Research challenges – Despite the recognition of the positive effect of EPS on soil structure and decades of research on the industrial potential of EPS (e.g. as bio lubricants, thickener and preservatives), the use of EPS-based products in agriculture as soil improver is still very limited. In addition, our knowledge on EPS composition, structure and function, is far from complete. Gaining understanding of the role of EPS in determining soil structure and aggregate stability and elucidation of the mechanisms that regulate the biosynthesis of EPS in soils, could enable the use of EPS-based solution in agriculture to improve soil structure and prevent soil degradation.
Objectives and methodology – The PhD project aims to elucidate the effect of different types of soil amendments (complex as well as more readily biodegradable substrates), and of varying carbon to nitrogen ratio’s on the development of microbial communities in the soil, particularly on EPS producing and degrading microbes. The ultimate goals of the project is to develop nature-based solutions to increase soil structure and resilience to drought. To reach this goal we will identify key microbial groups responsible in soils for EPS production. We will test abiotic conditions (i.e. C:N ratio, nutrient availability) that may trigger EPS formation and thus influence soil properties.
We are looking for a highly motivated soil scientist with a strong interest in (soil) microbiology, chemistry and with an affinity for agriculture (MSc degree). The ideal candidates should be a team player with excellent communication skills. Knowledge of microbial characterization and experience with microbiome analyses is considered an advantage.
Wageningen University & Research offers excellent terms of employment. A few highlights from our Collective Labour Agreement include:
- sabbatical leave, study leave, and paid parental leave;
- working hours that can be discussed and arranged so that they allow for the best possible work-life balance;
- the option to accrue additional holiday hours by working more, up to 40 hours per week;
- there is a strong focus on vitality and you can make use of the sports facilities available on campus for a small fee;
- a fixed December bonus of 8.3%;
- excellent pension scheme.
In addition to these first-rate employee benefits, you will of course receive a good salary.
Academic Supervisor(s): prof. Hardy Temmink (Wageningen University – Environmental technology (ETE) and Prof. Martijn Bezemer (Leiden University – Institute of Biology Leiden)
Wetsus Supervisor: dr. Valentina Sechi (Theme coordinator Soil)
University promotor: Prof. dr. ir Cees J.N. Buisman – Environmental Technology (ETE), Wageningen University
You can apply by selecting your vacancy on https://phdpositionswetsus.eu/available-research-position/. Applications directly to WUR will not be taken into consideration. The procedure to apply is written in detail on https://phdpositionswetsus.eu/guide-for-applicants/
Only applications that are complete, in English, and submitted via the application webpage before the deadline will be considered eligible.
Keywords: Extracellular polymeric substances, soil structure, aggregate stability, microbial community, water retention
Almost 40% of the total agricultural land in Europe is prone to soil degradation, at a moderate or even severe level. Climate change, accompanied by increasing temperatures and less frequent but more intense rainfall events accelerates soil degradation and further decreases the capacity of soils to store and release the water and nutrients required for plant growth. Soil aggregates, made of particles held together by cohesive forces and organic matter are the basic units that form the soil structure and determine the physical and mechanical properties of soil, including water retention, water movement and aeration. Microbial organisms and their metabolic products affect soil structure by binding loose soil particles into stable aggregates. In particular, extracellular polymeric substances (EPS), produced by soil microorganisms, are known to have positive effect on water retention and aggregate stability.
Therefore, agricultural strategies that enhance EPS production have the potential to improve soil structure and thus increase the ability of soil to store and provide water to plants during periods of drought.