Methodik zur Quantifizierung des Eintrages von Wurzelzellwandresten in den Boden während des Wachstums von Maispflanzen

Abstract

Root structural residues are one of the main sources for organic C input into the soil. However, little is known about the actual input of root residues into soil, and the influence of these materials (specifically cell wall residues) on humus formation and preservation of stabilized soil organic matter. Therefore we focussed on the development and testing of a procedure to estimate belowground primary production and the formation of root cell wall residues during plant growth in pot experiments with maize. This method is based on a repeated pulse-labelling of maize shoots by ¹⁴CO₂ in closed chambers under controlled conditions, followed by continuous recording of temporal changes in the rhizosphere C fluxes. Finally accumulated rhizosphere C fluxes could be calculated by means of crop growth and C distribution models from the results of these investigations. At the end of maize growth (94 days), approx. 19 % of the root cell walls which are formed during ontogenesis appeared already in the soil. Although further improvements are necessary, the procedure presented here is considered to be an appropriate way to study and to quantify the rhizosphere C fluxes, in particular the input of root structural components.