Advanced Series in Agricultural Sciences 24 Co-ordinating Editor: B. Yaron Editors: B.L. McNeal, F. Tardieu H. Van Keulen, D. Van Vleck
Advanced Series in Agricultural Sciences Volumes already published in the series Volume 10 Saline and Sodic Soils (1982) E. Bresler, B. L. McNeal, D. L. Carter Volume II A Theory of Feeding and Growth of Animals (1982) J. R. Parks Volume 12 Fertilization of Dryland and Irrigated Soils (1982) 1. Hagin, B. Tucker Volume 13 Agricultural Soil Mechanics (1983) A. 1. Koolen, H. Kuipers Volume 14 Energy and Agriculture (1984) G. Stanhill (Ed.) Volume 15 The Rhizosphere (1986) E. A. Curl, B. Truelove Volume 20 Water Flow and Solute Transport in Soils (1993) D. Russo, G. Dagan (Eds.) Volume 21 Production of Sugarcane: Theory and Practice (1993) G. Hunsigi Volume 22 Management of Water Use in Agriculture (1994) K. K. Tanji, B. Varon (Eds.) Volume 23 Woody Plants in Agro-Ecosystems of Semi-Arid Regions (1995) H. Breman, J.-J. Kessler Volume 24 Soilless Culture Management (1995) M. Schwarz Volume 16 Population Genetics: Basic Principles (1987) D. P. Doolittle Volume 17 Irrigation with Treated Sewage Effiuent (1991) A. Feigin, I. Ravina, 1. Shalhevet Volume 18 Advances in Statistical Methods for Genetic Improvement of Livestock (1990) D. Gianola, K. Hammond (Eds.) Volume 19 Electromagnetic Radiations in Food Science (1992) 1. Rosenthal
Meier Schwarz Soilless Culture Management With 30 Figures and 21 Tables Springer-Verlag Berlin Heidelberg New York London Paris Tokyo Hong Kong Barcelona Budapest
Prof. Meier Schwarz, Ph.D. Bone Hacho rna Old City, Jerusalem 97500 Israel and Jerusalem College of Technology P.O.B. 16031 Jerusalem 91160 Israel ISBN-13:978-3-642-79095-9 DOl: 10.1007/978-3-642-79093-5 e-isbn-13 :978-3-642-79093-5 Library of Congress Cataloging-in-Publication Data. Schwarz, M. (Meier), 1926-. Soilless culture management / M. Schwarz. p. cm. - (Advanced series in agricultural sciences; v. 24) Includes bibliographical references (p. ) and index. ISBN-13 :978-3-642-79095-9 1. Hydroponics. I. Title. II. Series: Advanced series in agricultural sciences; 24. SB 126.5.S33 1995 631.5' 85 - dc20 94-38472 This work is subject to copynght. All nghts are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of tltis publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. Springer-Verlag Berlin Heidelberg 1995 Softcover reprint of the hardcover I st edition 1995 The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Typesetting: Macmillan India Ltd, Bangalore 25 SPIN: 10056964 3113130/SPS - 5 4 3 2 1 0 - Printed on acid-free paper
Foreword The method of growing plants without soil, known as hydroponics, has long been a subject of much public interest in Israel. Israel, short on water supply and limited in agricultural soil, was looking for alternatives. The study of hydroponics in Israel received additional stimulus from a somewhat unrelated source. Owing to observance of the Sabbatical year (which required the land to be left follow every seventh year), certain religious settlements in Israel were faced with the problem of providing fresh vegetables for their members during that seventh year. In the course of seeking solutions to this problem, practical experiments with the gravel culture method began in 1952 at Kibbutz Hafetz-Hayim, of which the author was a member. Although the method was initially introduced for religious reasons, it soon became apparent that hydroponic culture might be an economically viable means of growing flowers and vegetables under the special conditions prevailing in Israel. In the Negev, the desert area of Israel, arable land and fresh water are scarce, and readily available water is brackish. A hope arose that, thanks to this method, less water would be required and brackish water could be utilized to enable development of the region. Research was carried out at the Negev Institute for Arid Zone Research in Beersheva, including field trials at desert settlements. The development of new and more economic methods, especially sand culture and rockwool culture, opens most regions for economic soilless culture. More than 30% of certain vegetables and flowers have been produced recently in Israel by these methods. The awaited blooming of the deserts will be fundamentally, connected with soilless culture methods. Soilless culture is already the future. In common with many countries around the world, in arid regions under controlled glasshouse conditions in agricultural
VI Foreword regions, and in space programs, salinity problems have contributed to the enormous progress in this field of plant production. Direct contact to many Agriculture Institutes, to research, as well as to agriculturists and their experience, enable us to present this subject. My thanks to International Groups such as The International Society of Soilless Culture in the Netherlands, the Hydroponic Society in the USA and in Germany, where the exchange of information stimulated new ideas. Special thanks to the Plant Protection and Production Department of the Food and Agriculture Organization (FAa) of UN in Rome, who opened the soilless culture methods to the Third World. I thank also my colleagues at the Jerusalem College of Technology, where our recent activities took place.
Preface In selecting material to be included in this book, emphasis has been placed on recent developments in rapidly expanding areas of applied research, and, new methods and ideas in modem agriculture. The book is intended to serve as a guide for students in the agricultural sciences, for agriculture instructors and for the soilless-culture farmer. The needs of the commercial soilless farmer fall between those of controlled scientific plant growth and those of ordinary agriculture. Advanced understanding of plant growth, nutrition and environment requirements, and their limitations, will provide the farmer with improved capability for observation of his crops. With the improved understanding that the farmer will gain about his plants from this book, he will be better able to ask more precise and pointed questions of the consultant. Jerusalem, Israel December 1994 M. SCHWARZ
Contents 1 History... 1 2 Types of Hydroponics and Nomenclature... 3 2.1 Advantages and Disadvantages... 4 3 Nutrients..................................... 7 3.1 The Elemental Composition of Plants... 7 3.2 Macroelements................................ 9 3.3 Microelements... 14 3.4 Nonrequired Elements... 17 3.5 Deficiency Symptom Considerations... 18 3.6 Interaction Between Nutrients... 19 3.7 Methods of Expressing Solution Concentration.. 20 3.8 Composition of the Nutrient Solution... 22 3.9 Mixed Fertilizers... 27 3.10 ph......... 28 3.11 Mobile and Immobile Nutrients... 28 3.12 Nutrient Concentration and Yield... 29 3.13 Preparation of Nutrient Concentrates... 29 3.14 Foliar Nutrition... 30 3.15 Nutrient Solution Analysis... 31 4 Culture Methods... 33 4.1 General Outlines... 33 4.2 The Supporting Media... 34 4.3 Sand Culture - Open System... 40 4.4 Rockwool Culture - Open System... 45 4.5 Gravel Culture - Closed System... 56 4.6 Nutrient Film Technique (NFT) and Water Culture - Closed System... 66 4.7 Water Culture - Closed System... 77 4.8 Bag Culture - Open Systems... 83 4.9 Other Systems... 90 5 Water... 92 5.1 General... 92
x Contents 5.2 The Process of Osmosis... 93 5.3 Transpiration... 93 5.4 Irrigation..................................... 96 5.5 Saline Water... 96 5.6 Wastewater (Sewage)... 104 6 Carbon Dioxide... 108 6.1 General Observations... 109 6.2 CO2 Sources... 113 6.3 Economics of CO 2 Enrichment................. 116 7 Root Environment... 117 7.1 Root Functioning... 117 7.2 Relations of Nutrient Absorption... 119 8 Plant Growth Effects and Plant Tests... 123 8.1 Photosynthetic Efficiency... 123 8.2 Harvest Index................................. 123 8.3 Root-Shoot Relationships... 125 8.4 Plant Tests: Choice of Tissue... 125 8.5 Plant Analysis... 127 8.6 Disease Control... 129 9 Controlling Systems... 131 9.1 Controllers... 131 9.2 Temperature... 135 9.3 Light......................................... 138 9.4 Automated Fertilizer Application... 143 9.5 EC Controller (Conductivity)... 144 9.6 CO 2 Controllers... 145 9.7 DO Controller... 145 10 Culture and Cultivation... 147 10.1 Plants Adaptable to Hydroponic Culture... 147 10.2 Tomato... 150 10.3 Cucumber... 153 10.4 Lettuce... 155 10.5 Flowers... 156 11 Establishing a Commercial Soilless Culture Unit 158 11.1 Economic Considerations... 159 11.2 Increased Technical Demands on the Management 161 12 Some Future Aspects... 162 12.1 Plant Nutrients....... 162 12.2 Initial Investment... 162 12.3 Growth Media... 163
Contents XI 12.4 Advanced Sand-Culture Methods 163 References... 165 Appendix... 171 Subject Index....................................... 193