Assessment of ancient land use in abandoned settlements and fields : a study of prehistoric and Medieval land use and its influence upon soil properties on Holne Moor, Dartmoor, England
Ignorance about the pattern of ancient land use within prehistoric and medieval fields on Dartmoor and elsewhere provided the catalyst for the research reported in this thesis, which explores new ways of assessing past land use in abandoned enclosures. The first chapter provides a brief, critical evaluation of relevant earlier archaeological research; the limitations of current procedures, which reveal little about pastoral land use, are discussed and it is concluded that, although there have been few scientifically rigorous studies of the soils in ancient settlements and fields, soil analysis accompanied by explicit modelling of the interaction of agricultural land use and soils could provide new information about past land use, but only within a framework of research that defines the natural trajectories of soil development as a prerequisite to the isolation of 'land use—deflected' pedogenesis. In Chapter 2, a review of some of the principal features of moorland soils is followed by an assessment of the ways in which they may have been modified by recent, 'extensive' land use. Information provided by pedological and agricultural research is then used to formulate models of changes in the physical and chemical properties of soil that might be expected to occur as a result of various forms of 'intensive' agricultural land use; particular attention is paid to the pattern of phosphorus redistribution in pastoral enclosures. An environmental and cultural history of Holne Moor on Dartmoor is presented in Chapter 3, and it is shown that this area possesses archaeological and pedological features that make it eminently suitable as a study area within which to test ideas and predictions about the way in which early land use may have modified soil properties; the chapter concludes with an account of the fieldwork and laboratory strategies that have been used to investigate the soils within this study area. The results of a field survey of the soils and vegetation on Holne Moor are described and interpreted in Chapter 4; it is concluded that many of the properties of the surface soils reflect a combination of features acquired during medieval farming and during subsequent pedogenetic reversion. The pattern of soil properties is shown to be consistent with a pattern of land use that can be inferred from archaeological investigations of the medieval enclosures themselves and provides additional information about land use within the enclosures and the sequence of land abandonment. Qunntitative investigations of soil phosphorus and organic matter are reported and analysed in Chapter 5. Palaeosol studies provide evidence of the general course of pedogenesis and also allow the conclusion that significant changes in soil phosphorus have occurred since prehistoric times and even over the past thousand years. Analyses of soils in prehistoric houses and monuments, and in the fields of nearby, modern farms are then used to establish a picture of the way in which the soils of the study area have responded to phosphorus inputs and agricultural management. Conclusions reached as a result of these studies, together with the models offered in Chapter 2 1 form the basis for interpretation of investigations of the soils within medieval and prehistoric agricultural enclosures; these are described in the concluding sections of the chapter, where it is shown that patterns consistent with the models can be identified within these ancient enclosures. Some of the more important conclusions arising from this research are set out in Chapter 6; the primary conclusions are that very detailed information about medieval land use can be, and has been obtained through intensive field survey alone, and that analysis of soil phosphorus can provide important, new information about the agricultural use of both medieval and prehistoric enclosures.