Printed on 4/12/2013 (version 9) TUc6 - Colenso Bioresource Programme A natural resources classification system for KwaZulu-Natal Disclaimer: All information relating to the Bioresource Classification of KwaZulu-Natal must be regarded as a first approximation. While every reasonable effort has been made by the authors to obtain objective and realistic results, neither they nor the Department of Agriculture and Environmental Affairs of KwaZulu-Natal make any warranty, or assume any legal liability or responsibility for the accuracy, completeness or usefulness of any information, product or process disclosed in reports relating to the Bioresource Program. Note: The parameters which follow apply to the Bioresource Unit (BRU) as a whole and may not necessarily reflect localized conditions of any particular farm or area within the BRU. References: 1. Camp, K.G.T. 1995. The Bioresource Units of KwaZulu-Natal. Cedara Report N/A/95/32. KZN Department of Agriculture. Pietermaritzburg. 2. Camp, K.G.T. 1999. Guide to the use of the Bioresource Programme. Cedara Report No N/A/99/1. KZN Department of Agriculture. Pietermaritzburg. 3. Camp, K.G.T. 1999. The Bioresource Groups of KwaZulu-Natal : Tall Grassveld including BRG 12 : Moist Tall Grassveld BRG 13 : Dry Tall Grassveld BRG 14 : Sour Sandveld BRG 15 : Moist Lowland Tall Grassveld BRG 16 : Dry Lowland Tall Grassveld Cedara Report No. N/A/99/15. KZN Department of Agriculture. Pietermaritzburg. 4. Smith,B. 2006. The Farming Handbook. University of KwaZulu-Natal Press. 5. Prof. Schultze, R.E. South African Atlas of Climatology and Agrohydrology. 6. Memoirs on the Agricultural resources of South Africa. Soil and Irrigation Research Institute (1986) 7. Planning for the Conservation and Development of Biodiversity in KwaZulu-Natal: Guideline to the use of planning outputs (Incomplete Draft). Dr Peter Goodman. 8. Linsley-Noakes, G.C., Louw, M. and Allan, P. (1995) Estimating Daily Positive Utah chill units using daily minimum and maximum temperatures. J.S. Afric. Soc. Hort. Sci. 5(1):9-23. Copies of any of the above references may be obtained from the DAEA Library at Cedara or the Natural Resources Section. Contact details: Piers Whitwell Tel: 033-3559392 [email protected] Felicity Mitchell Tel: 033-3559386 [email protected] Printed on 4/12/2013 (version 9) Page 1 TUc6 - Colenso Explanations and definitions Report title At the top of each report page is written the Bioresource Unit code followed by the name given to that Bioresource Unit. In the following report the title is TUc6 - Colenso where TUc6 is the Bioresource Unit code and Colenso is the name. TUc6 Each BRU is identified by means of a code based on rainfall and altitude. The upper case letters "R to Z" denote the rainfall range and the lower case letters "a to f" denote the altitude range. TUc6 is used as an example and indicates that the rainfall (TU) is from 650 to 750 mm p.a., the altitude (c) range is from 900 to 1400 metres above sea level. This is the 6th occurrence of the TUc code in KwaZulu-Natal. Rainfall symbols Altitude Symbols R < 600 mm a < 450 m Coast S 601 - 650 mm b 451 - 900 m Lowland T 651 - 700 mm c 901 - 1400 m Upland U 701 - 750 mm d 1401 - 1800 m Highland V 751 - 800 mm e 1801 - 2000 m Montane W 801 - 850 mm f > 2000 m Montane (Escarpment) X 851 - 900 mm Y 901 - 1100 mm Z > 1100 mm Bioresource Unit (BRU) This is defined as an ecological unit within which factors such as soil type, climate, altitude, terrain form and vegetation display a sufficient degree of homogeneity. Appropriate land use practices and production techniques can be defined for each unit. Note, however, that within a Bioresource Unit (BRU), due to the scale of mapping, there can be localised variations in the natural resources. Consequently one cannot directly relate BRU to production potential. Although broad production levels can be defined for a BRU, the variations of the natural resources within the BRU are described in terms of soil ecotopes with production levels defined for each ecotope. Bioresource Group (BRG) This is defined as a specific vegetation type characterised by an interplay of climate, altitude and soil factors and which consists of one or more BRUs. Subgroups of the BRGs are identified. In most cases the subgroups are separated geographically, but in some cases, such as the Moist Coast BRG, major soil changes have resulted in the identification of subgroups, even though these might be adjacent. Subgroups are given numbers. For example BRG 2 has four subgroups, BRG 2.1, BRG 2.2, BRG 2.3 and BRG 2.4. Further subdivisions may occur and are defined as separate areas which are sufficiently homogeneous to be regarded as portions of a particular sub-group. For example BRG 2.2 has four separate portions identified as BRG 2.2a, BRG 2.2b, BRG 2.2.c and BRG 2.2d. The only BRGs which are described fully as single units are the Montane and the Sandy Bush and Palm Veld. Production potential Accurate production potential of a land can only be assessed once a soil survey has been completed. This requires information on soil characteristics (depth, type, clay percentage, drainage and rockiness) before the agricultural potential can be ascertained. The production potentials given in the program are a first approximation based on general soils data described on a BRU basis. Soil ecotopes This is a class of land defined in terms of soil form, texture, depth, wetness, slope and soil surface characteristics (rockiness). Each ecotope has a narrow range of environmental variation such that uniformity exists in terms of land use. This includes farming enterprises, potential yield for each enterprise and the production techniques required. The following is the definition of a soil ecotope - soils.clay(%).depth(mm).slope(%).rockiness (eg. B.1.2.a.0) Printed on 4/12/2013 (version 9) Page 2 TUc6 - Colenso Soils Clay (%) A Humic Soils (>450 mm deep) (No,Kp,Ia,Ma) 1 > 35% B Well and moderately drained soils (Hu,Cv,Gf,Fw(10-22),Sd,Ct,Sp,Bv,Oa) 2 15 - 35% C Alluvial soils (Vf,Du) 3 < 15% D Mottled and moderately drained soils (Av,Pn,Gc) E Mottled and poorly drained soils (We,Lo,Wa,Cf,Kd(10-15) Depth (mm) F Black (Margalitic) soils (Bo,Ik,My,Mw,Tk,Ar) 1 >800 G Black (Margalitic) poorly drained soils (Wo,Rg) 2 500-800 H Young soils (Ms,Gs) 3 300-500 I Other poorly drained soils (Ka,Kd(16-19),Fw(>30) and 4 200-300 Wa,Lo in bottomlands) J Duplex soils (Sw,Va,Ss,Es,Se) Slope (%) K Organic soils and Wetlands a 0 - 3 Y Man made b 4 - 12 Z Podzol c 13 - 15 d 16 - 20 Rockiness e 21 - 40 0 No mechanical limitations x > 40 1 Many stones but ploughable 2 Large stones and boulders, unploughable 3 Very shallow soil on rock or lack of soil The soil types are based on the "Blue Book", namely Soil Classification, A Taxanomic System for South Africa, 1991. Annually arable soils for dryland crops Annually arable soils include soil types " A","B","C","D","F" and "H". Rooting depth must be no less than 500mm. Sandy soils (clay<15%) must not exceed a 3% slope. Soils containing 15% or more of clay must not exceed a 12% slope. Soils must be ploughable (rockiness classes 0 and 1). High potential soils High potential land includes soil types "A","B" and "C" only. Rooting depth must be no less than 800 mms. Sandy soils (clay<15%) must not exceed a 3% slope. Soils containing 15% or more clay must not exceed a 12% slope. There must be no mechanical limitations to ploughing (rockiness class 0). Irrigated annual crops Suitable soil types are "A","B" and "C". Rooting depth must be no less than 500mm. For soil type "D" rooting depth must be no less than 800mm. A slope of 12% is permissable for soil with at least 15% clay. For sandy soils (clay<15%) a maximum slope of 3% is permitted. Soils must be ploughable (rockiness classes 0 and 1). Irrigated perennial crops Suitable soil types are "A","B","C","D" and "F". Rooting depth must be no less than 500mm. For overhead irrigation slope may not exceed 12%. For drip irrigation slopes of up to 40% are permitted. Soils should be ploughable (rockiness classes 0 and 1). Irrigated annual pastures Soil types "A","B","C","D" or "F" are suitable. Rooting depth must be no less than 300mm A 12% slope is permitted. Soils must be ploughable (rockiness classes 0 and 1). Irrigated perennial pastures As above. However, a 20% slope is permitted. Printed on 4/12/2013 (version 9) Page 3 TUc6 - Colenso Orchards and timber Soil types "A","B","C","D","F" and "J" are suitable provided that the rooting depth is no less than 500mm. For sandy soils (clay<15%) a maximum of a 20% slope is allowed. For more clayey soil a maximum of 40% is permitted. Sugar Cane As above except that slope restrictions on sandy soils (clay<15%) are 12% and on more clayey soils (clay>=15%) are 20%. Dryland perennial pastures-stoloniferous Dryland stoloniferous perennial pastures may be grown on soil types "A","B","C","D","F","J","Z" and "Y". A minimum rooting depth of 300mm is required. Slope may not exceed 15%. Soils must be ploughable (rockiness classes 0 and 1). Dryland perennial pastures-tufted As above except that soil type "J" is not recommended.