Carbon and nitrogen in the soil–plant system along rainfall and land-use gradients in southern Africa

Feral, C. J.; Epstein, Howard E.; Otter, L.; Aranibar, Julieta N.; Shugart, Herman H.; Macko, Stephen A.; Ramontsho, J.

doi:10.1006/jare.2002.1091

Cited by 36 publications

(51 citation statements)

References 34 publications

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“…The model results generally show that there are higher soil C and N stocks and higher soil moisture at the wetter end of the transect (Pandamatenga) than that at the dry end (Tshane), where ecosystem productivity and litter inputs to the soil are smaller. These results are in agreement with field observations (Feral et al 2003;Veenendaal et al 2004). …”

Section: Discussionsupporting

confidence: 95%

“…In Pandamatenga, despite the different rates of N mineralization and immobilization, the ammonium and nitrate levels are similar in the under canopy and the open canopy soils, indicating that the nutrient losses (plant uptake and leaching) tend to decrease the inorganic pools in the soils under canopy. In general, changes in soil moisture availability along the KT rainfall gradient affect nutrient cycling: the levels of soil ammonium increase, while nitrate levels decrease (more leaching at the wet end) with increasing values of MAP along the KT (Table 3, Feral et al 2003). However, the rates of N mineralization are not consistently higher at the dry or at the wet end (Table 3), due to the combined effect of local vegetation heterogeneities and the large scale rainfall gradient.…”

Section: Discussionmentioning

confidence: 98%

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Soil carbon and nitrogen dynamics in southern African savannas: the effect of vegetation-induced patch-scale heterogeneities and large scale rainfall gradients

et al. 2009

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Savanna ecosystems are mixed plant communities in which trees and grasses co-exist thereby providing a heterogeneous landscape with a mosaic of tree-dominated and grass-dominated soil patches. Despite the important role that nutrient availability plays in these systems, detailed knowledge of differences in carbon and nitrogen cycling in soil patches predominantly covered by tree canopies or by grasses is still lacking. In this study, a process-based model was used to investigate the carbon and nitrogen dynamics in soil plots located in grass-dominated and tree/shrub-dominated soil patches along the Kalahari Transect (KT). The KT in southern Africa traverses a dramatic aridity gradient, across relatively homogenous soils, providing an ideal setting for global change studies. Here we show that there are distinctly different dynamics for soil moisture, decomposition and nitrogen mineralization between soil plots located under tree canopies and in open canopy areas, especially at the dryer end of the KT. Such differences diminished when approaching the wetter end of this transect. This study shows that in savanna ecosystems, water availability determines the patterns and rates of nutrient cycling at large scales, while at the local scales, vegetation patchiness plays an important role in nutrient cycling.

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Section: Discussionsupporting

confidence: 95%

Section: Discussionmentioning

confidence: 98%

Soil carbon and nitrogen dynamics in southern African savannas: the effect of vegetation-induced patch-scale heterogeneities and large scale rainfall gradients

et al. 2009

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“…This is a major limitation as the response of arid and semiarid ecosystems to changes in rainfall regime is mediated by variations in the soil moisture dynamics, which, in turn, depend on the soil hydraulic properties. In contrast, a few studies have investigated the biogeochemical properties of the Kalahari sands Bird et al, 2004;Dougill et al, 1998;Feral et al, 2003;Hudak et al, 2003;Pardo et al, 2003;Skarpe and Bergstrom, 1986), although a comprehensive synthesis of the main results remains to be accomplished. This paper provides a brief review of previous studies on the sandy Kalahari soils (hereafter called the Kalahari sands) combined with previously unpublished results from recent analyses of the soil physical (mostly hydraulic) and biogeochemical properties.…”

Section: Article In Pressmentioning

confidence: 88%

Biogeochemistry of Kalahari sands

Wang

D’Odorico

Ringrose

et al. 2007

Journal of Arid Environments

113

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“…In the long-term, rainfall conditions can determine the nutrient abundance at one location. For example, previous studies show that mean rainfall amounts affect ammonium/ nitrate ratios along rainfall gradients in both dry (Feral et al 2003) and wet environments (Houlton et al 2007). It has been shown that plants can adapt to these conditions by switching ammonium/nitrate uptake preference according to their long-term growing conditions (e.g., months to years) (Wang and Macko 2011).…”

Section: Vegetation Responsesmentioning

confidence: 99%

Dynamic interactions of ecohydrological and biogeochemical processes in water‐limited systems

et al. 2015

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Abstract. Water is the essential reactant, catalyst, or medium for many biogeochemical reactions, thus playing an important role in the activation and deactivation of biogeochemical processes. The coupling between hydrological and biogeochemical processes is particularly evident in water-limited arid and semiarid environments, but also in areas with strong seasonal precipitation patterns (e.g., Mediterranean) or in mesic systems during droughts. Moreover, this coupling is apparent at all levels in the ecosystems-from soil microbial cells to whole plants to landscapes. Identifying and quantifying the biogeochemical ''hot spots'' and ''hot moments'', the underlying hydrological drivers, and how disturbance-induced vegetation transitions affect the hydrological-biogeochemical interactions are challenging because of the inherent complexity of these interactions, thus requiring interdisciplinary approaches. At the same time, a holistic approach is essential to fully understand function and processes in water-limited ecosystems and to predict their responses to environmental change. This article examines some of the mechanisms responsible for microbial and vegetation responses to moisture inputs in water-limited ecosystems through a synthesis of existing literature. We begin with the initial observation of Birch effect in 1950s and examine our current understanding of the interactions among vegetation dynamics, hydrology, and biochemistry over the past 60 years. We also summarize the modeling advances in addressing these interactions. This paper focuses on three opportunities to advance coupled hydrological and biogeochemical research: (1) improved quantitative understanding of mechanisms linking hydrological and biogeochemical variations in drylands, (2) experimental and theoretical approaches that describe linkages between hydrology and biogeochemistry (particularly across scales), and (3) the use of these tools and insights to address critical dryland issues of societal relevance.

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Carbon and nitrogen in the soil–plant system along rainfall and land-use gradients in southern Africa

Cited by 36 publications

References 34 publications

Soil carbon and nitrogen dynamics in southern African savannas: the effect of vegetation-induced patch-scale heterogeneities and large scale rainfall gradients

Soil carbon and nitrogen dynamics in southern African savannas: the effect of vegetation-induced patch-scale heterogeneities and large scale rainfall gradients

Biogeochemistry of Kalahari sands

Dynamic interactions of ecohydrological and biogeochemical processes in water‐limited systems

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