The Soils And Land Use Of The District Around Aylesbury And Hemel Hempstead

First published in 1991. This is a more portable version of the Booker Tropical Soil Manual, in which the format (and weight) of the first edition have been reduced whilst retaining as much as possible of the original clarity. It also includes new content and appendices that cover the revised FAO publications on soil classification and on water quality for agriculture.

The first systematic and comprehensive account of the vegetation types of this country.

British Plant Communities is the first systematic and comprehensive account of the vegetation types of this country. It covers all natural, semi-natural and major artificial habitats in Great Britain (but not Northern Ireland), representing the fruits of fifteen years of research by leading plant ecologists. The book breaks new ground in wedding the rigorous interest in the classification of plant communities that has characterized Continental phytosociology with the deep concern traditional in Great Britain to understand how vegetation works. The published volumes have been greeted with universal acclaim, and the series has become firmly established as a framework for a wide variety of teaching, research and management activities in ecology, conservation and land-use planning.

The aim of the present volume is to review the effects of human activity on physical environment processes, and this is justified not only as a complement to the approach taken by G. P. Marsh his volume Man and Nature (1864), but also as a sequel to the work produced since 1864, with contributions since the mid-nineteenth century to the study of th

The formation of atmospheric nitrogen gas by denitrifying bacteria may represent a significant nutrient sink in natural ecosystems. The rate of denitrification has often been difficult to measure in situ, however, and new methodologies should stimulate research on distribution of activity in space and time. The load of fertilizer nitrogen in modem agriculture has led to increasing nutrient reservoirs in recipient subsoils, aquifers, inland waters and coastal seas. By its conversion of nitrate to atmospheric nitrogen, bacterial denitrification is the only biological process to potentially reduce the impact of increasing nutrient loadings by fertilizer nitrogen in the environment. As part of a scientific program set up by the Danish Ministry of Environment to study environment cycling of nitrogen, phosphorous and organic matter (NPO program) in the light of agricultural, domestic and industrial activities, a symposium on DENITRIFICATION IN SOIL AND SEDIMENT was held at the University of Aarhus, Denmark from 6-9 June 19i\9. On the basis of lectures given at the symposium, this book contains a number of invited contributions on the regulation of denitrification activity (control of enzyme synthesis and activity) and measurement of in situ rates of denitrification in terrestrial and aquatic environments (control factors, diel and seasonal variations, etc). Emphasis has been placed on including the recent improvements in methodologies and current understanding of process regulation, however the book also contains examples of integrated research on the significance of denitrification in environmental nutrient cycling.

The thirty papers in this 1986 volume review the scientific knowledge of the nature of flint and chert at this time. These papers were presented at a 1983 interdisciplinary and international conference on flint and other cherts. Each contribution has been meticulously assessed and edited prior to publication. This collection is principally concerned with the geology and geochemistry of flint in European chert. Topics include the origin of flint; scanning electron microscopy of surface textures; and the behaviour of flint under periglacial conditions. There is a companion volume, edited by G. de G. Sieveking and M. B. Hart, on the archaeological uses of flint.

Professor John Harper, in his recent Population Biology of Plants (1977), made a comment and asked a question which effectively states the theme of this book. Noting that 'one of the consequences of the development of the theory of vegetational climax has been to guide the observer's mind forwards', i. e. that 'vegetation is interpreted asa stage on the way to something', he commented that 'it might be more healthy and scientifically more sound to look more often backwards and search for the explanation of the present in the past, to explain systems in relation to their history rather than their goal'. He went on to contrast the 'disaster theory' of plant succession, which holds that communities are a response to the effects of past disasters, with the 'climax theory', that they are stages in the approach to a climax state, and then asked 'do we account most completely for the characteristics of a population by a knowledge of its history or of its destiny?' Had this question been put to R. S. Adamson, E. J. Salisbury, A. G. Tansley or A. S. Watt, who are amongst the giants of the first forty years of woodland ecology in Britain, their answer would surely have been that understanding lies in a knowledge of destiny. Whilst not unaware of the historical facts of British woodlands, they were preoccupied with ideas of natural succession and climax, and tended to interpret their observations in these terms.