Cumulic Soils Research Articles

THE MICROMORPHOLOGY OF AN SENSISITVE HILLY SOIL AS HABITAT FOR MICROBIOTA DELIVERING SOIL ECOSYSTEM SERVICES

The paper investigated the aspects related to the intimate processes taking place in a slope soil, located in the hilly region of Buzău County (Aldeni), an area highly affected by erosion processes. The study was focused on a Cambic-Cumulic Chernozem, located in the lower part of a convex slope facing south. The results showed that the plasma leaching process is very high in the upper Apt-A/B horizons: emphasised by the abundance of the impure clay coatings, which practically coated many structural aggregates. The granulometry data weakly emphasized these aspects: the differences between the clay content in the top Ap and Aph horizons is 1.1%, while the physical clay ( 0.01 mm) showed a higher difference of 1.8%. In contrast, the hydro-physical analysis showed impressive differences, comparing to the granulometry: total porosity is 53.5% in Ap and 43.2% in Aph, while the hydraulic conductivity is 10.29 mm/h in Ap, dropping to 4.57 mm/h in Aph. These differences could be due to the impure (and rich in Fe gels) clay coating which coated and even clog many pores. In the Bv horizon the clay attended a maximum (35.9%, comparing to 30.4% in the upper and 33.5% in the lower horizons respectively), the groundmass plasma is relatively stable, while the clay coatings are rarely. In stead, the plasma from the humic coprolites "massively" leached in the void space. The macro- and mesofauna activity is very high, suggesting a friendly habitat, and showing good conditions for high level of cumulic soil services delivery.

Sedimentation rates on the floodplains of lowland rivers in the center of the European Part of Russia according to the study of soil-alluvial chronosequences

The floodplain deposition rates for the Istra, Oka and Seim rivers valleys were estimated based on a combination of dating methods (radiocarbon, radiocesium and historical-archaeological) for various time windows of the Holocene. In addition, a new method to estimated sedimentation rate, based on the assessment of the degree of soil profile development of paleosols buried in alluvium was applied. Spatio-temporal differences in the rates of floodplain sedimentation have been established based on chronological and soil-geomorphological studies. It was found that sedimentation rates on the young floodplain of Seim and Istra rivers is 1.823 mm year1), 215 mm year1, respectively. While on the ancient floodplains of Oka and Seim rivers during different periods, the floodplain deposition rate varied within the range of 0.010.7 mm year1. The periods of increased sedimentation rates were short in time. Based on the study of a young, rapidly growing Istra River floodplain, the deposits of which are dated on the basis of historical and archaeological materials, new sedimentation rates that characterize the floodplains of the center part of the East European Plain were obtained: alluvium without signs of pedogenesis is formed at a sedimentation rate of more than 15 mm year1, with signs of pedogenesis at a rate of 215 mm year1, cumulative soils at a rate of 0.52 mm year1. Cyclic fluctuations in the sedimentation rate in the Holocene were established on the basis of14C and archaeological dates for to the Nikitino section located on the Oka River floodplain, where a large series of well-developed paleosols were distinguished. It was found that during periods with active accumulation of alluvium layers, sedimentation rate was about 2 mm year1, which is 20 times higher than in longer periods soil formation, when sedimentation rates were 0.070.14 mm yr1.

Using a post-glacial terrace sequence to better understand landscape evolution and paleohydrology in the eastern San Juan Mountains, USA

Terraces provide a unique record of environmental change as they form due to changes in sediment supply and hydrology. In the upper Rio Grande drainage, terraces are post-glacial in age and have not been impacted by tectonics during that period. As such, these terraces are the result of changes to the fluvial system since glaciers retreated. We mapped four terrace units across two sections of the upper Rio Grande. We then examined soil profiles on terrace units, described the sedimentology, and dated the terraces where possible. Our findings indicate that the upper terrace (FT1) formed as an outwash terrace during glaciation and that incision began immediately after glaciers had melted around 12.1 ka. Two intermediate terraces likely formed during brief pauses in post-glacial incision as aggradation of the lowest terrace (FT4, 7–14 m below FT1) had already begun by 9.6 ka. Cumulic soils and fine-grained sediment on FT4, combined with radiocarbon ages, indicate that FT4 aggraded consistently in both rivers throughout the Holocene. Specifically, overbank deposits emplaced during decadal-scale flooding have allowed FT4 to aggrade consistently since 9.6 ka. The main channel appears to have been stable throughout the entire Holocene given that it is pinched between fine-grained deposits. Previous work indicates that other authors have noted similar landforms although they seem to be underreported in the literature. The timing of terrace formation differs from that in nearby headwater streams, indicating that headwater systems are more responsive to hillslope processes while larger trunk streams appear to receive sediment from upstream. Apparent differences in flooding between the two basins may indicate that basins with water managed by reservoirs may flood the FT4 surface less often, thereby highlighting the impact of water management on both fluvial hydrology and sediment storage.

Factors controlling SOC stability in colluvial soils under contrasting climate and soil weathering conditions

AbstractAlthough agricultural colluvial soils are important storage for soil organic carbon (SOC), the mechanisms underlying colluvial (cumulative soils) SOC stability have received little attention so far. In this study, we aim to understand to what extent the main controls on colluvial SOC stability differ from those observed in non‐colluvial soils. Paired soil profiles (non‐colluvial versus colluvial) were collected from five sites which differ in climate, soil geochemical background and cultivation history. Topsoil (0–10 cm) and subsoil (30–50 cm) were analysed for SOC fractions, mineral composition, potential soil respiration and radiocarbon content. Our analysis showed that for non‐colluvial soils, climate, cultivation history and weathering degree have significant effects on potential soil respiration. In contrast, for colluvial soils, the most influential factor for potential soil respiration was the rate of accretion and this was independent of climatic and geochemical context. Furthermore, accretion rates indirectly affected potential soil respiration by interacting with the degree of weathering of deposited soil. This changed the mineral matrix of colluvial soil settings and thereby may enhance soil mineral‐related SOC stabilisation mechanisms. Together, these results suggest that the dominant controls on SOC stability in colluvial soils differ from those in non‐colluvial soils, and the soil accretion rate is the most important control on colluvial SOC stability in agricultural systems.Highlights The dominant controls on SOC stability in colluvial and non‐colluvial soils were compared. Climate and mineral weathering predominantly control SOC stability in non‐colluvial soils. In contrast, the accretion rate is the key factor controlling colluvial SOC stability. Accretion rate drives the role of mineral weathering in colluvial SOC stability.

Long-term response of respective grass types to variations in fire frequency in central Japan, inferred from phytolith and macrocharcoal records in cumulative soils deposited during the Holocene

Phytolith and charcoal records in cumulative soils provide a past history of vegetation transition with fire occurrence. By using these records, we assess the long-term response of respective grass types to variations in fire frequency in central Japan. We analyzed phytoliths and macrocharcoals in cumulative soils on the Kannabe Plateau in central Japan. The results of the analysis showed that prior to 8000 cal BP, Sasa species was dominant along with Pleioblastus species under conditions of low fire frequency. Between 8000 and 2000 cal BP, the plateau was covered by grasslands dominated by Pleioblastus species under a warmer climate and/or an increase in fire frequency. Since approximately 2000 cal BP, the grasslands have been covered by Miscanthus sinensis under a high fire frequency of repeated cycles of annual burning, as is present today. The establishment and maintenance of a M. sinensis grassland are probably related to human activity in this area because this species had many uses. Correlation coefficients for phytolith types versus charcoal concentrations in cumulative soils from three areas in central Japan, including the Kannabe Plateau area, were obtained to assess the habitats and related fire frequencies for their respective grass types. These correlations were consistent with their fire tolerance and degree of succession, as inferred from modern observations. This suggests that the modern fire ecology of these grass types can be used to understand their long-term fire ecology.

Fire history reconstructed from charcoal particles in cumulative soils and the taphonomy of charcoal

Fire history reconstructed from charcoal particles in cumulative soils and the taphonomy of charcoal

Fruit quality components of balsam pear (Momordica charantia L.) and soil respiration in response to soil moisture under two soil conditions

Balsam pear (Momordica charantia L.) is an important vegetable reported to have pharmacological properties. It contains abundant bioactive compounds which can be affected by viticulture and environment factors. Identification of the optimal cultivate condition is fundamental to enhance fruit quality components of balsam pear and to decrease carbon dioxide efflux of vegetable garden. The objective of this study was to identify changes of health-promoting bioactive compounds (flavonoids and saponins) and fruit nutritional quality of balsam pear, as well as seasonal variation of soil respiration (Rs) in response to soil moisture under different soil types. A field experiment was conducted using a 3 × 2 factorial involving three levels soil moisture including 50–60% (L), 70–80% (M), and 90–100% (H) of field moisture capacity (FC) under Loessial soil (L) and Cumulic cinnamon soil (C) conditions. The results indicated that moderate soil moisture was benefit for improving quality components, 70–80% FC was benefit for accumulation of health-promoting bioactive compounds on the Cumulic cinnamon soil, and 70–80% FC was benefit for the nutritional quality of fruit on the Loessial soil; soil respiration measured in Loessial soil were always higher than that in Cumulic cinnamon soil. Air temperature, photosynthetic active radiation, soil temperature had positive correlation with Rs to some extent, while air relative humidity had a negative correlation with Rs. This study would be potentially beneficial for efficiently producing functional and high quality balsam pear.

Risk factors of 12-month recurrence in patients with pancreatic ductal adenocarcinoma undergoing pancreatoduodenectomy

Studies of the palaeobiology of titanosaur eggs are significantly more common than studies of titanosaur-egg-bearing strata. Nevertheless, the latter provide significant insight into palaeoenvironmental conditions associated with the egg-laying behaviour. This study examines titanosaur-egg-bearing strata of the Upper Cretaceous Los Llanos Formation (La Rioja, Argentina) and relates them to the laying and preservation of titanosaur egg clutches. Los Llanos Formation is a predominantly sandstone succession throughout represented by palaeosol profiles. Five titanosaur egg clutches were recovered from the Bw horizon of an Inceptisol profile. This palaeosol type, named Tama pedotype, constitutes 69% of the entire succession, by thickness. Rare planar, and undulating lamination and cross stratification, quartz-grain surface microtextures and ventifacts are indicative of the interaction of fluvial-aeolian processes of sedimentation during accumulation of the parent material on the distal part of a coalescent alluvial fan system (bajada). Highly abundant root traces, reddish colour, clay coatings and calcium carbonate nodules testify that the Tama pedotype had abundant vegetation cover, and was developed in well-drained conditions under the influence of a semiarid climate regime. Palaeosol horizons with exaggerated thickness and diffuse boundaries indicate a cumulative pedotype, whereby the soil developed in response to continuous accretion via on-going sedimentary processes.Morphological features of eggshells suggest that titanosaurs dug holes in the topographic surface to lay eggs. Thus, palaeosols seem to have been putative areas for the laying of titanosaur eggs. Actually, it is uncommon for palaeosols to constitute sites for the preservation of eggs, since soils typically develop in response to long episodes of weathering. However, cumulative palaeosols can provide ideal conditions for egg burial and preservation. In cumulative soils, the residence time of an object within the weatherable thickness of a soil is reduced to < 103 years, thereby significantly increasing the long-term preservation potential of eggs.

Preservation of titanosaur egg clutches in Upper Cretaceous cumulative palaeosols (Los Llanos Formation, La Rioja, Argentina)

Studies of the palaeobiology of titanosaur eggs are significantly more common than studies of titanosaur-egg-bearing strata. Nevertheless, the latter provide significant insight into palaeoenvironmental conditions associated with the egg-laying behaviour. This study examines titanosaur-egg-bearing strata of the Upper Cretaceous Los Llanos Formation (La Rioja, Argentina) and relates them to the laying and preservation of titanosaur egg clutches. Los Llanos Formation is a predominantly sandstone succession throughout represented by palaeosol profiles. Five titanosaur egg clutches were recovered from the Bw horizon of an Inceptisol profile. This palaeosol type, named Tama pedotype, constitutes 69% of the entire succession, by thickness. Rare planar, and undulating lamination and cross stratification, quartz-grain surface microtextures and ventifacts are indicative of the interaction of fluvial-aeolian processes of sedimentation during accumulation of the parent material on the distal part of a coalescent alluvial fan system (bajada). Highly abundant root traces, reddish colour, clay coatings and calcium carbonate nodules testify that the Tama pedotype had abundant vegetation cover, and was developed in well-drained conditions under the influence of a semiarid climate regime. Palaeosol horizons with exaggerated thickness and diffuse boundaries indicate a cumulative pedotype, whereby the soil developed in response to continuous accretion via on-going sedimentary processes.Morphological features of eggshells suggest that titanosaurs dug holes in the topographic surface to lay eggs. Thus, palaeosols seem to have been putative areas for the laying of titanosaur eggs. Actually, it is uncommon for palaeosols to constitute sites for the preservation of eggs, since soils typically develop in response to long episodes of weathering. However, cumulative palaeosols can provide ideal conditions for egg burial and preservation. In cumulative soils, the residence time of an object within the weatherable thickness of a soil is reduced to <103years, thereby significantly increasing the long-term preservation potential of eggs.

Identification of the Core Set of Carbon-Associated Genes in a Bioenergy Grassland Soil.

Despite the central role of soil microbial communities in global carbon (C) cycling, little is known about soil microbial community structure and even less about their metabolic pathways. Efforts to characterize soil communities often focus on identifying differences in gene content across environmental gradients, but an alternative question is what genes are similar in soils. These genes may indicate critical species or potential functions that are required in all soils. Here we identified the “core” set of C cycling sequences widely present in multiple soil metagenomes from a fertilized prairie (FP). Of 226,887 sequences associated with known enzymes involved in the synthesis, metabolism, and transport of carbohydrates, 843 were identified to be consistently prevalent across four replicate soil metagenomes. This core metagenome was functionally and taxonomically diverse, representing five enzyme classes and 99 enzyme families within the CAZy database. Though it only comprised 0.4% of all CAZy-associated genes identified in FP metagenomes, the core was found to be comprised of functions similar to those within cumulative soils. The FP CAZy-associated core sequences were present in multiple publicly available soil metagenomes and most similar to soils sharing geographic proximity. In soil ecosystems, where high diversity remains a key challenge for metagenomic investigations, these core genes represent a subset of critical functions necessary for carbohydrate metabolism, which can be targeted to evaluate important C fluxes in these and other similar soils.

Disappearance and alteration process of charcoal fragments in cumulative soils studied using Raman spectroscopy

Raman spectra of charcoal fragments in cumulative soils in central Japan, where grasslands have been sustained using intentional burning for ~1000years, were obtained and compared to those of fresh charcoal fragments after modern grass burning to clarify their disappearance and alteration process in the soils. Although the values of each Raman-spectrum parameter of the soil charcoal and fresh charcoal fragments are partially similar, certain differences indicating their alteration or disappearance were observed. Charcoal fragments with lower graphitization in soils altered chemically with age at decadal to century scale, suggested by changes in distance between defects or defect type of their chemical structures. Charcoal fragments with higher graphitization were found in fresh charcoal samples, whereas very few charcoal fragments were found in both young and old soils, indicating that these charcoal fragments disappeared instantly after they were formed. This fact implies that charcoal fragments with higher graphitization tend to not remain in soils, possibly owing to their physical properties such as fragility, density, and hydrodynamic behavior. Our findings suggest that charcoal's physical properties have a vital influence on charcoal residues in soils, as do charcoal's chemical properties.

Forces driving late Pleistocene (ca. 77–12 ka) landscape evolution in the Cimarron River valley, southwestern Kansas

This study presents stratigraphic, geomorphic, and paleoenvironmental (δ13C) data that provide insight into the late Pleistocene landscape evolution of the Cimarron River valley in the High Plains of southwestern Kansas. Two distinct valley fills (T-1 and T-2) were investigated. Three soils occur in the T-2 fill and five in the T-1 fill, all indicating periods of landscape stability or slow sedimentation. Of particular interest are two cumulic soils dating to ca. 48–28 and 13–12.5 ka. δ13C values are consistent with regional paleoenvironmental proxy data that indicate the prevalence of warm, dry conditions at these times. The Cimarron River is interpreted to have responded to these climatic changes and to local base level control. Specifically, aggradation occurred during cool, wet periods and slow sedimentation with cumulic soil formation occurred under warmer, drier climates. Significant valley incision (~25 m) by ca. 28 ka likely resulted from a lowering of local base level caused by deep-seated dissolution of Permian evaporite deposits.

The relationship between past vegetation type and fire frequency in western Japan inferred from phytolith and charcoal records in cumulative soils

Phytolith and macrocharcoal records in cumulative soils were compared in five areas in western Japan, including two sites on the Tonomine Plateau where we examined those records. Past vegetation types, as represented by the compositions of phytolith assemblages, are closely related to macrocharcoal fluxes, regardless of age, suggesting that in Japan, fluxes in cumulative soils could be an indicator of fire frequency. On the Tonomine Plateau, phytolith and charcoal records indicate that, in the middle and late Holocene (at least 5000 to ∼1000 years ago), Sasa and Panicoideae species in a temperate climate. At least for approximately the last 600 years the Japanese pampas (Miscanthus sinensis) grassland has undergone annual burning. The results from the Tonomine Plateau site of this study and from four other sites suggest that macrocharcoal fluxes in cumulative soils of >10 particles·cm−2 y−1 indicate a high frequency of fires, resulting in the dominance of Andropogoneae species. Dominance of Pleioblastus species under the influence of fire was observed in soils with a charcoal flux of 2–10 particles·cm−2 y−1, suggesting that the species flourished under a moderate frequency of fire (possibly every several years or more). In soils with a charcoal flux of less than ∼1 particles·cm−2 y−1, there was no influence of fire on vegetation, and Sasa and Pleioblastus species flourished where the vegetation type was determined primarily by the climatic conditions. These findings indicate that macrocharcoal fluxes and phytolith assemblages exhibit a consistent relationship that is independent of age, and that macrocharcoal fluxes are linked to fire frequency, thus suggesting that the frequency of fire has determined the vegetation type in these areas. Therefore, phytolith and charcoal records in cumulative soils provide a context for quantitatively understanding the influence of fire on vegetation patterns in the past.

INTERACTION OF ALLUVIAL AND SOIL FORMATION PROCESSES AT DIFFERENT STAGES OF THE FLOOD PLAINS DEVELOPMENT DURING THE HOLOCENE (THE RIVERS OF THE CENTRAL PART OF THE EAST EUROPEAN PLAIN AS AN EXAMPLE)

The paper generalizes the data of the alluvium accumulation and soil formation rates in the flood plains of the plain rivers. The method of assessment is based on facies analysis of flood plain deposits containing series of buried soils. The Middle Oka, the Moscow, the Upper Don, and the Nepryadva rivers were investigated. The correlation of paleogeographic events with the conditions of soil formation and human activity in the Holocene were revealed, the stages of soil formation were discovered. We established that at the rate of accumulation more than 0.25 cm/y the soil formation doesn’t change the alluvium, at the rate of 0.1-0.25 cm/y the alluvium have traces of the soil, at the rate of 0.03-0.1 cm/y the cumulative sod-layered soils appear, and at the rate of 0.01-0.03 cm/y the well-developed sod and meadow soils are forming.

Chronosequence development and soil variability from a variety of sub-alpine, post-glacial landforms and deposits in the southeastern San Juan Mountains of Colorado

Surficial processes acting on post-glacial alpine and sub-alpine landscapes vary at small temporal and spatial scales and are thus often difficult to conceptualize in the context of large-scale landscape evolution models. Soils developing in this setting can thus provide valuable information about landform genesis, sedimentology and age. Relatively few post-glacial chronosequences have been examined in these settings however, particularly for the variety of landforms and parent materials that exist within alpine and sub-alpine environments. Here, we examine a chronosequence of relatively young, post-glacial landforms with varying parent materials and climate histories. We dug and described 39 soil pits in the upper Conejos River Valley of Colorado on a variety of deposits and landforms, including alluvial fans, terraces, colluvium, glacial till, and terminal moraines, and compared soil properties with radiocarbon ages from the area. Our results suggest that some typical chronosequence soil properties (e.g., pH, structure, color) do not correlate with time over short time scales. However, extractable iron ratios (Feo/Fed) show a relatively strong correlation with age across late-Pleistocene and Holocene time scales and maximum profile clay content shows a weak but statistically significant relationship with age. Both of these trends are stronger when examined across a single parent material. Differences in initial parent material texture and dust inputs seem to be the most significant complicating factors over post-glacial time scales. Soil property development through time is most inconsistent in cumulic alluvial fan soils. This observation may indicate that alluvial fans are more responsive to sub-basin scale processes as opposed to fluvial terraces that are more likely respond to processes active across the entire basin. These differences would explain why stratigraphically similar alluvial fans are mantled by soils with varying development. Nonetheless, horizonation, clay content, and extractable iron ratios provide a useful tool for correlating young deposits, assigning ages, and interpreting the geomorphic history of complex post-glacial environments.

栽培番茄的塿土和黄绵土水分和温度变化规律

In this paper we report the findings from experiments using soil columns to investigate changes in water content and temperature in cumulic cinnamon soils and loessial soils which were used to grow cherry tomatoes(Lycopersicon esculentum var.cerasiforme Alef.).A mathematical model for soil water distributions was used to simulate the vertical changes in soils water,and a sinusoid model was selected to analyse soil and air temperature as well as the changes in air humidity.The results show that the average soil water content and the infiltration rate in the cumulic cinnamon soils are higher than those in the loessial soils.The temperature in the cumulic cinnamon soils is higher than that in the loessial soils at the same depth.The soil temperature has obvious hysteresis as the depth increases.The water use efficiency of tomatoes in the loessial soils is higher than in the cumulic cinnamon soils.The air temperature,relative humidity,soil temperature and soil water content influence one another.The mathematical model in this study effectively simulates the water movement in the soil above 20 cm.Within the variable range of the variables in the mathematical equation,the water content in the small depths can be accurately determined using the elapsed time in the cherry tomatoes at the full fruit period,which provides a theoretical basis for improving the drought resistance,scheduling water-saving irrigation plans and improving water use efficiency.

Extensive middle Miocene weathering interpreted from a well-preserved paleosol, Cricket Flat, Oregon, USA

The high-resolution marine isotope climate record indicates pronounced global cooling during the Langhian (16–13.8Ma), beginning with the warm middle Miocene climatic optimum and ending with significant Antarctic ice sheet expansion and the transition to “icehouse” conditions. However, the timing and rate of cooling during the Langhian are uncertain. Terrestrial paleoclimate data from this interval is sparse and sometimes conflicting; in particular, there are gaps in the terrestrial record in the Pacific Northwest during the late Langhian and early Serravallian between about 14.5 and 12.5Ma. New terrestrial paleoclimate data from this time and region could help reconcile these conflicting records. Paleosols are particularly useful for reconstructing paleoenvironment because the rate and style of pedogenesis are primarily a function of surface environmental conditions; however, complete and well-preserved paleosols are uncommon. Most soils form in erosive environments that are not preserved, or in environments such as floodplains that accumulate in small increments; the resulting cumulic soils are usually thin, weakly developed, and subject to diagenetic overprinting from subsequent soils. The paleosol at Cricket Flat in northeastern Oregon is an unusually complete and well-preserved paleosol from a middle Miocene volcanic sequence in the Powder River Volcanic Field. An olivine basalt flow buried the paleosol at approximately 13.8±0.6Ma, based on three 40Ar/39Ar dates on the basalt. We described the Cricket Flat paleosol and used its physical and chemical profile and micromorphology to assess pedogenesis. The Cricket Flat paleosol is an Ultisol-like paleosol, chemically consistent with a high degree of weathering. Temperature and rainfall proxies suggest that Cricket Flat received 1120±180mm precipitationyear−1 and experienced a mean annual temperature of 14.5±2.1°C during the formation of the paleosol, significantly warmer and wetter than today. This suggests slower cooling after the middle Miocene climatic optimum than is seen in the existing paleosol record.

A Micromorphological Assessment of Anthropogenic Features in Pre-Columbian French Guiana Dark Soils (FGDS): First Results

In order to document site formation processes at microscale and to characterise pre-Columbian French Guiana dark soils (FGDS), micromorphology was performed on three sites. For the first time it was possible (i) to microscopically characterise pre-Columbian Anthrosols in different physical contexts and (ii), to identify anthropogenic features associated with past human occupation. Microfeatures of the Holocene alluvial terrace of the lower Maroni River witnessed (i) several episodes of clay enrichment and/or redistribution, (ii) seasonal waterlogging, and (iii), post-depositional biological activity. Clay en- richment and organic matter inputs together with biological activity processes might have alternated, probably in relation to vegetal cover and/or anthropogenic activities. On top of the alluvial terrace, bio- turbated dark layers are enriched in fine brown organic matter and charcoals. Cumulic soil development was favoured when successive sediment inputs due to episodic flooding and/or overland flow was pos- sible (Chemin Saint Louis site). On a lateritic hill, under rainforest, at the MC87 ring-ditched mountain (Montagnes Couronnees or Crowned Mountain), microscale identification of yellowish unburnt oxic B horizon aggregates together with anthropogenic features related to fire such as charcoals and burnt soil fragments (rubefied and dark brown aggregates) stress that lateritic soil acted as support for activities in the enclosure, and as reworked material in the ditch. These components could result from clearance for settlement, agricultural management and cultivation, or domestic activities. The obtained results allow first comparisons to be drawn between pre-Columbian FGDS and Brazilian dark earths (BDE). Except a similarity in colour, the former is revealed to be less rich in anthropogenic components with an absence of phosphatic elements such as bones.

Soil Phosphorus Extracted by Three Anion Exchange Membranes Compared to Water-Soluble and Truog-Extractable Phosphorus

Effects of different kinds of anion exchange membrane (AEM) on soil P extracted by AEM (AEM P) were investigated in three soils (Cumulic Andosol, Yellow soil, and Gray Lowland soil). There was no significant difference in AEM P among the AEMs tested (BDH-Prolabo 551642S, AGC Engineering Selemion AMT, and AGC Engineering Selemion AMV). The AEM P was greater than water-soluble P in all soils. Although AEM P was greater than Truog-extractable P in Cumulic Andosol, the reverse was true in the Yellow soil and Gray Lowland soil.

Holocene history of intentional fires and grassland development on the Soni Plateau, Central Japan, reconstructed from phytolith and macroscopic charcoal records within cumulative soils, combined with paleoenvironmental data from mire sediments

Phytolith and macroscopic charcoal in cumulative soils on the Soni Plateau, Central Japan, were evaluated to clarify the Holocene history of intentional fires and grassland development, and to compare the findings with those derived from pollen and charcoal records in sediments taken from a nearby mire in the previous study. Prior to ~1500 cal. BP, Bambusoid short-cell phytoliths and Pleioblastus-type and Bambusoideae-type bulliform cell phytoliths were abundant with scarce charcoal particles (&lt;1000 particles/cm3). In contrast, since ~1500 cal. BP Andropogoneae-type bulliform cell phytoliths and Bilobate short-cell phytoliths were dominant with abundant charcoal particles (&gt;1000 particles/cm3). Based on correlating these records with pollen and charcoal records in mire sediments, prior to ~1500 cal. BP, dwarf bamboo flourished on the forest floor under largely fire-free conditions, whereas since ~1500 cal. BP, grassland dominated by Japanese pampas grass has been sustained by periodic intentional burning that has continued until the present day.