Fire-patterned vegetation and the development of organic soils in the lowland vegetation mosaics of south-west Tasmania

2011 ◽  
Vol 59 (2) ◽  
pp. 126 ◽  
Author(s):  
S. W. Wood ◽  
Q. Hua ◽  
D. M. J. S. Bowman
Keyword(s):  
Soil Depth ◽  
Isotope Composition ◽  
Organic Soil ◽  
Fire Frequency ◽  
Organic Soils ◽  
Soil Profiles ◽  
Radiocarbon Age ◽  
South West ◽  
Vegetation Boundary ◽  
Vegetation Mosaics

Two contrasting ecological models have been proposed for the forest–moorland vegetation mosaics of south-west Tasmania that stress different interactions between fire, soils, vegetation and the physical environment to produce either stable or dynamic vegetation patterns. We investigated aspects of these models by sampling organic soil profiles across vegetation mosaics to determine variation in soil depth, organic carbon (C) content, nutrient capital, stable C isotope composition (δ13C) and 14C radiocarbon age in two contrasting landscape settings. 14C basal ages of organic soils ranged from recent (<400 calibrated (cal.) years BP) to mid Holocene (~7200 cal. years BP), with a tendency for older soils to be from poorly drained moorlands and younger soils from the forest. The long-term net rate of C accumulation ranged from 2.7 to 19.2 gC m–2 year–1, which is low compared with northern hemisphere peatland systems. We found that δ13C in organic soil profiles cannot be used to infer Holocene vegetation boundary dynamics in these systems. We found a systematic decrease of phosphorus from rainforest through eucalypt to moorland, but estimated that phosphorus capital in moorland soils was still sufficient for the development of forest vegetation. Our results suggest that the characteristics of organic soils across the landscape are the result of interactions between not only vegetation and fire frequency, but also other factors such as drainage and topography.

MONOLITH COLUMNS FOR STUDYING ORGANIC SOIL PROFILES

1986 ◽  
Vol 66 (4) ◽  
pp. 737-742
Author(s):  
J. A. MILLETTE ◽  
R. S. BROUGHTON
Keyword(s):  
Hydraulic Conductivity ◽  
Physical Properties ◽  
Bulk Density ◽  
Organic Soil ◽  
Saturated Hydraulic Conductivity ◽  
Fiber Content ◽  
Organic Soils ◽  
Soil Profiles ◽  
Sampling Procedures ◽  
Monolith Columns

Monolith column construction and sampling procedures were described for organic soil profiles and used to measure the variation with depth of saturated hydraulic conductivity, bulk density and fiber content. The top 0.30 m of the organic soil was more permeable, had a greater bulk density and had a greater fiber content than the soil layer between 0.60 and 0.90 m from the soil surface. These columns can be used for correlations studies between physical properties and studies of the dynamic nature of the physical properties of organic soils. Key words: Saturated hydraulic conductivity, bulk density, fiber content, organic soil, monolith columns

Precision N management for field vegetables in organic soils: a short review

2017 ◽  
Vol 8 (2) ◽  
pp. 308-311
Author(s):  
L. Longchamps ◽  
N. Tremblay
Keyword(s):  
Decision Support ◽  
Spatial Pattern ◽  
Soil Depth ◽  
Short Review ◽  
Organic Soil ◽  
Organic Soils ◽  
N Leaching ◽  
Vegetable Crops ◽  
Research Gaps ◽  
N Management

Field vegetables require large amounts of N and precision N management (PNM) may help increase their productivity, quality and profitability while reducing N leaching in the biosphere. Few studies investigated PNM for field vegetables. This may be explained by the great diversity in crops and cultivars which complicate the broad implementation of PNM discoveries. Field vegetables are often grown in histosols, which have unique properties such as quantity of N mineralized and the spatial pattern of organic soil depth. Finally, research gaps exist in the development of decision support systems adapted to field vegetable crops grown in histosols.

THE ESTABLISHMENT OF SYNCHRONY BETWEEN SUBSURFACE LAYERS AND ESTIMATION OF OVERALL SUBSIDENCE OF CULTIVATED ORGANIC SOILS BY A PALYNOLOGICAL METHOD

1982 ◽  
Vol 62 (2) ◽  
pp. 427-431 ◽  
Author(s):  
S. P. MATHUR ◽  
M. P. LÉVESQUE ◽  
P. J. H. RICHARD
Keyword(s):  
Bimodal Distribution ◽  
Organic Soil ◽  
Tsuga Canadensis ◽  
Organic Soils ◽  
Soil Profiles ◽  
Subsurface Layers ◽  
Physical Changes ◽  
Cultivated Soils

Pollen profiles of Tsuga canadensis in a virgin and two cultivated areas of a bog revealed the bimodal distribution characterized by easily recognizable minima, thus establishing synchrony between specific layers of the three organic soil profiles. This knowledge allowed estimation of overall subsidence of the cultivated soils, and would facilitate comparisons between subsurface layers now determinable as synchronous. Such comparisons should help determine the extent and depth of temporal biochemical and physical changes in subsurface layers of cultivated organic soils.

scholarly journals On the Configuration and Initialization of a Large Scale Hydrological Land Surface Model to Represent Permafrost

2019 ◽  
Author(s):  
Mohamed E. Elshamy ◽  
Daniel Princz ◽  
Gonzalo Sapriza-Azuri ◽  
Al Pietroniro ◽  
Howard S. Wheater ◽  
...  
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Land Surface Model ◽  
Organic Soil ◽  
Organic Soils ◽  
Surface Model ◽  
Soil Profiles ◽  
Computationally Efficient ◽  
Deep Soil ◽  
Mackenzie River

Abstract. Permafrost is an important feature of cold regions hydrology, particularly in basins such as the Mackenzie River Basin (MRB), and needs to be properly represented in hydrological and land surface models (H-LSMs) built into existing Earth System models (ESM), especially under the unprecedented climate warming trends that have been observed. Higher rates of warming have been reported in high latitudes compared to the global average resulting in permafrost thaw with wide-ranging implications for hydrology and feedbacks to climate. The current generation of H-LSMs is being improved to simulate permafrost dynamics by allowing deep soil profiles and incorporating organic soils explicitly. Deeper soil profiles have larger hydraulic and thermal memories that require more effort to initialize. This study aims to devise a robust, yet computationally efficient, initialization and parameterization approach applicable to regions where data are scarce and simulations typically require large computational resources. The study further demonstrates an upscaling approach to inform large-scale ESM simulations based on the insights gained by modelling at small scales. We used permafrost observations from three sites along the Mackenzie River Valley spanning different permafrost classes to test the validity of the approach. Results show generally good performance in reproducing present-climate permafrost properties at the three sites. The results also emphasize the sensitivity of the simulations to the soil layering scheme used, the depth to bedrock and the organic soil properties.

scholarly journals Populasi, Biomassa dan Jenis Cacing Tanah pada Lahan Sayuran Organik dan Konvensional di Bedugul

2019 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
ARFITA TRI MAYASARI ◽  
ANAK AGUNG ISTRI KESUMADEWI ◽  
NI LUH KARTINI
Keyword(s):  
Soil Depth ◽  
Block Design ◽  
Lumbricus Terrestris ◽  
Organic Soil ◽  
Research Area ◽  
Organic Soils ◽  
Morphological Identification ◽  
Important Indicator ◽  
Cultivation System ◽  
Randomized Block Design

Population, Biomass, and Types of Earthworm on Organic and Conventional Vegetable Land in Bedugul. Earthworm is an important indicator of soil fertility. The type of earthworm closelly associated with soil management system. This research aims to determine the population, biomass, and earthworms type that had been done on organic and conventional vegetable ecosystem in Bedugul from December 2017 until March 2018. The purposive research sites were located in Baturiti Village and Candikuning Village for organic and conventional vegetable systems, respectively. The research area was clustered following Randomized Block Design into three group sites and devided based on organic and conventional system as the first factor. The second factor was soil depth (0-10, 10-20 and 20-30 cm) that nested on cultivation system. Calculation of collected earthworm was done in situ while their morphological identification was done at The Soil Science and Environment Laboratory, Faculty of Agriculture,Udayana University.The results confirmed that earthworm population and biomass were affected by cultivation system but the values were not significantly difference among soil depths. The population and biomass of earthworm found in organic soils were two times higher than those in conventional land. Earthworms population in organic field ranged from 66.67 to 89.33 m-2 and on conventional land ranged from 16.00-45.33 m-2. The weight of earthworm biomass on organic land ranged from 1.00-1.93 g and on conventional land ranged from 0.03-0.06 g. The type of worm acquired on organic soil was Lumbricus terrestris and on conventional land was Pontoscolex corethrurus. We can summary from this research that cultivation systems highly influence the community of earthworm.

scholarly journals The occurrence of distinct prismatic & plary structures in organic soil profiles.

1963 ◽  
Vol 11 (5) ◽  
pp. 418-421 ◽  
Author(s):  
F. Kuiper ◽  
S. Slager
Keyword(s):  
Organic Soil ◽  
Groundwater Table ◽  
Organic Soils ◽  
Organic Layer ◽  
Soil Profiles ◽  
Seepage Water ◽  
High Permeability ◽  
Deep Groundwater ◽  
Peat Horizon

Prisms & plates occurring in organic soils were correlated with a deep groundwater table associated with the vicinity of a brook draining the area, sufficient thickness of the organic layer to form an impermeable reduced peat horizon preventing seepage-water from rising in the profile, or Fe coatings on the peds promoting high permeability of the oxidized peat. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals On the configuration and initialization of a large-scale hydrological land surface model to represent permafrost

2020 ◽  
Vol 24 (1) ◽  
pp. 349-379 ◽  
Author(s):  
Mohamed E. Elshamy ◽  
Daniel Princz ◽  
Gonzalo Sapriza-Azuri ◽  
Mohamed S. Abdelhamed ◽  
Al Pietroniro ◽  
...  
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Land Surface Model ◽  
Organic Soil ◽  
Organic Soils ◽  
Surface Model ◽  
Soil Profiles ◽  
Computationally Efficient ◽  
Deep Soil ◽  
Mackenzie River

Abstract. Permafrost is an important feature of cold-region hydrology, particularly in river basins such as the Mackenzie River basin (MRB), and it needs to be properly represented in hydrological and land surface models (H-LSMs) built into existing Earth system models (ESMs), especially under the unprecedented climate warming trends that have been observed. Higher rates of warming have been reported in high latitudes compared to the global average, resulting in permafrost thaw with wide-ranging implications for hydrology and feedbacks to climate. The current generation of H-LSMs is being improved to simulate permafrost dynamics by allowing deep soil profiles and incorporating organic soils explicitly. Deeper soil profiles have larger hydraulic and thermal memories that require more effort to initialize. This study aims to devise a robust, yet computationally efficient, initialization and parameterization approach applicable to regions where data are scarce and simulations typically require large computational resources. The study further demonstrates an upscaling approach to inform large-scale ESM simulations based on the insights gained by modelling at small scales. We used permafrost observations from three sites along the Mackenzie River valley spanning different permafrost classes to test the validity of the approach. Results show generally good performance in reproducing present-climate permafrost properties at the three sites. The results also emphasize the sensitivity of the simulations to the soil layering scheme used, the depth to bedrock, and the organic soil properties.

scholarly journals Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 666
Author(s):  
Guilin Han ◽  
Anton Eisenhauer ◽  
Jie Zeng ◽  
Man Liu
Keyword(s):  
Soil Depth ◽  
Isotope Composition ◽  
Soil Surface ◽  
Natural Soil ◽  
Calcium Isotope ◽  
Karst Forest ◽  
Content Ratio ◽  
The Difference ◽  
Preferential Uptake ◽  
Vital Factor

In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope (40Ca) is in the following order: farmland > burnt grassland > forests > grassland > shrubland. Our results further indicate that biological fractionation in a soil–plant system is a vital factor for Ca–geochemical transformations in soil surface systems.

RELATIONSHIPS BETWEEN SOME PROPERTIES OF ORGANIC SOILS FROM THE SOUTHERN CANADIAN SHIELD

1990 ◽  
Vol 70 (3) ◽  
pp. 363-377 ◽  
Author(s):  
D. ANN BROWN ◽  
S. P. MATHUR ◽  
ANTON BROWN ◽  
D. J. KUSHNER
Keyword(s):  
Principal Component Analysis ◽  
Acid Leaching ◽  
Principal Component ◽  
Organic Soil ◽  
Component Analysis ◽  
Soil Types ◽  
Organic Soils ◽  
Mining Districts ◽  
Two Populations ◽  
Inorganic Components

Different numerical methods used to distinguish between organic soil types are evaluated. The research was initiated by the suggestion that acid leaching from mining wastes could be prevented by capping the tailings with a self-renewing methane-producing muskeg bog, in order to prevent the penetration of oxygen to the wastes. Thirty organic soils from bogs in the mining districts of Elliot Lake, Sudbury, and Timmins, Ontario, and Noranda, Quebec, were sampled and 28 soil characteristics were measured. These characteristics, whose values are normally or lognormally distributed, were analyzed by several different statistical methods. Some characteristics indicate the existence of two populations, and others are bivariantly correlated. Canonical discriminant analysis was more successful than cluster analysis in separating the bogs into well-defined geographical groups. However, principal component analysis proved best at grouping the organic soils according to their organic and inorganic components, and we suggest that this is a suitable method for the general discrimination of organic soil types. Methane was present in all the 17 bogs tested for it, and in two very wet bogs more than 2 mmol of methane per liter were extracted. Key words: Muskeg bog, organic soils, soil characterization, principal component analysis

scholarly journals A Novel Approach to the Analysis of the Soil Consolidation Problem by Using Non-Classical Rheological Schemes

2021 ◽  
Vol 11 (5) ◽  
pp. 1980
Author(s):  
Kazimierz Józefiak ◽  
Artur Zbiciak ◽  
Karol Brzeziński ◽  
Maciej Maślakowski
Keyword(s):  
Constitutive Models ◽  
Organic Soil ◽  
Organic Soils ◽  
Soil Consolidation ◽  
Flexible Tool ◽  
One Dimensional ◽  
Novel Approach ◽  
Soil Skeleton ◽  
The One ◽  
The Relationship

The paper presents classical and non-classical rheological schemes used to formulate constitutive models of the one-dimensional consolidation problem. The authors paid special attention to the secondary consolidation effects in organic soils as well as the soil over-consolidation phenomenon. The systems of partial differential equations were formulated for every model and solved numerically to obtain settlement curves. Selected numerical results were compared with standard oedometer laboratory test data carried out by the authors on organic soil samples. Additionally, plasticity phenomenon and non-classical rheological elements were included in order to take into account soil over-consolidation behaviour in the one-dimensional settlement model. A new way of formulating constitutive equations for the soil skeleton and predicting the relationship between the effective stress and strain or void ratio was presented. Rheological structures provide a flexible tool for creating complex constitutive relationships of soil.

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