Eva Kaštovská
Soil Scientist
The role of plant-soil interactions in carbon and nutrient cycles in terrestrial ecosystems
This research programme deals with plant-microbial interactions in terrestrial ecosystems. The programme is mainly focused on differences in C:N:P stoichiometry between plant material entering the soil and soil microbial biomass which determine relation between C:N:P sequestration into the soil OM and mineralization. We characterize the rhizodeposition quality and elemental stoichiometry under N and P limitation and coupling with changes in microbial community composition and functioning, and trophic interactions in the soil. We collect data on plant and microbial stoichiometry and estimate the range of N and P availability under which plant and microbes are limited by the same nutrient. Microcosms and mesocosms are used to understand plant-microbe-soil interactions and feedbacks at well-defined conditions on the level of individual plants.
Key question
Differences in C:N:P stoichiometry of plant material entering the soil and C:N:P stoichiometry of soil microbial biomass determine relation between C:N:P sequestration into the soil OM and their mineralization rates.
Project team
Methodology
Microcosms and mesocosms are used to understand plant-microbe-soil interactions and feedbacks at well-defined conditions on the level of individual plants. Critical C:P and N:P ratios for plants and microbes are assessed from laboratory and literature data using models. The results are verified in the large scale mesocosm system and in the field and up-scaled to ecosystem level, that could improve understanding the role of plant-soil and their shifts caused by human impacts to ecosystem functioning. We use approaches as follows: (1) Stoichiometry principles (plant and microbial biomass, enzyme activities, communities composition, nutrient transformation rates)
to link (i) plant with microbial dynamics and (ii) different levels of complexity of studied systems; (2) Measuring of stable isotopes (C, N, O) to follow the fate and allocation of plant material, its influence on C:N:P mineralization, their sequestration and losses, and effect of environmental conditions including human impact on these processes and the whole ecosystem functioning; (3) Qualitative and quantitative determination of plant and microbial products with focus on DOM to estimate its effect on soil microbial dynamics and whole ecosystem functioning. Functional plant trait categorization are used.