P22 - Biogeochemical Gradients
Spatiotemporal patterns and controls of rhizosphere biogeochemistry of maize
The aim of this project is to give new insights in rhizosphere self-organization and help to understand soil carbon (C) inputs. Due to the lack of techniques which can analyse C dispersal in an undisturbed environment, it is until now not clear to which extent the spatial arrangement of roots, pores and solid soil matter control C dispersal, turnover and storage. We hypothesize that i) rhizodeposits have different spatial dispersibility depending on their chemistry as well as root morphology, age and soil texture, ii) root morphology, soil texture and moisture control residence times of rhizodeposits, and that iii) microbes feed differently on rhizodeposits depending on the spatial arrangements in soil.
Therefore, we want to identify spatiotemporal patterns of the rhizosphere biogeochemistry by studying radial gradients of deposits of both root and microbial origin, and determine to which degree they result from self-organization (root age and developmental stage) or are controlled by external factors (genotype and soil texture). Through the determination of C concentration, C turnover and biomarker gradients on a wide range of spatial scales (μm to cm), we are going to study and analyze the influence of root, pore and aggregate architecture on C dispersal and turnover as well as the spatial component of microbial response to differences in rhizodeposition. The previous statements will be carried out covering spatial scales from μm to cm and temporal scales from weeks to months.
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