Relict Soils and Early Arable Land Management in Lofoten, Norway

Relict arable soils dating fromc.AD700 provide an opportunity to identify early arable land management practices in the agriculturally marginal landscapes of the Lofoten archipelago, northern Norway. Synthesis of field survey and soil thin section micromorphology supported by image analysis suggests that there was deliberate management of erodible sandy soils in sloping locations to create small areas of cultivation terrace, with a range of materials used as soil amendments to stabilize the accumulated soil and enhance fertility. Small areas of sandy soils in more gently sloping locations were also cultivated, again with a range of materials used as amendments and which contributed to a significant increase in soil thickness. The last phase of cultivation commenced during the late 1800s and involved the reclamation of wetter, peaty soils by spade. These patterns of arable land management are repeated in different parts of Lofoten and indicate that despite the climatic and economic marginality of arable activity in Lofoten, land management practices were developed and applied to permit barley production from small areas.     

降雨时长对土壤结皮发育性能的影响研究

室外土遗址经常因遭遇降雨、水淹等发生结皮,造成土遗址表层性能改变,影响土遗址的进一步保护。以定量纯净黄土在等降雨大小下,通过控制不同降雨时长,试验了不同降雨时长下土壤结皮发育的过程,分别测试了降雨前后的结皮厚度、密度、硬度及孔隙结构。结果表明,在降雨量未达到饱和状态时,随降雨量增大,结皮层的厚度、密度、硬度迅速增大,表皮土壤颗粒被击碎,孔隙迅速减小;在降雨量达到饱和状态时,随降雨量增大,结皮层的厚度、密度、硬度缓慢增大,但表皮土壤裂缝迅速发育,由周围向中心形成同心圆状或辐射状裂隙。研究结论可为室外土遗址的保护提供参考。     

Multiple historical geographies: responses and resistance to colonial conservation schemes in East Africa

Examining four colonial soil conservation schemes in East Africa that were part of the modernising project of colonialism, this article considers multiple historical geographies of the colonised world. There were multiple modernities: while information and ideas flowed in many directions between (and within) the metropole and colonies, the particular ‘modernity’ that was put into practice was shaped by its context. The article highlights therefore that – despite playing to the same tune of modernity – colonialism was highly differentiated in the way that its policies played out on the ground. Furthermore, the ‘colonised’ acted and reacted to the policies in highly differentiated ways that depended on their particular context in time and space. All but one of the soil conservation schemes examined were rejected and there was significant resistance to them. Much of the existing literature on such schemes examines them in the context of essentially political processes, and in particular their influence on rising nationalism. Whilst these processes are important, this paper shows that there were other, non-political, factors that influenced the reception they were given, which need to be considered too. These ‘everyday’ details were about the practical and technical nature of the schemes, and by exploring these aspects of the schemes, and comparing them, the article highlights why most were rejected. It suggests that different aspects of conservation schemes need to be explored for a firm understanding of the reasons behind resistance to such schemes.     

Three-dimensional (3D) visualisation: the application of terrestrial laser scanning in the investigation of historical Scottish farming townships

Recent developments in digital technologies are heralding significant changes in the way we acquire, visualise and analyse archaeological data. Terrestrial laser scanners can be used to create photo-realistic virtual copies of landscapes, and archaeological features, and offer the potential to improve our understanding of three-dimensional (3D) spatial relationships at study sites. Here we present a methodology for the integration of a high-resolution 3D site model with soil chemical data obtained from an abandoned settlement site located in the Central Highlands of Scotland. At this site, the multi-element concentration in soil, co-visualised within a topographic setting, has an important role to play in elucidating settlement layout and activity. The methods described here are also of significance in archiving sites of archaeological/historical importance where development activities and/or environmental processes may destroy remains, or where access to field sites is restricted.     

A Survey of Soil Erosion in Australia using Caesium‐137

A survey of soil erosion was conducted in Australia using the fallout radioisotope caesium‐137 as an indicator of topsoil redistribution. Two hundred and six sites were sampled, 100 within rotational cropping and horticultural use, 52 within uncultivated permanent pasture and forest, and 54 in rangelands. Average net soil losses were approximately equal for cultivated cropping lands and rangelands (ca. 5.5 t ha^?1 yr^?1), and just over 1 t ha^?1 yr^?1 for pasture and forest. The Mann Whitney U Test revealed that losses under cropping and rangeland conditions were significantly higher (p < 0.05) than under uncultivated pasture and forest. Soil loss was negatively correlated with mean annual rainfall and slope gradient, and positively correlated with slope length (Spearman's rank correlation). There was no correlation between rates of soil loss and a rainfall erosi‐vity index. An assessment of erosional events was provided by landholders for 104 sites, with their ranking being weakly but significantly correlated with soil loss estimates (r =+0.35). Sixty percent of sites had net soil losses greater than 1 t ha^?1 yr^?1, and 74% of sites had losses of more than 0.5 t ha^?1 yr^?1. This latter rate may be regarded as a limit for a tolerable level of soil loss. These high rates of soil loss have occurred since the mid‐1950s despite there being significant landholder awareness of the soil erosion hazard.     

Late pre‐Islamic burials at Mleiha,Emirate of Sharjah (UAE)

The history of two monumental grave buildings (nos. 4 and 5), excavated in area P of the late pre‐Islamic city of Mleiha, has been studied in detail. Like all other tombs excavated up to the present day in Mleiha, their chambers had been emptied in ancient times. They were found devoid of human remains and grave‐goods. In the upper parts of the grave fills, however, skeletal remains were encountered. One of the skeletons was radiocarbon dated to AD 623–656, the time of the Islamisation of south‐east Arabia. A radiocarbon date of 384–233 BC for a wooden beam from the same tomb showed that it was built during the late pre‐Islamic period (PIR‐A). These dates and stratigraphic observations made clear that the interments were intrusive. The surrounding sediments were deposited by flooding. Directly underneath the skull of the dated skeleton, a layer of sandy loam was encountered, showing mud cracks. To understand the relationship between the burial and these deposits, micromorphological analyses of the surrounding sediments were conducted. The microstructural organisation of the sedimentary components implied that the skull was interred as part of a burial, and not deposited by natural processes.     

One-Dimensional Ground Response as a Preliminary Tool For Dynamic Analyses in Geotechnical Earthquake Engineering

This article discusses how to calibrate some parameters of two-dimensional finite element models for numerical analyses in geotechnical earthquake engineering. The calibration was made through the simulation of the one-dimensional vertical propagation of S-waves in elastic layers, whose theoretical solutions are available in literature. The numerical results were compared with those obtained by frequency domain analyses. The influence of several sources of damping arising in the model, including that deriving from boundary conditions and numerical integration, was investigated. The proposed calibration procedure constitutes a useful preliminary step for performing advanced dynamic analyses of any geotechnical system.     

Optimal Control of Structures under Earthquakes Including Soil-Structure Interaction

It is well known that the soil-structure interaction (SSI) changes the dynamic response of a structure supported on flexible soil. The analysis of optimally controlled SSI systems has certain difficulties due to the nature of the SSI and the optimal control problem. In this paper, a two-step iteration-based numerical algorithm is proposed to handle optimally controlled SSI systems under earthquakes. First, the optimal control forces are obtained by using a fixed-base system. Then, the optimal control forces are converted to the frequency domain by the Fourier transform technique to be used in the equations of the SSI system. The lateral displacement and the rocking of the foundation are obtained from the equations of the SSI system containing the optimal control forces in the frequency domain. The lateral displacement and rocking of the foundation are then converted to the time domain by the inverse Fourier transform technique, and the lateral accelerations and the rocking accelerations of the foundation are obtained by the forward finite difference method. During the second step, the optimal control forces are calculated again by using the lateral acceleration and the rocking acceleration of the foundation along with the earthquake ground motion. Using the method explained above, the optimal control forces obtained in the time domain are used in the equations of the soil-structure system from which the behavior of foundation and structure is obtained. In the final section of the paper, a numerical study is conducted for a controlled structure supported on flexible soil.     

Numerical Analyses of the Effectiveness of Soft Barriers into the Soil for the Mitigation of Seismic Risk

An approach to mitigate the seismic risk of existing structures by means of the creation of a continuous thin layer of grouted soil at a convenient depth is presented. A parametric numerical analysis is reported using different constitutive models with reference to two geometrical schemes. It is shown that if the grouted layer has a stiffness significantly lower than that of the surrounding soil, it may be effective in reducing the seismic demand. In the parametric analyses, the positive role of yielding is also observed, which indicates that the barrier is more effective with larger input amplitudes.     

良渚古城老虎岭水坝遗址考古剖面保护研究与工程实践

良渚古城老虎岭水坝遗址是我国迄今发现最早的大型水利工程系统中的一处典型遗存,对中国文明起源和世界文明史的研究具有重要意义。为清晰地展示老虎岭水坝土遗址上“草裹泥”筑坝工艺的痕迹,针对温热、潮湿、多雨环境土遗址保护的难题,在总结吸取国内土遗址保护经验教训的基础上,借助浙江大学的研究成果和敦煌研究院的工程经验,提出了一套避免使用化学材料加固,而以“黑屋+隔水+控湿”为主的小环境控制工程策略,包括:构建遮光大棚以避雨和抑制绿色生物生长;铺设防水毯以防止坝体渗水;设置电加热玻璃罩以保湿和封闭展示面;采用气相补水以调控空气湿度和土体含水率;采用植物精油等绿色环保技术防治微生物;同时做好遗址实时监测和管护等。这套综合保护措施是土遗址保护理念和工程实践的一次新的尝试。