Applied Principles of Horticultural Science Second Edition L. V. Brown BSc (Hons), PgD (LWM), AMIAgrE, MISoilSci, FRGS, Cert Ed OXFORD AMSTERDAM BOSTON LONDON NEW YORK PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO This Page Intentionally Left Blank Butterworth-Heinemann An imprint of Elsevier Science Linacre House, Jordan Hill, Oxford OX2 8DP 225 Wildwood Avenue, Woburn, MA 01801-2041 First published 1996 Reprinted 1999 Second edition published 2002 © Laurie Brown 2002. All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1T 4LP. Applications for the copyright holder’s written permission to reproduce any part of this publication should be addressed to the publishers British Library Cataloguing in Publication Data Brown, L. V. Applied principles of horticultural science – 2nd ed. 1. Horticulture 2. Soil science 3. Horticulture – Problems, exercises, etc. 4. Soil science – Problems, exercises, etc. I. Title 635 ISBN 0 7506 5342 6 Composition by Genesis Typesetting, Laser Quay, Rochester, Kent Printed and bound in Great Britain This Page Intentionally Left Blank Contents Preface xi Acknowledgements xv Part One Plant science 1 Plant kingdom classification and nomenclature 3 Background 3 Exercise 1.1 The plant kingdom 9 Exercise 1.2 Principles of classification 11 Exercise 1.3 Nomenclature for plant ordering 13 Exercise 1.4 Flowering plants (angiosperms) 15 Answers 19 2 Seed propagation (viability and vigour) 21 Background 21 Exercise 2.1 Seed structure and dissection 23 Exercise 2.2 Percentage germination 25 Exercise 2.3 Effect of seed age on germination 27 Exercise 2.4 Tetrazolium test 28 Exercise 2.5 Germination environment 30 Answers 31 3 Propagation 33 Background 33 Exercise 3.1 Vegetative propagation by cuttings 36 Exercise 3.2 Propagation and layering (stem rhizomes and stolons) 40 Exercise 3.3 Propagation and division (stem corms and bulbs) 42 Exercise 3.4 Propagation and division (bulbs) 44 Answers 45 4 Weed – biology and control 47 Background 47 v Contents Exercise 4.1 Weed collecting and identification 48 Exercise 4.2 Pressing and mounting weed specimens 51 Exercise 4.3 Root structure 52 Exercise 4.4 Cultural weed control 55 Exercise 4.5 Chemical weed control 58 Answers 60 5 The leaf and photosynthesis 62 Background 62 Exercise 5.1 Dicotyledonous leaf structure and photosynthesis 66 Exercise 5.2 Chlorophyll and photosynthesis 67 Exercise 5.3 Light and photosynthesis 69 Exercise 5.4 Carbon dioxide and photosynthesis 70 Exercise 5.5 Water and photosynthesis 72 Exercise 5.6 Oxygen and photosynthesis 73 Exercise 5.7 Cells and photosynthesis 75 Answers 77 6 Respiration and storage 80 Background 80 Exercise 6.1 Storage of plant materials 82 Exercise 6.2 Aerobic germination of pea seeds 85 Exercise 6.3 Anaerobic respiration of yeast 86 Exercise 6.4 Energy release during respiration 87 Answers 89 7 Plant water 92 Background 92 Exercise 7.1 Model of osmosis 93 Exercise 7.2 Diffusion 95 Exercise 7.3 Osmosis 96 Exercise 7.4 Plasmolysis 98 Exercise 7.5 Osmosis, diffusion and plasmolysis 99 Exercise 7.6 Root pressure osmosis 101 Answers 102 8 Water transportation pathways and processes 105 Background 105 Exercise 8.1 Stem tissue functions 107 Exercise 8.2 Transport through plant stems 108 Exercise 8.3 Water loss from leaf stomata 110 Exercise 8.4 Transpiration 112 Exercise 8.5 Transpiration balance 116 Exercise 8.6 The weather 117 Answers 119 vi Contents 9 Flower structure 123 Background 123 Exercise 9.1 Flower dissection 125 Exercise 9.2 Structure and function 126 Exercise 9.3 Floral structures 127 Exercise 9.4 Pollen investigation 129 Exercise 9.5 Insect-pollinated plants 130 Exercise 9.6 Fertilization 131 Answers 133 Part Two Soil science 10 Soil formation and texture 139 Background 139 Exercise 10.1 Properties of soil particles 143 Exercise 10.2 Features of coarse, medium and fine grade sand 146 Exercise 10.3 Sand grade investigation 148 Exercise 10.4 Soil texture assessment 149 Exercise 10.5 Soil texture assessment of personal plot sites 151 Answers 152 11 Soil structure and profile assessment 155 Background 155 Exercise 11.1 Soil structure and profile assessment 158 Answers 164 12 Soil water 166 Background 166 Exercise 12.1 Available water-holding capacity 167 Exercise 12.2 Effects of waterlogged soils 170 Exercise 12.3 Capillary rise 171 Exercise 12.4 Plants’ physiological responses to water stress 172 Answers 173 13 Measuring soil pH 176 Background 176 Exercise 13.1 Soil and compost pH testing 182 Exercise 13.2 Soil texture assessment 184 Answers 184 14 Raising soil pH 186 Background 186 Exercise 14.1 Soil texture and lime requirements 186 vii Contents Exercise 14.2 Liming materials and neutralizing values 188 Exercise 14.3 Integration of skills 191 Answers 192 15 Lowering soil pH (increasing soil acidity) 193 Background 193 Exercise 15.1 Soil and compost pH testing 194 Exercise 15.2 Soil texture 195 Exercise 15.3 Free lime (calcium carbonate) content 196 Exercise 15.4 Sulphur requirements to lower pH 198 Exercise 15.5 Lowering pH – integration of skills 199 Answers 200 16 Soil organisms and composting 203 Background 203 Exercise 16.1 Classification of soil organisms 204 Exercise 16.2 Biodiversity in a compost heap 208 Answers 210 17 Soil organic matter 211 Background 211 Exercise 17.1 Soil organic matter determination 211 Exercise 17.2 Properties of organic matter 213 Exercise 17.3 Organic matter and nitrogen 214 Answers 216 18 Plant nutrition 218 Background 218 Exercise 18.1 Plant nutrition 219 Exercise 18.2 Tomato plant deficiency symptoms 220 Exercise 18.3 Function of plant nutrients 222 Exercise 18.4 Major nutrient roles 222 Exercise 18.5 Nitrate fertilizers 226 Answers 228 19 Fertilizers 231 Background 231 Exercise 19.1 Fertilizer nutrient content 235 Exercise 19.2 Structure of fertilizers 236 Exercise 19.3 Fertilizer spreading 237 Exercise 19.4 Types of fertilizer 238 Exercise 19.5 Speed and mode of nutrient release 239 Exercise 19.6 Fertilizer recommendations and calculations 242 Exercise 19.7 Area and amount of fertilizer required 245 Exercise 19.8 Total fertilizer quantity measurements 246 Answers 247 viii Contents Part Three Pest and disease 20 Fungi 255 Background 255 Exercise 20.1 Mycelium investigation 259 Exercise 20.2 Spore cases and germinating spores 261 Exercise 20.3 Spore cases and spore survival techniques 261 Exercise 20.4 Rust disease 262 Exercise 20.5 Powdery mildew disease 263 Exercise 20.6 Structure of a mushroom 263 Exercise 20.7 Spore mapping 264 Answers 265 21 Insects and mites 268 Background 268 Exercise 21.1 Pit fall trapping 269 Exercise 21.2 Pooter bug hunting 271 Exercise 21.3 Vine weevils 272 Exercise 21.4 Wireworms and click beetles 274 Exercise 21.5 Leatherjackets and cranefly 275 Exercise 21.6 Cabbage root fly 276 Exercise 21.7 Cutworms 277 Exercise 21.8 Common gooseberry sawfly 278 Exercise 21.9 Cabbbage white butterfly 279 Exercise 21.10 Red spider mite 280 Exercise 21.11 Aphids 281 Answers 283 22 Nematodes 287 Background 287 Exercise 22.1 Vinegar nematode 289 Exercise 22.2 Nematode damage to plants 290 Exercise 22.3 Potato cyst nematodes (Globodera) in soils 291 Answers 294 23 Biological control 295 Background 295 Exercise 23.1 Common uses of biological control agents 300 Exercise 23.2 Diagnosis of pest damage 306 Exercise 23.3 Monitoring pest levels 308 Exercise 23.4 Predators and prey 310 Answers 312 Useful suppliers 315 Bibliography 317 Index 319 ix This Page Intentionally Left Blank www.taq.ir Preface Aims This is a completely new revision, designed for people who wish to explore and investigate the natural resources of the land-based technologies and, through this, apply their science knowledge in practical professional situations. It is intended to enable the learner to competently carry out routine scientific applications of horticultural principles. The book is best regarded as a method to import practical understanding to the learner in a ‘hands-on’ environment, very much on the basis that ‘an ounce of practical is worth a tonne of theory’. This is approached through relating and presenting the science principles of plants, soils and organisms, as an interactive applied process. There is therefore, in one textbook, coverage of most of the primary science used in the land-based technologies. Approach to the subject The handbook assumes no scientific knowledge above compul- sory school education. This book differs from others in that special emphasis is laid on evidence gained from practical experimental studies. This is integrated with knowledge of the theoretical concepts gained from the greatly expanded supple- mentary text sections presenting a coherent stand-alone text book. Through observing and applying the science of horticulture the learner may increase understanding of how plants grow to become mature, healthy specimens established in either soils or containers. Practical exercises enhance study points and greater topic exploration emphasizes their relevance to growing plants, thus deepening underpinning knowledge. xi www.taq.ir Preface The book presents exercises succinctly, in the context of their relationship within the horticultural environment. The learner should make his or her own notes and drawings since this practice can aid absorption and understanding in a relaxed informal manner. The presence of questions supports independ- ent learning and private study; they enhance the link to related studies and check that understanding has taken place.