14C estimation of soil C02 turnover rates in Ultisols with different land use

2020 ◽  
Author(s):  
Alexander Cherkinsky ◽  
Ravi Prasad ◽  
Hong Sheng ◽  
Zachary Brecheisen ◽  
Daniel Richter
Keyword(s):  
Land Use ◽  
Ecosystem Respiration ◽  
Isotope Composition ◽  
Soil Surface ◽  
Turnover Rates ◽  
Old Field ◽  
Gas Reservoirs ◽  
Total Ecosystem Respiration ◽  
First Time ◽  
Soil Gases

<p>The CO<sub>2</sub> flux from soil is a large and significant flux in most ecosystems and can account for more than 2/3 of total ecosystem respiration. In many cases, CO<sub>2</sub> flux from soil is estimated by the eddy covariance technique or by classical chamber method with measures of bulk concentration and isotopic composition of carbon dioxide. Whereas most these studies estimated CO<sub>2</sub> flux from the soil surface, we analyzed its concentration and isotope composition directly in soil profiles down to 5m depth.</p><p>This experiment was conducted in Sumter National Forest by NSF Calhoun CZO research program. A 10cm diameter auger was used to core up to 5 m depth and capped PVC pipe segments of 750 cm<sup>3</sup> volume serve as gas reservoirs, each with two gas impermeable tubes that connected the gas reservoirs. Soil gas reservoirs are installed at 5m, 3m, 1.5m, and 0.5m depths from the soil surface. On a three-week interval, soil gases were extracted with a pump and analyzed in the field for CO<sub>2</sub> and O<sub>2</sub> concentration with samples collected in Tedlar bags for analysis. The samples were collected in summer 2016 under 3 different land uses: hardwood stands that are taken to be never cultivated; old-field pine stands, which had been used for growing cotton in 19<sup>th</sup> century and then abandoned; and cultivated sites which were used growing cotton, but for the last 50-60 years for growing corn, wheat, legume, sorghum, and sunflowers.</p><p>The radiocarbon analyses in the soil CO<sub>2</sub> profile were conducted for the first time. It was discovered that concentration of 14C increased with depth and Δ<sup>14</sup>C changed from 40-60%o in the top 0.5m to about 80-140 ‰ at 5m depth depending on land use.</p><p> </p>

scholarly journals Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 666
Author(s):  
Guilin Han ◽  
Anton Eisenhauer ◽  
Jie Zeng ◽  
Man Liu
Keyword(s):  
Soil Depth ◽  
Isotope Composition ◽  
Soil Surface ◽  
Natural Soil ◽  
Calcium Isotope ◽  
Karst Forest ◽  
Content Ratio ◽  
The Difference ◽  
Preferential Uptake ◽  
Vital Factor

In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope (40Ca) is in the following order: farmland > burnt grassland > forests > grassland > shrubland. Our results further indicate that biological fractionation in a soil–plant system is a vital factor for Ca–geochemical transformations in soil surface systems.

Climate and land-use effects on hydrological and vegetation signals during the last three millennia: Evidence from sedimentary leaf waxes in southwestern Morocco

The Holocene ◽  
2021 ◽  
pp. 095968362098805
Author(s):  
Asmae Baqloul ◽  
Enno Schefuß ◽  
Martin Kölling ◽  
Lydie Dupont ◽  
Jeroen Groeneveld ◽  
...  
Keyword(s):  
Land Use ◽  
Carbon Isotope ◽  
Vegetation History ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Economic Stress ◽  
Published Data ◽  
Leaf Waxes ◽  
Argan Tree ◽  
Precipitation Changes

The southwest of Morocco is considered to be an area of refuge within the Mediterranean region, hosting the endemic tropical Argan tree. This region is presently subject to severe droughts, desertification and land degradation, and likely facing increased climate variability and socio-economic stress in the future. Here, we use the stable hydrogen and carbon isotope composition (δD and δ13C) of plant-waxes in a high-resolution marine sediment core (GeoB8601-3) collected off Cape Ghir in southwestern Morocco, in combination with published data on pollen and XRF element ratios from the same archive. We aim to reconstruct the hydroclimate and vegetation history during the last 3000 years. Stable carbon isotope compositions of leaf waxes (δ13Cwax) show that natural vegetation in southwestern Morocco consists of C3 plants. Minor variations in δ13Cwax were positively correlated to changes in stable hydrogen isotope compositions of leaf waxes (δDwax) before 700 CE. Changes in rainfall amounts and water use efficiency indicate a clear vegetation response to precipitation changes and thus to climate forcing. After 700 CE, δDwax and δ13Cwax became de-coupled suggesting that the plant wax discharge and their isotope signals were no longer solely controlled by climate; the waxes likely mainly originate from the lowlands and carry an enriched (dry) δD signal but a depleted 13C signature. The depletion of δ13Cwax correlates with the increase of Argan pollen concentration in the record. The period between ~700 and 900 CE coincides with the Arabization of Morocco which had an impact on the demographic composition of the country leading to new agricultural habits and, as a result, on the land-use triggering a higher erosion of lowland material by the Souss River.

Accumulation patterns of soil organic matter in forests as a legacy of historical charcoal burning

2021 ◽  
Author(s):  
Anna Schneider ◽  
Alexander Bonhage ◽  
Florian Hirsch ◽  
Alexandra Raab ◽  
Thomas Raab
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Large Scale ◽  
Soil Surface ◽  
Landscape Scale ◽  
Legacy Effects ◽  
Charcoal Production ◽  
Study Region ◽  
Land Use Legacies

<p>Human land use and occupation often lead to a high heterogeneity of soil stratigraphy and properties in landscapes within small, clearly delimited areas. Legacy effects of past land use also are also abundant in recent forest areas. Although such land use legacies can occur on considerable fractions of the soil surface, they are hardly considered in soil mapping and inventories. The heterogenous spatial distribution of land use legacy soils challenges the quantification of their impacts on the landscape scale. Relict charcoal hearths (RCH) are a widespread example for the long-lasting effect of historical land use on soil landscapes in forests of many European countries and also northeastern USA. Soils on RCH clearly differ from surrounding forest soils in their stratigraphy and properties, and are most prominently characterized by a technogenic substrate layer with high contents of charcoal. The properties of RCH soils have recently been studied for several regions, but their relevance on the landscape scale has hardly been quantified.</p><p>We analyse and discuss the distribution and ecological relevance of land use legacy soils across scales for RCH in the state of Brandenburg, Germany, with a focus on soil organic matter (SOM) stocks. Our analysis is based on a large-scale mapping of RCH from digital elevation models (DEM), combined with modelled SOM stocks in RCH soils. The distribution of RCH soils in the study region shows heterogeneity at different scales. The large-scale variation is related to the concentration of charcoal production to specific forest areas and the small-scale accumulation pattern is related to the irregular distribution of single RCH within the charcoal production fields. Considerable fractions of the surface area are covered by RCH soils in the major charcoal production areas within the study region. The results also show that RCH can significantly contribute to the soil organic matter stocks of forests, even for areas where they cover only a small fraction of the soil surface. The study highlights that considering land use legacy effects can be relevant for the results of soil mapping and inventories; and that prospecting and mapping land use legacies from DEM can contribute to improving such approaches.</p>

scholarly journals Estimating population and livestock density of mobile pastoralists and sedentary settlements in the south-eastern Lake Chad area

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Vreni Jean-Richard ◽  
Lisa Crump ◽  
Abbani Alhadj Abicho ◽  
Ali Abba Abakar ◽  
Abdraman Mahamat II ◽  
...  
Keyword(s):  
Land Use ◽  
Population Density ◽  
Small Ruminants ◽  
Dry Season ◽  
Land Use Management ◽  
Lake Chad ◽  
Mobile Pastoralists ◽  
Livestock Density ◽  
Density Dynamics ◽  
First Time

Mobile pastoralists provide major contributions to the gross domestic product in Chad, but little information is available regarding their demography. The Lake Chad area population is increasing, resulting in competition for scarce land and water resources. For the first time, the density of people and animals from mobile and sedentary populations was assessed using randomly defined sampling areas. Four sampling rounds were conducted over two years in the same areas to show population density dynamics. We identified 42 villages of sedentary communities in the sampling zones; 11 (in 2010) and 16 (in 2011) mobile pastoralist camps at the beginning of the dry season and 34 (in 2011) and 30 (in 2012) camps at the end of the dry season. A mean of 64.0 people per km2 (95% confidence interval, 20.3-107.8) were estimated to live in sedentary villages. In the mobile communities, we found 5.9 people per km2 at the beginning and 17.5 people per km2 at the end of the dry season. We recorded per km2 on average 21.0 cattle and 31.6 small ruminants in the sedentary villages and 66.1 cattle and 102.5 small ruminants in the mobile communities, which amounts to a mean of 86.6 tropical livestock units during the dry season. These numbers exceed, by up to five times, the published carrying capacities for similar Sahelian zones. Our results underline the need for a new institutional framework. Improved land use management must equally consider the needs of mobile communities and sedentary populations.

scholarly journals Geodynamics and Oil and Gas Potential of the Yenisei-Khatanga Basin (Polar Siberia)

Minerals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 510 ◽  
Author(s):  
Valery Vernikovsky ◽  
Georgy Shemin ◽  
Evgeny Deev ◽  
Dmitry Metelkin ◽  
Nikolay Matushkin ◽  
...  
Keyword(s):  
Lower Cretaceous ◽  
Oil And Gas ◽  
Foreland Basin ◽  
Gas Reservoirs ◽  
The North ◽  
Western Arctic ◽  
Folded Structures ◽  
Gas Potential ◽  
First Time ◽  
North Western

The geodynamic development of the north–western (Arctic) margin of the Siberian craton is comprehensively analyzed for the first time based on our database as well as on the analysis of published material, from Precambrian-Paleozoic and Mesozoic folded structures to the formation of the Mesozoic-Cenozoic Yenisei-Khatanga sedimentary basin. We identify the main stages of the region’s tectonic evolution related to collision and accretion processes, mainly subduction and rifting. It is demonstrated that the prototype of the Yenisei-Khatanga basin was a wide late Paleozoic foreland basin that extended from Southern Taimyr to the Tunguska syneclise and deepened towards Taimyr. The formation of the Yenisei-Khatanga basin, as well as of the West-Siberian basin, was due to continental rifting in the Permian-Triassic. The study describes the main oil and gas generating deposits of the basin, which are mainly Jurassic and Lower Cretaceous mudstones. It is shown that the Lower Cretaceous deposits contain 90% of known hydrocarbon reserves. These are mostly stacked reservoirs with gas, gas condensate and condensate with rims. The study also presents data on oil and gas reservoirs, plays and seals in the Triassic, Jurassic and Cretaceous complexes.

Effects of land use and nitrogen fertilizer on ecosystem respiration in alpine meadow on the Tibetan Plateau

2016 ◽  
Vol 17 (6) ◽  
pp. 1626-1634 ◽  
Author(s):  
Caiyun Luo ◽  
Shiping Wang ◽  
Liang Zhao ◽  
Shixiao Xu ◽  
Burenbayin Xu ◽  
...  
Keyword(s):  
Land Use ◽  
Tibetan Plateau ◽  
Nitrogen Fertilizer ◽  
Alpine Meadow ◽  
Ecosystem Respiration ◽  
The Tibetan Plateau ◽  
Effects Of Land Use

scholarly journals DEGRADASI LAHAN PADA KEBUN CAMPURAN DAN TEGALAN DI KABUPATEN DHARMASRAYA

Jurnal Solum ◽  
2007 ◽  
Vol 4 (1) ◽  
pp. 5
Author(s):  
Syafrimen Yasin ◽  
Gusnidar Gusnidar ◽  
Dedy Iskandar
Keyword(s):  
Land Use ◽  
Soil Depth ◽  
Soil Surface ◽  
Soil Samples ◽  
Imperata Cylindrica ◽  
Undisturbed Soil ◽  
Fertility Status ◽  
Land Use Types ◽  
Bulk Volume ◽  
Soil Fertility Status

A research conducted in Sungai Rumbai, Dharmasraya Regency and in Soil Laboratory Andalas university was aimed to evaluate soil fertility status on the depth below 0-20 cm from several land use types , especially under Mixed Garden and annual cultivated dryland soil.  Soil samples were taken on Ultisol at 0-8% slope (late-waving soil surface).  Land use types evaluated were forest, annual cultivated dryland, bush land, rangeland covered by Imperata cylindrica and mixed garden.  Composite soil samples for soil chemical analysis were taken on the 0-20 cm soil depth with four replications, and 5 drillings for each replication.  Undisturbed soil samples by using sample ring were used to analyze sol bulk volume.  The data resulted were compared to the criteria and were statistically tested using Analysis of Variance and then were continued by LSD at 5% level.  From the results of analyses could be concluded that land use  for mixed garden had the higher Organic Carbon (OC) content and the lower bulk volume (BV) than those for annual cultivated dryland soil.Key Words: Degradasi Lahan, Kebun Campuran, Tegalan

Interacting land use and soil surface dynamics control groundwater outflow in a montane catchment of the lower Mekong basin

2018 ◽  
Vol 268 ◽  
pp. 90-102 ◽  
Author(s):  
Olivier Ribolzi ◽  
Guillaume Lacombe ◽  
Alain Pierret ◽  
Henri Robain ◽  
Phabvilay Sounyafong ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Surface ◽  
Surface Dynamics ◽  
Mekong Basin ◽  
Lower Mekong Basin ◽  
Groundwater Outflow

Frequent Prescribed Fire Sustains Old Field Loblolly Pine–Shortleaf Pine Woodland Communities: Results of a 53-Year Study

2021 ◽  
Author(s):  
Kevin M Robertson ◽  
Sharon M Hermann ◽  
Eric L Staller
Keyword(s):  
Land Use ◽  
Loblolly Pine ◽  
Prescribed Fire ◽  
Wildlife Habitat ◽  
Ecosystem Structure ◽  
Pinus Echinata ◽  
Shortleaf Pine ◽  
Old Field ◽  
Southeastern Us ◽  
Pine Savannas

Abstract Frequently burned old field shortleaf pine (Pinus echinata)–loblolly pine (Pinus taeda) woodlands in the southeastern US provide important wildlife habitat and multiple ecosystem services. Because these communities differ in composition of dominant plant species and have different land use legacies than native pine savannas, the ability to prevent encroachment by off-site broadleaf woody tree species using fire alone is in question. We use a long-term fire experiment to demonstrate that old field pine communities have been prevented from transitioning to hardwood forests for over 50 years through judicious application of prescribed fire applied at 1–2 year intervals, whereas communities with three-year fire intervals show signs of transitioning to hardwood forest. We emphasize tailoring fire regimes to particular contexts of land use history to achieve the most historic and sustainable ecosystem structure and function possible for conservation of native flora and fauna. Study Implications: Demonstrating the ability to maintain natural forest structure of old field loblolly pine–shortleaf pine communities in the southeastern US using frequent prescribed fire has implications for the future sustainability of hundreds of thousands of hectares of such land used to provide critical habitat for many species of imperiled and culturally valued wildlife. It also provides insight into restoration of longleaf pine communities on postagricultural land as promoted by multiple highly funded government initiatives. Frequently burned pine savannas and woodlands are resilient to wildfire and sustain natural hydrological cycles, both important for mitigating the effects of global climate change.

scholarly journals Spatial and temporal variation of CO<sub>2</sub> efflux along a disturbance gradient in a <i>miombo</i> woodland in Western Zambia

2011 ◽  
Vol 8 (1) ◽  
pp. 147-164 ◽  
Author(s):  
L. Merbold ◽  
W. Ziegler ◽  
M. M. Mukelabai ◽  
W. L. Kutsch
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Temporal Variation ◽  
Carbon Content ◽  
Ecosystem Respiration ◽  
Spatial And Temporal Variation ◽  
Co2 Efflux ◽  
Forest Reserve ◽  
Disturbance Gradient ◽  
Total Ecosystem Respiration

Abstract. Carbon dioxide efflux from the soil surface was measured over a period of several weeks within a heterogeneous Brachystegia spp. dominated miombo woodland in Western Zambia. The objectives were to examine spatial and temporal variation of soil respiration along a disturbance gradient from a protected forest reserve to a cut, burned, and grazed area outside, and to relate the flux to various abiotic and biotic drivers. The highest daily mean fluxes (around 12 μmol CO2 m−2 s−1) were measured in the protected forest in the wet season and lowest daily mean fluxes (around 1 μmol CO2 m−2 s−1) in the most disturbed area during the dry season. Diurnal variation of soil respiration was closely correlated with soil temperature. The combination of soil water content and soil temperature was found to be the main driving factor at seasonal time scale. There was a 75% decrease in soil CO2 efflux during the dry season and a 20% difference in peak soil respiratory flux measured in 2008 and 2009. Spatial variation of CO2 efflux was positively related to total soil carbon content in the undisturbed area but not at the disturbed site. Coefficients of variation of efflux rates between plots decreased towards the core zone of the protected forest reserve. Normalized soil respiration values did not vary significantly along the disturbance gradient. Spatial variation of respiration did not show a clear distinction between the disturbed and undisturbed sites and could not be explained by variables such as leaf area index. In contrast, within plot variability of soil respiration was explained by soil organic carbon content. Three different approaches to calculate total ecosystem respiration (Reco) from eddy covariance measurements were compared to two bottom-up estimates of Reco obtained from chambers measurements of soil- and leaf respiration which differed in the consideration of spatial heterogeneity. The consideration of spatial variability resulted only in small changes of Reco when compared to simple averaging. Total ecosystem respiration at the plot scale, obtained by eddy covariance differed by up to 25% in relation to values calculated from the soil- and leaf chamber efflux measurements but without showing a clear trend.

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