Soil Rhizosphere Food Webs, Their Stability, and Implications for Soil Processes in Ecosystems

doi:10.1016/B978-012088775-0/50007-0

The Rhizosphere

An Ecological Perspective

2007, Pages 101-125

https://doi.org/10.1016/B978-012088775-0/50007-0 Get rights and content

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This chapter discusses soil rhizosphere food webs, their stability, and their implications for soil processes in ecosystems. The rhizosphere includes plant roots and the surrounding soil that is influenced by plant roots. The carbon flux in the rhizosphere helps to support the rhizosphere food web function aimed to describe it in mathematical form. The exudates and sloughed root cells provide carbon for bacteria and fungi, which in turn immobilize nitrogen and phosphorous. The mathematical depictions of the food webs within the rhizosphere presented are based on the three types of food web descriptions presented by connectedness, energy flow, and interaction. Connectedness descriptions are based on observations of the species that are present and their feeding behaviors. The rhizosphere food web of the North American shortgrass steppe is described. The connectedness and energy flux descriptions reveal two patterns in the distribution of energy, nutrients, and biomass within the system. The relative dominance of the root, bacterial, and fungal energy channels is important to key processes and stability. The trophic interactions within the rhizosphere, particularly symbiotic mutualisms, affect plant growth and community structure aboveground. The empirical evidence on mutualism, coupled with the earlier discussion of nutrient enrichment afforded by the trophic interactions within the energy channels, illustrates clear connections among soil biota, plant growth, and community structure. Rhizosphere is best studied as a group of subwebs not only operating in concert but also possessing quasi-independent tendencies.

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The rhizosphere is considered the ideal site to modify microbial populations for various applications in the soil [119]. According to Moore et al. [120], the rhizosphere is the neighbouring region around the roots and the root surface that extends to approximately 4 mm where the electrodes are installed during the operation of the bioelectrochemical system, i.e., P-MFC. The anodes of the P-MFCs present a great diversity of bacterial genera that depend exclusively on the nature of the inoculum, the fuel, and also on the type of P-MFC used [121,122].
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CHAPTER 5 - Soil Rhizosphere Food Webs, Their Stability, and Implications for Soil Processes in Ecosystems

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