PREFACE

In this volume of ACTA HORTICULTURAE the papers, presented either orally or by poster, are published. The oral papers are listed in the order given in each session, followed by the appropriate posterbased papers, which are labeled as poster.

Only very few of the papers presented were not sent to us for publication. Nevertheless, the title of these presentations have been included and marked as not submitted.

Some of the authors wanted to have their paper refereed. This is now possible in ACTA HORTICULTURAE. Therefore, all of the submitted papers have been examined by two or three members of the scientific committee. Those, which reached an acceptable scientific standard, have been marked refereed.

Unfortunately, the very interesting discussions and comments could not be reproduced in this ACTA HORTICULTURAE. On the other hand, the contents of the papers give an idea of the many aspects of growing media and plant nutrition discussed at the symposium in Weihenstephan.

Freising-Weihenstephan, Germany, April 1997

Rolf U. Roeber


WORDS OF WELCOME - OPENING SESSION

As convenor of this symposium I would like to extend a very warm welcome to you here in Germany.

Many of you may not know that Germany is a federal state made up of 16 different states, each with its own traditional and cultural values. Bavaria is one of these states - in fact it is officially called the Freestate of Bavaria.

It is our advantage that the Freestate of Bavaria has been generous in helping us financially in our work on susbstrates and above all in compost research. This development has resulted from the newer laws on waste disposal. Therefore, it seems reasonable that this symposium is taking place in Weilhenstephan and I believe we will have a very intersting exchange of ideals here.

Now, I would like to welcome a few people personally.

First of all I would like to extend a warm welcome to Francis Lemaire, who is the chairman of the Commission for “Plant Substrates”. I would like also to welcome Bill Carlile, who is chairman of our Working Group on “Substrates other than Soils in situ” and Robert Gabriela chairman of the Working Group “Standardisation of analytical Methods and Evaluation of the Results”. Furthermore, our welcome goes to Manfred Schenk, who is president of the German Society Horticultural Science. We are also please to welcome Omer Verdonck, who was formerly on the board of the International Society for Horticultural Science. I woul like to introduce you to the Dean of the Faculty or Horticulture in the Fachhochschule Weihenstephan Lutz Köhler. Last but not least I would like to welcome Klaus Schmidt, who is the vicepresident of the Fachhocshschule Weihenstephan. I think you will agree the symposium programme is wide ranging and scientificallu interesting, thanks to your contributions.

We will undertake a number o short excursion to give you an impression of the substrate industry in Southern Bavaria. We will visit the companies Humobact (bark processing), Patzer (peat-clay substrates) and Euflor (peat harvesting and peat substrates). During our excursions we will also have the opportunity of showing you some of our beautiful Bavarian countryside and monuments.

I would like to take this opportunity to thank my colleagues who helped in organising this symposium. I hope they will continue to help to make this symposium a success with the same verve as to date in the organisation committee.

We hope also that this symposium will be a success and that you will enjoy your short stay with us in Bavaria.

Peter Fisher, convenor