The Professorship's Research

Project start: 01.05.2023
Project end: 30.04.2029
Sponsor: Federal Office for Agriculture and Food

In the HUMAX project, different measures for humus build-up are to be investigated in different combinations. The aim is to identify possible synergies of the measures and to show combined application options. The innovative potential of the HUMAX project lies in the fact that established humus building measures (catch crops, winter greening, undersowing, compost application, etc.) are to be combined and tested with promising measures such as plant charcoal. A unique feature of the HUMAX project is that these measures will be applied in combination with agri-photovoltaic systems and agroforestry systems. The combination with agroforestry systems opens up further potential as a carbon sink, in addition to the humus build-up, as the trees and shrubs store carbon in the above- and below-ground biomass and also bring with them a large substitution potential through the wood products and the material accumulating during the management of the woody plants. This should be precisely quantified in order to be able to make statements not only about the total carbon storage in the soil and the biomass, but also to quantify the substitution effects and biomass potentials for the production of plant carbon through pyrolysis. By combining the various humus-building measures, ways are to be found to maximise humus build-up and thus carbon sequestration, i.e. the function of the soil as a C sink. Based on this, a modular system will be developed that allows farmers to put together the best possible combination of measures for targeted carbon and humus management on their farms.

Project start: 15.09.2023
Project end: 14.09.2026
Sponsor: Fachagentur Nachwachsende Rohstoffe e.V.

In the project UpgoeS, it will be tested whether organo-mineral (OM) substrate residues from hydroponic tomato cultivation can be upcycled and used as alternative fertilizers, for soil improvement and for yield and quality increases for outdoor vegetable cultivation at two geologically and climatically different locations (Berlin and Geisenheim). The organic fraction (wood fiber substrate) originates as residual material in a sawmill, whereas the mineral fraction are nutrient ions that accumulate in the wood fiber substrates during the cultivation period. The incorporation of OM substrate residues into field plots is expected to provide baseline knowledge on the resulting changes in physical soil properties, particularly air and water holding capacity, and reduced nitrogen leaching to groundwater. It is expected that the nitrate retention time will be increased and the water storage capacity will increase at the same time. Thus, both the drought stress tolerance of the soil in the era of climate change might be increased and the conventional fertilizer application and drinking water pollution due to nitrogen inputs should be reduced. This could imply a large savings potential in terms of production-related energy input for fertilizer production and CO2 emissions. In addition, the reuse of OM substrate residues can reduce the amount of growing media requiring disposal, thus improving the circular economy. Thus, biological resources are used that can be upcycled and used in cascades. Guidelines for the processing and proper use of OM substrate residues from hydroponic vegetable cultivation are to be developed with the involvement of decision-makers for outdoor vegetable cultivation, so that the use of raw materials with regard to both types of cultivation is more resource-conserving and sustainable.

Project start: 01.02.2023
Project end: 01.03.2026
Sponsor: German Research Foundation

In Europe, agriculture faces two main challenges: soil water scarcity and the need to reduce nitrogen supply to prevent water pollution by nitrates. These challenges are interconnected as low water availability affects nutrient uptake like nitrate (NO3-) and chloride (Cl-) by crop plants. The presence of NO3- and Cl- in leaves impacts stomatal movements, influencing water usage by crops. This study will focus on two crops, broad bean and barley, to understand their dependence on NO3- and Cl- for stomatal regulation. The project consists of four work packages (WPs). In WP1, the relationship between soil NO3--to-Cl- ratio and stomatal regulation in model plants will be examined. WP2 will analyze how different NO3--to-Cl- ratios affect ion, metabolite, and hormone concentrations in leaf and guard cells. WP3 will investigate the impact of anion composition (NO3-, Cl-) on stomatal movements. It will test whether broad bean and barley guard cells prefer NO3- or Cl- to drive stomatal opening. WP4 will focus on NPF transporters' role in NO3- and Cl- uptake by guard cells and SLAC1-like anion channels' release of these anions. The results will predict the effects of soil drying and reduced NO3--N input on transpiration in dicotyledonous and cereal crops. This mechanistic information can be integrated into breeding programs for crops with better regulatory capabilities for stomatal conductance and water consumption.

Project start: 01.05.2022
Project end: 30.04.2025
Sponsor: Forschungsring des Deutschen Weinbaus

The aim of the research project is to gain a better understanding of the effect of nitrogen (N) foliar fertilisation in grapevine (Vitis vinifera L. cv. Riesling) on the pattern (quality and quantity) of root exudates. This will also clarify the extent to which the potentially changing exudation pattern influences the composition of microorganisms in the grapevine rhizosphere, which in turn is relevant for the growth of the vine. The latter is due to the fact that there are growth-promoting bacteria in the rhizosphere that are literally "fed" by root exudates. This causal structure is to be investigated as a function of varying amounts of N applied to the leaves.

Project start: 15.01.2022
Project end: 14.03.2025
Sponsor: German Research Foundation

The plant nutrient magnesium (Mg2+) has many functions. For instance, it is relevant for photosynthetic electron transport, for extrusion of protons (H+) by contributing to the activity of the plasma membrane (PM) H+-translocating ATPase, or for sugar partitioning. Under Mg2+-deficiency, mesophyll cells show a reduced operating efficiency of the photosystem (PS) II and accumulate sugars in photosynthetic sources. There is a wealth of information witnessing the relevance of Mg2+ for these processes in the mesophyll tissue. However, current research has not yet achieved to clarify whether the same processes are affected within guard cells (GCs), should these cells contain not enough Mg2+. After all, there is a pressing need to clarify this because evidence is increasing that these Mg2+-dependent processes, i.e. GC-photosynthesis, GC-sugar partitioning, and GC-H+-extrusion are pivotal for regulating stomatal pore size. In GCs at post-dawn, the PM-H+-ATPase energizes stomatal opening upon illumination via hydrolysing ATP for acidifying the apoplast, while GC photosynthesis is a source of this ATP. Disturbed sugar partitioning changes osmotic potential in the GCs with implication on GC swelling. The pressing question is: Is there a link between the amount of Mg2+ in the GCs and light-induced stomatal opening? This research program seeks elucidation if a reduced amount of Mg2+ in GCs of field bean (Vicia faba) obstructs light-induced stomatal opening. As soon as there is not enough Mg2+ in the GCs, it is hypothesized that light-induced stomatal opening is delayed because of a reduced GC PS II operating efficiency (i.e. reduced production of ATP) and a reduced PM-H+-ATPase–mediated extrusion of H+. Moreover, it is anticipated that sugar partitioning is disturbed within GCs that are characterized by a reduced amount of Mg2, which may change GC solute concentration, influencing GC swelling.

Project start: 01.03.2022
Project end: 28.02.2025
Sponsor: Federal Ministry of Education and Research

Meeting the 1.5°C and also the 2.0°C target requires not only a rapid reduction in global greenhouse gas emissions, but also - in addition - a net removal of CO2 from the atmosphere (so-called Carbon Dioxide Removal, CDR). There are four terrestrial CDR methods that can be rapidly implemented, each of which supports a range of sustainable development goals (such as food security and a clean environment): (1) pyrogenic carbon sequestration (plant carbon), (2) enhanced weathering (EW), (3) soil organic carbon (SOC), and (4) biomass carbon capture (BCC), for example through the use of agroforestry systems. However, in order to maximise carbon sequestration (per area), the synergies of these methods must also be investigated and understood. So far, this has almost exclusively been studied separately - the potential synergies are part of our PyMiCCS project goals. Vegetable charcoal and volcanic rock flour for EW not only sequester carbon in soils, but also balance soil pH and redox potential, provide nutrients, improve soil hydrology and promote soil biodiversity, root growth, crop yields and thus BCC. If theoretically two tonnes of plant charcoal-based fertiliser and one tonne of volcanic rock dust were applied per hectare annually, carbon sinks would be of 5.4 t CO2eq would be created - without any synergies on SOC and BCC. Scaled up to 50% of the world's agricultural land, this would be 13 Gt CO2eq with improved food and feed productivity. feed. In a wide range of iterative experiments and analyses from laboratory from laboratory to field scale, with and without soils and plants, we are generating data to for the parameterisation of global models for C-sink potential analyses and for the evaluation of economic feasibility.

Project start: 01.01.2020
Project end: 31.12.2022
Sponsor: German Academic Exchange Service

After a successful partnership of Geisenheim University (HGU) with the University of Thessaly in Greece (ZuGAbe-Project), HGU would now like to establish a partnership with the University of West Attica (UNIWA) and particularly with the Department of Wine, Vine and Beverage Sciences. The cooperation between the two Universities is called Future Challenges in Viticulture, Enology and Wine Business (WOW-project) and is funded by DAAD. The main objective of the project, namely a long-term partnership between the two institutions, will be achieved through common events, such as workshops, conferences, summer schools etc., but also through an exchange program for students and scientists of both universities.