C & N rhizodisposition of peas (2012-2015)

Living plant roots continuously exudate organic and inorganic compounds to the surrounding soil. This process is defined as rhizodeposition and is a major source of C and N inputs into the soil. More precise knowledge would improve estimating C sequestration in crop rotation and developing accurate N balances for land use systems. Thus the aim of this project is to quantify spatial and temporal distribution of rhizodeposition of peas and the transfer into the micriobial soil biomass, to the intercropping partner and the subsequent crop. To evaluate the relevance of different transfer paths (root contact, mycorrhiza, diffusion) pot experiments will be set up to quantify C and N rhizodeposition on time course and the assembly of the rhizodeposits in different soil compartments. Moreover, the C and N transfer derived from rhizodeposition into both, subsequent crops and inter-cropped cereals with and without symbiotic mycorrhiza will be determined. A substantial part of the project contains field-experiments to quantify the spatial (horizontal and vertical soil sectors) and temporal distribution of rhizodeposition from peas in pure stands and in intercropping (cereal partner). Additionally the integration of rhizodeposits into the microbial biomass and, for the first time under field conditions, the C and N transfer derived from rhizodeposition to the intercropping partner will be analysed.

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