Spatial analysis of fine root distribution on a recently constructed ecosystem in a water-limited environment
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(1) to investigate the spatial distribution of fine roots and its correlation with selected soil properties on an artificial ecosystem dominated by woody vegetation species, and (2) to compare the root distribution to that predicted using a global model for natural ecosystems.
Root diameter distribution (≤ 5 mm), root biomass density (RBD), root length density (RLD), soil pH, soil electrical conductivity and dry soil bulk density were measured on soil core samples (217) collected from a trench wall using a 20 × 20-cm grid sampling.
Approximately 90% of the RBD (mean ± standard error: 0.27 ± 0.027 kg m−3) and RLD (1.57 ± 0.023 cm cm−3) occurred in the top 40 cm, decreasing exponentially to a maximum rooting depth of 150 cm. RBD exhibited a vertical spatial structure associated with soil pH (p < 0.05; r2 = 0.48), and a random lateral distribution. Coefficients of variation (CV) of RBD were high irrespective of orientation (vertical: 79–200%, lateral: 50–236%). The root extinction parameter β (0.944) for the global model was lower (p < 0.05) than that of woodlands (β = 0.964–0.976), indicating a shallow root distribution resembling that of grasslands (β = 0.943).
The superficial root distribution indicated subsoil chemical constraints to root growth, while high lateral variability was attributed to sparse vegetation. The findings stress the need to account for both vertical and lateral variability of roots for accurate modelling of water use and productivity on certain artificial ecosystems with sparse vegetation.
KeywordsGlobal root distribution model Vegetated engineered cover Root biomass density Root diameter distribution Root length density
Soil electrical conductivity in 1:5 soil to water suspension
Root biomass density
Root length density
Dry soil bulk density
The authors thank the anonymous reviewers whose insightful critique of the manuscript significantly improved it. We are also grateful to the Cover Project (Ex-Australian Centre for Mining Environmental Research) for research funding. The design and implementation of the experiment, and analysis and interpretation of the data were solely the responsibilities of the authors. Scholarship support for WG was provided by The University of Western Australia through the Scholarship for International Research Fees (SIRF), University Postgraduate Award (International Student) (UPAIS) and an Ad-hoc top-up scholarship. Mr. Johannes Albers assisted with fieldwork and laboratory analysis.
- Addinsoft (2009) XLSTAT version 2010. Available online: www.xlstat.com, Addinsoft USA, New York
- Beard JS (1984) Biogeography of the Kwongan. In: Pate JS, Beard JS (eds) Kwongan: plant life of the Sandplain. Biology of south-west Australian shrubland ecosystem. University of Western Australia Press, Nedlands, pp 1–26Google Scholar
- Bengough AG, Castrignano A, Pages L, van Noordwijk M (2000) Sampling strategies, scaling and statistics. In: Smit AL, Bengough AG, Engels C, van Noordwijk M, Pellerin S, van De Geijn SC (eds) Roots methods. Springer, Berlin, pp 147–173Google Scholar
- Blake GR, Hartge KH (1986) Bulk density. In: Klute A (ed) Methods of soil analysis Part 1 ASA Monograph No. 9. 2nd edition. Madison, Wisconsin, pp 363–376Google Scholar
- Deutsch CV, Journel AG (1998) GSLIB: geostatistical software library and user’s guide, 2nd edn. Oxford University Press, New YorkGoogle Scholar
- Eamus D, Hatton T, Cook P, Colvin C (2006) Ecohydrology: vegetation function, water and resource management. CSIRO Publishing, CollingwoodGoogle Scholar
- Goovaerts P (1997) Geostatistics for natural resources evaluation. Applied geostatistics series. Oxford University Press, New YorkGoogle Scholar
- Gwenzi W (2010) Vegetation and soil controls on water redistribution on recently constructed ecosystems in water-limited environments. PhD Dissertation, University of Western AustraliaGoogle Scholar
- Kafkafi U, Bernstein N (1996) Root growth under salinity stress. In: Waisel Y, Eshel A, Kafkafi U (eds) Plant roots the hidden half, 2nd edn. Marcel Dekker Inc, New YorkGoogle Scholar
- Ostonen I, Lõhmus K, Alama S, Truu J, Kaar E, Vares A, Uri V, Kurvits V (2006) Morphological adaptations of short roots in Scots pine, silver birch and black alder stands in recultivated opencast oil shale mining and semi-coke areas. Oil Shale 23:187–202Google Scholar
- Quinn GP, Keough MJ (2002) Experimental design and data analysis for biologists. Cambridge University Press, CambridgeGoogle Scholar
- Rayment GE, Higginson FR (1992) Australian laboratory handbook of soil and water chemical methods. Inkata Press, MelbourneGoogle Scholar
- Szota C, Veneklaas EJ, Koch JM, Lambers H (2007) Root architecture of jarrah (Eucalyptus marginata) trees in relation to post-mining deep ripping in Western Australia. Restor Ecol (Supplement) 15(14):65–73Google Scholar
- Warrick AW (2002) Soil physics companion. CRC Press, Boca RatonGoogle Scholar
- Wong JWC, Ho GE (1993) Use of waste gypsum in the revegetation on red mud deposits: a greenhouse study. Waste Manage Res 11:249–256Google Scholar