Carbon input and turnover in subsoil biopores

DFG 2014-2017 KU 1184/29
Callum C. Banfield, Thu Duyen Hoang, Yakov Kuzyakov, Johanna Pausch

The carbon (C) input into the subsoil and especially the importance of biopores remains unclear. The aim of this project is to evaluate the contribution of biopores to the C transport and C turnover into the subsoil depending on crops with contrasting root systems.
Biochemical properties of biopores of various origins (earthworm-derived, root-derived and mixed) will be studied in detail. C turnover in biopores of various origins will be studied by incubation and CO2 analysis. C input into the subsoil depending on the root system and on biopore density will be estimated by 13C labeling in the crop sequence experiment (CeFiT). The utilization of rhizodeposits by microbial groups in and out of biopores will be analyzed by 13C-PLFA. The distribution of enzyme activities around the biopores will be measured by recently developed soil zymography. The biopore formation by preceding crops and their use by main crops will be analyzed by 14C pulse labeling and imaging under controlled conditions. Mycorrhization of roots in and out of biopores will be analyzed in the CeFiT experiment and related to soil depths, depending on moisture and nutrient contents of the topsoil.
Based on these studies, we will quantify the importance of biopores for C transport and C turnover and for microbial activity in the subsoil depending on preceding crops.