Project properties

Title Is permanganate oxidizable carbon (POXC) a good and reliable predictor of soil quality for Dutch arable soils?
Group Soil Biology
Project type thesis
Credits 24-39
Supervisor(s) Marie Zwetsloot, Mirjam Pulleman, in collaboration with Gerard Korthals (Center for Soil Ecology)
Examiner(s) prof.dr. Rachel Creamer
Contact info marie.zwetsloot@wur.nl or mirjam.pulleman@wur.nl
Begin date 2020/05/01
End date
Description Soil organic matter (SOM) is of paramount relevance to soil quality and to greenhouse gas mitigation. Changes in total SOM content in response to changing (agricultural) management practices are slow, but especially the more active SOM fractions (i.e. easily degradable carbon) are considered to be more readily affected by land management. One such active SOM fraction is the permanganate oxidizable carbon (POX-C). This soil parameter is widely proposed as a proxy for soil quality and as an early indicator of soil organic matter accumulation. As POXC is easy and cheap to measure in comparison to other labile or active SOM pools, e.g. microbial biomass or activity or particulate organic matter fractions, there is a strong interest in the POXC method as part of soil monitoring programs. On the other hand, there are increasing concerns that the use of POXC may be compromised by its sensitivity to methodological parameters, such as the ratio of permanganate to soil mass, or SOC mass used.
In the Netherlands, POXC is among the 17 soil indicators that are currently being tested for routine use in Dutch national monitoring of arable soils. This thesis topic aims to address major research questions about the utility and reliability of POXC as a general soil quality indicator across arable soils at the national level: For example: How does POXC correlate with other potential soil indicators across a wide range of soil conditions? How sensitive are POXC results to methodological parameters such as SOC mass or soil mass used? How can we establish meaningful reference values for the interpretation of POXC levels under Dutch conditions?
Used skills Literature review, writing proposal and thesis, chemical laboratory work, data analysis (own laboratory measurements to be combined with available data sets of soil parameters on the same sample set).
Requirements Required courses for MSc thesis Soil Biology