INTEGRATED CROP MANAGEMENT OF SRC PLANTATIONS TO MAXIMISE CROP VALUE, WILDLIFE BENEFITS AND OTHER ADDED VALUE OPPORTUNITIES ETSU B/W2/00400/REP Contractor The Game Conservancy Trust Prepared by R Sage K Tucker The work described in this report was carried out under contract as part of the New and Renewable Energy Programme, managed by the Energy Technology Support Unit (ETSU) on behalf of the Department of Trade and Industry. The views and judgements expressed in this report are those of the contractor and do not necessarily reflect those of ETSU or the Department of Trade and Industry. First published 1998 © Crown copyright 1998 CONTENTS *COMPLETE REPORT NOT AVAILABLE ELECTRONICALLY* PAGE EXECUTIVE SUMMARY 1.0 INTEGRATED CROP MANAGEMENT IN SRC - 1 INTRODUCTION CROP AND SITE CHARACTERISTICS 2.0 SRC STUDY SITES 4 3.0 CROP GROWTH 12 3.1 SUMMARY 12 3.2 INTRODUCTION 12 3.3 LEAFING TIMES 13 3.4 LEAF AREA 13 3.5 COPPICE HEIGHT 14 3.6 BIOMASS DATA 15 4.0 NON-DESTRUCTIVE ASSESSMENTS OF SRC 19 BIOMASS 4.1 SUMMARY 19 4.2 INTRODUCTION 20 4.3 METHOD 20 4.3.1 Theory 4.3.2 Trial site 4.3.3 Data collection 4.3.4 Analyses 4.3.5 Case study 4.4 RESULTS 23 4.4.1 The relationships between actual biomass and stem dimensions 4.4.2 How many stools need to be measured? 4.4.3 Case study results 4.5 DISCUSSION 32 4.5.1 The best measure of biomass 4.5.2 How many stools? 4.5.3 Case study discussion 4.6 REFERENCES 37 5.0 QUANTIFYING CROP SHADINESS 38 5.1 SUMMARY 38 5.2 INTRODUCTION 38 5.3 METHODS - EQUIPMENT AND SAMPLING 39 STRATEGY 5.4 RESULTS 40 5.5 DISCUSSION 41 5.6 REFERENCES 41 6.0 THE EFFECTS OF EXPOSURE ON CROP GROWTH 43 6.1 SUMMARY 43 6.2 INTRODUCTION 43 6.3 STUDY SITE AND METHOD 44 6.4 RESULTS 44 6.4.1 Wildlife and landscape 6.4.2 Exposure trial 6.5 DISCUSSION 46 6.6 REFERENCES 46 INVERTEBRATES 7.0 INVERTEBRATES COLONISING UK SRC 48 PLANTATIONS - BIODIVERSITY POTENTIAL 7.1 SUMMARY 48 7.2 INTRODUCTION 48 7.3 METHODS 50 7.3.1 Site selection and sampling strategy 7.3.2 Sampling invertebrates from the coppice canopy 7.3.3 Sampling ground and rove beetles using pitfall traps 7.3.4 Invertebrate identification 7.3.5 Analysis 7.4 RESULTS 53 7.4.1 Invertebrates in the canopy of the coppice plantations 7.4.2 Ground and rove beetles 7.5 DISCUSSION 55 7.5.1 Phytophagous insects on free-living willows and poplars 7.5.2 Comparing invertebrate numbers between willow and poplar 7.5.3 Comparing the number of invertebrates on SRC with cereal crop 7.6 REFERENCES 59 8.0 WHICH INVERTEBRATES ARE, OR COULD 66 BECOME, PESTS? 8.1 SUMMARY 66 8.2 INTRODUCTION 67 8.3 METHODS 67 8.31. Site selection and invertebrate sampling 8.3.2 Measuring crop leaf area, defoliation and stem growth 8.3.3 Investigating the relationships between crop growth, defoliation and invertebrate abundance 8.4 RESULTS 69 8.4.1 The main abundant invertebrates 8.4.2 Other species that have pest potential 8.4.3 Defoliation 8.4.4 The impact of defoliation on crop growth 8.5 DISCUSSION 85 8.5.1 The common herbivorous insects 8.5.2 Defoliation and pest numbers 8.5.3 Defoliation and stem growth 8.6 REFERENCES 90 9.0 THE NATURAL CONTROL AGENTS OF THE PESTS 94 OF SRC 9.1 SUMMARY 94 9.2 INTRODUCTION 95 9.3 METHODS 96 9.3.1 The predatory beetles of SRC 9.3.2 The insect predators of SRC pests 9.3.3 The avian predators of SRC pests 9.3.4 Parasitism and other causes of mortality in over ­ wintering chrysomelids 9.4 RESULTS 104 9.4.1 The predatory beetles of SRC The insect predators of SRC pests The avian predators of SRC pests Parasitism and other causes of mortality in over­ wintering chrysomelids 9.5 DISCUSSION 121 9.6 REFERENCES 125 10.0 THE ABUNDANCE AND DISTRIBUTION OF 128 CHRYSOMELIDS BETWEEN SITES 10.1 SUMMARY 128 10.2 INTRODUCTION 129 10.3 METHODS 129 10.3.1 Quantifying beetle abundance 10.3.2 The distribution of beetles between sites and years 10.3.3 The distribution of other common herbivores between sites and years 10.4 RESULTS 132 10.4.1 The abundance and distribution of chrysomelids 10.4.2 Factors affecting the distribution of chrysomelids between sites 10.4.3 The distribution of other common herbivores between sites and years 10.5 DISCUSSION 136 10.6 REFERENCES 139 11.0 PREFERENCES EXHIBITED BY CHRYSOMELIDS 142 FOR DIFFERENT VARIETIES 11.1 SUMMARY 142 11.2 INTRODUCTION 143 11.3 METHODS 143 11.3.1 Comparisons between varieties at a range of sites 11.3.2 A comparison between mixed and monovarietal blocks 11.4 RESULTS 1 44 11.4.1 Species selection 11.4.2 Varietal selection 11.4.3 Mixed v monovarietal 11.5 DISCUSSION 157 11.5.1 Varietal selection by chrysomelids 11.5.2 Varietal selection 11.5.3 Mixed v monovarietal 11.5.4 Plant traits that influence varietal selection 11.6 REFERENCES 162 12.0 OVERWINTERING AND DISPERSAL OF 165 CHRYSOMELIDS INTO SRC - AN OPPORTUNITY FOR CONTROL 12.1 SUMMARY 165 12.2 INTRODUCTION 166 12.3 METHODS 166 12.3.1 Study sites and overwintering surveys 12.3.2 Trapping emerging chrysomelids 12.3.3 Chrysomelids in the coppice canopy (1995) 12.3.4 Chrysomelids in the coppice canopy (1996) 12.3.5 Analyses 12.4 RESULTS 170 12.4.1 Overwintering 12.4.2 Beetle trapping 12.4.3 Canopy beat sampling (1995) 12.4.4 Canopy beat sampling (1996) 12.4.5 Temperature and leafing times 12.5 DISCUSSION 179 12.5.1 Overwintering 12.5.2 Emergence and dispersal 12.5.3 Colonising the crop edge 12.5.4 Dispersing to the crop interior 12.5.5 An opportunity to control chrysomelids 12.6 REFERENCES 182 13.0 INTEGRATED PEST MANAGEMENT - INSECTS 185 13.1 SUMMARY 185 13.2 INTRODUCTION 186 13.3 THE MAIN PESTS AND DAMAGE 186 13.3.1 Economic thresholds and cost benefit 13.4 NATURAL CONTROLS 188 13.5 PLANTATION DESIGN 189 13.6 VARIETAL SELECTION 189 13.7 THE USE OF LOCAL INSECTICIDES 190 13.8 DISEASE 192 13.9 REFERENCES 193 THE VERTEBRATE FAUNA 14.0 BIRDS IN WINTER 194 14.1 SUMMARY 194 14.2 INTRODUCTION 194 14.3 METHODS 195 14.4 RESULTS 196 14.5 DISCUSSION 199 14.6 REFERENCES 201 15.0 SNIPE IN WINTER 205 15.1 SUMMARY 205 15.2 INTRODUCTION 205 15.3 METHODS 206 15.3.1 Winter bird surveys 15.3.2 Snipe habitat use 15.4 RESULTS 209 15.5 DISCUSSION 211 15.6 REFERENCES 212 16.0 THE BREEDING BIRDS OF SRC 214 16.1 SUMMARY 214 16.2 INTRODUCTION 215 16.3 METHODS 215 16.4 RESULTS 216 16.5 DISCUSSION 232 16.6 REFERENCES 235 17.0 GAMEBIRD USE OF SRC 240 17.1 SUMMARY 240 17.2 INTRODUCTION 240 17.3 METHODS 241 17.3.1 Study site 17.3.2 Gamebird use assessment method 17.4 RESULTS 242 17.5 DISCUSSION 244 17.6 REFERENCES 244 18.0 MAMMALS AND OTHER VERTEBRATES OF SRC 246 18.1 SUMMARY 246 18.2 INTRODUCTION 246 18.3 MAMMALS 247 18.4 REPTILES NAD AMPHIBIANS 248 18.5 CONCLUSIONS 248 18.6 REFERENCES 248 THE GROUND FLORA 19.0 CHANGES IN GROUND FLORA WITH TIME 249 19.1 SUMMARY 249 19.2 INTRODUCTION 250 19.3 METHODS 251 19.3.1 Collection of the vegetation data 19.3.2 Analysis of the vegetation data 19.4 RESULTS 255 19.4.1 General trends and statistics from the species data 19.4.2 Results of analysis using TABLEFIT 19.4.3 Results of analysis using DECORANA 19.4.4 Results of analysis using plant ecological strategies 19.5 DISCUSSION 265 19.6 REFERENCES 271 20.0 GROUND FLORA INTRODUCTIONS 276 20.1 SUMMARY 276 20.2 INTRODUCTION 277 20.3 METHODS 278 20.3.1 Site selection and site characteristics 20.3.2 Measuring crop shadiness 20.3.3 Plant species selection 20.3.4 Plot design and preparation 20.3.5 Sowing and planting 20.3.6 Monitoring 20.4 RESULTS 285 20.4.1 Site characteristics 20.4.2 Crop shadiness 20.4.3 Species selection 20.4.4 Monitoring 20.5 DISCUSSION 297 20.6 REFERENCES 301 21.0 THE EFFECTS OF WEEDS ON THE GROWTH OF 307 SRC 21.1 SUMMARY 307 21.2 INTRODUCTION 308 21.3 METHODS 310 21.3.1 Study sites 21.3.2 Trial design 21.3.3 Treatments 21.3.4 Coppice growth 21.3.5 Weediness 21.3.6 Soil survey 21.3.7 Percentage active radiation 21.3.8 Analysis 21.4 RESULTS 317 21.4.1 Weediness 21.4.2 Pre-treatment stool growth 21.4.3 Stool growth during year one 21.4.4 Stool growth during year two 21.4.5 Stool growth over two years 21.4.6 Soil analysis 21.4.7 Number of stems per stool 21.4.8 First year crop height 21.4.9 Canopy light penetration 21.5 DISCUSSION 333 21.5.1 The relationship between growth losses and weediness 21.5.2 Causes of growth losses 21.6 REFERENCES 337 22.0 INTEGRATED CROP MANAGEMENT IN SRC 340 PLANTATIONS - AN OVERVIEW 22.1 SUMMARY 340 22.2 INTRODUCTION 341 22.3 WEED COMPETITION AT ESTABLISHMENT 341 22.4 WEED COMPETITION IN ESTABLISHED COPPICE 342 22.5 THE DEVELOPMENT OF PLANT COMMUNITIES IN 342 SRC 22.6 THE ECONOMIC THRESHOLD FOR WEEDS IN 344 ESTABLISHED COPPICE 22.6.1 Cost benefit analysis 22.6.2 Cutting weeds 22.7 FERTILISATION 346 22.8 REFERENCES 347 ACKNOWLEDGEMENTS EXECUTIVE SUMMARY Objectives The primary objective of the work described in this report is to develop an Integrated Crop Management (ICM) approach for SRC willow and poplar crops.