether (1) defoliation-induced enhancement of rhizodeposition would stimulate rhizosphere N availability and plant N uptake, and (2) defoliation-induced enhancement of rhizodeposition, and associated effects on soil N availability, would increase under elevated CO(2). Both species were grown at ambient (400 μL L(-1)) and elevated (780 μL L(-1)) atmospheric [CO(2)] under water-limiting conditions. Plant, soil and microbial responses were measured 1 and 8 days after a defoliation treatment. Contrary to our hypotheses, we found that defoliation and elevated CO(2) both reduced carbon inputs to the rhizosphere of Bouteloua gracilis (C(4)) and Pascopyrum smithii (C(3)). However, both species also increased N allocation to shoots of defoliated versus non-defoliated plants 8 days after treatment. This response was greatest for P. smithii, and was associated with negative defoliation effects on root biomass and N content and reduced allocation of post-defoliation assimilate to roots. In contrast, B. gracilis increased allocation of post-defoliation assimilate to roots, and did not exhibit defoliation-induced reductions in root biomass or N content. Our findings highlight key differences between these species in how post-defoliation C allocation to roots versus shoots is linked to shoot N yield, but indicate that defoliation-induced enhancement of shoot N concentration and N yield is not mediated by increased C allocation to the rhizosphere.

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Section: Rhizosphere Responses To Defoliationsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Rhizosphere interactions, carbon allocation, and nitrogen acquisition of two perennial North American grasses in response to defoliation and elevated atmospheric CO2

et al. 2010

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“…Perhaps it is to attract microorganisms that service the plant through secreting growth promoting hormones, preventing disease, or acquiring nutrients via the excretions of a biochemically active root system. For example, Hamilton and Frank (2001) demonstrated that a grazing tolerant grass, Poa pratensis, is capable of concentrating microbes that facilitate the uptake of a limiting soil resource needed for growth, in this case N, in its rhizosphere when under herbivore attack. White lupin, on the other hand, is able to discourage microbial growth by drastically decreasing the soil pH in the rhizosphere via the release of organic acids, lowering the competition for P acquisition (Weisskopf et al 2006).…”

Section: The Effect Of Plants On the Soil Microbiomementioning

confidence: 98%

Manipulating the soil microbiome to increase soil health and plant fertility

et al. 2012

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A variety of soil factors are known to increase nutrient availability and plant productivity. The most influential might be the organisms comprising the soil microbial community of the rhizosphere, which is the soil surrounding the roots of plants where complex interactions occur between the roots, soil, and microorganisms. Root exudates act as substrates and signaling molecules for microbes creating a complex and interwoven relationship between plants and the microbiome. While individual microorganisms such as endophytes, symbionts, pathogens, and plant growth promoting rhizobacteria are increasingly featured in the literature, the larger community of soil microorganisms, or soil microbiome, may have more far-reaching effects. Each microorganism functions in coordination with the overall soil microbiome to influence plant health and crop productivity. Increasing evidence indicates that plants can shape the soil microbiome through the secretion of root exudates. The molecular communication fluctuates according to the plant development stage, proximity to neighboring species, management techniques, and many other factors. This review seeks to summarize the current knowledge on this topic.

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Feedbacks between nitrogen fixation and soil organic matter increase ecosystem functions in diversified agroecosystems

Blesh

2019

Ecological Applications

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Nitrogen (N) losses from intensified agriculture are a major cause of global change, due to nitrate (NO 3 À ) export and the eutrophication of aquatic systems as well as emissions of nitrous oxide (N 2 O) into the atmosphere. Diversified agroecosystems with legume cover crops couple N and carbon (C) inputs to soil and reduce N pollution, but there is a need to identify controls on legume N 2 fixation across ecosystems with variable soil conditions. Here, I tested the hypothesis that N mineralization from turnover of soil organic matter (SOM) regulates legume N 2 fixation across 10 farms that spanned a gradient of SOM levels. I separated soil samples into two SOM fractions, based on size and density, which are indicators of soil nutrient cycling and N availability (free particulate organic matter and intra-aggregate particulate organic matter [POM]). This study indicates downregulation of legume N 2 fixation in diversified agroecosystems with increasing N availability in intra-aggregate POM and increasing N mineralization. Intercropping the legume with a grass weakened the relationship between N in POM and N 2 fixation due to N assimilation by the grass. Further, mean rates of N and C mineralization across sites increased with two seasons of a legume-grass cover crop mixture, which could enhance this stabilizing feedback between soil N availability and N 2 fixation over time. These results suggest a potential mechanism for the diversity-ecosystem-function relationships measured in long-term studies of agroecosystems, in which regular use of legume cover crops increases total soil organic C and N and reduces negative environmental impacts of crop production.

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Can Plants Stimulate Soil Microbes and Their Own Nutrient Supply? Evidence from a Grazing Tolerant Grass

Cited by 151 publications

References 0 publications

Rhizosphere interactions, carbon allocation, and nitrogen acquisition of two perennial North American grasses in response to defoliation and elevated atmospheric CO2

Rhizosphere interactions, carbon allocation, and nitrogen acquisition of two perennial North American grasses in response to defoliation and elevated atmospheric CO2

Manipulating the soil microbiome to increase soil health and plant fertility

Feedbacks between nitrogen fixation and soil organic matter increase ecosystem functions in diversified agroecosystems

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