Management effects on carbon stocks and fluxes across the Orinoco savannas

José, José J. San; Montes, R.

doi:10.1016/s0378-1127(00)00588-0

Cited by 20 publications

(16 citation statements)

References 81 publications

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“…However, the woodland site, protected from fire and grazing since 1981, also showed low soil organic carbon. This observation is in accordance with other data from the region of the Orinoco Llanos (San José & Montes, 2001), which showed that soil carbon stock in the native woodland savannas are generally lower as compared with semideciduous forests (100% of tree canopy cover) from the same areas. However, the low organic C in the woodland soil might also be because of a slow recovery of soil organic carbon at predisturbance level.…”

Section: Resultssupporting

confidence: 93%

“…The low organic carbon observed in the soil (Table 1) probably depends in part on the fast mineralization, which is favoured by high temperatures and generally stimulated by rain, in particular at the beginning of the rainy season (Bate, 1981). On the other hand, land preparation, involving clearing and burning of plant residues in herbaceous savanna and tree savannas, induces significant reduction of soil carbon stocks (San José & Montes, 2001). However, the woodland site, protected from fire and grazing since 1981, also showed low soil organic carbon.…”

Section: Resultsmentioning

confidence: 99%

“…However, the low organic C in the woodland soil might also be because of a slow recovery of soil organic carbon at predisturbance level. In fact, San José & Montes (2001) observed that such recovery can take several decades in woodland ecosystems of the Orinoco Llanos region.…”

Section: Resultsmentioning

confidence: 99%

“…We investigated the effect of change of savanna use on soil CH 4 and N 2 O fluxes, in the Orinoco region of Venezuela, where the anthropogenic pressure leads to an annual average rate of clearing of native vegetation (2.3%, San José & Montes, 2001), almost threefold the rate reported for neotropical forests (0.8%, FAO, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Nitrous oxide and methane fluxes from soils of the Orinoco savanna under different land uses

Castaldi¹,

Ariangelo²,

Grace

et al. 2004

Global Change Biology

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The study investigates the effect of land-use change on nitrous oxide (N 2 O) and methane (CH 4 ) fluxes from soil, in savanna ecosystems of the Orinoco region (Venezuela). Gas fluxes were measured by closed static chambers, in the wet and dry season, in representative systems of land management of the region: a cultivated pasture, an herbaceous savanna, a tree savanna and a woodland (control site). Higher N 2 O emissions were observed in the cultivated pasture and in the herbaceous savanna compared with the tree savanna and the woodland, and differences were mainly related to fine soil particle content and soil volumetric water content measured in the studied sites. Overall N 2 O emissions were quite low in all sites (0-1.58 mg N 2 O-N m À2 day À1 ). The cultivated pasture and the woodland savanna were on average weak CH 4 sinks (À0.05 AE 0.07 and À0.08 AE 0.05 mg CH 4 m À2 day À1 , respectively), whereas the herbaceous savanna and the tree savanna showed net CH 4 production (0.23 AE 0.05 and 0.19 AE 0.05 mg CH 4 m À2 day À1 , respectively). Variations of CH 4 fluxes were mainly driven by variation of soil waterfilled pore space (WFPS), and a shift from net CH 4 consumption to net CH 4 production was observed at around 30% WFPS. Overall, the data suggest that conversion of woodland savanna to managed landscape could alter both CH 4 and N 2 O fluxes; however, the magnitude of such variation depends on the soil characteristics and on the type of land management before conversion.

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Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nitrous oxide and methane fluxes from soils of the Orinoco savanna under different land uses

Castaldi¹,

Ariangelo²,

Grace

et al. 2004

Global Change Biology

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“…Overgrazing, human activities, and climate variation have contributed to the desertification and degradation of more than two-thirds of these fragile ecosystems [34]. Changes in the vegetation and the release of carbon from these drier regions must be considered when discussing carbon balance on a global scale [35]–[36]. Desertification is estimated to affect approximately 1.137 Bha of soils and an additional 2.576 Bha of rangeland vegetation in drylands around the world.…”

Section: Introductionmentioning

confidence: 99%

Effect of Land Use History and Pattern on Soil Carbon Storage in Arid Region of Central Asia

Wang

Liu

et al. 2013

PLoS ONE

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The purpose of this study is to investigate variations in soil organic carbon (SOC) in arid areas due to differences in the cultivation history, land use, and soil salinization. The study area is the lower Sangong River basin on the piedmont of the northern TianShan mountains, which experiences heavy land-use activities. In 1982 and 2005,127(152) and 74 (161) samples in old (new) oasis were collected from each site at the surface soil (i.e., 0–20 cm). The data reveal that the mean value of the surface soil organic carbon content of the old oasis was higher than that of the new oasis by 4.01 g/kg in 1982 and 3.79 g/kg in 2005. Additionally, the soil organic carbon content decreased more rapidly in the newly reclaimed oasis than in the old oasis from 1982 to 2005. The spatial pattern of the SOC content was correlated with the exploitation time in the new oasis, the agricultural land use history, and the SOC content. The decreasing trend is clearer in the high SOC content area than in the low SOC content area. Farmland is the largest carbon pool in both the new and old oases. The carbon density of the old oasis was higher than that of the new oasis by 4.01 and 3.79 g/kg in 1982 and 2005 respectively. The loss of SOC in the agricultural watershed of the arid region in NW China is obvious. Improvements of land management practices, such as no tillage, straw returning to soil, and balanced fertilization techniques, should be adopted to increase the SOC content.

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