Document Type

Article

Journal/Book Title/Conference

Plant and Soil

Publication Date

5-2017

DOI

10.1007/s11104-017-3277-y

Abstract

Aims

Our aim was to examine how soil type and precipitation affect fine-root abundance in savanna ecosystems across Kruger National Park (KNP), South Africa.

Methods

Fine-root distributions were measured in four sites that represent the natural factorial combination of soil types (basalt-derived clay or granite-derived sand) and precipitation regimes [wet (~750 mm mean annual precipitation) or dry (~500 mm mean annual precipitation)] that occur in KNP. Root area and biomass (at soil depths of 0–75 cm) were estimated from measurements of root number, length and width in images from minirhizotron tubes at each site. Measurements were made during one mid-season sampling during three subsequent years.

Results

Fine-root area was more than twice as large in clay (2.3 ± 0.0 mm2 cm−2) than sand (0.8 ± 0.3 mm2 cm−2) sites but did not differ between wet and dry sites. Root number, length and width, used to derive area, showed similar patterns to fine-root area. Fine-root biomass estimated from these values was 5.5 ± 0.6 Mg ha−1 in clay sites and 2.2 ± 0.9 Mg ha−1 in sand sites.

Conclusions

Across the four sites, a change from sand to clay soils had a greater effect on fine-root abundance and distributions than a 50% increase in precipitation from dry to wet sites. Results highlight the importance of soil properties on root dynamics and carbon pools in the region.

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