Cemetery soils, their properties and applications in practice

Abstract

Cemetery soils are a very specific type of urban or anthropogenic soil, which exist for centuries and even millennia but due to their small spatial extent and limited importance (no food and raw material production) are aside of the attention of soil science. For this reason their description and classification is a significant unresolved challenge. Their classification is not straightforward. They are sometimes referred to as “necrosols” (or “nekrozem” in Slovak). Their characteristics are diverse (lack of natural horizonation due to mixing, alteration of original soil texture and organic matter content, etc). These soils exhibit high levels of phosphorus and nitrogen, as well as excessive concentrations of metals. They form through the interaction of soil with human remains and materials associated with burial practices, such as coffins, textiles, and metals (artifacts). Phosphorus serves as the most critical soil indicator for classifying cemeteries and burial grounds, as it is the least susceptible to alteration or leaching. It is important to emphasize, however, that the properties of these soils are crucial for determining the measures required under Act No. 131/2010 Coll. on Funeral Services. These measures concern the assessment of site suitability for cemeteries and burial grounds, as well as the determination of the decay time for remains depending on different soil conditions of the cemeteries. Soil properties are evaluated not only from a hydrogeological perspective but also by prioritizing a hydropedological approach. This paper presents the results of studies aimed on characterization and management of selected cemetery soils in Slovakia. Three particular topics are involved. The first topic was the evaluation and classification of cemetery soils. Their classification is a subject of discussion, particularly regarding the World Reference Base (WRB 2022) and the Morphogenetic Soil Classification System of Slovakia (MSCS). The second topic was the assessment of the site suitability for a cemetery (case study at Horné Obdokovce site, Topoľčany District). The suitability depends especially on the hydropedological (soil moisture status and regime) and hydrogeological (ground water table and fluctuation) characteristics of the proposed site. From a hydrological standpoint, graves must meet specific criteria: the bottom of the grave must lie at least 0.5 m above the groundwater level. The third topic was determining the decay time (Case study at Dolný Kubín site, Dolný Kubín District). We have described a modal Necrosol calcareous, loamy soil formed from mixed anthropogenic material.  The decay time was determined for areas characterized by unsuitable soil and climatic conditions. We found that the processes accelerating the decay of biological material depend primarily on climatic conditions, especially temperature and rainfall and on soil texture, structure and porosity, which control soil aeration and moisture, its seasonal dynamics and possible percolation and lateral movements of gravitation soil water on sloping land. Sandy and sandy-loam soils located on gently sloping, sunny sites, predominantly with a southern exposure prove to be most suitable. The classification of cemetery soils relates to the WRB soil system and is being discussed in the context of the proposed MSCS version.

Keywords: necrosol, decay period, cemetery location, phosphorus, organic carbon, cemetery legislation