Contrasting rooting patterns of some arid-zone fruit tree species from Botswana – I. Fine root distribution

To assess the possible degree of root competition from fruit trees which could potentially be used in agroforestry systems, fine root density of fruit trees Strychnos cocculoides Bak., Strychnos spinosa Lam. (Loganiaceae) and Vangueria infausta Burch. (Rubiaceae), as well as from the shrubby species, Grewia flava DC. (Tiliaceae) was investigated. Vangueria infausta had the highest fine root densities in both vertical and horizontal extensions. In Vangueria infausta fine root density decreased with increasing soil depth. For the other species in the 80 cm soil profile investigated, no significant changes in fine root density with soil depth were found. For Strychnos cocculoides almost no fine roots were detected in the upper soil horizon (0–20 cm). Using fine root surface area densities, exploration and exploitation indices were calculated. Vangueria infausta had the highest value of the exploration index compared to the other species. For use in agroforestry systems Vangueria infausta was estimated to be the most competitive of the investigated species, whereas Strychnos cocculoides seems to be the less competitive. Strychnos cocculoides has additionally spatial arrangements of fine roots favourable for agroforestry, slowly increasing with depth and additionally low concentrations in upper soil layers.

[1]  G. Berntson.  Modelling root architecture: are there tradeoffs between efficiency and potential of resource acquisition? , 1994 .

[2]  I. Noy-Meir,et al.  Desert Ecosystems: Environment and Producers , 1973 .

[3]  Alastair H. Fitter,et al.  Architectural analysis of plant root systems , 1992 .

[4]  A. Nardini,et al.  Influence of the ectomycorrhizas formed by Tuber melanosporum Vitt. on hydraulic conductance and water relations of Quercus ilex L. seedlings. , 2000 .

[5]  M. Noordwijk,et al.  Nutrient harvesting - the tree-root safety net , 1997 .

[6]  Moritz Büsgen.  Studien über die Wurzelsysteme einiger dicotyler Holzpflanzen , 1905 .

[7]  W. A. Cannon.  The root habits of desert plants , 1908 .

[8]  Gail W. T. Wilson,et al.  Architectural analysis of plant root systems 1. Architectural correlates of exploitation efficiency , 1991 .

[9]  G. Bohrer,et al.  Effects of environmental variables on vesicular‐arbuscular mycorrhizal abundance in wild populations of Vangueria infausta , 2001 .

[10]  W Kurth,et al.  Topology, scaling relations and Leonardo's rule in root systems from African tree species. , 2001, Tree physiology.

[11]  William Austin Cannon,et al.  The root habits of desert plants, by William Austin Cannon. , 1911 .

[12]  C. Black,et al.  Above and below ground interactions in agroforestry systems , 1991 .

[13]  P. Gandar,et al.  Kiwifruit root systems 1. Root-length densities , 1988 .

[14]  Alastair H. Fitter,et al.  Characteristics and Functions of Root Systems , 2002 .

[15]  J. Syvertsen,et al.  INFLUENCE OF VESICULAR–ARBUSCULAR MYCORRHIZA ON THE HYDRAULIC CONDUCTIVITY OF ROOTS OF TWO CITRUS ROOTSTOCKS , 1984 .

[16]  H. D. Silva,et al.  Exploration and exploitation of soil by apple, kiwifruit, peach, Asian pear and grape roots , 1995, Plant and Soil.

[17]  C. Ong,et al.  Growth and resource utilization of perennial pigeonpea (Cajanus cajan (L) Millsp.) at the tree-crop interface , 1991, Agroforestry Systems.

[18]  A. Fitter,et al.  The ecological significance of root system architecture: an economic approach. , 1991 .

[19]  Alastair H. Fitter,et al.  Architectural analysis of plant root systems 2. Influence of nutrient supply on architecture in contrasting plant species , 1991 .

[20]  F. Nachtergaele.  Soil taxonomy—a basic system of soil classification for making and interpreting soil surveys: Second edition, by Soil Survey Staff, 1999, USDA–NRCS, Agriculture Handbook number 436, Hardbound , 2001 .

[21]  J. Ehleringer,et al.  Water use trade‐offs and optimal adaptations to pulse‐driven arid ecosystems , 2001 .

[22]  H. Walter,et al.  CHAPTER V – A NEW APPROACH TO THE WATER RELATIONS OF DESERT PLANTS , 1974 .

[23]  Alastair H. Fitter,et al.  Functional significance of root morphology and root system architecture , 1985 .

[24]  Helge Dzierzon.  Development of methods for characterizing plant and stand architectures and for model comparisons , 2003 .

[25]  J. Groot,et al.  Root distribution of trees and crops: competition and/or complementarity , 1996 .

[26]  D. Cohen.  The expected efficiency of water utilization in plants under different competition and selection regimes. , 1970 .

[27]  G. Schroth,et al.  Species and site characteristics that permit the association of fast-growing trees with crops: the case of Eucalyptus deglupta as coffee shade in Costa Rica , 2003 .

[28]  Winfried Kurth,et al.  Structure and fractal dimensions of root systems of four co-occurring fruit tree species from Botswana , 2000 .

[29]  Winfried Kurth,et al.  Die Simulation der Baumarchitektur mit Wachstumsgrammatiken , 1999 .

[30]  P. D. J. Anderson,et al.  Physiological Ecology of North American Desert Plants , 1996, Adaptations of Desert Organisms.

[31]  Joel s. Brown,et al.  Tragedy of the commons as a result of root competition , 2001 .

[32]  R. Azcón,et al.  Hyphal contribution to water uptake in mycorrhizal plants as affected by the fungal species and water status , 1995 .