This investigation combines two independent methods of identifying crop growing conditions and husbandry practices—functional weed ecology and crop stable carbon and nitrogen isotope analysis—in order to assess their potential for inferring the intensity of past cereal production systems using archaeobotanical assemblages. Present-day organic cereal farming in Haute Provence, France features crop varieties adapted to low-nutrient soils managed through crop rotation, with little to no manuring. Weed quadrat survey of 60 crop field transects in this region revealed that floristic variation primarily reflects geographical differences. Functional ecological weed data clearly distinguish the Provence fields from those surveyed in a previous study of intensively managed spelt wheat in Asturias, north-western Spain: as expected, weed ecological data reflect higher soil fertility and disturbance in Asturias. Similarly, crop stable nitrogen isotope values distinguish between intensive manuring in Asturias and long-term cultivation with minimal manuring in Haute Provence. The new model of cereal cultivation intensity based on weed ecology and crop isotope values in Haute Provence and Asturias was tested through application to two other present-day regimes, successfully identifying a high-intensity regime in the Sighisoara region, Romania, and low-intensity production in Kastamonu, Turkey. Application of this new model to Neolithic archaeobotanical assemblages in central Europe suggests that early farming tended to be intensive, and likely incorporated manuring, but also exhibited considerable variation, providing a finer grained understanding of cultivation intensity than previously available.Electronic supplementary materialThe online version of this article (doi:10.1007/s00334-015-0524-0) contains supplementary material, which is available to authorized users.

Breastfeeding patterns were subject to a number of fads in 18th and 19th century Britain. Feeding infants by hand, rather than maternal breastfeeding or wet-nursing, became more prevalent among both the wealthy and poor. Substitute foods may have been a convenient alternative for mothers employed away from the household. This study used stable isotope ratio analysis to examine the weaning schedule in the 18th and 19th century skeletal assemblage from Spitalfields, London, UK. Analysis of 72 juvenile ribs revealed δ(15) N elevations of 2-3‰ above the adult mean for individuals up to the age of two, while elevations of 1-2‰ were observed in δ(13) C for the first year of life. This suggests that the introduction of solid foods took place before the end of the first year, and that breastfeeding had entirely ceased by 2 years of age. The age at death of many of these infants is known from historical records, and can be used to pinpoint the amount of time required for the breast milk signal to be observed in the stable isotope ratios of rib collagen. Results show that a δ(15) N elevation can be detected in the ribs of individuals who died as young as 5-6 weeks. Not all individuals at Spitalfields were breastfed, and there may not have been a single uniformly practiced weaning scheme. There is, however, more evidence for prolonged breastfeeding during the 19th century than the 18th century.

This study measured d 13 C and d 15 N of fresh and charred seeds from six different taxa of cereals and pulses. For each taxon, 12 different batches of seeds, all from the same growing context or field, were charred for 4, 8, or 24 hours at 215, 230, 245, or 2608C, with the thirteenth batch left uncharred. The least charred samples showed no average offset compared to their uncharred counterparts, but among the charred seeds, every 158C increase resulted in an increase in d 15 N by 0.12‰, while increasing the duration of charring by 4 hours resulted in an average increase of 0.04‰. Differences in d 13 C among the charred samples were only minimally dependent on time (þ0.016‰/4 hours duration), but not temperature. The average offset for all batches and all taxa was minimal for d 13 C, at þ 0.11‰ (95% confidence interval (CI) 0.003-0.22‰). The average offset for d 15 N of 0.31‰ (95% CI 0.05-0.57‰) is smaller than the conservative estimate of 1‰ used in previous studies. We demonstrate that using this new, smaller charring offset for d 15 N makes a significant difference in paleodietary models, one that further emphasizes the potentially high d 15 N of manured crops relative to animal forage. Statement of significance Archaeologists and scientists measure carbon and nitrogen isotope ratios in ancient crop remains that have been preserved by charring to understand how crops were grown in the past. The charring process preserves the seed's physical form but results in a slight alteration to the carbon and nitrogen isotope ratios. Our study systematically measured this offset within a window of charring temperatures and times: a window in which the seeds and grains have been completely chemically converted into a stable form, but where this process has been gentle enough that the physical form of the seed has not been distorted. From this study, we understand more precisely the size of the small adjustment we need to make to our measurements of ancient charred crop remains so that we can work back to the original values that reflect the conditions in which these crops were once grown.

RationaleStable isotope analysis of archaeological charred plants has become a useful tool for interpreting past agricultural practices and refining ancient dietary reconstruction. Charred material that lay buried in soil for millennia, however, is susceptible to various kinds of contamination, whose impact on the grain/seed isotopic composition is poorly understood. Pre-treatment protocols have been adapted in distinct forms from radiocarbon dating, but insufficient research has been carried out on evaluating their effectiveness and necessity for stable carbon and nitrogen isotope analysis.MethodsThe effects of previously used pre-treatment protocols on the isotopic composition of archaeological and modern sets of samples were investigated. An archaeological sample was also artificially contaminated with carbonates, nitrates and humic acid and subjected to treatment aimed at removing the introduced contamination. The presence and removal of the contamination were investigated using Fourier transform infrared spectroscopy (FTIR) and δ13C and δ15N values.ResultsThe results show a ca 1‰ decrease in the δ15N values of archaeological charred plant material caused by harsh acid treatments and ultra-sonication. This change is interpreted as being caused by mechanical distortion of the grains/seeds rather than by the removal of contamination. Furthermore, specific infrared peaks have been identified that can be used to detect the three types of contaminants studied. We argue that it is not necessary to try to remove humic acid contamination for stable isotope analysis. The advantages and disadvantages of crushing the grains/seeds before pre-treatment are discussed.ConclusionsWe recommend the use of an acid-only procedure (0.5 M HCl for 30 min at 80°C followed by three rinses in distilled water) for cleaning charred plant remains. This study fills an important gap in plant stable isotope research that will enable future researchers to evaluate potential sources of isotopic change and pre-treat their samples with methods that have been demonstrated to be effective. © 2014 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.

We integrate functional weed ecology with crop stable carbon and nitrogen isotope analysis to assess their combined potential for inferring arable land management practices in (semi-)arid regions from archaeobotanical assemblages. Weed and GIS survey of 60 cereal and pulse fields in Morocco are combined with crop sampling for stable isotope analysis to frame assessment of agricultural labour intensity in terms of manuring, irrigation, tillage and handweeding. Under low management intensity weed variation primarily reflects geographical differences, whereas under high management intensity fields in disparate regions have similar weed flora. Manured and irrigated oasis barley fields are clearly discriminated from less intensively manured rain-fed barley terraces in southern Morocco; when fields in northern and southern Morocco are considered together, climatic differences are superimposed on the agronomic intensity gradient. Barley δ 13 C and δ 15 N values clearly distinguish among the Moroccan regimes. An integrated approach combines crop isotope values with weed ecological discrimination of low-and high-intensity regimes across multiple studies (in southern Morocco and southern Europe). Analysis of archaeobotanical samples from EBA Tell Brak, Syria suggests that this early city was sustained through extensive (low-intensity, large-scale) cereal farming. ARTICLE HISTORY

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This is a repository copy of A bottom-up view of food surplus: using stable carbon and nitrogen isotope analysis to investigate agricultural strategies and diet at Bronze Age Archontiko and Thessaloniki Toumba, northern Greece.

Although key elements defining the juvenile growth phase remain unmeasured, our results broadly support SPL theory in that phytometer and leaf size are a product of the size of the initial shoot meristem (≅ seed mass) and the duration and quality of juvenile growth. These allometrically constrained traits combine to confer ecological specialization on individual species. Equally, they appear conservatively expressed within major taxa. Thus, 'evolutionary canalization' sensu Stebbins (Stebbins GL. 1974. Flowering plants: evolution above the species level . Cambridge, MA: Belknap Press) is perhaps associated with both seed and leaf development, and major taxa appear routinely specialized with respect to ecologically important size-related traits.