Institut für Epidemiologie und Pathogendiagnostik
The project deals with the elucidation and quantification of rhizosphere processes leading to yield differences in wheat grown after different preceding crops and approaches to mitigate the yield decline in wheat grown after wheat. Additionally, methods will be tested to mitigate yield reduction. Methodologically, different complementary approaches will be combined at various scales. The target system will be studied in field trials as well as in rhizobox experiments using methods ranging from DNA/RNA profiling of the rhizosphere to remote sensing. Building upon the results of the first phase of the project, the subsequent project phase will focus on the investigation of wheat variety effects. Characteristics of genotypes leading to different yield reactions will be examined both physiologically (water use efficiency, canopy temperature, root health) and molecularly (rhizosphere microbiome, wheat gene expression). Moreover, an expanded range of preceding crops will be tested. In addition to wheat and rapeseed, maize, faba bean, and sugar beet will be included. The aim is to elucidate the effects of different preceding crops on winter wheat and contrast them with wheat grown in self-succession. The rhizosphere microbiome will be investigated with the goal of describing the potential of preceding crops that create favorable conditions for wheat. Aboveand below-ground plant growth, soil nitrogen dynamics, soil structure, as well as radiation, water, and nitrogen use efficiency will also be assessed. Organisms that have shown promise for improving root health in the first phase of the project will be tested in rhizobox experiments. Finally, insights from field and rhizobox experiments will be incorporated into scenario calculations. These calculations will simulate the effects of different genotypes, preceding crops, and nitrogen supply on plant growth and yields under current and projected climatic conditions.Crop rotation experiments, a variety trial, and rhizobox experiments will be used as the basis for achieving the research objectives. The experiments are designed to meet the needs of different participating research groups for their respective aspects. To achieve the project goals within three years, preparatory work will begin as early as the 2023 harvest season. The experiments will investigate a cross-scale, complementary selection of parameters ranging from molecular biological methods to remote sensing. Crop growth will be observed using drone-based multispectral imaging, and canopy temperatures will be captured through thermal imaging. Water supply will be measured using FDR probes, and root growth will be assessed both destructively through soil cores and non-destructively using minirhizotron technology in the field. Soil and plant samples from the field experiments will be made available to the molecular biology research groups. For example, enzymatic kinetics in soil and rhizosphere will be examined. Additionally, larger amounts of soil will be provided for the rhizobox experiments. In these experiments, two genotypes will be tested after different preceding crops, as well as with microbial seed treatments. The composition of root exudates will be determined and quantified, and the frequency of fungal pathogens and beneficial bacteria will be determined using qPCR. Shotgun metagenomic sequencing will be performed in selected treatments to gain insights into the functional potential of the microbiome's response to compost and seed treatments. Simulation models at different scales will be used to integrate the acquired process knowledge and scale it quantitatively to higher levels of aggregation. Ultimately, this will enable predictions of yield decline in winter wheat grown in self-succession under various environmental conditions.
Federal Ministry of Education and Research
