Land Resource Assessment of the Brisbane Valley, Queensland
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DNRQ990065 B.P. Harms S.M. Pointon Department of Natural Resources Queensland 276 Land Resources Bulletin Land Resource Assessment of the Brisbane Valley, Queensland B.P. Harms and S.M. Pointon Department of Natural Resources Department of Natural Resources Brisbane 1999 DNRQ990065 ISSN 1327-5763 This publication is for general distribution. The National Landcare Program largely funded this project and their support is gratefully acknowledged. This report is intended to provide information only on the subject under review. There are limitations inherent in land resource studies, such as accuracy in relation to map scale and assumptions regarding socio-economic factors for land evaluation. Readers are advised against relying solely on the information contained therein. Before acting on the information conveyed in this report, readers should be satisfied they have received adequate information and advice. While all care has been taken in the preparation of this report, neither the Department of Natural Resources nor its officers or staff accepts any responsibility for any loss or damage that may result from any inaccuracy or omission in the information contained herein. © State of Queensland, Department of Natural Resources 1999 Department of Natural Resources Locked Bag 40 Coorparoo DC Qld 4151 ii CONTENTS List of figures v List of tables v List of maps vi Summary vii 1. INTRODUCTION 1 2. THE BRISBANE VALLEY AREA 2 2.1 LOCATION AND SIZE 2 2.2 LAND USE AND POPULATION 3 Land use 3 Population 4 2.3 CLIMATE 5 Rainfall 5 Temperature 7 Climate and agriculture 7 2.4 GEOLOGY AND LANDFORM 9 Geological units and physiography 9 Geological history 13 Geology and soils 17 2.5 VEGETATION 18 Open forest and woodland communities 18 Closed forest (softwood scrub) 20 Native pastures 20 2.6 HYDROLOGY 22 Surface water 22 Groundwater 23 Water allocation 25 3. METHODOLOGY 27 3.1 SOIL MAPPING 27 3.2 SOIL ANALYSIS 27 3.3 RESOURCE INVENTORY COMPILATION 28 3.4 LAND SUITABILITY EVALUATION 29 Land use limitations 29 Land suitability classification 29 Land suitability assessment 30 Agricultural land classes 31 3.5 THE DATABASES 32 4. SOILS 33 4.1 DESCRIPTION OF THE SOIL PROFILE CLASSES 33 Soils overlying alluvium 33 Soils overlying coarse-grained sedimentary rocks 40 Soils formed on intermediate to basic volcanic rocks 42 iii Soils overlying fine-grained acid igneous rocks 43 Soils overlying coarse-grained acid igneous rocks 43 Soils overlying fine-grained sedimentary rocks 43 Soils overlying metamorphic rocks 44 4.2 SOIL – VEGETATION RELATIONSHIPS 44 4.3 SOIL ANALYTICAL DATA 46 Surface soil fertility 46 Soil profile properties 50 5. LAND DEGRADATION 58 5.1 SOIL EROSION AND PASTURE DEGRADATION 58 Sheet erosion 58 Rill and gully erosion 59 Tunnel erosion 60 Mass movement 60 Saline seepages 62 Streambank erosion 62 Pasture degradation 63 5.2 SOIL ERODIBILITY AND RUNOFF FOR BRISBANE VALLEY SOILS 63 5.3 CONTROL MEASURES FOR SOIL EROSION 67 6. LAND EVALUATION 68 6.1 LAND USE LIMITATIONS BY SOIL PROFILE CLASS 68 Soil water availability 68 Workability 69 Surface condition 69 Nutrient deficiency 70 Soil reaction (pH) 70 Flooding 71 Frost 71 Rockiness 72 Soil depth 73 Microrelief 73 Wetness 74 Water erosion 74 6.2 LAND SUITABILITY ASSESSMENT 75 Land suitability for dryland cropping 76 Land suitability for irrigated small crops 76 Land suitability for dryland sown pastures 77 Land suitability for irrigated pastures 78 Land suitability for tree and vine crops 78 6.3 AGRICULTURAL LAND CLASSIFICATION 79 Acknowledgements 80 References 81 iv Appendices Appendix 1 Surface soil fertility summaries: 85 Table 1 Mean surface soil fertility of soil groups (by geological unit) Table 2 Mean surface soil fertility of soil profile classes Appendix 2 Description of the soil profile classes 91 Appendix 3 Morphological and analytical data for representative soil profiles 117 Appendix 4 Soil attribute levels by soil profile class 145 Appendix 5 Land suitability assessment by soil profile class 147 Appendix 6 Laboratory methods used 149 List of figures Figure 1 Location of the Brisbane Valley survey area 2 Figure 2 Sown pasture and cropping in the Esk Shire 3 Figure 3 Landscape photograph – alluvial flat 4 Figure 4 Monthly and annual rainfall variability for Esk 5 Figure 5 Landscape photograph – horticulture 8 Figure 6 Map showing geological units in the survey area 10 Figure 7 Landscape photograph – Neara Volcanics 12 Figure 8 Diagrammatic representation of the rock units of the Esk Trough at Linville 12 Figure 9 Landscape photograph – Esk Formation 13 Figure 10 Landscape photograph 14 Figure 11 Progressive development of the Brisbane River Valley 15 Figure 12 Occurrence of high-level alluvial terraces in the Brisbane Valley survey area 16 Figure 13 Landscape photograph – Jimna Phyllite 17 Figure 14 Landscape photograph – Queensland blue gum 18 Figure 15 Suggested effects of stocking rate on the composition of speargrass pastures 21 Figure 16 Landscape photograph – degraded pasture 21 Figure 17 Landscape photograph – irrigation 26 Figure 18 A sample sheet from the UMA database showing all the information recorded 32 Figure 19 Soil photograph – the bleached A2 horizon in a gully exposure (Beppo soil) 40 Figure 20 Mean surface soil pH (laboratory) for Brisbane Valley soil groups 46 Figure 21 Mean surface soil organic carbon for Brisbane Valley soil groups 47 Figure 22 Mean Organic Carbon/Total Nitrogen ratios for Brisbane Valley soil groups 48 Figure 23 Mean surface soil extractable phosphorus (P) for Brisbane Valley soil groups 49 Figure 24 Mean surface soil extractable potassium (K) for Brisbane Valley soil groups 49 Figure 25 The salinity (Cl–) profile for three Brisbane Valley soils 50 Figure 26 ESP profiles for three sodic soils in the Brisbane Valley 56 Figure 27 Landscape photograph – severe sheet erosion (Eskvale soil) 59 Figure 28 Landscape photograph – severe gully erosion (Spencer soil) 60 Figure 29 Infiltration rates during rainfall 65 Figure 30 Relative soil loss versus soil cover for each soil profile class 67 List of tables Table 1 Population estimates for Esk and Kilcoy Shires 4 Table 2 Mean annual rainfall and seasonal variation for six stations 5 Table 3 Mean monthly rainfall, average number of rain days ( 0.1 mm) and average EI30 6 for Esk, Kilcoy and Amberley v Table 4 Mean monthly rainfall and pan evaporation for Gatton 6 Table 5 Occurrence of drought at Esk, 1886 – 1993 7 Table 6 Temperature and frost data for Gatton-Lawes and Somerset Dam 8 Table 7 Geological units in the survey area according to major structural elements 11 Table 8 Catchment areas of major tributaries and reaches of the Brisbane River 22 Table 9 Mean monthly flow (ML) and mean annual flow (ML) at selected stream gauging 22 stations in the upper Brisbane Valley Table 10 Analysis results for water sampled at stream gauging stations in the Brisbane Valley 23 Table 11 On-stream storages in the Brisbane Valley area, and their capacities 23 Table 12 Average groundwater characteristics of selected aquifers – south-east Queensland 25 Table 13 Analysis results for water sampled from aquifers in the upper Brisbane Valley 25 Table 14 Licensed allocations and nominal annual surface water usage in the Upper Brisbane 26 River Catchment Table 15 Laboratory analyses performed for each standard depth soil sample 28 Table 16 Agricultural land classes for the Brisbane Valley 31 Table 17 Major attributes, classification and vegetation associations of the soil profile classes 34 Table 18 Summary of subsoil pH and salinity for Brisbane Valley soils 52 Table 19 Summary of subsoil clay content, CEC, clay activity ratio, Ca:Mg ratio, ESP and 54 dispersion ratio (R1) for major Brisbane Valley soils Table 20 Sheet and gully erosion in the Brisbane Valley survey area 61 Table 21 Streambank erosion in the Brisbane Valley 62 Table 22 Runoff, infiltration and soil loss data for four sites in the Brisbane Valley 64 Table 23 Relative soil loss and soil erodibility at four sites in the Brisbane Valley 66 Table 24 Soil water availability limitation 68 Table 25 Workability limitation 69 Table 26 Surface condition limitation 70 Table 27 Nutrient deficiency limitation 70 Table 28 Soil pH limitation 71 Table 29 Flooding limitation 71 Table 30 Frost limitation 72 Table 31 Rockiness limitation 72 Table 32 Soil depth limitation 73 Table 33 Microrelief limitation 73 Table 34 Wetness limitation 74 Table 35 Water erosion limitation 74 Table 36 Summary of the land suitability assessment for the Brisbane Valley 75 Table 37 Summary of the land suitability assessment for soil groups (by geological unit) 75 Table 38 Agricultural land classification of the Brisbane Valley survey area 79 Accompanying maps Map 1 Soils – Esk Sheet DNR Ref. No. 99-BVL-I-P-3232 Map 2 Soils – Moore Sheet DNR Ref. No. 99-BVL-I-P-3233 Map 3 Land suitability – Esk Sheet DNR Ref. No. 99-BVL-I-P-3239 Map 4 Land suitability – Moore Sheet DNR Ref. No. 99-BVL-I-P-3240 vi SUMMARY With the assistance of funding from the National Landcare Program over five years, the land resources of a 1374 km2 portion of the upper Brisbane Valley have been described and documented. The upper Brisbane Valley (570 300 ha) is essentially the most extensive sub-catchment of the Brisbane River System. Apart from its water harvesting function, the area also supports significant agricultural and pastoral activity. Traditionally, the lands have remained forested or have been used for the grazing of native pastures and dryland farming. However, there is a move toward more intensive (often irrigated) cropping and animal husbandry. The capacity of the land to sustain such changes needs to be considered in terms of the limitations imposed by the soil, topography and climate. The survey takes in the central portion of the sub-catchment (137 376 ha) corresponding to the Esk and Moore 1:50 000 map sheets.