Investigating crop processing using phytolith analysis: the example of rice and millets

The application of crop processing models to macro-botanical assemblages has traditionally been used to interpret past husbandry practices and organisation of labour involved in crop-processing. Phytoliths offer an alternative method of analysis because they are durable in most environments, regardless of whether plant parts are charred, and the identification of plant types and plant parts allows them to be used in much the same way as macro-botanical remains. Indeed macro-remains and phytoliths are complementary datasets for examining the input of plant parts, such as crop-processing waste, into archaeological deposits. We outline crop-processing models in relation to macro-remains and then develop the framework for their application to archaeological phytolith assemblages. Rice and millet processing models are explored in relation to patterns expected in both macro-remains and phytoliths. The utility of these models is demonstrated with archaeological evidence from the site of Mahagara, an early farming site in North-Central India. The results indicate a way to employ phytoliths in archaeology which complements the fragmentary evidence available from plant macroremains.     

Morphometric distinction between bilobate phytoliths from <Emphasis Type="Italic">Panicum miliaceum</Emphasis> and <Emphasis Type="Italic">Setaria italica</Emphasis> leaves

The development of identification criteria for crop plants based on phytoliths is of high relevance for archaeology, palaeoecology and plant systematics. While identification criteria are available for major food crops, these are mostly based on phytoliths from inflorescences, while other plant parts remain undetected. This paper focuses on bilobate phytoliths from leaves of Panicum miliaceum L. (common millet) and Setaria italica (L.) P. Beauv. (foxtail millet), two taxa that co-occur in regions of Asia and Europe since prehistory and regularly occur at archaeological sites in Eurasia. Leaves of the investigated taxa were systematically sampled to explore the variation of short cells and to collect 27 morphometric variables of bilobate phytoliths with newly developed open-source software. The data was analysed by discriminant analysis, analysis of variance and multiple comparison tests. The resulting morphometric data from five populations per species enables a distinction between the bilobate phytoliths of P. miliaceum and S. italica. Observed differences between populations within species affect only few parameters. This possibility to classify populations of bilobate phytoliths from P. miliaceum and S. italica leaves offers a new method for the detection and identification of these taxa in archaeology, amongst others.     

Subsistence practices in an arid environment: a geoarchaeological investigation in an Iron Age site,the Negev Highlands,Israel

The Negev Highlands (southern Israel) is an arid zone characterized by settlement oscillations. One settlement peak occurred in the early Iron Age IIA (late 10th and early 9th centuries BC). The most conspicuous structure in many sites of this period is an oval compound comprised of an internal courtyard surrounded by rooms. Two hypotheses for the function of these oval compounds are that they served as Israelite fortresses which guarded the southern border and routes of the Solomonic kingdom, or that they represent local agro-pastoral groups. In order to gather more information regarding the subsistence practices conducted in these oval compounds, we carried out a small-scale excavation at the site of Atar Haroa. We focused on sediment sampling and used several geoarchaeological, as well as isotopic, techniques in order to identify macroscopic and microscopic remains related to animal husbandry and crop agriculture. The remains identified from the archaeological sediments were compared with modern reference materials collected from abandoned Bedouin camps. The excavation included two half rooms and several test pits in the courtyard of the oval compound, featuring one Iron Age occupation level composed of gray sediments and relatively small amounts of pottery, bones and macro-botanical charred remains. Micromorphological, mineralogical, dung spherulite and isotopic analyses carried out on the gray occupational sediments from the rooms show that they originate from wood ash and dung, both used as fuel. Similar analyses of the gray sediments in the courtyard show that they originate only from degraded livestock dung. Phytolith analyses show that the gray anthropogenic sediments have similar concentrations of phytoliths as in control (yellowish) sediments and in the dung of winter free-grazing desert livestock and lichen-grazing black dwarf Bedouin goats. Phytoliths indicative of cereal crops are completely absent in the archaeological dung remains, indicating that cereal crops were not processed by the site inhabitants. Based on ethnographic and archaeological parallels, and on the presence of grinding stones and absence of sickle blades in the excavated rooms, we infer that the inhabitants at the oval compound at Atar Haroa subsisted on livestock herding and bought or exchanged cereal grains. Our results support the hypothesis that the inhabitants at the oval compound at Atar Haroa were desert-adapted pastoralists, rather than garrisoned soldiers.     

Sweet potato (Ipomoea batatas) and banana (Musa sp.) microfossils in deposits from the Kona Field System,Island of Hawaii

Analysis of plant microfossils (pollen, phytoliths, starch grains and xylem cells) was carried out on 12 soil samples from a variety of pre-contact archaeological features in South Kona within a portion of what has been termed the Kona Field System, on the Island of Hawaii. The oldest radiocarbon ages of the sampled deposits are 1300–1625 AD and 1310–1470 AD. The pollen and phytolith evidence suggests a change from more to less trees and shrubs in the area as a result of human activity. We found phytoliths of banana (Musa sp.) leaves in most and starch grains and xylem cells of tuberous roots of c.f. sweet potato (Ipomoea batatas) in all of the samples, suggesting that the sampled features were associated with these crops and that both crops were cultivated intensively within the study area. Higher concentrations (volumetric) of starch and xylem in samples from older deposits suggest that cultivation was more intensive then. The apparent absence of starch and xylem remains of other tuberous crops archaeologically identified elsewhere in Polynesia suggests that tuberous cropping within the study area was mono-specific.     

TAPHONOMIC OBSERVATIONS OF ARCHAEOLOGICAL WHEAT PHYTOLITHS FROM NEOLITHIC ÇATALHÖYÜK,TURKEY, AND THE USE OF CONJOINED PHYTOLITH SIZE AS AN INDICATOR OF WATER AVAILABILITY*

An investigation of wheat husk phytoliths from a midden deposit at Neolithic Çatalhöyük provided the opportunity to investigate the impact of taphonomic processes on conjoined phytolith size. Wheat husk phytoliths from a possible crop processing deposit were examined using three methods. The results indicate that the size of conjoined forms decreases significantly as a result of laboratory extraction and slide preparation. Observations of the phytolith layer in thin section show some of the depositional and post‐depositional processes affecting phytolith size. These results indicate that these taphonomic factors need further investigation before conjoined phytolith size can be used to infer past water availability and agricultural practices.     

A statistical approach to the archaeological identification of crop processing

Since the processing of crops has a direct effect on the composition of archaeobotanical samples, variation due to crop processing must be filtered out before using samples for the study of crop economy and husbandry. As the archaeological context of plant material does not often provide a reliable basis for the identification of crop processing products and byproducts, this paper presents a method based on the statistical comparison of archaeological samples with ethnographically collected material and on an internal statistical analysis of the archaeological samples themselves. These analyses make use of differences in the categories of weed seeds extracted at each stage of the crop processing sequence and are thus more reliable and more widely applicable than simple calculations of the relative quantities of grain, chaff and weed. Ethnographic and archaeological material from Greece is used to illustrate the method and some of the wider implications of the results are discussed.     

Optimum temporal and spectral window for monitoring crop marks over archaeological remains in the Mediterranean region

This paper aims to explore the formation of crops marks over archaeological features using remote sensing data. Crop marks are very important to archaeological research since they can reveal in an indirect way buried archaeological remains. Several researches have been able to locate subsurface relics via interpretation of multispectral and hyperspectral satellite images. However the best phenophase (time-window) where these crop marks are enhanced and which spectral bands are the most capable for this enhancement are still an open question for the scientific community. This study aims to address these fundamental aspects of Remote Sensing Archaeology. For this reason an extensive dataset was used: two control archaeological sites were constructed in two different areas of Cyprus (Alampra and Acheleia). In these areas both barley and wheat, were cultivated. In situ spectroradiometric measurements were taken over a whole phenological cycle (2001–2012) for both areas. More than 30 in situ campaigns were performed and more than 2600 ground measurements were collected. The phenological analysis of these measurements have shown that a period of only 15 days is best suitable for monitoring crop marks which is connected with one phenological stage; during the beginning of the boot stage of the crops. This period can be used in areas having similar climatic condition as Cyprus (Mediterranean region). Also as it was found, this phenological stage of crops might be also influenced by the climatic conditions of the area. The evaluation of a proposed Archaeological Index was performed at the Thessalian plain (central Greece), where several Neolithic settlements are established. The evaluation was made using both Hyperion and Landsat images. The results have shown that the proposed Archaeological Index is suitable for the enhancement of crop marks in satellite imagery.     

汉晋时期河西走廊张掖地区的开发研究——以黑水国汉代墓葬为例

黑水国汉代墓葬出土的农具、动物骨骼、农作物遗存和人骨为人们了解河西走廊张掖地区汉晋时期生业经济和农业发展等问题提供了重要证据。通过动物骨骼、农作物遗存鉴定结果和人骨碳氮同位素检测结果,可以揭示汉晋时期黑水国人群的食物结构和生业模式特点。墓葬出土的农作物有粟、黍、稻,随葬动物有鸡、猪、绵羊、黄牛、狗、马,人骨骨胶原碳稳定同位素主要呈现C₃和C₄混合信号,部分呈现C₃信号和C₄信号,氮稳定同位素值相较牛羊等家养食草动物较高。综合研究说明汉晋时期河西走廊形成麦类、粟黍和豆类的混合农业模式,所以黑水国汉代先民摄取的粮食作物来源呈多样化。同时,河西走廊畜牧业发达,使当时人群摄取了大量的肉食资源,导致蛋白质摄入量较高。     

Phytolith taphonomy: a comparison of dry ashing and acid extraction on the breakdown of conjoined phytoliths formed in Triticum durum

Durum wheat plants grown under optimum irrigation conditions in Jordan were processed in three different ways: 1) using a dry ashing method, 2) using acid extraction and 3) using both these methods, first dry ashing and then acid extraction. The aim was to determine if the laboratory processing method employed has an impact on the number of conjoined phytoliths recovered. This is important because it has been proposed that the number of conjoined phytoliths, or multi cells, can be an indication of water availability in arid and semi-arid regions (Rosen and Weiner 1994). The results showed that the processing method does have an impact on the resulting assemblage, with dry ashing producing a greater number of multi-cells than acid extraction. It is proposed that either the more violent oxidation of organic matter during acid extraction causes the breakup of conjoined phytoliths, or that the silica dehydrates during dry ashing resulting in a slight fusion between the individual phytoliths and hence more conjoined forms.     

Stability of phytoliths in the archaeological record: a dissolution study of modern and fossil phytoliths

Opaline phytoliths are important microfossils used in archaeological and ecological research. Relatively little is known about the stability of phytoliths after burial. Under alkaline pH conditions they can dissolve, and mechanical disturbances can cause a loss of their more delicate appendages. Here we present an experimental study of phytolith stability (combination of solubility and abrasion). Modern and fossil phytoliths were extracted from wheat using new methods to minimize dissolution, and by burning in an oven. These assemblages were placed in a solution buffered to pH 10 and maintained under constant temperature and shaking conditions. The silicon concentrations in the solution were monitored once a week for 5 weeks. The phytolith morphologies in each assemblage were determined at the outset of the experiment and after 5 weeks. The results show that there are differences in stability between various assemblages. Modern inflorescence wheat phytolith assemblages are more unstable than those from leaves/stems. Burnt assemblages are less stable than unburnt assemblages, and a fossil phytolith assemblage about 3000 years old is more stable than the modern wheat assemblages. The results also show that individual phytolith morphotypes have different stabilities, and as a result of dissolution and abrasion, some morphotypes may resemble others. This study further shows that archaeological and/or paleo-environmental interpretation of phytolith assemblages may change with the assemblage’s state of preservation.     

Criminalized crops: Environmentally-justified illicit crop interventions and the cyclical marginalization of smallholders

Despite decades of efforts to curb the global supply of illicit drugs and significant shifts in how those efforts are designed and implemented, illicit crop cultivation persists. In this paper, we examine state and international development efforts to eradicate coca in Peru, opium poppies in Laos, and cannabis in California, USA and the ever-changing discourses used to justify and design these interventions. Scholarship in political geography frames eradication interventions as serving ongoing efforts to extend state and market power into the regions in which illicit crops are grown and to marginalize the people growing them. We find that environmental discourses are increasingly used to assert the need for continued illicit crop interventions, and that these discourses articulate with historical and ongoing portrayals of smallholders as environmentally destructive. Environmental harm narratives that justify enforcement and eradication efforts under the guise of protecting ecosystems from illicit crop farmers can become self-fulfilling prophecies when they disproportionately impact smallholders and push them into marginal geographic and economic positions. Our cases illustrate that environmentally-justified interventions drive cycles of marginalization for illicit crop smallholders, often conditioned by race or ethnicity, who are then portrayed as environmental criminals. Meanwhile, new state-sanctioned spaces of opportunity and profit are created for more powerful actors who are able to capitalize on the removal of illicit crop growers from the land.     

Ethno-geochemical and Phytolith Studies of Activity Related Patterns: A Case Study from Al Ma’tan,Jordan

ABSTRACT

Understanding Neolithic sites in southwest Asia is often difficult because of the lack of preservation of organic remains and the effects of various taphonomic processes that alter the original record. Here, we use an ethnographic approach to test the potential of using plant phytoliths and geochemistry to aid our interpretation of southwest Asian Neolithic sites. Our study of a recently abandoned stone and mud constructed village in Jordan, shows that for certain activity types, phytoliths and geochemistry can help distinguish different construction methods and functions, particularly for burnt areas, animal use areas and where there has been the addition of a specific construction material. For features constructed from the same source materials distinctions are more problematic. Geochemical and phytolith proxies were individually effective in distinguishing activity areas and construction materials, but signals were diminished when the statistical analysis was run on both forms of evidence combined. It is therefore recommended that the data from plant phytolith and geochemical analyses are subject to separate statistical tests and that the two sets of results are used in combination to interpret archaeological sites and their uses.     

Reconstructing subsistence at the Yingpanshan and Gaoshan sites in Sichuan province,China: Insights from isotope analysis on bone samples and charred crop remains

During the Neolithic period, the Chengdu Plain was a key region where two important crops, rice and millet, were cultivated together. Millet was probably introduced from north-western China c.3500–3300 cal. bce , and rice came from the Middle Yangtze River c.2600 cal. bce . In this study, human and faunal remains, as well as charred crop grains, were collected from the Yingpanshan (3300–2600 cal. bce ) and Gaoshan (2500–2000 cal. bce ) sites where the dominant crop was millet and rice, respectively. Carbon and nitrogen isotope analyses were conducted on human bones and the ecofact samples in order to reconstruct the subsistence at the sites. The results indicate that the diets of two individuals recovered from the Yingpanshan site consisted of both C₃- and C₄-based foods, predominantly the former. By contrast, Yingpanshan pigs consumed a large quantity of C₄ fodder. This result, combined with the ecofact evidence, suggests that millet was the main crop at the Yingpanshan site. It also highlights the fact that the two Yingpanshan individuals might be non-locals and/or belonged to later periods. On the other hand, the diet of the Gaoshan community was dominated by C₃-based foods. When considering the archaeobotanical evidence at Baodun, a site contemporaneous with and near to the Gaoshan site, it can be stated that rice was an important food resource for the Gaoshan community. This study also suggests how crops were managed at the two sites. The Yingpanshan people might have used manure for growing millet. Both manuring and irrigation might have also been practised by Gaoshan's rice farmers. However, more studies are required to understand the extent of manuring and irrigation in their agricultural economies.     

Food production in the Early Woodland: macrobotanical remains as evidence for farming along the riverbank in eastern Tennessee

ABSTRACT

Open riverbanks and disturbed floodplains are targeted by archaeologists as optimal habitats for the growth of many of the weedy indigenous seed crops in eastern North America, but there is still little evidence for garden locations in the archaeological record. This article combines macrobotanical and geoarchaeological analyses from the Birdwell site (40GN228), located on the Nolichucky River, to give insight into where cultigens were planted and how they were managed in eastern Tennessee during the Early Woodland period. The recovery of uncharacteristic amounts of edible seeds and wood charcoal from the lower terrace of this site suggests that inhabitants were actively managing cultigens along the floodplain of this settlement. The presence of these remains in a non-midden context is evidence that precontact farmers in the Tennessee foothills took advantage of the newly created floodplains of the Early Woodland by implementing a burning regime, an early agricultural strategy aimed at increasing soil productivity and encouraging the growth of weedy annuals on the riverbank. In absence of lines of evidence such as preserved paleosols that can be examined for soil micromorphology, pollen, and phytoliths, integrated paleoethnobotanical and geomorphological analyses can be used to reconstruct land use and archaeologically identify prehistoric cultivated fields.     

Bread and surpluses: the Anglo-Saxon ‘bread wheat thesis’ reconsidered

This paper presents a fundamental new assessment of crop husbandry in the Mid Saxon period in England (c. AD 650–850), using data from charred plant remains. While recent archaeological studies have begun to emphasise the importance of agricultural development in this period – focusing especially upon field systems and livestock – crops have received comparatively little attention. This study challenges one popular model of Anglo-Saxon arable farming, here dubbed the ‘bread wheat thesis’, which posits a Mid Saxon shift whereby bread wheat supplanted hulled barley as the most important cereal crop in this period. The empirical basis for this model is here re-examined in the light of an updated archaeobotanical dataset from selected regions in southern Britain. No evidence for bread wheat supplanting hulled barley is discovered. It is argued instead that rye and oats became substantially more important in the 7th–9th centuries, regional patterns in cereal cultivation in this period correlate with differences in the natural environment and Anglo-Saxon farmers were able to produce greater arable surpluses from the 7th century onwards.     

Geoarchaeology in an urban context: The uses of space in a Phoenician monumental building at Tel Dor (Israel)

Interpretation of past urban societies in the Near East, whose settlements are known mostly as tell sites, is largely based on macro-stratigraphy and on the association of architecture with macroscopic artifacts. Analyses of sediments, common in prehistoric sites, are rare in tell sites. Here we show the results of a detailed geoarchaeological study of the micro-stratigraphy of a sedimentary sequence associated with early Iron Age Phoenician monumental architecture. The study involves mineralogical, micromorphological and phytolith analyses and provides new insights into the stratigraphic sequence and the use of architectural spaces. The sedimentary sequence examined comprises alternating layers of gray ‘fill’ deposits and white ‘floors’. We show that ‘floors’ made from local calcareous sandstone in the lower part of the sedimentary sequence were heated and are thus in effect ‘plaster floors’. A concentration of micro-laminated, trampled fish remains above the most elaborate of these plaster ‘floors’ indicates activities related to fish processing. Fine white layers in the upper part of the sedimentary sequence that were considered as plaster based on macroscopic examination are in fact composed almost entirely of opaline grass phytoliths. The phytoliths appear in an undulating micro-laminated structure and are associated with dung spherulites and phosphate nodules, thus probably reflecting livestock penning. The formation of ‘phytolith floors’ involves extensive volume reduction due to the degradation of the organic material and this may result in ‘floor’ subsidence, a phenomenon that is often observed in archaeological sites. Most ‘fill’ deposits include macroscopic and microscopic remains of wood ash, bones, phytoliths, charcoal, ceramics, plaster and mollusk shells, reflecting the debris produced from household activities. This study shows how a combination of macro-stratigraphy with microscopic and mineralogical analyses of the sediments within architectural spaces can provide information on the varying ways in which the space was used through time, and also contributes to solving macro-stratigraphic problems.     

Extended depth of focus image for phytolith analysis

This paper proposes a new phytolith analysis method by extended depth of focus technology. The extended depth of focus image is sharp throughout by the image processing of a series of photos, while each acquisition of the original photo will be compromised and show certain parts of the specimen in and out of focus. Consequently, the extended depth of focus image is suitable for computer-assisted morphometrics analysis. Meanwhile, the extended depth of focus image can be used for three-dimensional reconstruction images. Experiments on rice husk multi-cell panel show that the three-dimensional reconstruction image method can reconstruct multiple double-peaked phytoliths at one time. We also measure the parameters of multiple double-peaked phytoliths from the reconstructed three-dimension image. Comparative experiments show that the reconstructed three-dimensional image is precise enough for rice identification. Based on the above experiments, we recommend the extended depth of focus method as a promising tool in phytolith research.     

An Ethnoarchaeological Study on Anthropic Markers from a Shell-midden in Tierra del Fuego (Southern Argentina): Lanashuaia II

ABSTRACT

For many years the identification of activity areas has been carried out through the spatial distribution of lithics, zooarchaeological remains and specific features such as fireplaces. However, these data are rarely combined and integrated with results from specific analytical techniques such as phytoliths, organic matter, carbonates and multielemental analysis. This research presents the first results of an intrasite spatial analysis on a layer from the site Lanashuaia II, a shell-midden located on the Beagle Channel coast (Tierra del Fuego, Argentina). Ethnoarchaeology is used as a methodological tool to give content to the concept of anthropic markers by means of formulating archaeological hypothesis on the basis of ethnological information. This paper presents the application of specific anthropic markers, which have been designed and applied to identify ashy remains and waste areas through different combinations of proxies. The results show how an approach that integrates different techniques enhances data interpretation and allows to give visibility to activities that may not leave visible evidences.     

A Comparative Analysis of Wet and Dry Ashing Techniques for the Extraction of Phytoliths from Plant Material

Two methods are commonly used for the extraction of phytoliths from plant material to be used as reference in the analysis of archaeological phytolith samples: (1) spodograms or dry ashings; and (2) acid digestions or wet ashing. It has been suggested that these techniques may modify the resultant samples in different ways. Dry ashing, in particular, has been implicated as a cause of shrinkage and warping in phytolith assemblages when incineration occurs at ≥450°C. The results of a morphometric comparative analysis between the dry ashing and wet ashing methods do not support these claims. This study establishes that differences in patterns of dimension and curvature of short bilobate phytoliths and of elongate phytoliths both subjected to dry and wet ash preparation are not statistically significant. There is, therefore, no detectable evidence of morphological impact as a result of these methods. This finding implies that any differences that do occur in phytolith size and curvature are typical, possibly random permutation within assemblages, or that they are the result of variation in leaf cell structure rather than the consequence of a particular extraction procedure. This suggests that the practice of using different methods of preparation of reference samples for fossil analysis can be reliably continued.     

Agricultural change in Copper Age Croatia (ca. 4500–2500 cal B.C)?

The Copper Age in the Carpathian Basin is marked by a distinct change in settlement patterns, material culture, social traditions and subsistence practices; however, few studies address the nature of crop cultivation in the region. This paper examines new archaeobotanical data from 13 Copper Age (ca. 4500–2500 cal BC) sites located in continental Croatia, in order to assess the extent to which crop agriculture may have changed and contributed to overall subsistence economies in the Copper Age. From the archaeobotanical results, a dominance in einkorn and emmer is seen followed by barley. Less frequently millet, naked wheat and spelt/new glume wheat are also recovered, but due to their limited numbers, it is less clear whether they were grown as crops or represent weeds. Pulses (e.g. lentil, pea and grass pea), fruit remains (e.g. cornelian cherry and chinese lantern) and wild plant and weed species are also recovered, although more commonly from the late Copper Age sites. The archaeobotanical results show a clear reduction in the quantity and range of plant species recovered during the early/middle Copper Age; however, this is likely the result of taphonomic bias rather than a reduction in crop cultivation. The results therefore highlight problems of recovery bias in the region, which makes comparisons between sites as well as the reconstruction of crop husbandry regimes difficult. Overall, the results from continental Croatia suggest that the type of crops cultivated continued relatively unchanged from the late Neolithic, although it is clear that more research is desperately needed to explore the relationship between crop agriculture and the changing socio-economic environment of the Copper Age in the region.