Search

The southeast coast of China is a crucial area for the spread of agriculture from mainland Asia to Taiwan and the islands of Southeast Asia. However, whether prehistoric rice cultivation in this region was lowland or upland remains unclear. This study used a detailed phytolith analysis to evaluate temporal changes in structure at three coastal sites of varying altitudes in the Fujian Province of China, Longgang, Zhengjiashan, and Gehongshan. Samples were collected from two cultural phases, the Neolithic Huangguashan and Bronze Age Huangtulun cultures. Additionally, a new physical index, the sensitive-to-fixed phytolith ratio, was used to identify the environmental conditions in which crops were cultivated. Using this method, the number of sensitive types can be less or greater than that of fixed types, corresponding to drought or paddy field rice cultivation systems, respectively. The results showed an interplay of rice and millet farming at these sites. The crop phytolith ratio revealed that rice was dominant in the crop structure. However, notable differences existed in the proportion of different crops and phytolith assemblages across the various sites. The sensitive-to-fixed phytolith ratios, indicative of wet-dry environmental changes, were 1.56 and 1.07 at the low-altitude Longgang and water-rich Zhengjiashan sites, respectively, suggesting lowland rice cultivation. In contrast, the sensitive-to-fixed ratio at the high-altitude Gehongshan site was only 0.8, implying upland rice cultivation. The phytolith assemblage variation among the different sites also revealed an increase in dryland crops from low to high altitudes, indicating that the inhabitants of the southeastern coastal mountainous area modified their crop structure and rice cultivation methods during the Neolithic–Bronze Age transition to overcome environmental limitations. In summary, this study presents phytolith evidence for prehistoric upland rice cultivation on the southeast coast of China, offering valuable insights into the development of the prehistoric subsistence economy in the region. [ABSTRACT FROM AUTHOR]

Background and aims: Phytolith analysis is a promising tool for paleovegetation reconstruction. However, compared with grass phytoliths, there are few studies that have classified the phytoliths of trees. Therefore, reliable definitions of phytolith types in woody plants and studies of representative woody phytoliths in soils are needed to provide an improved basis for reliable phytolith-based vegetation reconstruction. Methods: To explore the morphology of woody phytoliths and their preservation in soils, we described the phytolith morphology of 60 common broadleaved woody plants in the mid-subtropical zone of China, based initially on anatomical origin, and then on shape and finally on texture. We also for the first time established an index (R value) to explore the preservation of broadleaved woody phytoliths in soil in this region. Results: We divided the phytoliths of broadleaved woody plants into 6 major types and 35 sub-types. The 6 major types are: Epidermal Cell, Silicified stomata, Tracheary, Favose, Haircell, and Others. We found some degree of correspondence between different phytolith types and the parent plants. Fagaceae, Lauraceae, Magnoliaceae, Rosaceae, Anacardiaceae and Euphorbiaceae could be clearly distinguished from other families based on phytoliths. Only eight types of broadleaved woody phytoliths were present in the soils. Elongate attenuate, Elongate entire, and Polyhedral were better preserved in soils than the other types (Elongate entire attenuate, Tabular sinuate, Hair, Sclereid, and Favose). Conclusion: Our results provide a more accurate reference for broadleaved wood phytoliths in interpreting paleovegetation in this region. [ABSTRACT FROM AUTHOR]

The middle and lower Huai River Valley, located between the Yangtze and Yellow Rivers, was a key transitional zone for the northward spread of rice and southward migration of millet agriculture in central-eastern China during the Holocene. Knowing when millets spread here, how they were combined with rice in mixed farming, the reasons for their spread, and the temporal variation of cropping patterns is of crucial significance to the development of our understanding of ancient adaptation strategies adopted by human societies in response to climatic and cultural changes. Focusing on crops, phytolith analyses of the soil samples, in tandem with radiocarbon dating from the Wanbei site, reveal evidence of a multicropping pattern of combining rice (Oryza sative), broomcorn millet (Panicum miliaceum), and foxtail millet (Setaria italica) during the Dawenkou culture period between 5720 and 4426 cal. BP in the middle and lower Huai River Valley, China. The data show that rice was always the principal crop of the pattern, and that domesticated rice was developed during the early and middle Dawenkou culture periods. However, its domestication rate became lower during the late Dawenkou culture period. Broomcorn millet and foxtail millet with domesticated traits appeared only in lower proportions of the total produced throughout the period. The proportions of rice and foxtail millet increased slightly, while the proportions of broomcorn millet decreased over time. Finally, the formation of the multicropping pattern at Wanbei may have been primarily influenced by both the warm and wet climatic environment and the cultural exchange and communication between the Haidai region and the middle and lower Huai River Valley during the Dawenkou culture period. The findings in this paper may not only contribute to mapping the spatiotemporal route for the northward expansion of rice agriculture and southward spread of millet agriculture, but also assist in understanding the human adaptation strategies employed in eastern China during the Holocene. [ABSTRACT FROM AUTHOR]

China is one of the main locations in which rice agriculture occurs, with East China now playing a significant role in research on rice domestication and culture interactions. However, the exact timing of sustained rice domestication and the process of prehistoric cultural exchange in East China remain unclear. Here, we present phytolith records of two profiles from Lingjiatan in the Chaohu Lake Basin. Our results show that rice cultivation was practiced throughout the Lingjiatan culture period (5800-5300 cal BP), and that sustained rice domestication began around 5500 cal BP, which was later than on the Taihu Plain (∼6200 cal BP), Ningshao Plain (∼5800 cal BP), and along the middle and lower Huai River (∼5800 cal BP). Combining other archaeological records and geomorphological features in East China, we hypothesize three possible routes for the spread of rice cultivation and cultural exchange between the lower Yangtze River and the middle and lower Huai River. Lingjiatan, situated at the intersection of two of the possible routes, experienced a gradual increase in its settled population as a result of cultural exchange and technological innovations in cultivation, thereby giving rise to its distinctive culture. This study demonstrates the significant role of Lingjiatan in facilitating transportation and fostering cultural exchange in East China during the mid-Holocene. • First study to reconstruct the process of rice cultivation at Lingjiatan (5800-5300 cal BP). • Evidence to elucidate the timing of sustained rice domestication in East China. • Three possible routes of cultural exchange in East China are proposed. [ABSTRACT FROM AUTHOR]

The paddy field ecosystem and diversified plant food resources in the middle and late Liangzhu Culture were revealed at the Zhumucun site. Based on pollen and phytolith records, this paper presents local vegetation landscape of the site: (1) evergreen-deciduous broad-leaved forests dominated by Quercus , Castanopsis , and Ulmus distributed on the nearby hills, (2) terrestrial herbs represented by Poaceae plants tend to expand on the plain, (3) aquatic plants such as Typha , Trapa , Myriophyllum and Euryale ferox grew in rivers and lakes, and (4) plants such as Phragmites australis , Echinochloa , Polygonum lapathifolium , Haloragidaceae, Rumex , Cyperus , Cyperaceae, and Polygonaceae were distributed in and around the wetland. Water activities tended to be intense, and the climate was generally warm and humid with short-term anomalously cold or wet fluctuations. This is in line with the characteristics of environmental changes revealed by regional natural accumulations. In this conditions, local rice ecosystem was recorded with diachronic changes. [ABSTRACT FROM AUTHOR]

Located on the southeast coast of China, Fujian is an important junction for the spread and migration of agriculture and populations from mainland Asia to Taiwan and the Island Southeast Asia. Research on the emergence of agriculture and its relationship with the regional environmental context is key to understanding the evolution of ancient human-land interactions in the coastal zone of China. This paper presents a detailed microfossil analysis of the Dapingding site, which is located in the lower reaches of the Min River on the southeast coast of China. We found a large number of phytoliths produced in rice stems and leaves from the cultural layers of this site, dated to 7,500 cal. a BP. In addition, we found rice husk impressions and rice phytoliths in the pottery sherds of these cultural layers. Among these phytoliths, rice bulliform phytoliths with ≥9 fish-scale patterns indicating the degree of rice domestication, accounted for 44%. This percentage is much higher than the established standard for wild rice bulliform phytoliths with fish-scale patterns, suggesting that rice cultivation had already occurred on the southeast coast of China approximately 7,500 years ago. Subsequently, the starting time of agricultural activity on the southeast coast of China was pushed from 5,000 to 7,500 years ago. Comparing the regional history of sea level and coastline changes in the early to mid-Holocene, we suggest that the emergence of early rice cultivation in Southeast China was associated with high sea levels in the mid-Holocene and the last transgression in the Fuzhou Basin. The 'Fuzhou Bay', formed by the retreating coastline and transgression driven by high sea levels, may have provided a sea channel for the southward movement of northern rice farmers. [ABSTRACT FROM AUTHOR]

It has been unclear whether Holocene lake evolution in the Badain Jaran Desert of northwestern China, an area in which lakes are mainly recharged by groundwater, responded to climate change. In this study, we analyzed the Mg/Ca ratio and phytolith assemblages from 10 Holocene calcareous root tube samples from the desert to reconstruct changes in effective moisture and mean annual precipitation (MAP) at the millennial scale during the Holocene and to explore the factors affecting lake evolution. Our results revealed that the effective moisture at 7000-5000 cal yr BP was higher than that of 5000-2000 cal yr BP. Similarly, the MAP was higher at 7000-5000 cal yr BP (175 ± 37 to 205 ± 37 mm) than at 5000-2000 cal yr BP (145 ± 37 to 165 ± 39 mm). The expansion of the lakes during the Early Holocene would have resulted from the input of groundwater from the meltwater in the recharge area. High lake levels in the Middle Holocene corresponded to increased monsoonal precipitation and groundwater recharge. The gradual decline of lake levels in the Late Holocene indicated a relatively arid climate with decreased monsoonal precipitation and groundwater recharge. [ABSTRACT FROM AUTHOR]

Aboveground vegetation can significantly affect soil PhytOC (phytolith occluded organic carbon) accumulation. To clarify the response of soil PhytOC accumulation to long‐term vegetation restoration in Southwest China karst, the four typical vegetation restoration engineering types of tree, shrub, vine forest, and grassland construction including seven species planting measures carried out 28–31 years ago were selected as study objects. And studies on their effects on soil PhytOC content and storage were conducted. Results showed that long‐term vegetation restorations obviously increased soil PhytOC accumulation and changed the proportion of soil PhytOC to total soil organic carbon. Among the different engineering types or species planting measures of vegetation restoration, there were significant or extremely significant differences in effects on soil PhytOC accumulation. Among the four types of restoration engineering, the tree forest construction had the best increase effect on soil PhytOC accumulation. And among the seven kinds of planting measures, the increased effect on soil PhytOC accumulation of Tectona grandis ('teak' an angiosperm tree species) planting was the highest. Vegetation biomass and litters were the key influencing factors on soil PhytOC accumulation. Soil C:P and N:P had significant effects on soil PhytOC accumulation by changing aboveground vegetation biomass and litters. Human activities could significantly change soil PhytOC content and storage, and reducing human activities of tilling and harvesting would be beneficial to soil PhytOC accumulation. The present results not only provided scientific bases for the vegetation rehabilitation of increasing soil PhytOC accumulation in outhwest China karst but also were great of significance in promoting stable soil C sequestration of the global terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Grassland is an important component of terrestrial ecosystems and plays a crucial role in the global carbon cycle. PhytOC (phytolith-occluded organic carbon) is an extremely important long-term and stable carbon pool in terrestrial ecosystems. Southwest China karst soil exhibits obvious characteristics of alkalinity, high silicon content, and rich calcium, which can significantly influence the characteristics and mechanisms of PhytOC sequestration in vegetation. To elucidate the sequestration characteristics and mechanisms of PhytOC in the karst grasslands, three typical karst grasslands of tropical shrub tussock (TST), warm-temperate shrub tussock (WST), and mountain meadow (MM) from Guizhou province of southwest China were studied. The following results and conclusions were obtained that: 1) the range of PhytOC content of aboveground plant parts, underground roots, and soil in the karst grasslands was 4.03-16.54 g·kg -1 , 10.67-33.92 g·kg -1 , and 0.63-1.89 g·kg -1 , respectively. The underground roots are an important site for phytolith carbon sequestration in grassland ecosystems, and the PhytOC content of underground roots may be higher than that of the aboveground parts. 2) The PhytOC sequestration rate of vegetation was 7.34-15.93 kg·ha -1 ·yr -1 , and the annual sequestration amount of PhytOC of the whole grasslands in southwest China could reach 0.48 × 10 3 -1.48 × 10 3  t CO 2 . Compared to grasslands in non-karst regions of China, karst grasslands in southwest China have a higher sequestration rate of PhytOC in vegetation and a greater capacity for phytolith carbon sequestration. 3) Soil available silicon, pH, and stoichiometric characteristics of C, N and P nutrients significantly affected the phytolith carbon sequestration of vegetation and the soil accumulation of PhytOC in the karst grasslands. The research results are of great significance for estimating the phytolith carbon sequestration capacity of grassland ecosystems and for grassland construction and management based on enhancing carbon sequestration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Located in the transitional region between northern and southern China, the middle Han River valley is of pivotal significance for current debates on rice domestication and the formation of mixed farming in early China. Based on phytoliths and macro-plant remains from 10 sites, along with radiocarbon dating, this study has narrowed the 2000-year gap in early rice utilization by 700 years in the middle Han River valley, and demonstrated the continuous development of rice agriculture in this region. This new evidence also reveals that as early as 7000 cal. BP, mixed farming emerged in this region and facilitated the further southward dispersal of foxtail millet and broomcorn millet into southern China and beyond. In addition, a sample-by-sample comparison of our results with phytoliths and macro-plant remains highlighted the potential biases inherent in these methods. This work emphasized the importance of multi-index archaeobotanical analysis to reconstruct ancient crop assemblages. [ABSTRACT FROM AUTHOR]

Despite decades of investigation, consensus has yet to be reached on when and where wheat replaced millet as the primary crop in the core regions of early Imperial China. Previous studies have suggested that wheat cultivation likely became widespread prior to or during the Han Dynasty (202 BC–AD 220). Here, we tested this hypothesis by applying archeobotanical tools to plant remains found in five pottery model granaries (cang) entombed in a newly excavated late Western Han burial at the Longzaocun cemetery in the Guanzhong Basin. This analysis allowed us to explore the extent of wheat expansion and agricultural strategies in the heartland of early dynastic China. Macro- and micro-botanical evidence shows that the Longzaocun residents consumed two kinds of crops: foxtail and common millet. Combining these findings with previous studies, we argue that millet-based multi-crop farming dominated the regional agricultural system during the Western Han Dynasty (202 BC-AD 8) and analyze the political and cultural motivations for the Han people's usage on millet crops from the burial concepts and fiscal systems. Echoing previous studies, we argue that millets remained the most valuable subsistence food for inhabitants of the Loess Basins in the Han core, and that wheat was not cultivated on a large scale in this area during the Western Han Dynasty. [ABSTRACT FROM AUTHOR]

Neolithic rice remains were recovered from a mixed rice–millet farming area in China outside the original centers of rice farming. Whether the rice remains were the result of local cultivation or obtained through trade remains unclear. Rice paddy fields are direct evidence of local cultivation. In this study, phytolith samples from the Zhangwangzhuang site were analyzed. The discriminant function distinguished 17 of 30 samples in the suspected paddy field area as rice paddy fields with an average probability of 74%; The proportion of rice bulliform phytoliths with ≥9 scales indicated that rice (Oryza sativa) was still being domesticated and, moreover, six η-type phytoliths from broomcorn millet (Panicum miliaceum) were identified. These results suggested that the suspected paddy field at Zhangwangzhuang might be the earliest rice paddy field (ca. 6000 cal. BP) in northern China and that mixed farming was practiced here since the early Yangshao period. This study adopted discriminant analysis methods to discover ancient rice paddy fields, observed rice paddy fields outside the core rice origin area, and provided the earliest evidence regarding the development of mixed rice–millet farming in the upper Huai River region. [ABSTRACT FROM AUTHOR]

The origin and subsequent development of rice agriculture enabled humans to transition from hunter-gatherers to farmers, thereby profoundly changing human society. However, less attention is focused on when and how rice cultivation practices began to alter the landscape. In this study, sediment from the reservoir inside the Mifenglong dam, Liangzhu hydraulic system was sampled. Accelerator mass spectrometry (AMS) radiocarbon dating and optically stimulated luminescence (OSL) dating results revealed that the duration of the Mifenglong reservoir ranged from 4900 cal BP to 1500 cal BP. The results showed that between 2500 cal BP and 1500 cal BP, intensive rice farming practices transformed the surrounding vegetation and landscapes through deforestation and changes in herbaceous plant structure. This study provides an insight into the impact of human activities and how they influenced the environment on a local scale, as well as contributing to a deeper understanding of the relationships between agricultural development and landscape changes. [ABSTRACT FROM AUTHOR]

Increasing use is being made of phytoliths for quantitative palaeovegetation and palaeoclimatic reconstruction, and consequently studies of phytolith transport are attracting increasing attention. In this context, we conducted a detailed study of factors affecting the soil phytolith transport in six representative natural soil types in Northeast China. We define a phytolith transport index (T) which indicates that transport rates are the lowest in chernozem and chestnut soils, intermediate in dark brown and albic soils, and obviously higher in black and alluvial soils. Additionally, there are differences in the vertical transport of different phytolith types in the soils; however, the transport characteristics are essentially the same among the different soil types. Transport rates are lowest for tabular and blocky phytoliths, followed by bulliform phytolith. By contrast, the rates for short cell, lanceolate and elongate phytoliths are significantly higher, and, notably, these phytolith types have different size and aspect ratios. The transport of phytoliths is also mainly influenced by mean annual precipitation (MAP), soil pH and soil clay content. Climatic factors, especially MAP, are a more significant factor for phytolith transport than phytolith size and aspect ratio. Overall, our findings are significant for the palaeoenvironmental interpretation of soil phytolith assemblages in topsoils. [ABSTRACT FROM AUTHOR]

Rice is among the world's most important and ancient domesticated crops. However, the spatial and temporal pattern of the early rice domestication process remains unclear due to the lack of systematic study of wild/domesticated rice remains and corresponding dates during the early Holocene. Here, we collected 248 samples from five typical Shangshan cultural sites in the lower Yangtze region where is the most likely origin place of rice for phytolith analysis. The results showed the following. (1) Rice bulliform phytoliths from the five sites all present domestication traits, suggesting that the rice domestication process had begun across the region by the early stage of the Holocene. (2) The relative domestication rates reflected by the rice bulliform phytoliths were different between sites, the sites with higher domestication rates were distributed closer to the mainstream river. (3) The rice domestication process revealed by bulliform phytoliths can be divided into three periods during the early Holocene: from 10 to 9 ka, rice domestication began and stayed at a low level under 35%; from 9 to 8.5 ka, rice domestication level increased to 50%; and from 8.5 to 8 ka, rice domestication level was in a fluctuating state. (4) By 9 ka BP, rice double-peaked phytoliths from glume cells are present in most of the studied sites, which imply the presence of crop dehusking processing. This study reconstructed the spatial and temporal patterns of rice domestication during the early Holocene, which will improve our knowledge of early crop domestication and enhance our understanding of changes in rice status. [ABSTRACT FROM AUTHOR]

Purpose: Soil organic carbon (SOC), especially the stable SOC, have the important ecological function in the carbon cycle. As a typical stable SOC, soil phytolith-occluded organic carbon (PhytOC) is one of the important mechanisms of long-term soil carbon sink in terrestrial ecosystems. However, the distribution characteristics, accumulation law, and cycle process of soil PhytOC in fragile karst ecosystems are still not cognized. The purpose of the present study is to obtain the distribution pattern and change law of total SOC and soil PhytOC in different land cover types and to clarify the influencing factors and driving mechanism of land cover change on total SOC and soil PhytOC content and storage in the karst ecosystem. Materials and methods: In the typical karst area of Southwest China, five representative land cover types, including bamboo forest (BF), coniferous and broad-leaved mixed forest (CBF), shrub (SH), grassland (GL), and agricultural abandoned land (AAL), were selected as the research objects. The total SOC contents, soil PhytOC contents, and soil physical and chemical properties were determined in the lab. Soil PhytOC and total SOC storage were calculated by the formulas. Data were analyzed statistically by linear regression, Pearson correlation analysis, LSD multiple comparison, and principal component analysis. Results and discussion: Land cover change can affect obviously total SOC and soil PhytOC content and storage in the karst subtropical forest. Among the five land cover types, soil phytolith content, soil PhytOC content and storage, and total SOC storage of each soil profile in the BF were all significantly higher than those of the other four land covers. Among the three different soil profiles of 0~10, 10~20, and 20~30 cm, total SOC and soil PhytOC contents of the surface soil layer in the five land cover types were all the most, and the content decreased obviously with the increase of soil depth. There were significant positive correlation between the contents of soil available silicon, phytolith, and PhytOC. Soil available silicon content, soil phytolith content, and soil C/N were significantly positive related with the accumulation of total SOC and soil PhytOC. Soil PhytOC content or storage was significant or extremely significant related with total SOC content or storage. Conclusions: The results of the present study provided scientific bases for further evaluating the carbon sink capacity of soil PhytOC in the karst ecosystem, in SW China, and have important values in the reduction of carbon emission and increase of carbon sink to combat the global warming. In addition, the results of the present study also can provide theoretical references for the vegetation restoration of karst rocky desertification in Southwest China. [ABSTRACT FROM AUTHOR]

It is generally considered that the main carbon sequestration capacity of seagrass beds depends on the burial of organic matter in anaerobic sediments, and plants in aerobic conditions contribute little to carbon sequestration due to decomposition. However, the role of phytolith-occluded carbon (PhytOC) in eelgrass to protect against aerobic degradation shows a long term mechanisms of carbon stabilization that is poorly understood. Eelgrass is a silicon-rich plant, and plants with a high silicon content generally contain phytoliths that occlude carbon. Thus, it is speculated that eelgrass contains phytoliths and sequesters carbon through PhytOC. To confirm this inference, eelgrass in Swan Lake, Yangjia Bay and Shuangdao Bay, China, was investigated. The solids extracted from eelgrass did not discolor when they were exposed to iodine, and their morphology was similar to the phytoliths of land plants. Thus, these solids were phytoliths rather than starch grains. The phytolith morphology varied with eelgrass habitat and plant part, but it was mainly irregular. The sequestrated carbon stock of eelgrass plants through PhytOC in Shuangdao Bay in March, June and November were 87.30, 252.70 and 36.09 mg/m2, respectively. Thus, PhytOC is a potentially important and unrealized form of carbon sequestration in eelgrass beds. • Contrary to previous thinking, eelgrass contains phytoliths. • The main type of phytolith in eelgrass is irregular. • Carbon sequestration of eelgrass plants through PhytOC is important. [ABSTRACT FROM AUTHOR]

Ecological responses to past climate change as determined from palaeorecords offer insights into responses that may accompany future climate change. In arid and semi‐arid lands, the interactions between regional vegetation and climate change are not yet well understood, partly due to a lack of suitable palaeovegetation proxies that can provide accurate and continuous tracers for past vegetation dynamics. To gain a better understanding of long‐term vegetation dynamics, this study employs a multiproxy approach applied to sand‐palaeosol sediments of northeastern China's Songnen grasslands. Phytolith analyses and data on the stable carbon isotope composition (δ13C) of organic matter are used to reconstruct palaeovegetation composition, namely, the changing abundance of C3 and C4 species, whereas a geochemical weathering index (Fed/Fet ratios) tracks past East Asian summer monsoon (EASM) intensity. The phytolith assemblages and indices and δ13C of the soil indicate that C4 species' abundance has been increasing in the Songnen grasslands since the mid‐Holocene, although C3 vegetation is still dominant. Statistically significant negative correlations between the δ13C data and Fet/Fed ratios suggest that continuous weakening of the EASM since the mid‐Holocene may be responsible for the 13C‐enrichment of the sediments in the Songnen grasslands. Field vegetation surveys, modern topsoil phytoliths and δ13C calibration data indicate that the expansion of C4 species since the mid‐Holocene is mainly due to their ability to cope with aridity when growing season temperature is not undergoing a significant decrease. Future precipitation decreases in arid and semi‐arid lands should make C4 species more competitive in the grasslands of northeastern China. HighlightsA continuous grassland landscape history is reconstructed from a sand‐palaeosol sequence via phytolith analysis.Multiple independent approaches were used to reconstruct past EASM intensity and palaeovegetation patterns.Phytolith and δ13C analyses indicate an increase in C4 species since the mid‐Holocene.Aridification drives the increase in C4 species within the grassland ecosystem. [ABSTRACT FROM AUTHOR]

South China preserves a rich archaeological record elucidating the evolution of early modern humans during the Late Pleistocene. However, few studies on plant utilization were conducted in this region. We used phytolith analysis from Yahuai Cave, Guangxi, to infer human use of plant resources over the past 30000 years. AMS 14C dating was used to constrain the chronological framework. Results indicate that several economically essential species were present throughout the sequence including Urticineae (cf. Ulmus sp.), which appears in the lower layers of the sequence (Marine Isotope Stage 3 through Heinrich 1); bamboo and palm which appear throughout the sequence, and wild rice which appears in a clear archaeological context dating to 16000 years ago. This is the earliest record of wild rice in South China and a prerequisite for rice domestication. The unique stone tool assemblages, which resemble those in north China as opposed to South China, point to the possibility that humans, seeking refuge from the colder north, brought their tool kit with them and utilized familiar northern taxa. Warmer South China would have served as a refuge for human populations escaping the cold, harsh climate in the north with more ameliorate conditions in the south. [ABSTRACT FROM AUTHOR]

Background and aims: Silicon (Si) deficiency is a major constraint on rice production. The objective of this study was to evaluate the long-term influence of phytolith-rich straw return and groundwater table management on labile Si fractions in paddy soil and subsequent plant Si uptake. Methods: A field experiment was conducted over 36 years in subtropical China with different application doses of phytolith-rich straw and a groundwater table of either 20 or 80 cm. An optimized sequential chemical extraction procedure allowed us to determine labile Si fractions, represented by CaCl2-Si, Acetic-Si, H2O2-Si, Oxalate-Si, and Na2CO3-Si. Additional analyses included the determination of amorphous silica particles in soil, phytoliths in supplied straw, Si in planted rice straw, and the dissolution rate of phytoliths extracted from supplied straw. Results: Long-term application of phytolith-rich straw significantly increased the H2O2-Si and Na2CO3-Si contents. The CaCl2-Si (5.21–7.91 mg kg− 1), H2O2-Si (50.0–72.4 mg kg− 1) and Na2CO3-Si (3.33–4.60 g kg− 1) contents were positively correlated with soil organic carbon. The Si content (13.6–28.9 g kg−‍1) in planted rice straw significantly (p < 0.05) increased with the application dose of phytolith-rich straw under both groundwater tables. This effect was significantly (p < 0.05) greater under 80 cm groundwater table than under 20 cm groundwater table for matching straw amendments. Conclusions: This study indicates that long-term application of phytolith-rich straw and groundwater management significantly increase soil Si bioavailability by promoting accumulation of organic matter and phytoliths, and enhancing the soil-plant Si cycle. [ABSTRACT FROM AUTHOR]

Phytoliths are a reliable paleovegetation proxy and have made an important contribution to paleoclimatic studies. However, little is known about the depositional processes affecting soil phytoliths, which limits their use for paleoclimate and paleovegetation reconstructions. Here, we present the results of a study of the vertical translocation characteristics of phytoliths in 40 natural soil profiles in Northeast China. The results show that phytolith concentration decreases within the humic horizon of the soil profiles and that ∼22% of the phytoliths are translocated below the surface of the studied soils. In addition, we find that the translocation rate of phytoliths varies markedly with phytolith type and that phytolith size and aspect ratio also have a significant effect. Phytoliths with length >30 μm and with aspect ratio >2 and those with length <20 μm and aspect ratio <2 are preferentially translocated compared to those with length >25 μm and aspect ratio <2. Our results demonstrate that differential translocation of phytoliths within soil profiles should be considered when using soil phytoliths for paleoclimate and paleovegetation reconstruction. [ABSTRACT FROM AUTHOR]

Phytolith radiocarbon dating can be traced back to the 1960s. However, its reliability has recently been called into question. Piperno summarized recent dating evidence, but most phytolith dating results from China were not included in the review because they are written in Chinese. Herein, we summarize and evaluate previous phytolith dating results from China. We also review recent debates on the nature and origin of phytolith-occluded carbon (abbreviated as PhytOC), as well as the older age of phytoliths retrieved from modern plants. We conclude that although PhytOC includes a small amount of old carbon absorbed from the soil, this carbon fraction has not always biased phytolith ages, indicating that in certain situations, phytoliths can be tried as an alternative dating tool in archaeological and paleoecological research when other datable materials are not available. [ABSTRACT FROM AUTHOR]

Terrestrial biogeochemical silicon (Si) and carbon (C) cycles couple through various processes, such as silicate weathering and the dynamics resulting from different phytolith assemblages. For example, small amounts of organic C (typically ranging from 0.2 to 5.8%) can be occluded during phytolith formation. Phytoliths play an important role in coupled Si and C cycles. In this study, we analyzed variations in C sequestration and the seasonal dynamics of phytoliths formed in different vegetation types in order to clarify the processes and characteristics of phytolith-occluded-carbon (PhytOC) cycles. Firstly, we measured the variation range of phytolith content in the litter and soil of different vegetation types at 11.87–151.90 and 1.81–14.72 g kg−1, respectively, while we measured the corresponding variation range of PhytOC content at 3.58–24.13 and 0.04–0.65 g kg−1, respectively. We also found that seasonal changes in phytolith and PhytOC content were significant (P < 0.01), both exhibiting a significant decreasing trend from litter to soil and from the surface soil to 0–60 cm of soil layers. Secondly, we measured the variation range of PhytOC storage in the litter and soil (0–60 cm) of different vegetation types at 1.26–6.89 and 28.24–75.2 t, respectively. Finally, our study determined the contribution of PhytOC storage in soil (0.42%) compared with conventionally recognized soil C sequestration storage (0.64%). The phytolith C pool is an important component of the forest ecosystem C pool, which plays a critical role in mitigating global warming. [ABSTRACT FROM AUTHOR]

We investigated climate niches of grasses at regional scales and quantitatively reconstruct Asian monsoon precipitation at the sand-loess transitional zone in northern China. Our results provide direct evidence that certain grass lineages have been specialized in specific habitats: Pooideae grasses stand out and occupy a much cooler environment than all other subfamilies; Pooideae, Aristidoideae, and Chloridoieae occupy dry environments. Pooideae grasses occupy the coldest and driest environments compared to all other subfamilies, with a mean annual temperature (MAT) and precipitation (MAP) of ~13.6 to ~15.3°C and 224 to ~1674 mm, respectively, at a regional scale. We built a database for grasses and their corresponding climate parameters. Based on this database, past climate parameters at the margin of the Asian summer monsoon since ~70 ka were quantitatively reconstructed by phytolith assemblages. They show that this area was dominated by cold- and dry-adapted grasses since ~70 ka with a MAT and MAP of ~3.3 to ~11.0 °C and ~442 to ~900 mm, respectively, generally consistent with the results of phytolith-based transfer function reconstructions and with the results of previous nearby pollen-based quantitative reconstructions. With the improvement of the species-climate and ecosystem dataset, our database-based method is a promising quantitative reconstruction approach to past climatic change in the monsoon region. [ABSTRACT FROM AUTHOR]

Despite decades of research and intervention programs, the epidemic of esophageal squamous cell carcinoma (ESCC) in the Taihang Mountain area of north China has not seen convincing explanation by any risk factor yet and the incidence has not seen a substantial decrease. Based on recently disclosed association of aridity and wheat consumption with esophageal cancer, we revisited the hypothesis of biogenic silica in esophageal cancer development. From the archives of the Pathology Department of Heping Hospital, Changzhi Medical College, we selected three pairs of formalin-fixed samples, tumor tissues and distant normal tissues, of three patients operated for ESCC who had no history of workplace exposure to silica dust. Two pairs of dried tissue samples were used for phytolith (silica body) analysis and another pair for microanalysis with Transmission Electron Microscope (TEM). One of the phytoliths in ESCC tumor tissue was similar to the prickle hair on the surface of wheat bract. In the mineral particles detected in the tumor tissue the predominant elements were Si, Ca, and P, whereas Si signals were not obvious in the distant normal tissue. The preliminary findings on the detection of phytoliths and the higher than normal Si concentration in ESCC tumor tissue warrants further testing the role of biogenic silica in esophageal cancer. • Silica fibers were detected in esophageal cancer tissues from north China. • Silica fibers in cancer tissues were similar to the siliceous hairs on wheat bracts. • Si levels were higher in esophageal tumor tissue than in distant normal tissues. • The role of biogenic silica fibers in esophageal cancer warrants further studies. [ABSTRACT FROM AUTHOR]

With the improvements in our knowledge of the phytolith morphology of different Poaceae subfamilies and even different species, phytolith records in paleosols provide valuable information on past vegetation in situ, especially for herbaceous plants. Nevertheless, the reliability of phytolith records for the reconstruction of forest vegetation needs to be further verified, and it needs to be assessed before they can be used in palaeoecological contexts. In this study we analyzed the topsoil phytolith assemblages of 39 sampling sites and established a modern soil phytolith reference dataset for five plant communities in the mid-subtropical zone of China. We then used the phytolith reference dataset to analyze a stratigraphic sequence of fossil phytolith assemblages from the same region. The results show that the topsoil phytolith assemblages and phytolith indices (Ic and Iph) vary substantially among different plant communities, and that there is a good correlation with the aboveground vegetation composition. This shows that modern soil phytoliths are reliable analogues for reconstructing the paleovegetation. The results of a paleovegetation reconstruction based on the modern phytolith reference dataset show that the SWGT region has experienced substantial vegetation changes during the Holocene—from evergreen and deciduous broadleaved mixed forest to evergreen broadleaved forest, and finally to evergreen broadleaved forest with occasional shrub and herbaceous communities. The phytolith-based Holocene vegetation types are consistent with those reconstructed by a pollen record from the same stratigraphic profile. Moreover, the phytolith reconstruction also records changes in the understory herbaceous plants and C 3 /C 4 grasses, which supplements the results of the pollen-based paleovegetation reconstruction. Overall, our results confirm the reliability of phytolith analysis for interpreting the entire vegetation landscape and forest composition in the mid-subtropical zone of China. They also provide a new perspective for the application of phytoliths to the study of forest dynamics in this region. • Topsoil phytolith assemblages and indices exhibit notable differences among the five vegetation types, and they agree well with the vegetation characteristics defined in the field. • Topsoil phytolith assemblages beneath different modern vegetation types can be used as analogues for paleovegetation reconstruction using a stratigraphic sequence of phytoliths. • SWGT section record a process of substantial vegetation changes during the Holocene—from evergreen and deciduous broadleaved mixed forest to evergreen broadleaved forest, and finally to evergreen broadleaved forest with occasional shrub and herbaceous communities. [ABSTRACT FROM AUTHOR]

Depth to water table (DWT, the depth from the water surface to the top of the peat surface) is one of the most important environmental variables related to the habitat types and distribution of vegetation within a subalpine peatland. The distribution of phytolith assemblages and basic environmental data from 43 surface soil samples with significant ecological and hydrological gradients were investigated to generate transfer functions for quantitative reconstruction of paleoenvironmental changes in Dajiuhu peatland, central China. Detrended correspondence analysis (DCA) and redundancy analysis (RDA) were employed to explore the relationship between main environmental variables and phytolith morphotypes and distributions. Our results indicate that the spatial distribution of phytoliths was significantly correlated with the DWT (25% variance), total organic carbon (TOC, 10% variance) and magnetic susceptibility (χ, 7% variance). We established the transfer functions for the significant variables based on modern analogue technique (MAT), weighted averaging techniques (WA) and weighted averaging partial least squares (WA-PLS), and model performance was assessed using bootstrap cross-validation. The high correspondence of the predicted DWT results based on phytolith-environment calibration data with observed data reflects that the phytolith-based WA-PLS is a reliable effective calibration method for the quantitative DWT reconstruction of ombrotrophic (rain-fed) subalpine peatland. [ABSTRACT FROM AUTHOR]

The assessment and calibration of representational bias in modern soil phytolith assemblages provide the basis for improving interpretation of fossil phytolith assemblages. We studied soil phytolith representation by comparing phytoliths from living plant communities with those from paired surface soils, representing 39 plant communities in Northeast China. Together with the use of representation indices, the 34 and 30 soil morphotypes observed in forest and grassland samples, respectively, were both classified into the following four groups: “Associated types” were similarly represented in soils and in the corresponding species inventory data; “Over-represented types” and “Under-represented types” were respectively over- and under-represented in soils compared to the inventory data; and, in the case of “Special types,” the relationship with the parent plants was unclear. In addition, the diagnostic types exhibited different degrees of representation, while the most common morphotypes were equally represented between grassland samples and forest samples. On this basis, a comparison between the original and corrected soil phytolith indices of the additional 29 soil samples was conducted. The soil phytoliths frequencies corrected by R-values differed between plots with differing plant compositions, and were moderately consistent with actual plant richness in the plot inventory data. We therefore confirmed that R-values are a promising means of correcting soil phytoliths for representational bias in temperate regions. The corrected soil phytoliths can be used to reliably reflect vegetation variability. Overall, our study provides an improved understanding of soil phytolith representation and offers a potential method for improving the accuracy of paleovegetation reconstruction. [ABSTRACT FROM AUTHOR]

The Songnen grasslands were traditionally thought to be dominated by Artemisia and Chenopodiaceae plants as early as the late Pleistocene. However, increasing evidence has called that interpretation into question. To shed new light on the paleovegetation evolution of the arid and semi-arid steppe in North China, phytolith assemblages preserved in the region's sand-paleosol sequence (section Daike) are used as a proxy for paleovegetation structure. Results show that both the sand and paleosol layers in the Songnen grassland sections contain well-preserved phytoliths attributed to different families of grass. This is the first direct evidence of the nature of the vegetation that existed during the sandy layer episodes. Moreover, the phytolith evidence represented in the samples indicates that plant successions happened within the subfamilies of Poaceae through the time. Referring to phytoliths in modern plants and topsoils, and using statistical analyses, we propose that phytolith assemblages in the section Daike originated from Poaceae-dominant communities rather than an Artemisia-Chenopodiaceae ecosystem. The phytoliths, and evidence from the historical and modern pollen-vegetation relationships, lead to rejection of the hypothesis of a past widespread Artemisia-Chenopodiaceae ecosystem in the Songnen grasslands. Using published radiocarbon and thermoluminescence data, it is proposed that the present Poaceae-dominated grasslands developed as early as the early Holocene. This study also highlights the usefulness of phytolith analysis in paleovegetation reconstruction in arid and semi-arid lands. [ABSTRACT FROM AUTHOR]

This study presents the first direct evidence of millet cultivation in Neolithic southeast coastal China. Macroscopic plant remains and phytoliths, together with direct accelerator mass spectrometry (AMS) radiocarbon dates on crops, have shown that both foxtail millet and broomcorn millet were cultivated with rice in the Huangguashan and Pingfengshan sites in Fujian province around 4000-3500 cal. BP. Ratios of different parts of crop remains revealed that crop processing activities such as dehusking and sieving were conducted within the site and thus demonstrated the local production of these crops. The new data, especially the discovery of foxtail millet and broomcorn millet, have greatly changed the current knowledge about the ancient distribution of millet in South China and have now identified southeast China among the potential source-region of Neolithic crops transported overseas to Taiwan and Island Southeast Asia. This study further draws a potential dispersal route of Austronesian languages and people from southern China through Taiwan throughout Southeast Asia. [ABSTRACT FROM AUTHOR]

Accuracy of paleovegetation reconstruction and understanding of phytolith formation would both be improved by further study of phytolith size in the Phragmites australis under different environmental conditions. Leaves of P. australis were collected from 11 sampling sites in northeast China with differences in temperature, precipitation and habitat. Principal component analysis of environmental factors (climatic and edaphic) indicated that the annual averages of temperature and precipitation were the main factors influencing phytolith size. Moreover, three-way analyses of variance (ANOVAs) further showed that phytolith size differed significantly under conditions of different temperature or precipitation gradients, whereas habitat differences had little effect. The changes in phytolith size with temperature differed in the humid, semi-humid and semi-arid areas of northeast China. In the humid and semi-humid areas, moving from the temperate to the warm temperate zone, increasing temperature reduced phytolith size; whereas in the semi-arid area, phytolith became larger with increasing temperature. In the warm temperate and temperate zones, the changes of phytolith size with precipitation showed the same trend—moving from the semi-arid to semi-humid to humid areas, as precipitation increased, phytolith grew larger. Finally, ANOVA revealed that phytoliths were also sensitive to habitat. These findings demonstrated that the size of P . australis phytoliths was sensitive to environmental factors: for regional research, the annual averages of temperature and precipitation were the major factors influencing size, but in the same climate district, habitat differences seemed to also have a significant impact on phytolith size. Consequently, phytolith analysis has potential utility in the study of global climate change, palaeoenvironment reconstruction, and environmental conservation and restoration. [ABSTRACT FROM AUTHOR]

In plants, silicon (Si) accumulates in phytoliths, which can contain 0.1-6.0 % occluded organic carbon (phytolith-occluded organic carbon, PhytOC). Globally, phytolith formation has implications for the long-term terrestrial carbon balance, and thus, global climate change. In this study, we analyzed the Si contents of 108 species of plants from Inner Mongolia and Hebei, China, to demonstrate the relationships between plant Si content and various phylogenetic and ecological characteristics, and to estimate PhytOC production in the forests of north China. Variations in Si content were related to the plant's higher-level phylogenetic position, according to the Angiosperm Phylogeny Group III classification. In angiosperms, the commelinoid monocot orders accumulated substantially more Si than did the other monocot orders, and the asteroid dicot orders accumulated more Si than did the other dicot orders. In an ecological context, herbs had the highest Si content (0.47 ± 0.26 % dry weight), followed by trees (0.33 ± 0.13 % dry weight) and shrubs (0.24 ± 0.09 % dry weight). The total PhytOC production rate in the forests of north China corresponded to 0.48 ± 0.20 × 10 t CO year, approximately 44 % of which was contributed by the understory vegetation comprising herbs and shrubs. This finding indicates that the phytolith carbon sequestration potential of the forests may be further enhanced by afforestation/reforestation, preserving the understory vegetation, and maximizing the aboveground net primary productivity of all forest layers, especially herbs that accumulate high Si contents. [ABSTRACT FROM AUTHOR]

Occlusion of carbon (C) within phytoliths (PhytOC) is becoming one of the most promising terrestrial C sequestration mechanisms. This study explored the production of PhytOC within 35 bamboo species belonging to three ecotypes using methods of microwave digestion. The aim of this study is to explore the present and potential C sequestration rate within phytoliths of bamboo species from three ecotypes. PhytOC content in bamboos of three ecotypes ranges from 0.07 % to 0.42 %. The mean PhytOC production flux decreases as: clustered bamboo (0.050 ± 0.016 t CO ha a) ≈ mixed bamboo (0.049 ± 0.016 t CO ha a) > scattered bamboo (0.038 ± 0.020 t CO ha a). The phytolith carbon sequestration in Chinese bamboo is estimated to be 0.293 ± 0.127 Tg (1 Tg = 10 g) CO a; approximately 75 %, 3 %, and 22 % of which is contributed from scattered, mixed and clustered bamboo, respectively. Taking the PhytOC production flux of 0.18 ± 0.12 t CO ha a and current annual area increasing rate of 3 %, global bamboo phytoliths would sequester 11.9 ± 7.9 Tg CO a by 2050. Consequently, bamboo forests have significant potential to mitigate the increasing concentration of atmospheric CO by maximizing PhytOC production flux and expanding bamboos. [ABSTRACT FROM AUTHOR]

Ferns are important plants both to ecosystems and humans, while the organic tissues of ferns might be hard to find due to the taphonomical condition. Thus, phytoliths in ferns might provide helpful information while other proxies were absent. In this study, we surveyed the production and morphology of phytoliths in 25 fern species belonging to 15 families. The results showed that more than half of the studied species were non-phytoliths producers, while in phytoliths producers, the production rate could reach 712,995 grains/g of dry material. We confirmed and found that I rregular anticlinal , P rismatic elongate , E longate sinuate , S pheroidal cavate granulate , S ilicified epidermis granulate , A moeboid branchiate and P rismatic cubic might be the potential diagnostic phytoliths types for ferns. • We studied the common ferns in southern China to understand phytolith production in them. • Phytolith production ranged from 0 (not observed) to 712995 grains/g in the studied 25 specimens. • 12 morphotypes of phytoliths have been observed, and 7 of them might be the potential diagnostic phytoliths types for ferns. • This study could aid colleagues in finding fern residues both in natural and anthropological sediments. [ABSTRACT FROM AUTHOR]

This paper presents a description of the river terrace at Tangjia Village in Lhasa, Tibet. Selected types of phytolith and pollen were used as proxies to study the paleoclimate in the study area. Ancient climate and vegetation changes since 10 ka BP were examined. The results demonstrated that between 10.2 and 8.9 ka BP, the dominating phytolith was the cold type and the dominating vegetation type was grassland-forest. This indicated that the climate changed from cool-humid to cool-dry and later turned back into a cool-humid climate. Between 8.9 and 8.1 ka BP, the main types of phytoliths were tooth, dumbbell, and polyhedral. This suggests that the vegetation consisted of forest-grassland and the period's climate had become warmer. Between 8.1 and 6.7 ka BP, the warm index of phytolith assembelage gradually increased, whereas the spore and pollen assembelage revealed that the vegetation was forest with hardwood. This suggested that the paleoclimate was warmest in this period. The herbaceous vegetation increased gradually, indicating that the climate had become colder since 7.5 ka BP. Between 6.7 and 4.6 ka BP, cold type phytolith such as tooth and cap were found. Simultaneously, the pollen assembelage indicated that the vegetation shifted from grassland to forest and then turned back into grassland. This implies that the climate fluctuated from cold-dry to cool-humid. Between 4.6 and 1.9 ka BP, the dominate type of phytolith was cold type and its warm index was in the range 0.04-0.28, suggesting a herbaceous vegetation cover and indicating that the climate was cold. The phytolith warm index from 1.9 ka BP revealed that the climate was continuously decreasing, and most of the pollen assembelage consisted of Chenopodiaceae and Artemisia. This conclusion is in agreement with the phytolith result that indicates that the climate was becoming colder and colder. [ABSTRACT FROM AUTHOR]

Among the most promising approaches of long-term atmospheric CO2 sequestration is terrestrial biogeochemical carbon sequestration. One of the most promising terrestrial biogeochemical carbon sequestration mechanisms is the occlusion of carbon within phytoliths, the silicified features that deposit within plant tissues. Using phytolith content-biogenic silica content transfer function obtained from our investigation, in combination with published silica content and above-ground net primary productivity ( ANPP) data of China's grasslands, we estimated the production of phytoliths and phytolith-occluded carbon ( PhytOC) in grasslands. The results show that the average above-ground phytolith production rates of China's grasslands (10.9 106 t yr−1 or 1.45% of world grasslands) are much lower than those of other grasslands (e.g. North American nonwoody grasslands) mainly because of much lower ANPP. Assuming a median content of PhytOC of 1.5%, the average above-ground PhytOC production rates of China's grasslands and world grasslands are estimated to be 0.6 106 t CO2 yr−1 and 41.4 106 t CO2 yr−1, respectively. The management of grasslands to maximize ANPP has the potential to result in considerable quantities of phytoliths and securely bio-sequestered carbon. [ABSTRACT FROM AUTHOR]

Among the most promising approaches of long-term atmospheric CO2 sequestration is terrestrial biogeochemical carbon sequestration. One of the most promising terrestrial biogeochemical carbon sequestration mechanisms is the occlusion of carbon within phytoliths, the silicified features that deposit within plant tissues. Using phytolith content-biogenic silica content transfer function obtained from our investigation, in combination with published silica content and above-ground net primary productivity ( ANPP) data of China's grasslands, we estimated the production of phytoliths and phytolith-occluded carbon ( PhytOC) in grasslands. The results show that the average above-ground phytolith production rates of China's grasslands (10.9 106 t yr−1 or 1.45% of world grasslands) are much lower than those of other grasslands (e.g. North American nonwoody grasslands) mainly because of much lower ANPP. Assuming a median content of PhytOC of 1.5%, the average above-ground PhytOC production rates of China's grasslands and world grasslands are estimated to be 0.6 106 t CO2 yr−1 and 41.4 106 t CO2 yr−1, respectively. The management of grasslands to maximize ANPP has the potential to result in considerable quantities of phytoliths and securely bio-sequestered carbon. [ABSTRACT FROM AUTHOR]

Abstract: Analyses of sedimentary evidence in the form of spores, pollen, freshwater algae, dinoflagellate cysts, phytoliths and charcoal from AMS 14C-dated, Holocene-aged sequences provide an excellent opportunity to examine the responses of Neolithic agriculturalists in the lower Yangtze to changing environments. Evidence from two sites close to the southern margin of the Yangtze delta and separated by what is now Hangzhou Bay attests the critical importance to early attempts at food production of access to freshwater resources. More readily, if episodically, available freshwater resources during the early to mid-Holocene on the Hangjiahu plain may have encouraged an early reliance on rice-based agriculture, which in turn facilitated the accumulation of agricultural surpluses and cultural diversification. Cultural change was relatively attenuated and human population pressures possibly lower on the Ningshao plain, seemingly because of much more profound environmental impacts of variations in local hydrological conditions, and because predominantly saline conditions, associated with rising relative sea level, hampered the early development of irrigated agriculture. The evidence, although largely dating to the early and middle parts of the Holocene, provides a timely warning of the complexity of vulnerability to climate change-induced processes of agriculture, and indeed human activities more generally, on megadeltas in Asia. [ABSTRACT FROM AUTHOR]

Measuring the response of terrestrial ecosystems to elevated CO2 concentrations is very important for understanding the effects of global change. In this study, OTC (open top chambers) were used to simulate elevated CO2 concentrations in the Songnen Grassland. As well, phytoliths in Leymus chinensis were extracted to study the relationships between phytoliths and CO2 concentration. The results show the rondel is abundant in Leymus chinensis, while the trapeziform polylobate is rare. When phytolith production is increased, the rondel phytoliths grow bigger and the proportions of the different phytolith types changes under high CO2 concentration. These types include elongate hollow, acicular hair cell, square and laminate and are only observed in samples grown under high CO2 concentrations. All this evidence demonstrates that phytoliths in Leymus chinensis are sensitive to CO2 concentration, and indicate that phytolith analysis may have potential use in the study of global change, identifying different ecotypes of Leymus chinensis and for the reconstruction of paleoatmospheric CO2 concentrations. [ABSTRACT FROM AUTHOR]

Abstract: A variety of phytoliths, together with prolific microcharcoal particles, sponge spicules and diatoms were extracted and identified in four cultural layers from an archeological site at Jinluojia, Macheng, Hubei Province, Central China. The warmth (Iw) and aridity (Iph) indices calculated from grass phytoliths reveal warm and wet periods during the West Zhou, early East Zhou, Tang and Song Dynasties whilst cool and dry periods occurred during the late East Zhou, Ming and Qing Dynasties. The paleoclimate conditions reconstructed on the basis of grass phytoliths extracted from archeological sediments are in agreement with those from natural sediments in the Middle Yangtze region. In contrast, the woody phytoliths show a positive correlation with microcharcoal particles, suggesting an anthropogenic contribution to the woody phytoliths from the use of woody plants for fuel during cooking and heating. Two episodes of the enhanced abundance of woody phytoliths and microcharcoal particles were found to occur at East Zhou Dynasty and from Ming and Qing Dynasties to the Present, proposed to be a consequence of the population expansion and/or the frequent wars. [Copyright &y& Elsevier]

An improved understanding of past interactions between terrestrial vegetation and various forcings, such as climate change, human impact, and paleofire, is crucial for assessing impacts of future global change on terrestrial ecosystems. This study seeks to find the key factor or factors that have driven Holocene vegetation change along the East Asian monsoon margin. Several high-resolution pollen records are reviewed and new phytolith-based paleovegetation reconstructions and physical geochemical datasets are presented from a peatland in northeastern China. Using 108 modern topsoil samples as a training set, canopy cover and vegetation composition are estimated for the period since 5100 cal. yr BP. Variation partitioning analysis (VPA) is used to determine the relative importance of climate change, human impacts, and paleofire disturbance. The generalized dynamic vegetation model LPJ-GUESS is forced with climate anomaly output from an atmospheric general circulation model to simulate vegetation dynamics during the mid-Holocene and the pre-industrial era. The proxy-based estimates are compared to modelling output. Results indicate that regional tree cover varied from 10% to 40% during the past five millennia. The single-core, phytolith-based reconstructions are generally consistent with stacked tree pollen z-scores calculated from different records along the East Asian monsoon margin, implying that mid-Holocene tree cover decrease was persistent and almost synchronous over extensive areas. VPA demonstrates that long-term monsoon marginal vegetation successions were mainly caused by climate effects. Numerical modelling suggests that since the mid-Holocene the retreat of forests along the monsoon margin was primarily associated with precipitation deficits. Our investigation highlights that the precipitation associated with the East Asian monsoon system has exerted a stronger influence than the westerlies on the monsoon margin climate and vegetation change. With ongoing global change, close attention to variations in precipitation patterns and amounts should be especially helpful in efforts aimed at ecological monitoring, change prediction, and restoration. • Phytoliths provide complementary paleovegetation evidence to pollen for the monsoon margin area in northeastern China. • Phytolith-based quantitative tree coverage reconstructions suggest persistent forest cover since the mid-Holocene. • Vegetation dynamics within the monsoon margin area is strongly associated with East Asian monsoon variability. • DGVMs modelling suggests the dominant role of precipitation in regulating vegetation change. [ABSTRACT FROM AUTHOR]

• The aeolian soils along East Liao River and West liao River have have similar provenance and dynamic mechanism. • River-floodplains are the main source of this type of aeolian soil sediments. • Sediment component content of the profile is strongly influenced by changes in sedimentary environment. • Shrubland planting along rivers is an effective way to prevent regional desertification. There are many stabilized sand dunes along the East and West Liao rivers in the eastern side of the Horqin Sandy Land, and they pose a threat to the surrounding ecological environment and the livelihood of inhabitants once the ecological balance is destroyed. In order to explore the sediment provenance, dynamic mechanism and sedimentary environment of these aeolian soils, and to provide assistance in desertification prevention, two aeolian soil profiles and some topsoil samples were collected for grain size, loss on ignition and phytolith analysis in the East and West Liao River and Horqin Sandy Land, respectively. After end-member analysis of the grain size data, it is concluded that the aeolian soil profiles along the East Liao River and West Liao River have similar provenance and dynamic mechanism. The river-floodplain contributes most to the formation of these aeolian soils and then the Horqin Sandy Land and the interior of Eurasia, and the sediments were transported to the river banks by creep, saltation and suspension in different proportions. The Ic index reconstructed by phytolith, combined with the surrounding sedimentary environmental reconstruction records, the climate experienced several warm-wet and cold-dry periods from 7,720 to 400 cal yr BP, and it significantly influenced the percentages of each component of the profile in each period. The research suggests that planting drought-tolerant shrub plants along the rivers to form shrub belts can effectively prevent the transport of aeolian soils along the rivers, and planting trees and grass on the aeolian soils to increase the vegetation cover, combined with publicity and management, is viable for desertification prevention. [ABSTRACT FROM AUTHOR]

This paper presents a multi-proxy reconstruction of the climate change in Caotanhu wetland using pollen, phytolith and charcoal records, and the data of loss of ignition (LOl), grain size analysis, and susceptibility. Results reveal that between 4550 and 2500 cal. a BP, a dry climatic condition was not favorable for the accumulation of peat. Since 2500 cal. a BP, the climate became humid and the wetland developed with abundant freshwater aquatic plants, which contributed to peat accumulation. Nevertheless, alternate periods of rain and dry climate occurred during that period. Between 2500 and 1810 cal. a BP (550 BC-140 AD), the climate was more humid than at present. A lot of emerged plants, such as Phragmites, Typha and Sparganium, and freshwater green algae grew in the wetland which was surrounded by desert-steppe vegetation composed mainly of Chenopodiaceae, Artemisia, Compositae and Thalictrum. However, from 1810 to 1160 cal. a BP (140-790 AD), the water level started to decrease and hydrophyte species reduced greatly, but some Phragmites still grew in the wetland and around it was desert vegetation with high proportion of Chenopodiaceae and Artemisia. Then from 1160 to 650 a BP (790-1300 AD), it entered a period of desert-steppe with abundant mesic and xerophytic plants. And a lot of aquatic plants prevailed in the wetland. Here, what is noticeable is that percentages of arboreal pollen, consisting mainly of Betula and Picea, increased greatly and reached a maximal value of 27.2%, in which, Betula percentages rose to 23.2%. Hence, it is reasonable to conclude that Betula grew in the highland of the wetland, or Picea timberline shifted downward resulting in the increase of percentages of Betula and Picea pollen, which were transported into the wetland by flood or wind. But since 650 cal. a BP, desert vegetation prevailed around the wetland again with dominant Chenopodiaceae and Artemisia, and the climate was similar to modern one. Despite some aquatic plants still growing in the wetland at that time, their amounts diminished greatly. [ABSTRACT FROM AUTHOR]

• Millet-based beer production and consumption at the core area of the Shimao site. • Beer ingredients include multiple grains and diverse herbs. • Ritual feasting activities in the first urban center of the north Loess Plateau, China. • Specialized serving and drinking pottery vessels and alcohol as sociopolitical paraphernalia in the early urbanization process along middle Yellow River region. Alcoholic beverages were used in ancient rituals and feasting, often to embody elite status and power, to mark communal activities, or simply for everyday consumption. Scholars have traditionally interpreted pitchers, a common pottery vessel type in late Neolithic China, as specialized alcohol serving vessels. However, little research has been done to characterize the true use of these vessels through scientific analysis of excavated materials from the middle Yellow River region. In this study, by analyzing microbotanical residues on ten pitchers, two cups, three lids, and one storage jar from the Shimao site (ca. 4300–3800 cal. BP), one of the earliest urban centers in late Neolithic north China, we discover remains of a beer brewed using a malting method. The main ingredients include millet, Triticeae, rice, lily, snake gourd root, Zingiberaceae root (ginger or turmeric), and beans. The pitchers may have been used for serving and heating the fermented beverages. This result not only reveals for the first time the production and consumption of alcoholic beverages in the late Neolithic Loess Plateau, but also highlights the interplay among feasting activities, social hierarchies, and interregional interactions in the process of early urbanization in this region. [ABSTRACT FROM AUTHOR]

Crop dispersal has long been recognised as an important topic in agricultural archaeology and food globalisation. The southern coastal region of China, including Fujian Province, is of particular interest as a key junction for crop dispersal into Taiwan and the Pacific islands from mainland China. However, due to poor preservation of macro-plant fossils caused by the acidic soil condition, questions about when and where millet first arrived in this region remain a topic of debate. Our study focused on the millet phytoliths remains from three Neolithic sites in southeast coastal Fujian. Multiple dating methods, including charred carbon dating, phytolith carbon dating, and optically stimulated luminescence were used to construct the chronologies of the sites. The results reveal that the earliest millet phytoliths emerged in the Lower Tanshishan cultural layer of the Baitoushan site, which was initially occupied at 5.5 ka BP. After ca. 5.0 ka BP, common millet phytoliths were found in the Tanshishan cultural layers of all three sites. The microfossil of millet examined in this study was likely the earliest millet remains found in Fujian, indicating that millet may have arrived in the southern coast of China at least 5,500 years ago. These findings not only provide new insights to millet dispersal routes in China, but also have significant implications for crop communications between Taiwan and mainland China during the Neolithic age. • Phytolith analysis was carried on three Neolithic sites in the South China Coast. • The millet phytoliths first occurred in the Lower Tanshishan culture at BTS site. • The millet dispersal into the South China Coast took place at least 5500 years ago. [ABSTRACT FROM AUTHOR]

• Warm-dry and cold-wet hydroclimate modes were showed according to 18,000-year temperature and DWT changes in Dajiuhu Basin. • Peatland ecology sensitively responded to palaeo-hydroclimatic changes. • More bulliform phytoliths induced by exaggerated plant leaf water loss occurred during warm-dry mid-Holocene. • Plant water regulation, climate, and irradiance showed a synchronous ~1000-yr cycle. Peatland ecosystem processes are strongly influenced by hydrology linked to climate change. However, how transpiration, as major water loss pathway in closed peatland, responds to climate change and then regulates ecosystem water balance that remains poorly understood. Here, we reported an 18,000-year fossil phytolith record from an herbaceous community-dominated mountain peatland in central China to reconstruct climate changes and vegetation evolution and reveal the interactions between regional climate changes and peatland ecosystem. The abundance of bulliform phytoliths—a silicified type of cells that regulate the movements of plant leaves to reduce light exposure and transpiration rate—shows close correlations with the Holocene climate variations with higher bulliform abundance in response to warm-dry climate (11,500–9600 cal yr BP; 7500–3000 cal yr BP) and lower values associated with cold-wet climate (13,000–11,500 cal yr BP; 3000 cal yr BP-present). Spectral analysis reveals that bulliform abundance and reconstructed climate vary with a major ~1000-year periodicity during the Holocene, suggesting a possible causal relationship to solar activity. A high bulliform abundance and warm-dry climate correspond with enhanced solar activity, and vice versa. We interpret that the resultant leaf water deficit resulted from greater light interception, high temperature and drought promoted the production of bulliform cells to fold leaf for water conservation, which is an effective protective mechanism of peatland grasses from the environmental stress. These results expand our understanding of how grass-dominated peatland plant water regulation recorded by bulliform phytoliths responds to solar radiation and local hydroclimate during geological period. [ABSTRACT FROM AUTHOR]

Recent increases in archaeobotanical and genetic evidence offer insights into agricultural origins and plant domestication, which suggest a protracted process taking thousands of years that began by 10,000 cal a BP or in the late Pleistocene. Compared to the cereal domestication that was accomplished in the early Holocene in Southwest Asia and Mesoamerica, the reasons for the delay in rice domestication in China until the middle Holocene remain unclear. In the present study, the dynamic influence of environmental change on rice domestication was revealed by evidence from sedimentary facies and phytolith analysis of the high-resolution HMD1602 core from the Hemudu site. Rice phytoliths were recovered from beneath the neritic sediment at this site for the first time, which pushes the history of human activities and the process of rice domestication in the Yaojiang Valley back to 8200-7600 cal a BP. The process of rice domestication at the Hemudu site developed discontinuously with an obvious interruption during 7600-7100 cal a BP, which was significantly influenced by marine transgression and palaeo-typhoon events. Furthermore, synthesis of palaeoenvironmental and archaeobotanical records suggests that rice exploitation and domestication was interrupted three times during 13,000-10000, 7900-7400 and 6400-5600 cal a BP, respectively. The first interruption of rice exploitation was induced by the Younger Dryas, which triggered the onset of cultivation at approximately 10,000 cal a BP in Southwest Asia and China, while the second two interruptions of rice domestication were caused by marine transgressions, which postponed the domestication of only rice. Therefore, the delayed accomplishment of rice domestication until the middle Holocene resulted from an unstable climatic environment and sea-level fluctuations, which ultimately led to the discontinuous process of rice domestication. • Rice recovered beneath the neritic sediment for the first time in the Hemudu site. • Rice domestication developed discontinuously since 8200 BP in the Yaojiang Valley. • Three interruption events of rice exploitation and domestication were recognized in the Yangtze River. • Combined effects of climate and sea-level fluctuation protracted rice domestication. [ABSTRACT FROM AUTHOR]

Modern phytolith research is the premise to accurately reconstruct the regional paleovegetation and paleoclimate. It is thus particularly important to study the spatial distribution characteristics of the phytolith assemblages and the response of the phytolith to environmental factors. In this study, we collected 54 topsoil samples along the isohyet of 600 mm in Northeast China to examine the distribution patterns of phytolith along the gradient of single environmental factor. With this special sampling method, we targeted to reveal the responses of phytolith assemblages in the topsoil to the variation of temperature. The results showed that there were a large number of phytoliths with various morphotypes in the 54 topsoil samples in Northeast China. The phytolith morphotypes were the same, including elongate, lanceolate, blocky, cuneiform, tabular, saddle, rondel, bilobate, trapeziform polylobate, prism, silicified stomata, conduit, papillae, sclereid and carinate. In gene-ral, the contributions of elongate and lanceolate were high; the contributions of short cell phytoliths, blocky, tabular and cuneiform were small relatively; the contributions of the other types of phytoliths were less than 1.0% and appeared sporadically in the topsoil samples. Besides, the phytolith assemblages of the topsoil samples were different among Xiaoxing'an Mountains, Songliao Plain and Liaoxi hills. Combined with the discriminant analysis, the samples from the three regions could be effectively separated based on the phytoliths assemblages, with a total accuracy of 94.4%. Specifi-cally, the average percentage of elongate, lanceolate, prism was the largest in Xiaoxing'an Mountains, and was the smallest in Liaoxi hills; the percentage of saddle, bilobate, papillae was the largest in Liaoxi hills and the smallest in Xiaoxing'an Mountains; the percentage of blocky, tabular, cuneiform was the largest in Songliao Plain. Meanwhile, the percentages of the elongate, lanceolate, prism, saddle, bilobate, papillae, blocky, tabular, cuneiform were significant diffe-rences among the three regions. There were significant negative correlations between the percentages of elongate, lanceolate, prism and the annual average temperature, and positive relationships between the percentages of the blocky, tabular, cuneiform, bilobate, papillae and the annual average temperature. However, the percentage of saddle, rondel and trapeziform polylobate did not change with increasing annual average temperature.

The use of exogenous silicon (Si) amendments, such as Si fertilizers and biochar, can effectively increase crop Si uptake and the formation of phytoliths, which are siliceous substances that are abundant in numerous plant species. Phytolith-occluded carbon (C) (PhytOC) accumulation in soil plays an important role in long-term soil organic C (SOC) storage. Nevertheless, the effects of both Si fertilizer and biochar application on PhytOC sequestration in forest plant-soil systems have not been studied. We investigated the impact of Si fertilizer and biochar applications on 1) the PhytOC pool size, the solubility of plant and soil phytoliths, and soil PhytOC in soil physical fractions (light (LFOM) and heavy fractions of organic matter (HFOM)) in Moso bamboo (Phyllostachys pubescens) forests; and 2) the relationships among plant and soil PhytOC concentrations and soil properties. We used a factorial design with three Si fertilizer application rates: 0 (S0), 225 (S1) and 450 (S2) kg Si ha - 1 . The concentrations of PhytOC in the bamboo plants and topsoil (0-10 cm) increased with increasing Si fertilizer addition, regardless of biochar application. Biochar addition increased the soil PhytOC pool size, as well as the LFOM- and HFOM-PhytOC fractions, regardless of Si fertilizer application. The Si fertilizer application increased or had no effect on soil phytolith solubility with or without biochar application, respectively. Soil PhytOC was correlated with the concentration of soil organic nitrogen (R - 1 . The concentrations of PhytOC in the bamboo plants and topsoil (0-10 cm) increased with increasing Si fertilizer addition, regardless of biochar application. Biochar addition increased the soil PhytOC pool size, as well as the LFOM- and HFOM-PhytOC fractions, regardless of Si fertilizer application. The Si fertilizer application increased or had no effect on soil phytolith solubility with or without biochar application, respectively. Soil PhytOC was correlated with the concentration of soil organic nitrogen (R 2  = 0.32), SOC (R 2  = 0.23). Furthermore, Si fertilizer application increased plant and soil PhytOC by increasing soil available Si. Moreover, biochar application increased soil PhytOC concentration in LFOM-PhytOC and the unstable fraction of PhytOC. We conclude that Si fertilizer and biochar application promoted PhytOC sequestration in the plant-soil system and changed its distribution in physical fractions in the Moso bamboo plantation in subtropical China.2  = 0.28), and available Si (R 2  = 0.23). Furthermore, Si fertilizer application increased plant and soil PhytOC by increasing soil available Si. Moreover, biochar application increased soil PhytOC concentration in LFOM-PhytOC and the unstable fraction of PhytOC. We conclude that Si fertilizer and biochar application promoted PhytOC sequestration in the plant-soil system and changed its distribution in physical fractions in the Moso bamboo plantation in subtropical China., Competing Interests: Declaration of competing interest The manuscript has been approved for publication by all authors. We declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. We declare on behalf of my co-authors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part., (Copyright © 2020 Elsevier B.V. All rights reserved.)