Soil and organic carbon losses from varying land uses: a global meta‐analysis

Soil (SL) and organic carbon losses (SOC_L) have increased with human population and climate change linked extreme events. While SL and SOC_L are clearly associated with surface run‐off, the impact of land use is still not well understood. This article elucidates the effects of land use, surface cover, and other environmental factors on SL and SOC_L using data from 55 published studies. The overall SL (12.34 ± 2.25 Mg ha^?1 year^?1) and SOC_L (21.80 ± 0.91 g C m^?2 year^?1) suggests substantial losses of the fertile topsoil globally. Grasslands (4.19 ± 1.22 Mg ha^?1 year^?1) had 77%, 66%, and 41% lower SL than orchards, croplands, and forests, respectively, which is attributable to higher soil organic matter and surface cover. Croplands had the highest SOC_L at 22.78 ± 2.22 g C m^?2 year^?1. Natural vegetation had 98% and 70% lower run‐off and SL than did plant residue mulched plots, indicating its great potential for surface run‐off and soil erosion control. Rainfall and slope were key drivers of soil erosion, while soil surface cover, SOC, and clay content decreased. These findings improve our knowledge on soil and organic carbon losses, which is useful for fostering sustainable management of soils and natural vegetation to enhance ecosystems functionality.     

Organic Loss in Drained Wetland Monuments: Managing the Carbon Footprint

Abstract

The recent installation of land drains at Star Carr, Yorkshire, UK, has been linked with loss of preservation quality in this important Mesolithic buried landscape, challenging the PARIS principle. Historically captured organic carbon, including organic artefacts, is being converted to soluble organic compounds and less soluble carbon gases. At the same time sulphur and nitrogen compounds are oxidized to species that are chemically destructive of artefacts and ecofacts. Two of the carbon products, CO₂ and methane, are ‘greenhouse gases’ whose environmental impact can be costed in terms of carbon equivalents, which can be set against an assessment of the gain in agricultural productivity of the land arising from drainage, at Star Carr being the improved cereal crop. Wetland studies elsewhere suggest that such decay processes could be slowed by restoring the historic soil environment, and even reversed to create carbon capture, enabling the farmer to claim carbon credits.     

Investigating the dietary life histories and mobility of children buried in St Gertrude Church cemetery,Riga, Latvia, 15th–17th centuries ad*

Carbon and nitrogen isotope profiles were obtained from incremental dentine analysis of 19 non-adults from a cemetery in Riga, Latvia. The research compared the life histories and diet between people buried in two mass graves and the general cemetery. The δ¹³C profiles of several children from the mass graves were similar but did not resemble the patterns seen in children from the general cemetery, suggesting that they probably represented a different population group. The rise in δ¹⁵N values towards the end of the life of four individuals from one mass grave suggests they were victims of an historically documented famine.     

The Ben Lawers Historic Landscape Project: Simultaneous Multi-element Analysis of Former Settlement and Arable Soils by X-ray Fluorescence Spectrometry

X-ray fluorescence spectrometry (XRFS) was used in the analysis of A horizon soil samples collected from a former farming settlement and its associated area of infield (i.e. arable) located in the Central Highlands of Scotland. To date, XRFS has not been extensively used in geoarchaeological research, but in our study the simultaneous multi-element capabilities of this instrumental technique allowed the total concentrations of 25 major, minor, and trace elements to be fully quantified with acceptable levels of accuracy and precision. Included within this group of chemical elements are a number (e.g. Ba, Ca, P, Pb, Sr and Zn) that have proved to be of value to archaeological interpretation in earlier investigations undertaken in Scotland. In our preliminary work documented here, significant differences were found between the A horizon soils of former settlement and infield areas for 18 chemical elements. Subjecting the XRFS data—and three other measured variables: soil organic carbon (SOC), pH and A horizon depth—to discriminant analysis indicates that soils of former settlement and arable farming can be effectively classified according to their pH, SOC content and Ca, Cu, Mg, Rb, and Zn concentrations. The inference is that areas of former infield and settlement elsewhere at this study location in the Central Highlands may be able to be identified according to their soil chemical composition and use of discriminant function, even though the surface remains of pre-eighteenth century settlement sites are not readily evident today because they were constructed of perishable materials.     

COMPOSITION PROFILES AND TIME EVOLUTION OF BURIED MARBLE PATINAS BY LA–ICP–MS AND LASER‐INDUCED MICRO‐PHOTO‐LUMINESCENCE

The present work aims to study surface composition profiles on buried marbles as well as their time evolution. Fifty samples from gravestones, buried for up to 80 years, were analysed by laser‐induced photoluminescence and LA–ICP–MS. The results include profiles of ²⁵Mg, ²⁷Al, ⁵⁵Mn, ⁵⁷Fe, ⁸⁸Sr and organic complexes of calcium, existing in the marble patina. The depth at which ⁸⁸Sr reaches its bulk value proved to be the best parameter to measure patina thickness. A diffusion model adopted from dissolution studies made on gravestones exposed to the atmosphere was successfully applied to the patina thickness data. The model fails to predict patina thicknesses for ancient excavated objects. However, it seems that ‘Sr alteration depth’ values alone can be used for discriminating ancient from recently buried surfaces.     

Stable Isotope Record of Human and Sheep Enamel Carbonate from the Ancient Middle Euphrates Valley (Syria)

Stable isotope analyses of human tooth enamel have allowed us to reconstruct the isotope composition of dietary carbon, changes in the oxygen isotope composition of drinking water and the possible migration of humans in ancient Terqa and Tell Masaikh (SE Syria). δ¹⁸O_carbonate values of human tooth enamel from the interval comprising the Neo‐Assyrian to the modern Islamic periods (from 900 BC to AD 1949) generally mirror the isotope composition of Euphrates water, which is believed to have been a major drinking water source. Lower δ¹⁸O_carbonate values of human Bronze Age apatite are linked to a different hydrologic system that was present in the Middle Euphrates valley at that time (2650–1700 BC). Higher δ¹⁸O_carbonate values of some individuals in the Neo‐Assyrian (900–700 BC) and Islamic periods (AD 600–1200) may indicate human migration from the interior of the Near East. Low δ¹³C_carbonate values (−11.3 to −12.4‰) of human tooth enamel from the interval comprising the Early Bronze to the Islamic periods (from 2650 BC to AD 1200) indicate C₃ plants as a predominant source of dietary carbon. Changes in human dietary customs in SE Syria (with inferred usage of C₄ plants) occurred in the modern Islamic period only (AD 1850–1949). Oxygen and carbon isotope data of sheep enamel show the usage of water bodies characterised by an enhanced evaporation rate during the Neo‐Assyrian time (900–700 BC) and grazing sheep herds on drier areas during the Islamic and the modern Islamic periods (after AD 600). Copyright © 2015 John Wiley & Sons, Ltd.     

Subsistence practices and pottery use in Neolithic Jordan: molecular and isotopic evidence

This paper presents direct evidence of subsistence practices and pottery use at a Late Neolithic site at al-Basatîn, northern Jordan. Measurable concentrations of C_16:0 and C_18:0 were recovered from 8 of 10 archaeological pottery fragments through use of a microwave-assisted silica gel and aminopropyl solvent protocol developed for the isolation and concentration of free fatty acids in marine sediments. Subsequent isotopic analysis of the surviving C_16:0 and C_18:0 saturated fatty acids revealed ∂¹³C ratios consistent with those of adipose fats of ruminant and non-ruminant animals pastured on lands adjacent to the Jordan Valley. The high recovery of diagnostic compounds from the al-Basatîn material is discussed in context of a wider examination of the initial development and use of pottery in the Fertile Crescent, and the emerging debate concerning the efficacy of stable carbon isotope values in characterizing organic residues embedded in pottery fragments recovered from the earliest ceramic horizons in the Middle East and Europe.     

Social stratigraphy in Late Iron Age Switzerland: stable carbon,nitrogen and sulphur isotope analysis of human remains from Münsingen

The Iron Age cemetery of Münsingen in Switzerland with 220 abundantly equipped burials marked a milestone for Iron Age research. The horizontal spread throughout the time of its occupancy laid the foundation for the chronology system of the Late Iron Age. Today, skulls of 77 individuals and some postcranial bones are still preserved. The aim of the study was to obtain information about diet, mobility and social stratification of the individuals. Stable isotope ratios of carbon, nitrogen and sulphur were analysed for 63 individuals. For all of them, C₃ plants were found to be the staple food. There are significant differences between males and females in δ¹³C and δ¹⁵N values. This points to a gender restriction in the access to animal protein with males probably having more access to meat and dairy products. Differences in δ¹⁵N values were also observed for different age classes. δ³⁴S values indicate a terrestrial-based diet with no significant intake of marine or freshwater fish. Seven adults with enriched δ³⁴S values might have immigrated to Münsingen, four of which were found in the oldest part of the cemetery. Furthermore, possible changes of the vegetation are indicated by the more positive stable carbon ratios in the later phases. The results lead to the suggestion that especially males buried with weapons might have played a special role in the Iron Age society.     

They did not Live by Grass Alone: the Politics and Palaeoecology of Animal Fodder in the North Atlantic Region

Abstract

A five year research project was set up to monitor soil moisture and groundwater levels of an extensive buried, mainly alluviated landscape located at the interface between the lower Great Ouse valley and the fen-edge in western Cambridgeshire. The intention was to monitor changes in hydrology, soil structure and geochemical status before, during and after large scale gravel extraction. The results presented here concern the pre-extraction monitoring period over three years. The project has identified three major landscape zones – shallowly buried former dryland, several sets of relict palaeochannel systems which still remain waterlogged, and a marginal zone between these where the monitored parameters fluctuate on a seasonal basis. The moisture levels of the alluvial overburden, buried soils and infills of the palaeochannel systems appear to act independently of each other, controlled by a combination of rainfall, agricultural land management, height above sea level and depth of burial. It is predicted that the removal of 1–3m of overburden accompanied by water abstraction when gravel extraction commences will lead to changes in the moisture regime of the immediate area and therefore of any contained archaeological contexts and the superficial sediments in this river valley/fen-edge landscape.     

Short-chain n-alkanes (C16–20) in ancient soil are useful molecular markers for prehistoric biomass burning

The incorporation of plant biomass into soil usually leads to long-chain n-alkanes with a relative predominance of odd carbon numbered homologues. Contrastingly, an increase in short-chain even carbon numbered n-alkanes was found in charred biomass with progressing temperatures. We applied lipid analysis to buried ancient topsoils that contained charred organic matter and to corresponding control soils, which were characterized by a lighter color and lower contents of charred materials. Commonly, the proportion of lipid extracts was found to be lower in the ancient soil than in the control samples, which indicated an enhanced degradation of organic matter, e.g., by thermal degradation. All samples displayed a particular pattern of short-chain and even carbon numbered n-alkanes (maximum at n-C₁₆ or n-C₁₈). The ratios CPI (carbon preference index) and ACL (average chain length) for the investigated soil samples matched the ratios found for maize and rye straw charred at 400 °C or 500 °C, respectively. These molecular ratios indicate the presence of charred biomass. The predominance of short-chain and even carbon numbered n-alkanes was a result of thermal degradation of biomass. The degradation products were preserved in ancient soils and could be applied as molecular markers in archaeological or palaeoenvironmental research.     

Soils and vegetation history of abandoned enclosures in the New Forest,Hampshire, England

Soil profiles buried beneath earth banks of five abandoned enclosures, ranging in age from late Bronze Age to early 19th century AD, were compared with unburied profiles inside and outside the enclosures. Soil particle size analyses and micromorphological studies show that the banks were constructed of mixed topsoil and subsoil from adjacent ditches; on some banks the soil has begun to podzolize. At the two oldest sites (Dark Hat and Long Slade Bottom, which are late Bronze or Iron Age) the soils within the enclosures were homogenized, probably by occasional cultivation for cereal growing. At Dark Hat an ironpan has developed on the upper surface of a layer compacted by smearing during cultivation. The later enclosures, at Burley Moor (Anglo-Saxon), East Boldre (mediaeval) and Hatchet Gate (early 19th century AD), were probably used entirely for pasture. Pollen assemblages from the buried soils and overlying banks, and chemical comparisons of the buried soils with profiles inside and outside the enclosures together provide new evidence for a history of soil and vegetation changes over the past 2500–3500 years. Heathland vegetation associated with podzolic soils existed on plateau gravels before the late Bronze Age, but on other parent materials heath vegetation and acidic soils with incipient podzolization appeared only in later periods. The present patchy vegetation pattern of mainly deciduous woodland with open areas of ferny grassland and heath seems to have persisted since before the late Bronze Age. The most obvious human influences on the vegetation during the last 2000 years have been periodic temporary use of open areas and woodland clearings for protected grazing.     

Relation between radiocarbon,archaeological dating and sediment properties on the example of colluvial deposits (NE Poland)

This study focuses on the analysis of the structural and textural features of the colluvial (deluvial) deposits in the Suwałki Lake District (NE Poland) and their absolute age. The colluvium has a thickness of up to 150 cm. The dates of the peat under colluvium or lowermost fossil humus-rich horizons point to the ages from 5405±80 BP to 480 BP. Deposition of material at the footslope is a result of a denudation triggered by human action (surface water erosion and tillage erosion) and usually corresponds with the settlement stages. The ¹⁴C dating of deposited sediment sometimes indicated to older dates of colluvium then the archaeological evidence available for examined sites. Locally, the overlying fossil humic horizon was older then the lowermost one. The textural features of the colluvial deposits such as: the content of fine fraction, weak sorting and relationship between the mean grain-size (Mz) and the sorting index (σ₁) were used to recognize sediment redeposited from the upper part of the slope. Basing on the mineral composition and electrical conductivity of fossil humus horizon it is possible to say whether the soil was degraded or aggraded. These features of the humus-rich horizons occurring between colluvial sediments can be used to explain discrepancy between the radiocarbon dating and archaeological evidence.     

Persistence of the cultural landscape in Campania (Southern Italy) before the AD 472 Vesuvius eruption: archaeoenvironmental data

Cultural landscapes were prominent during the Early Roman period when agronomic knowledge allowed the spread of intensive land exploitation in most of the available land. The aim of this contribution is to explore whether for the Campania region (Southern Italy) archaeoenvironmental data would support continuity or change in the cultural landscape of Roman tradition in the 4th and 5th centuries. To do so, new data from two sites located on the northern slopes of the Vesuvius, both buried by the AD 472 eruption have been investigated. Charcoal analysis, ¹⁴C dating, and chemical analysis of organic residues were carried out in order to study the landscape and the food production at these sites. The results suggest the persistence of the Roman cultural landscape until the 4th and 5th centuries in this area. The landscape is in fact strongly marked both in agriculture and woodland exploitation and management, being characterized by managed chestnut forests as well as valuable cultivations of walnut, large vineyards, olive groves, and probably orchards and crops. The integrated approach with archaeobotanical and archaeometric analyses proves to be a powerful method for the study of the past landscapes, providing a good insight into the environment. Furthermore, this study provided the most ancient evidence of chestnut silviculture for wood.     

Testing flora as bioindicator of buried structures in the archaeological area of Maxentius’s villa (Rome,Italy)

The flora of the archaeological area of Maxentius’s villa (Rome) was tested as bioindicator of buried remains of masonry and pavements. A total of 53 floristic surveys provided the occurrence of each species in sample units, as well as some their phenological features. The data were elaborated through multivariate statistical analysis in order to assess floristic affinities/differences among sample units, and define their ecological characteristics. The fuzzy set methodology was applied to evaluate relation between floristic richness, plant cover and soil depth. Results showed that the buried remains of stonework create a discontinuity in the ground, influencing the flora growing above it. This phenomenon may give rise to differential presence of some species (e.g., Cota tinctoria, Trifolium scabrum ssp. scabrum on thin soil; Ranunculus bulbosus, Trifolium pratense on deeper soil), but will not have such a great effect on floristic richness. The bioindication of this phenomenon also occurs through phenological irregularities in single specimens and changes in plant cover. Nevertheless other environmental factors (soil moisture/aridity, trampling, enrichment of nitrogen, cutting, ground depression) can interfere with the use of plants as bioindicators of buried structures. It is therefore necessary to consider other factors ecological influencing each site when you want to use plants as bioindicators in archaeological prospection.     

深圳铁仔山古墓群出土铜器腐蚀情况研究

受深圳地区海洋气候及土壤环境影响,铁仔山古墓群出土铜器锈蚀情况严重。为了给后续的保护修复处理提供科学依据,需研究出土铜器锈蚀情况。为此,通过硝酸银定性分析、X射线荧光能谱分析、拉曼光谱分析等手段,对其表面锈蚀物进行综合分析。结果表明,该批铜器矿化严重,其锈蚀成分以孔雀石为主。其中一件铜器表面锈蚀物中含有氯磷钠铜矿,这在潮湿地区土壤环境出土的铜器中较为少见。此外,在另一件铜器表面锈蚀物中还发现疑似纳米SnO2成分。实验结果可对该批铜器的保护修复处理提供有力的理论依据和数据支持,并为深圳地区出土的其他青铜类文物的保护提供参考。     

A NEW METHOD FOR EXTRACTION,ISOLATION AND TRANSESTERIFICATION OF FREE FATTY ACIDS FROM ARCHAEOLOGICAL POTTERY

This paper presents evidence for increased recovery of organic residues from archaeological pottery through use of a microwave‐assisted liquid chromatography protocol. C_16:0 and C_18:0 saturated fatty acids were obtained from archaeological potsherds recovered from nine Neolithic settlements in the Middle East dating between 4700 and 7300 cal bc , including materials that had not produced evidence for the survival of any lipid species through use of ‘conventional’ solvent extraction techniques. Compound‐specific isotopic analyses of C_16:0 and C_18:0 fatty acids in potsherd extracts subsequently revealed δ¹³C/δ¹²C compositions consistent with modern subcutaneous fats of wild boar and goats pastured on lands adjacent to the Jordan Valley, and residues from a modern pottery vessel used in the manufacturing of butter, cheese and yogurt in central Turkey. These results are presented as an illustration of capabilities of the microwave‐assisted recovery protocol. The reclamation of saturated and unsaturated fatty acids from archaeological pottery fragments recovered from a number of the earliest ceramic horizons in the Middle East is herewith reported, and the extraction methods and instrumental analytical techniques are described.     

Molecular transport of methane, ethane and nitrogen and the influence of diffusion on the chemical and isotopic composition of natural gas accumulations

Laboratory experiments have been performed to determine diffusion coefficients of natural gas components (methane, ethane and nitrogen) and isotope fractionation effects under simulated in situ pressure (up to 45 MPa effective stress) and temperature conditions (50–200°C) in water‐saturated pelitic and coarse‐grained rocks. Effective diffusion coefficients of molecular nitrogen (0.39 × 10^?11 to 21.6 × 10^?11 m² sec^?1 at 90°C) are higher than those for methane (0.18 × 10^?11 to 18.2 × 10^?11 m² sec^?1 at 90°C). Diffusive flux rates expressed in mass units are generally higher for N₂ than for CH₄. Both methane and (to a lesser extent) nitrogen diffusion coefficients decrease with increasing total organic carbon (TOC) content of the rock samples because of sorption processes on the organic matter. This effect decreases with increasing temperature. Effective diffusion coefficients increase upon a temperature increase from 50 to 200°C by a factor of four. Effective diffusion coefficients and steady‐state diffusive flux decrease with effective stress. Stationary diffusive fluxes drop by 50–70% for methane and 45–62% for nitrogen while effective diffusion coefficients are reduced by 38% (CH₄) and 32–48% (N₂), respectively. Isotope fractionation coefficients of diffusive transport are higher for methane (?1.56 and ?2.77‰) than for ethane (?0.84 and ?1.62‰). Application of the experimental results to geological systems show that diffusive transport has only a low transport efficiency. Significant depletion of natural gas reservoirs by molecular diffusion is only expected in cases of very poor caprock qualities (in terms of thickness and/or porosity) and over extended periods of geological time. Under these circumstances, the chemical and isotopic composition of a gas reservoir will change and maturity estimates based on these parameters may be deceptive. To account for these potential effects, nomograms have been developed to estimate diffusive losses and apply maturity corrections.     

Nitrogen cycling in western India as revealed by nitrogen isotopes,and the historic production of saltpetre

Saltpetre (KNO₃) manufacture was a principal monopoly industry in early Modern India when the United Kingdom governed the social and economic systems. The process represented microbial transformation of excrementitious livestock and human wastes deposited around habitats, resulting in formation of salt efflorescence at an economic scale. Low caste people collected these wastes for extraction and production of rough saltpetre under the administrative control of British India. Stable isotope composition (δ¹⁵N and δ¹⁸O) was used to trace details of the microbial transformation processes, often involving the isotopic fractionation of nitrogen and oxygen. Marked elevation in δ¹⁵N and δ¹⁸O values for nitrates in soils and deposits, relative to those of primary organic nitrogen in diets and water sources, characterizes the unique processes of historic saltpetre manufacture in British India.     

Manuring and stable nitrogen isotope ratios in cereals and pulses: towards a new archaeobotanical approach to the inference of land use and dietary practices

This paper explores the impact of animal manure application on the δ¹⁵N values of a broad range of crops (cereals and pulses), under a range of manuring levels/regimes and at a series of locations extending from northwest Europe to the eastern Mediterranean. We included both agricultural field experiments and areas where ‘traditional’ farming is practised. Our aim is to ground-truth interpretation of δ¹⁵N values in archaeobotanical crop remains as evidence of past growing conditions and husbandry practices. The results confirm the potentially radical impact of manuring on δ¹⁵N values in cereals, depending on manuring level, but indicate only a slight effect on pulses, which can fix atmospheric nitrogen. The expected geographical trend towards greater δ¹⁵N with increasing climatic aridity is not apparent, probably because the growing conditions for crops are ‘buffered’ through crop management. Each of these observations has fundamental implications for archaeobotanical interpretation of δ¹⁵N values as evidence of land use practices and (together with analysis of bone collagen/tooth enamel in potential consumers) palaeodiet.     

Carbon and nitrogen stable isotope analysis of hunter–gatherers from the Coleman site,a Late Prehistoric cemetery in Central Texas

We report on a stable isotopic analysis of 17 hunter–gatherer burials from the Coleman site (41BX568), a Late Prehistoric Toyah Interval (700–350 years BP) occupation in Texas. Prior to our analysis, isotopic research on Toyah populations in Central Texas was represented by a single burial at site 41BX677. That burial showed an isotopic pattern suggestive of a diet heavily focused on CAM/C₄ plants and C₄ fauna. Coleman burials show a different pattern. While interpretations are complicated by high variability in the isotopic signatures of children and by differences in male and female diets possibly related to mate exchange, the 11 adult and adolescent burials at Coleman show a diet focused on C₃ fauna and the use of both C₃ and CAM/C₄ plants. The moderate CAM/C₄ plant use is a radical departure from a trend of increasing C₃ plant use that characterized hunter–gatherers in this region for at least 6200 years prior to the start of the Toyah Interval. Protein sources among Coleman adults probably centered on deer, but also included high nitrogen (δ¹⁵N) animals, such as fish. Males seem to have differential access to these high nitrogen sources. Two different isotopic patterns, one reflecting a focus on C₃ fauna and moderate use of CAM/C₄ plants, and a second reflecting C₄ fauna and extensive use of CAM/C₄ plants, are represented during Toyah. While interpretations are complicated by small sample sizes, these two patterns could simply reflect temporal differences, different acquisition strategies based on availability, or hint at different subsistence strategies. It may also be the case that the 41BX677 individual represents an immigrant into the Central Texas region, one with a different isotopic history.