Impacts of the ancient Maya on soils and soil erosion in the central Maya Lowlands

Many studies across the central and southern Maya Lowlands of Belize, Guatemala, Honduras, and Mexico have produced records of land degradation, mostly sedimentation and soil erosion, during the ancient Maya period from before 1000 BC to the Maya Collapse of c. AD 900. This paper provides new data from two sites (Blue Creek and Cancuén), synthesizes more than a decade of the authors' research in Guatemala, Belize, and Mexico, and synthesizes other findings from this region. These research projects analyzed more than 100 excavations in upland and depression sites, cored lakes and wetland sediments, and studied sediments in the field and laboratory using radiocarbon dating, a battery of soil chemistry tests, stratigraphic analysis, magnetic susceptibility, elemental analyses, and artifact identification. Our objective was to date when sedimentation and soil erosion occurred, identify stable surfaces, and correlate them with the state of knowledge about past land use. These findings indicate three general epochs of accelerated soil erosion and identified two major paleosols. The three waves of soil erosion occurred in the Preclassic period (c. 1000 BC to AD 250), the Late Classic (AD 550 to 900), and in the last several decades. The major paleosol (‘Eklu'um’) in these sites is a well-developed Mollisol or Vertisol that started forming in the early Holocene and was buried in either the Preclassic or Classic periods (AD 250 to 900). At some sites the Eklu'um paleosol lies beneath sediments with a fainter paleosol, which in turn lies buried below Classic period and later sediments. This picture shows higher than expected soil erosion linked to the region's first pioneer farmers in the Preclassic and less than expected soil erosion in the Late Classic when population peaked and land use was the most intensive. In other regions like Cancuén, Guatemala, however, most soil erosion occurred during the Maya Late Classic (AD 550–830). Erosion here was intense but short-lived: depressions record 1–3 m of aggradation in two centuries. A third epoch of accelerated soil loss and aggradation arose with the rapid land use changes brought by new pioneers during the last several decades.     

Density and distribution of the Australian bustard Ardeotis australis

The density and distribution of the Australian bustard Ardeotis australis was determined from observations made during aerial surveys of kangaroos. Bustards were most abundant in the northern half of Australia, particularly on mitchell grass plains. They were rare or absent in much of southern Australia, on parts of which they were reported as common 100 years ago. Bustard density and distribution seems to be influenced by vegetation structure, land use and predation.     

Characterization of relict Late Pleistocene and Early Holocene paleosols buried in wedge-shaped structures on the southern coast of the Finnish Gulf

The physical and physicochemical properties and morphogenetic characteristics of the buried soddy gleyic and gleyed paleosols developed from the glaciolacustrine loamy sediments on the southern coast of the Finnish Gulf in the Late Pleistocene and Early Holocene (12–9 ka, calibrated) are considered. It is shown that the morphology and properties of these paleosols sharply differ from those of the enclosing gravelly sands deposited in the ancient basins. The latter substrates serve as the major type of soil-forming materials for the modern surface soils. The studied paleosols fill wedge-shaped structures dissecting the gravelly sediments. Their profiles are well preserved, though their normal horizontal orientation is disturbed; large soil blocks were displaced into the open wedges. The presence of these soils attests to the fact that the initial soil cover in the studied region was formed in the Late Glacial epoch soon after the retreat of the glacial sheet. The good degree of preservation of the paleopedogenic information recorded in the profiles of these paleosols is of great value for the paleoenvironmental reconstructions.     

昌黎黄金海岸国家级自然保护区土地利用/覆被变化及驱动力分析

以新开口南部公路至七里海东侧小路为界,将昌黎黄金海岸国家级自然保护区陆域分为北部研究区和南部研究区,利用1991年和2010年两期遥感影像数据解译图分别获取昌黎黄金海岸国家级自然保护区南、北两部分土地利用数据,基于GIS空间分析与数理统计方法分别对1991-2010年南北两部分的土地利用/覆被变化特征进行定量分析,运用区域生态环境质量指数和区域土地利用变化类型生态贡献率,对南北两部分土地利用变化的生态环境效应及导致其生态环境质量变化的土地利用变化类型进行了分析与评价.结果表明:1991-2010年期间北部研究区和南部研究区的土地利用变化主要表现为草地的减少,耕地、林地、建设用地、水域和未利用地面积增加的态势;1991-2010年北部研究区和南部研究区的生态环境质量均呈下降趋势,区域生态环境质量指数分别从0.7592下降至0.5855和0.6626下降至0.5292;北部研究区的生态环境质量劣于南部研究区,致使北部研究区生态环境质量下降的主要驱动力是建设用地规模的扩大,而引起南部研究区生态环境质量下降的主要驱动力是土地退化.     

Rhizoliths in Devonian and Early Carboniferous Paleosols and Their Paleoecological Interpretation

Eurasian Soil Science - Collected in situ rhizoliths (>20) from Devonian and Early Carboniferous paleosols in the southern part of the Russian Platform (Kaluga, Belgorod, and Voronezh...     

基于地形梯度的皖南地区土地利用分布特征

以安徽省皖南地区为例,利用GIS空间分析技术,通过计算高程、坡度和地形位指数等地形梯度上的土地利用分布指数,分析了3种地形梯度上不同土地利用类型的分布特征,探讨了该区土地利用分布特点与地形间的关系。结果表明:(1)研究区在高程0~600 m、坡度0~21°和地形位指数0~1.575 0区域内的面积占皖南地区总面积的93.10%、83.11%和93.89%,影响着该区的土地利用类型分布;(2)土地利用类型分布分层明显,耕地、水域和建设用地主要分布在海拔较低、坡度平缓和地形位指数较小的区域,相应的土地利用分布指数随地形梯度的增大而减少直至趋于0;林地、草地分布则与之相反;(3)依据土地利用和地形的关系,皖南地区土地利用格局趋于合理,但不合理的土地利用方式仍然存在,需要加强其土地利用的规划管理。     

Utilization for agriculture and forestry of Graulehme,Tertiary paleosols in central Europe

The Graulehme (grey loams) are relict soils or paleosols formed during the Tertiary or earlier but persisting locally on land surfaces. Thus, for example, the Permotriassic peneplain of the Rhinish Massif in Germany was mantled by deep soils during most of the Tertiary, but these were largely removed during a period of uplift and dissection in the Late Tertiary and the Pleistocene. Graulehme remained on the parts of the massif that lagged behind in the general uplift and therefore suffered little erosion. These paleosols now occupy the flat and low-lying positions in the landscape. Other components of the soil pattern are Rankers, acid brown earths and Rotlehme, the last also being paleosois but of limited extent.The Graulehme are high in silt and clay, plastic, virtually impermeable and low in base saturation and plant nutrients. Consequently, the soils are not suitable for cultivation generally. Exceptions are local bodies of the paleosols where materials from acid brown earths have been mixed with or mantle the Graulehme. The paleosols are suitable for pasture without drainage but require lime, complete fertilizer and modern management. The Graulehme are also suitable for forestry. Spruce is the best adapted species, but beech and oak can also be grown.     

从古土壤看北京环境变迁

古土壤是在古自然环境条件下形的土壤,西胡林黄土剖面位于北京低山丘陵区,埋藏有七层古土壤,根据形态和微形态特征,可以划分出碳酸盐型古土壤、普通褐土型古土壤,淋溶褐土型古土壤和棕壤型古土壤。其地球化学特征和土壤学特性的研究表明,各古土壤类型之间和发生层之间存在着显著差异,通过古城磁测年和地层对比,确定古土壤的年龄。在研究古土壤性状的基础上,配合孢粉分析,可以勾画出北京低山丘陵区的环境变迁,北京地区自50万年前至1万前,交替经历了14次温湿、冷干的气候变化。     

南方红壤丘陵区退耕还林还草工程土壤保持效应评估

以南方红壤丘陵区为研究对象,应用修正通用土壤流失方程,根据2000年、2005年、2010年、2015年土地利用数据,识别出了近15年南方红壤丘陵区退耕还林还草的空间范围,并估算了退耕还林还草实际发生区的土壤保持效应。结果表明,2000—2015年,南方红壤丘陵区退耕还林还草面积约2 052.61 km²。期间土壤保持量增加9.18×10⁸ t,单位面积土壤保持量变化量为447 327.54 t/km²,土壤保持效应整体显著提升,但仍有部分区域出现负效益。此外,对提升土壤保持功能而言,将裸地转换为林地是效果最显著的土地利用变化方式。退耕还林还草的实施提高了区域的土壤保持功能。研究结果对南方红壤丘陵区退耕还林还草工程的实施及管理具有指导意义。     

青海省土地集约利用与经济发展时空差异分析

以青海省土地利用变更数据和社会经济发展数据为依据,建立土地集约利用与经济发展水平评价指标体系,运用基于结构熵权法的多因素综合评价法,对青海省2000—2009年间土地集约利用度以及经济发展水平进行评价;并运用统计方法,对比分析青海省土地集约利用和经济发展的时空差异特征及其二者相关性。结果表明:从时间变化特征来看,青海省土地集约利用度和经济发展水平总体呈上升趋势,但地区之间存在差异,2003年起州（地、市）域间土地集约利用度和经济发展水平的差距不断变大;从空间变化特征来看,经济发展水平北部高于南部,全省经济发展具有显著的空间差异性,而土地集约利用度北部地区高于南部地区,由东北向西北递减,且在东北部地区,以西宁市为中心向外递减;土地集约利用与经济发展空间相关度较低,协调度较差。     

大同市南郊区土地利用生态服务价值空间分布及变化

本研究以中国生态服务价值当量因子表为基础计算了大同市南郊区不同土地利用生态服务价值单价,结合该区1987年和2002年Landsat TM/ETM 影像分类数据,借助Fragstats和ENVI软件支持进行了矩形单元土地利用生态服务价值的空间模拟,然后采用ENVI的波段运算功能、分类功能进行大同市南郊区土地利用生态服务价值空间分布及变化研究。结果显示:大同市南郊区1987年和2002年土地利用正生态服务区面积大于负生态服务区面积,但生态服务质量等级都不高。1987年平原区生态服务质量好于山丘区,2002年山丘区生态服务质量好于平原区。大同市南郊区从1987年至2002年土地利用生态服务增加区面积大于减小区,且以轻度增加为主。平原区生态服务增加区面积小于山丘区,生态服务减小区面积大于山丘区。平原区生态服务增加区面积小于减小区面积;山丘区生态服务增加区面积大于减小区面积。     

Stratigraphy and land use of the Post-Diamond Hill Paleosol,western Oregon

The Post-Diamond Hill Paleosol generally underlies Late Pleistocene sediments of the Willamette Formation. However, in numerous localities in the Willamette Valley, reddish gray clay paleosols either outcrop at the surface or occur within soil profile depth. Then they are part of soils of the modern landscape. Where the paleosols outcrop, the soils are mostly Typic Pelloxererts in the fine, montmorillonitic, mesic family. Because of the nature of the paleosols, these soils are poorly suited for nearly all intensive uses; the dominant use is hay and pasture.     

Permian paleosols in relation to general issues of paleopedology

The study of Upper Permian paleosols in the eastern part of the Russian Plain enables us to consider general problems, like interrelation of pedogenic and lithogenic memory, the development of Pre-Quaternary loess-paleosol series, the use of red beds as a paleogeographic archive, the paleoenvironmental reconstructions based on the study of paleosols, pedostratigraphy, and the relationships between pedogenesis and sedimentation.     

Soil phosphorus and tree cover modify the effects of livestock grazing on plant species richness in Australian grassy woodland

The effects of grazing on the richness of understorey plant communities are predicted to vary along gradients of resources and tree cover. In temperate Australia livestock management has involved phosphorus addition and tree removal but little research has examined how the effects of grazing on plant species richness may vary with these management regimes. Patterns of understorey plant species richness were examined in 519, 0.09 ha quadrats in grazed pastures and remnant grassy forests and woodlands in southern Australia. Sheep grazing was the primary land use and sites varied widely in grazing frequency and density, tree cover and phosphorus fertiliser history. Using an information theoretic approach the available data provides strong evidence that the effect of grazing on total species richness varies according to available phosphorus and tree cover. Intermittent grazing and no grazing were associated with high total and native plant richness, but only at low phosphorus concentrations. Phosphorus was strongly negatively correlated with richness, particularly at low grazing frequency. Total species richness was positively correlated with tree cover except under frequent grazing at high stocking rates, suggesting that heavy grazing eliminates spatial and temporal heterogeneity imposed by trees. Native plant species richness was negatively correlated with a history of cultivation, positively correlated with tree cover and varied according to landscape position and geological substrate. Frequent high density grazing, particularly when associated with clearing, cultivation and fertiliser addition, was associated with the persistence of very few native plant species. In contrast, the richness of exotic plant species was relatively invariant and performance of the best model was low. While several studies have highlighted the importance of the grazed and cleared matrix for the conservation of native plant species, this benefit may be limited in landscapes where intensive grazing management systems dominate. Strong evidence for interactions between grazing, phosphorus and tree cover suggest that failure to consider other land use practices associated with grazing management systems could lead to erroneous conclusions regarding vegetation responses to livestock grazing.     

Environment of the East Carpathian Foreland during periods of Palaeolithic man's activity

Several Palaeolithic sites have been discovered in the Halyč Prydnistrov'ja (East Carpathian Foreland) during the last 20 years; thereby this region becomes important when studying the development of Palaeolithic cultures in Eastern Europe. The cultural layers are associated with different horizons of paleosols in loess profiles. Palaeolithic materials were found in four stratigraphic horizons: two of them are of Middle Palaeolithic and two others of Upper Palaeolithic. Palaeogeographical and stratigraphical studies of loesses were the basis of reconstructions of the past landscapes. The palaeopedological study as well as pollen analysis give information about the past environment. Moreover, the molluscan fauna indirectly shows the character of vegetation cover. Relatively open deciduous or mixed forests were the environment of the older Middle Palaeolithic phase of settlement, open forests with patches of steppe and meadow habitats characterized the younger one. Open vegetation dominated during the Upper Palaeolithic. The qualities of local relief as well as local climate and environment in the East Carpathian Foreland and especially in the Dniester River valley were favourable for Palaeolithic hunters.     

Microbiological investigations of paleosols of archeological monuments in the steppe zone

Microbiological studies of the paleosols of archeological monuments (burial mounds) of the Neolithic, Bronze, Early Iron, and Middle Ages (the fourth millennium BC to the fourteenth century AD) located in the dry and desert steppe of the Lower Volga River basin were conducted. The microbial communities that existed at the time of creating the burial mounds were shown to be preserved up to the present time. This fact was confirmed by the regularities of the distribution of the microorganisms in the “mound-buried soil” system and by the data on the determination of the age for the microbial fraction of the paleosols using the method of ¹⁴C atomic mass spectrometry. The total biomass of the microbial communities in the paleosols amounted to 20–40% of the microbial biomass in their background analogues. In all the paleosols, a special pool of viable microorganisms was present. In the microbial community of the paleosols, the biomass of the active microorganisms corresponded to 0.30–41.0% of the biomass in the present-day soil; the content of mycelium of microscopic fungi composed 43–50% of that in the recent soil. In the mycelium structure in the paleosols, the share of the dark-colored mycelium increased to 98–100%. The microbiological parameters that give a contrasting characterization of the state of the microbial communities in the soils during the arid and humid climatic periods were revealed. The changes of the arid and humid climatic epochs were reflected in the structure of the microbial communities in the paleosols at the ecological-trophic, metabolic, and genetic levels.     

Specific features of paleosols of burial mounds involved in current farming practices and their contemporary pedogenesis (using the early Alanian burial mounds in the North Caucasus region as an example)

Paleosols of three burial sites—Brut 1, Brut 2, and Beslan—in the Northern Osetia Republic (Alania) of the North Caucasus region were studied. A part of the Brut 2 burial site was subjected to intensive agricultural use (more than 30-year-long irrigation and regular tillage). This led to the leveling of the burial mounds and changes in some properties of the buried paleosols. A comparative analysis of paleosols of the same age under the burial mounds involved not included in the intensive agricultural use made it possible to determine the degree of preservation of the initial properties in the irrigated paleosols and to use them for reconstruction of the paleoclimates. Some specific features of the soil evolution were revealed, and paleoclimate reconstructions were performed for the period of the Early Alan civilization in the North Caucasus region (from the second half of the 2nd century AD to the middle of the 5th century AD).     

Future of land use in Australia: An economic perspective

It is proposed that the standard economist's model of optimum land use is extended to include the interaction with land cover and land condition. Such a model allows consideration of the influence of market factors and government policies and programmes on land use patterns and management practices, and the feedback effect on land cover and land condition. Recent developments in the approach to modelling land condition, which include the joint consideration of economic factors and physical processes, are discussed. Factors affecting the pattern of agricultural land use in Australia are then reviewed. The importance of considering economic and physical interactions when assessing land use patterns is increasingly being recognized in research and policy development. If research is to meet the needs of land managers in the future then economists and physical scientists will need to integrate their data modelling capabilities in order to address natural resource management issues.     

Late pleistocene paleosol sequences as an instrument for the local paleographic reconstruction of the Kostenki 14 key section (Voronezh oblast) as an example

A sequence of five paleosol units (with seven individual paleosol profiles) buried in the Late Pleistocene (20–40 ka) deposits was studied at the Kostenki 14 (K14) key section in Voronezh oblast with the use of a set of morphological, physicochemical, and instrumental methods. The upper-lying paleosols differed from the lower-lying paleosols in the less pronounced gley features, stronger aggregation of the soil material, more significant accumulation of carbonates, and higher percentage of calcium humates and fulvates. These features attested to the higher aridity of the paleoclimate and the development of the upper-lying paleosols under grassy vegetation. Within the studied paleosol sequence, the most developed profiles were typical of the soils that formed 27–32 ka ago during the Bryansk interstadial. The good aggregation, the presence of features left by the soil fauna activity, the high magnetic susceptibility, and the morphology of the secondary carbonates in the studied paleosols suggest that they were formed under meadow-steppe vegetation in well-drained positions and resembled modern cryoarid soils.     

Gefügeänderung bei Andosolen Südchiles als Folge der Nutzung seit der Rodung

Changes in soil structure as caused by land use after clearing virgin forest Three groups of volcanic ash soils from southern Chile were investigated to evaluate the change of porosity, penetrometer resistance and packing characteristics of virgin forest soils due to different forms of land use during a variable length of time. The different forms of land use were pasture, arable land and reforestation with Pinus radiata. Afforestation tended to loosen the soil and to increase soil strength, whereas pasture use or a pasture-arable land rotation showed severe compressions. Compressions, as noticed in the ash soils under study, appeared to be more pronounced than is generally observed in mineral soils.