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Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands

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dc.contributor.author Aranibar, JN en_US
dc.contributor.author Otter, L en_US
dc.contributor.author Macko, SA en_US
dc.contributor.author Feral, CJW en_US
dc.contributor.author Epstein, HE en_US
dc.contributor.author Dowty, PR en_US
dc.contributor.author Eckardt, F en_US
dc.contributor.author Shugart, HH en_US
dc.contributor.author Swap, RJ en_US
dc.date.accessioned 2007-03-16T07:24:30Z en_US
dc.date.accessioned 2007-06-07T10:02:03Z
dc.date.available 2007-03-16T07:24:30Z en_US
dc.date.available 2007-06-07T10:02:03Z
dc.date.copyright en_US
dc.date.issued 2004-03 en_US
dc.identifier.citation Aranibar, JN, et al. 2004. Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands. Global Change Biology, vol. 10(3), pp 359-373 en_US
dc.identifier.issn 1354-1013 en_US
dc.identifier.uri http://hdl.handle.net/10204/1961 en_US
dc.identifier.uri http://hdl.handle.net/10204/1961
dc.description.abstract Nitrogen (N) cycling was analyzed in the Kalahari region of southern Africa, where a strong precipitation gradient (from 978 to 230 mm mean annual precipitation) is the main variable affecting vegetation. The region is underlain by a homogeneous soil substrate, the Kalahari sands, and provides the opportunity to analyze climate effects on nutrient cycling. Soil and plant N pools, N-15 natural abundance (delta(15)N), and soil NO (Nitric oxide) emissions were measured to indicate patterns of N cycling along a precipitation gradient. The importance of biogenic N-2 fixation associated with vascular plants was estimated with foliar delta(15)N and the basal area of leguminous plants. Soil and plant N was more N-15 enriched in arid than in humid areas, and the relation was steeper in samples collected during wet than during dry years. This indicates a strong effect of annual precipitation variability on N cycling. Soil organic carbon and C/N decreased with aridity, and soil N was influenced by plant functional types. Biogenic N-2 fixation associated with vascular plants was more important in humid areas. Nitrogen fixation associated with trees and shrubs was almost absent in arid areas, even though Mimosoideae species dominate. Soil NO emissions increased with temperature and moisture and were therefore estimated to be lower in drier areas. The isotopic pattern observed in the Kalahari (N-15 enrichment with aridity) agrees with the lower soil organic matter, soil C/N, and N-2 fixation found in arid areas. However, the estimated NO emissions would cause an opposite pattern in delta(15)N, suggesting that other processes, such as internal recycling and ammonia volatilization, may also affect isotopic signatures. This study indicates that spatial, and mainly temporal, variability of precipitation play a key role on N cycling and isotopic signatures in the soil-plant system. en_US
dc.format.extent 242068 bytes en_US
dc.format.mimetype application/pdf en_US
dc.language.iso en en_US
dc.publisher Blackwell Publishing Ltd en_US
dc.rights Copyright: 2004 Blackwell Publishing Ltd en_US
dc.source en_US
dc.subject Nitrogen fixation en_US
dc.subject Nitric oxide emissions en_US
dc.subject Soil nitrogen pools en_US
dc.subject Plant nitrogen pools en_US
dc.subject Kalahari region - Southern Africa en_US
dc.subject Biodiversity conservation en_US
dc.subject Environmental sciences en_US
dc.title Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands en_US
dc.type Article en_US
dc.identifier.apacitation Aranibar, J., Otter, L., Macko, S., Feral, C., Epstein, H., Dowty, P., ... Swap, R. (2004). Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands. http://hdl.handle.net/10204/1961 en_ZA
dc.identifier.chicagocitation Aranibar, JN, L Otter, SA Macko, CJW Feral, HE Epstein, PR Dowty, F Eckardt, HH Shugart, and RJ Swap "Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands." (2004) http://hdl.handle.net/10204/1961 en_ZA
dc.identifier.vancouvercitation Aranibar J, Otter L, Macko S, Feral C, Epstein H, Dowty P, et al. Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands. 2004; http://hdl.handle.net/10204/1961. en_ZA
dc.identifier.ris TY - Article AU - Aranibar, JN AU - Otter, L AU - Macko, SA AU - Feral, CJW AU - Epstein, HE AU - Dowty, PR AU - Eckardt, F AU - Shugart, HH AU - Swap, RJ AB - Nitrogen (N) cycling was analyzed in the Kalahari region of southern Africa, where a strong precipitation gradient (from 978 to 230 mm mean annual precipitation) is the main variable affecting vegetation. The region is underlain by a homogeneous soil substrate, the Kalahari sands, and provides the opportunity to analyze climate effects on nutrient cycling. Soil and plant N pools, N-15 natural abundance (delta(15)N), and soil NO (Nitric oxide) emissions were measured to indicate patterns of N cycling along a precipitation gradient. The importance of biogenic N-2 fixation associated with vascular plants was estimated with foliar delta(15)N and the basal area of leguminous plants. Soil and plant N was more N-15 enriched in arid than in humid areas, and the relation was steeper in samples collected during wet than during dry years. This indicates a strong effect of annual precipitation variability on N cycling. Soil organic carbon and C/N decreased with aridity, and soil N was influenced by plant functional types. Biogenic N-2 fixation associated with vascular plants was more important in humid areas. Nitrogen fixation associated with trees and shrubs was almost absent in arid areas, even though Mimosoideae species dominate. Soil NO emissions increased with temperature and moisture and were therefore estimated to be lower in drier areas. The isotopic pattern observed in the Kalahari (N-15 enrichment with aridity) agrees with the lower soil organic matter, soil C/N, and N-2 fixation found in arid areas. However, the estimated NO emissions would cause an opposite pattern in delta(15)N, suggesting that other processes, such as internal recycling and ammonia volatilization, may also affect isotopic signatures. This study indicates that spatial, and mainly temporal, variability of precipitation play a key role on N cycling and isotopic signatures in the soil-plant system. DA - 2004-03 DB - ResearchSpace DP - CSIR KW - Nitrogen fixation KW - Nitric oxide emissions KW - Soil nitrogen pools KW - Plant nitrogen pools KW - Kalahari region - Southern Africa KW - Biodiversity conservation KW - Environmental sciences LK - https://researchspace.csir.co.za PY - 2004 SM - 1354-1013 T1 - Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands TI - Nitrogen cycling in the soil-plant system along a precipitation gradient in the Kalahari sands UR - http://hdl.handle.net/10204/1961 ER - en_ZA


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