The University of Kassel is a modern and growing University with round about 21.000 students. The university’s wide range of expertise covers subjects in the natural, applied, cultural and social sciences.
University of Kassel, Faculty of Organic Agricultural Sciences – Soil Science Research Group (Prof. Dr. Tobias Weber) offers the following position as soon as possible and subject to funding approval:
Research Assistant / Doctoral Researcher in Soil Physics (m/w/d), EG 13 TV-H, part-time (currently 30 hours per week)
Application deadline:
16.10.2025
Date of hire:
as soon as possible
vacancy number: 38757
This is a part-time position with 75 percent of the working hours of a full-time employee. This is a fixed term-position of three and a half years subject to funding approval with the opportunity of obtaining a doctoral degree in the field of geosciences (§ 2 Abs. 2 WissZeitVG).
Climate change affects the functions of agricultural soils, particularly their filtering, buffering, and production functions. In order to evaluate climate change and its effects on soil functions and groundwater, laboratory findings need to be transferred to the landscape level using process modelling in order to develop management options for adapted and optimized water management. Soil plays an essential role as a reactor in influencing the environmental behaviour of substances. This leads to two possible different research priorities that should be the focus of work:
Research Focus 1: Soil hydraulic properties are an important factor that determines the partitioning,. the amount of precipitation water which leaves the soil as either evaporation, transpiration, or deep seepage, and the distribution of water in the soil profile. These are generally assumed to be static, although they are subject to temporal dynamics. Macroporosity, which is very important for soil aeration and mass transport, is particularly affected by this. Failure to take this into account can have far-reaching consequences for modelled evaporation processes at the soil surface and for the transport of dissolved and undissolved substances. The mathematical modelling of flow processes and mass transport in soils close to water saturation is complicated, among other things, by the fact that conventional methods for determining the hydraulic conductivity of soils in this moisture range are too inaccurate.
Research Focus 2: Agrohydrological models are mechanistic representations of dynamic plant growth and the associated processes of unsaturated soil water flow and nutrient turnover. The models are used to test hypotheses, make predictions, and quantify uncertainties. This mathematical modelling of biophysical processes is usually based primarily on sensor data. Since measurement data are always subject to error and the amount of data is often insufficient to determine all relevant processes and model parameters, the modelling process usually also incorporates expert knowledge resulting from a system understanding developed over a long period of time through accumulated experience. However, this part of the modelling process is not included in the mathematical formulation of the model and is therefore difficult to communicate and understand.
Tasks:
1. Working in and supporting the Soil Science Section in research and teaching.
2. The candidate may select one of the two research foci, or a combination, thereof.
3. Close collaboration with soil scientists and hydrologists from the University of Kassel
4. Research focus 1:
The multi-step flux method provides more detailed measurement results of water conductivity near saturation. In this method, a defined flux density is set in a soil sample by controlling the matrix potential at the edges. This method will be used to conduct laboratory experiments on water and material transport in arable soils. The aim is to gain insights into the temporal dynamics of soil hydraulic properties and material transport properties and the influence of agricultural management on these.
The design and construction of a multi-step flux system in collaboration with technicians, university workshops, and external service providers is a significant part of the work. Another task will be to incorporate appropriate model concepts for the temporal dynamics of soil hydraulic properties into the Expert-N soil-plant model.
5. Research focus 2:
Develop a procedure that formalizes the incorporation of expert knowledge into agrohydrological modeling processes. The plausibility of a specific range of values for parameters is expressed mathematically by a likelihood and can thus be explicitly taken into account in model calibration. This is intended to prevent excessive reliance on erroneous measurement data from leading to unjustified confidence in the resulting model, while at the same time making the influence of expert knowledge visible in the mathematical approach itself. One possible practical application of this approach is the development of model-based decision-making tools in which, in addition to a data-based prediction model, expert knowledge, for example in the form of empirical values from farmers, can also be incorporated.
Requirements:
6. Completed university degree in mathematics, physics, engineering, computer science, agricultural sciences, environmental sciences, biology, or related disciplines. The required degree must be obtained by the date of employment at the latest
7. Very good written and spoken English skills
Beneficial additional qualifications:
8. Knowledge of mathematical modeling of physical, chemical, and/or biological processes
9. Knowledge of numerical simulation and/or surrogate modeling using machine learning
10. Knowledge of statistics, particularly in the estimation of model parameters and Bayesian statistics
11. Basic understanding of agricultural sciences and soil science/hydrology
Applicants are requested to submit a single PDF file containing:
Your motivation for applying to the position and your research interests, in particular in relation to one of the two research focii (max. 1 page, written in English)
Curriculum vitae (written in English)
Copy of transcript(s)
Proof of at least 2 references is desirable
In the event of any differences between the German and English versions of this call for application, the German wording is legally binding.
Our Offer:
As an employee of the University of Kassel
12. you will be offered an interesting and diverse range of tasks within the framework of a modern and ambitious university,
13. you will be part of an interdisciplinary team with a good and collegial working atmosphere,
14. you will have the opportunity to participate in professional and interdisciplinary further education measures,
15. is your workplace with good connections to public transport, which you can currently use free of charge.
In addition, you will benefit from the advantages of employment in the public service such as:
16. an additional company pension (VBL),
17. an optional child supplement in accordance with TV-Hessen, a family-friendly university (including childcare for emergencies),
18. an annual bonus
19. an entitlement to capital-accumulation benefits,
20. a promotion of voluntary commitment,
21. low-cost participation in university sports and a full range of fitness activities as part of Unifit, as well as workplace health management
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In exceptional cases, we will also accept your application documents in paper form addressed to: The President of the University of Kassel, 34109 Kassel, Germany, or via mail to
Information and FAQ about applying for a job offer:
The University of Kassel is very interested in the professional satisfaction of its employees. It is distinguished as a family-friendly university and, in the interests of equal opportunities, strives to offer everyone the same opportunities for development and to counteract existing disadvantages. It promotes the Family Welcome Service and also the Dual Career Service for positions that are scientifically and academically filled. One of the strategic goals of the University of Kassel is to significantly increase the proportion of women in research and teaching. Applications from women are therefore particularly welcome. Seriously handicapped and equivalent applicants are given preference if they have the same suitability, qualifications and professional performance. Full-time positions are generally divisible (except when filling civil servant positions). Applications indicating the Position Number, which may be in digital form, should be sent to the President of the University of Kassel, 34109 Kassel, Germany quoting the applicable reference number.