Editors' introduction

ix

Editors' Introduction The aim of the conference on Methods of Research on Soil Structure/Soil Biota Interrelationships, which we organized 24-28 November, 1991, was to provide a thorough review of established and innovative methods of study and assessment at the microscopic scale, that can be used in all aspects of research on this subject in soil ecology and soil science. It appears that much research on the transformation and transport of elements such as carbon and nitrogen is either concerned with soil biota/plant relationships or with soil structure/plant relationships, but very few studies explicitly take the interrelationships between soil structure and soil biota into account: plant; land qualities

soil structure; texture

organic matter; soil microbes and fauna

Since both in reduced input agriculture and in (semi-)natural ecosystems the plant depends on the contribution of the soil biota to the formation of soil structure and to the release of nutrients, it is obvious that all aspects of the triangle deserve adequate consideration. This calls for interdisciplinary research among soil microbiologists, soil zoologists, soil mi~cromorphologists, soil physicists and root ecologists. It appears, however, that state-of-the-art research in these disciplines is often carried out on different scales, depending, e.g., on the size of the biota that is studied or, rather trivial, on the technical equipment available. There is also insufficient knowledge on techniques used in sister disciplines and on the prospects of using those in one's own field of expertise. So one of the chal-

X

EDITORS' I N T R O D U C T I O N

lenges we face is to develop an adequate methodology for the study of soil structure/soil biota interrelationships and for the translation of results from such research to plant performance and land qualities, as indicated in the figure. Dealing with this challenge different levels of adequate methodology can be distinguished:

features

]

identification . location . distribution interrelations quantification

[ ~

. identification . strength/frequency = interrelations actuality

t

observations

& descri )tion/ table etc.

reflect

[

processes

interpretation

result in

I effects I

function/properties extrapolation/ generalization • models . predictions

7 synthesis

j /

The first level concerns the collection of the basic data: observation, description and quantification of primary features. Focussing on methodology the question is: how do we observe, describe and quantify these features, the interaction between soil structure and soil biota, in situ. The second level deals with the arrangement of diagnostic features into processes. The question here is: how do we translate observed soil features into biologically mediated processes. The third level concerns the translation of processes into effects. The basic question is: how to evaluate effects of the features and processes on soils and plants: This set-up was chosen for the workshop and the articles in the proceedings are arranged accordingly.

EDITORS" INTRODUCTION

xi

Although the conference was on innovative methodology in the first place, we also received a number of excellent contributions in which conventional methods were applied. It was therefore decided not to restrict the proceedings entirely to methodology. The response we have had from the scientific community, both in terms of participation and in terms of manuscripts received, has convinced us that the conference was timely and relevant. The financial support of the sponsors, mentioned elsewhere in this volume, created the possibility to participate for most of the invited speakers and for a considerable number of scientists from developing countries. Finally, we are confident that the proceedings, like the conference itself, will stimulate co-operation among scientists interested in soil structure and soil biota, to the benefit of application of knowledge in environmentally sound plant production and use of land qualities. Wageningen, 19 November 1992

L. BRUSSAARD M.J. KOOISTRA