Climate proof soils by steering soil and residue microbiomes to improve the physical, chemical and microbial properties of compost with clay
Climate proof soils by steering soil and residue microbiomes to improve the physical, chemical and microbial properties of compost with clay
Microbiële EcologieContact Person:
Droevendaalsesteeg 10
6708 PB Wageningen
This research is part of the ClipsMicro (Climate proof soils by steering soil and residue microbiomes) project and aims to make Maize cultivation on sandy Dutch soils more sustainable and resilient by designing and testing a climate proof soils management strategy. We integrate cover crops with biological nitrification inhibition (WP 3) and clay-amended compost (WP 2). Here you can contribute to WP 2, focusing on the clay-amended compost research.
Composting can transform waste into valuable soil amendments, supporting agricultural circularity and improving soil properties and thereby mitigate soil degradation and restore soil quality. Compost can be amended with clay minerals which has been shown to reduce greenhouse gas emissions during the composting process. In our research we test if clay-rich waste material added to the composting process at the optimal moment and optimal quantity can enhance the resource use efficiency by transforming labile carbon and nitrogen (e.g., microbial necromass and extracellular polymeric substances) in protected soil organic carbon pools.
Objectives
To goal of our work is to determine the dynamics of labile C and N fractions during the composting process and evaluate if clay mineral addition at the optimal moment during the composting process can help to protect these fractions from rapid mineralization. Additionally, we are trying to understand the underlying physical, chemical and microbial mechanisms. Specifically, we will address the following hypotheses:
- The optimum moment of clay addition corresponds to the overlaying peak of labile C and N fractions (i.e., EPS, necromass, microbial biomass, DOC).
- Especially microbial necromass and ESP generated during the composting process can be absorbed and stabilized by clay amendments.
- Clay amendment during the composting process can enhance C sequestration after applied to soil.
- Materials with higher clay content will protect more C from rapid mineralization during the composting process.
- 2:1 clay minerals will absorb more C compared to 1:1 clay minerals and will have higher CEC and SSA.
Experiments
To test the interactions of clay and compost, we mix clay material with compost (in different ratios) in metal mesh. These bags are incubated for two weeks inside a commercial compost pile. Clay has unique physical properties that could help to adsorb organic molecules during the composting process and thereby protect them from rapid mineralization. We hypothesize, that specific surface area (SSA), cation exchange capacity (CEC), and clay-mineralogy are good predictors for C stabilization. After the incubation, the material is analyzed for quality and quantity of stabilized C.
Contribution Internship/research project
- Helping with testing methodology to evaluate the quality and quantity of absorbed C in incubation experiments.
- Help with laboratory work and working independently in the laboratory
- Working location for laboratory work will be NIOO-KNAW in Wageningen
Timing
Student wanted from February
Contact
Benedikt Boppré b.boppre@nioo.knaw.nl / e.kuramae@nioo.knaw.nl
Literature
- Chang, Y., Sokol, N. W., van Groenigen, K. J., Bradford, M. A., Ji, D., Crowther, T. W., Liang, C., Luo, Y., Kuzyakov, Y., Wang, J., & Ding, F. (2024). A stoichiometric approach to estimate sources of mineral-associated soil organic matter. Global Change Biology, 30(1), e17092. https://doi.org/10.1111/GCB.17092
- Nuñez, J., Moinet, G. Y. K., Graham, S. L., Turnbull, M. H., Grelet, G. A., & Whitehead, D. (2022). Addition of sorptive mineral phases to soils decreases short-term organic matter decomposition by reducing microbial access to substrates. European Journal of Soil Science, 73(1), e13176. https://doi.org/10.1111/EJSS.13176
- Vidal, A., Klöffel, T., Guigue, J., Angst, G., Steffens, M., Hoeschen, C., & Mueller, C. W. (2021). Visualizing the transfer of organic matter from decaying plant residues to soil mineral surfaces controlled by microorganisms. Soil Biology and Biochemistry, 160, 108347. https://doi.org/10.1016/J.SOILBIO.2021.108347
- Joergensen, R. G. (2018). Amino sugars as specific indices for fungal and bacterial residues in soil. Biology and Fertility of Soils, 54(5), 559–568. https://doi.org/10.1007/S00374-018-1288-3/TABLES/3