XII CONVEGNO NAZIONALE INTERDISCIPLINARE
UNICITA', UNIFORMITA' E UNIVERSALITA' NELLA
IDENTIFICAZIONE DEL MOSAICO PAESISTICO - CULTURALE
Aquileia 18 - 19 settembre 2008
Sala Romana Piazza Capitolo
Are soil and soilscapes a cultural heritage?
Claudio Bini 1, Diana Zilioli 1
1 Università Ca’ Foscari di Venezia – Dorsoduro, 2137 – 30123 Venezia
bini@unive.it
Abstract.
Soil has been currently studied with reference to its primary functions and economic value, in terms of biomass production, agriculture fertility, environmental filter, genic reserve, organic carbon sink.
More recently, attention has been paid to soils as stratigraphic records and privileged archives of paletnological, paleontological and archaeological findings, i.e. as cultural heritage, not easily valuable in economic terms, but with important scientific, didactic and even technical relapses.
Different aspects qualify soils as cultural heritage; soils can be evaluated as a single profile, or as part of the landscape, assuming different value for each case. Numerous examples of soil profiles and soil landscapes as cultural heritage are available in current literature. A provisional list of Italian pedosites is also available. Most of them are paleosols, or are related to archaeological sites. Some study cases are proposed in order to overcome the balk between pedology and archaeology.
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1. Introduction.
When people speak of soil, they often refer to different concepts:
a physical substrate for plants, in agriculture and forestry;
a fastidious weathering cover of rocks and sediments, in geology;
an areal for buildings and urban infrastructures, in architecture;
a claim for catastrophic events, in engineering geology.
Instead, soil is a living natural body, not only for the billions of microorganisms that live within the soil, but also for the reactions (dissolution, precipitation, oxidation, reduction, weathering, hydrolisis, chelation) that occur at the interface rock-soil-biosphere, and are responsible for horizon differentiation.
As declared more than thirty years ago in the Soil European Chart (European Council, 1972), soil is a fundamental resource for humanity, and plays major functions, both biological (biomass producer, ecological filter, genic reserve, habitat for plants and animals, including humans) and abiological (physical substrate for infrastuctures, source of inert materials, cultural and historical sink).Therefore, its conservation and sustainable use is a major concern for decision makers and Public Authorities, as it was depicted by Ambrogio Lorenzetti (half of XIII century) in the paints of good and bad land government in the Municipal Palace of Siena, and it is suggested by the European Union (2002).
More recently, attention has been paid to soils as stratigraphic records and privileged archives of paletnological, palaeontological and archaeological findings (Bini, 2002; Bini et al., 2005), i. e. as cultural heritage, not easily valuable in economic terms, but with important scientific, didactic and even technical relapses. Particularly concerning the relationships between pedology and archaeology, there is an
unexplored balk to examine (Frink, 2003). To the archaeologist, soil is the matrix defining spatial relations between artifacts. Soil is the material used in costructing monumental architecture. Soil is the media within which past human activities, life itself, took place. Soil is an artifact of culture – a fossil, whose analytical treatment must be taphonomic rather than (bio)chemical or (bio)mechanical. Yet, as stressed by Jenny (1941, 1989), and is well appreciated by the pedologists, the soil is a living entity, a dynamic system evolving along trajectories constrained by the five factors of soil formation (climate, organisms, relief, parent material, time). While the time dependent processes leading to the soil development are of millennial or million scale, the time scales involved in soil formation are incompatible with the archaeologist’s research focused into cultural changes which are at the decadal or century level.
2. Archaeological soil research.
Before the relationship between soil science and archaeological science can realize its full potential, it is necessary to overcome the balk that frustrates consilience, and the view of soils as an expression of genetic and diagenic processes, coeval through time. The descriptive approach, normal to pedological analyses, fails to capture these coeval processes.
What is needed is a “physiological” approach that explores those processes fundamental to all soils (e.g. weathering, leaching, pedoturbation, organic matter dynamics), and their specific and measurable effects on cultural material.
Archaeological soils are often far too complex in nature and origin;
however, this very complexity that results from natural geological, edaphic and culturally-induced processes can yield information and insights into archaeology, that no other discipline can access. Soils should be tackled through “environmental and archaeological profiling”, so that interpretations are robust enough to withstand both experimental testing and holistic archaeological analysis (Macphail, 2003).
The chief elements required for such sustainable interpretations are:
1. a sampling regime that is focused on the archaeological questions, but within a budget that allows lateral and other control sampling;
2. sampling should be exactly complemented by sampling for other disciplines (e.g. mineralogy, geochemistry, palynology);
3. laboratory studies that flexibly combine morphological, micromor- phological, microchemical and bulk analytical techniques;
4. characterisation and identification of fabrics, pedofeatures, and anthropogenic inclusions in soil thin sections;
5. development of independent interpretations that can be tested both within the soil database and against findings from archaeo- logical feature analysis and artefact recovery, with the final prod- uct being the development of consensus interpretations.
This is what has been realised in various research projects in Italy.
Examination and analysis of soil samples from trenches excavated at archaeological sites made it possible to identify old settlements and the overlying cultural layers, which consist of remains of prehistoric sites, both shelters and open sites (Bini and Pilli, 2001; Fig. 1), floor and walls
of historical buildings, burial and open areas (Bini et al., 1978, 1985, 2005), devoted to human activities (cultivation, working, metallurgy, etc.). Also palaeoclimate and palaeoenvironmental conditions of archaeological sites could be inferred from soil properties (Bini, 1999, 2002).
Figure 1. Excavation of the prehistoric (Mesolithic) site at Mount Putia, Val Badia, Dolomites (Bolzano).
Human artifacts found at some depth within the soil at archaeological sites enhance reconstruction of site history, paleoenvironment, plaeoclimate
3. The soil cultural heritage.
Soil development is the result of a series of natural and anthropic processes which take place under the control of the factors of soil formation. With few exceptions, natural soils have horizons. In most cases, the typical “soil” has its distinct O, A, and B horizons, which
provide evidence that this “soil profile” formed on a relatively stable location, and evolved on, within and concurrently with its landscape. By examining and analyzing a soil profile and its position in the landscape, it is possible to acquire information about the succession of natural events that took place at a given site. In this sense, the oldest, more or less well preserved soils, genetically related to previous conditions of climate and morphology (paleosols), are of particular relevance and considerable scientific interest, since they comprehend, in a more or less explicit manner, the soil-landscape evolutionary memory, in spatial- temporal continuity/contiguity. It is something like a “phylogenesis” that drives soil evolution from soil profile to soil sequences and soil landscape (Fig.2).
Figure 2 – The red soils are the typical paleosols (“terra rossa”) that characterize the pedolandscape of karst areas in the whole Mediterranean basin, contributing to the scenic value (Castel di Pietra, Tuscan Maremma, Grosseto).
In the same sense, soils exemplifying pedogenetic processes responsible for current soil formation (e.g. podsolization, Fig. 3), or regulating delicate environmental equilibria (e.g. coastal dune soils), or displaying a perfect harmony of different agricultural fields with the
anthropogeographic landscape (e.g. the Tuscan landscape, Fig. 4) are of relevant interest and can be included in the National Act n° 394/1981 about protected areas, being “sites showing at best the natural processes”. In this perspective, soils and soilscapes may be considered as worthy of preservation, and therefore qualified as “cultural heritages”.
Figure 3 – The typical horizonation of a Podzol in mountain environment (Val Visdende, Belluno), caused by a specific pedogenetic process. These soils, together with rendzina, contribute substantially to the unique scenery of Dolomites.
Figure 4 – A typical view of Tuscan country (Val di Pesa, Florence), displaying the perfect harmony of different crops with the anthropogeographic landscape. Soils, with their specific properties, influence land characteristics and socio-economic value of a territory.
Different aspects qualify soils as cultural heritages; soils can be evaluated as a single profile, or as part of the landscape, assuming different value for each case. A provisional list is reported hereafter.
Paleosols and soils at archaeological sites: witnesses of past envi- ronments or ancient settlements (historical valency);
Soils that exemplify natural and/or anthropic processes, like evolu- tionary sequences, catenas, representative taxonomic units (scien- tific valency);
Soils that contribute to the outliving of fragile ecosystems, like wetland areas or volcanic sites (ecological valency);
Soils of areas in delicate environmental equilibrium, like mine ar- eas, polluted sites, instable slopes subjected to degradation or ero- sion (social valency);
Soils that characterize a determined agriculture landscape, like that of the traditional mixed culture (cultural valency);
Soils that contribute to the amenities of the landscape, with their colours like the “terra rossa” soils of the Mediterranean basin, or those of the Dolomites scenery (aesthetic valency);
Soils that contribute to the touristic and economic exploitation of marginal and mountain areas (social-economic valency).
4. Conclusions.
Cultural heritage is a very important economic resource for countries where one of the major attractions is the unique composition of the landscape, like Italy. The role played by the soil in this ambit is generally little considered, whereas the spectacular scenery is universally appreciated.
In recent years, however, it has been recognized that the different functions (ecological and biodiversity reserve, custom of archaeological and palethnological records) the soil exerts, make the soil itself an actual “cultural container”, historical record of natural and anthropic events, source of information and knowledge: in a sole word, soil is an actual “cultural heritage”.
In analogy to biotopes and geotopes (Arnoldus-Huyzenveld et al., 1995), some suggestions for identification and conservation of pedological emergencies (“pedosites”) have been proposed recently (Costantini, 2000; Costantini et al., 2000). In this perspective, major scientific importance is assigned to those soils which represent palaeoenvironmental records (paleosols and vetusols, e.g. Terra Rossa), or to pedosites which have an ecological valency with regard to
particular phytocoenoses (e.g. edaphic determinism for plants like Rhododendrum ferrugineum vs R. hirsutum), or to soils that display didactic exemplarity (e.g. profile morphology or characteristic pedofeatures, as in Podzols: see Fig. 3).
Once recognized the international (or national, or local) importance of soils as cultural heritage, the criteria for their evaluation and protection must be selected. Among all the possible combinations of study cases, the following items have been proposed (Costantini et al., 2000):
i) rarity: soils scarcely diffused at local scale, or outcropping over a limited area at general scale, should be protected as particu- lar landscape heritage;
ii) conservation: soils assume major environmental and scenic value if they are well preserved or present limited disturbance (wetland areas);
iii) information: knowledge of soils and the history they contain makes easier to evaluate their potential scientific and didactic value as cultural heritage (archaeological soils);
iv) social impact: the easier are soil accessibility, visibility, and ob- servability, the bigger is its fruition by man and its value as pub- lic heritage (national parks, urban soils).
The current development of environmental impact procedures has forced landscape planners to consider the soil among the possible factors that influence the value of a place, including the historical, cultural, artistic (archaeology, art history…) and natural (geology, vegetation, landscape, wilderness.…) aspects . Numerous initiatives have been developed in the last years to corroborate the image of soil
as cultural heritage, in conjunction with the other land resources.
Attention has been devoted, f.i. in Tuscany, to prehistoric and historical settlements, medieval mining, soil and wine production, greenways, trekking walks, horse cross country, agritourism, Slowfood organization. Other initiatives concern medieval pilgrim roads through Roman churches, Napoleonic itineraries, sites of the first world war and historical wars.
All these initiatives point to the valorisation of natural and cultural land resources, including soil, in a territory where one of the major attractions is the unique composition of the landscape.
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