scholarly journals A new method for performing smouldering combustion field experiments in peatlands and rich-organic soils

2017 ◽  
Vol 26 (12) ◽  
pp. 1040 ◽  
Author(s):  
E. Pastor ◽  
I. Oliveras ◽  
E. Urquiaga-Flores ◽  
J. A. Quintano-Loayza ◽  
M. I. Manta ◽  
...  
Keyword(s):  
Field Experiments ◽  
Organic Soil ◽  
Ecological Effects ◽  
Organic Soils ◽  
Rating Systems ◽  
Environmental Implications ◽  
Combustion Dynamics ◽  
Peruvian Andes ◽  
Undisturbed Soils ◽  
Smouldering Combustion

Smouldering ground fires have severe environmental implications. Their main effects are the release of large amounts of carbon to the atmosphere with loses of organic soil and its biota. Quantitative data on the behaviour of smouldering wildfires are very scarce and are needed to understand its ecological effects, to validate fuel consumption and smouldering propagation models and to develop danger-rating systems. We present, for the first time, a methodology for conducting smouldering experiments in field conditions. This method provides key data to investigate smouldering combustion dynamics, acquire fire behaviour metrics and obtain indicators for ecological effects of smouldering fires. It is to be applied in all types of undisturbed soils. The experimental protocol is based on a non-electric ignition source and the monitoring system relies on combining both point and surface specific temperature measurements. The methodology has been developed and applied by means of large series of replicate experiments in highly organic soils at the forest–grassland treeline of the Peruvian Andes. The soil tested exhibited weak ignition conditions. However, transition to oxidation phase was observed, with smouldering combustion during 9 h at 15-cm depth and residence times at temperatures above dehydration of ~22 h.

scholarly journals Smouldering Combustion Dynamics of a Soil from a Pinus halepensis Mill. Forest. A Case Study of the Rocallaura Fires in Northeastern Spain

2020 ◽  
Vol 10 (10) ◽  
pp. 3449
Author(s):  
Miquel Àngel Xifré-Salvadó ◽  
Núria Prat-Guitart ◽  
Marcos Francos ◽  
Xavier Úbeda ◽  
Marc Castellnou
Keyword(s):  
Pinus Halepensis ◽  
Mineral Soil ◽  
Chemical Properties ◽  
Fire Regimes ◽  
Organic Soils ◽  
Ignition Probability ◽  
Combustion Dynamics ◽  
Wildfire Hazard ◽  
The Impact ◽  
Smouldering Combustion

This study analyses the smouldering combustion on soils that took place during the wildfires that occurred in Rocallaura (Northeastern Spain). The smouldering combustion after the first event, 23 June, was the potential source of flaming fire re-ignition of the second event, 19 July 2016. Re-ignitions are an important challenge for the firefighting system. Budget and efforts are spent on controlling these re-ignitions that can ultimately cause the collapse of the response system if the re-ignitions happen during periods of simultaneous fire events. Our objective is to contribute to better understand the dynamics of the smouldering combustion of organic soils associated with these wildfires and the impact on the Pinus halepensis Mill. forest ecosystem. Transects were established in adjacent control and post-fire zones. Laboratory analyses were conducted to determine some physical and chemical properties of both the duff and mineral soil. Using these variables, we estimate thresholds of duff ignition probability, percentage of duff consumption and smouldering combustion spread rates. Overall, we provide a set of tools for evaluating re-ignitions in forest ecosystems. We conclude that the concept of fire persistence should be a new variable for consideration in present and future analysis of fire regimes and demonstrates the significance of introducing smouldering combustion and re-ignition within the strategic framework of the wildfire hazard and integrating these phenomena into forest planning and management.

Response by sugar beet to various amounts and times of application of sodium chloride fertilizer in relation to soil type

1982 ◽  
Vol 98 (3) ◽  
pp. 579-592 ◽  
Author(s):  
A. P. Draycott ◽  
Susan M. Bugg
Keyword(s):  
Sodium Chloride ◽  
Sugar Beet ◽  
Field Experiments ◽  
Sodium Concentration ◽  
Organic Soil ◽  
Organic Soils ◽  
Predictive Test ◽  
Mineral Soils ◽  
Sugar Beet Crop ◽  
Sodium And Potassium

SUMMARYTwo-thirds of the sugar-beet crop in the U.K. receives sodium chloride as part of the fertilizer programme. It is well known that the crop responds profitably on sandy soils which contain relatively little sodium and potassium, and most of these fields now receive sodium chloride. Few crops on clays, silts and organic soils are treated because the value of sodium chloride has never been clearly defined. Thus 36 field experiments were made over the 5 years 1975–9 on contrasting soil types testing five amounts of sodium chloride, 0, 100, 200, 400 and 800 kg/ha, and at two times, either autumn or spring. All the fields chosen were in continuous arable rotations where potassium chloride was applied regularly and nearly all the soils contained more than 120 mg exchangeable K/l.Sodium chloride (400 kg/ha costing £12) increased sugar yield on average by about 0·2 t/ha (worth £40) on the mineral soils but no crop responded on organic soil. Exchangeable soil sodium concentration was not a good predictive test of which fields would respond but all the large increases in yield were on fields with less than 20 mg Na/1. A few crops responded on soils with 20–40 mg Na/1 but no crop responded on soil with more than 40 mg Na/1. A survey of sodium concentrations in 800 soils showed that most mineral soils contained less than 40 mg Na/1 so it is suggested that all mineral soils regardless of texture should receive 400 kg sodium chloride/ha. Crops on organic soils did not respond to sodium chloride because the soils already contained sufficient.Autumn and spring applications of sodium chloride on mineral soils gave similar increases in yield provided the fertilizer was not applied just before sowing, when in 2 years it decreased plant establishment. This effect was particularly damaging on clays and silts where it is frequently difficult for other reasons to obtain good seed beds and full establishment. It is concluded that sodium-containing fertilizers should always be applied well ahead of sowing to allow rainfall and cultivations to incorporate them into the soil. On clays and silts it is suggested that they should be applied before ploughing to avoid soil compaction but on sands there may be advantages in post-ploughing application.

scholarly journals Weed Control and Radish (Raphanus sativus) Response to S-metolachlor on Organic Soils

HortScience ◽  
2016 ◽  
Vol 51 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Dennis C. Odero ◽  
Jose V. Fernandez ◽  
Nikol Havranek
Keyword(s):  
Weed Control ◽  
Raphanus Sativus ◽  
Logistic Model ◽  
Field Experiments ◽  
Organic Soil ◽  
Effective Control ◽  
Yield Reduction ◽  
Organic Soils ◽  
Common Lambsquarters ◽  
Root Crops

Field experiments were conducted to determine weed control and radish (Raphanus sativus) response to S-metolachlor on organic soil in the Everglades Agricultural Area (EAA) using a dose–response bioassay. S-metolachlor was applied preemergence at 0.35, 0.7, 1.4, 2.8, 5.6, and 11.2 kg·ha−1. The rate of S-metolachlor required to provide 90% weed control (ED90) and result in 5% and 10% radish injury were determined by fitting a three-parameter log-logistic model. The ED90 values for common lambsquarters, spiny amaranth, and fall panicum control were 2.7, 1.6, and 1.2 kg·ha−1 of S-metolachlor, respectively, at 14 days after treatment (DAT). At 28 DAT, the ED90 values were 3.8, 1.9, and 1.5 kg·ha−1 of S-metolachlor, respectively. Injury on radish increased as S-metolachlor rates increased with maximum injury of 24% and 19% at 14 and 28 DAT, respectively. S-metolachlor at 2.1 and 3.1 kg·ha−1 at 14 DAT and 2.6 and 3.7 kg·ha−1 at 28 DAT would result in 5% and 10% radish injury, respectively. Radish yield decreased with increasing rates of S-metolachlor. At the proposed S-metolachlor use rate of 1.4 kg·ha−1 for root crops, radish yield was 80% of the weed-free yield probably resulting from competition from common lambsquarters, which was controlled 74%. These results show that preemergence S-metolachlor would provide effective control of spiny amaranth and fall panicum in radish on organic soils of the EAA at the proposed use rate for root crops while about three times the proposed use rate would be required to provide effective common lambsquarters control. This implies that infestation of common lambsquarters on radish fields on organic soils will not be effectively controlled by S-metolachlor at the proposed use rate resulting in yield reduction.

A LACK OF BACTERICIDAL EFFECT OF SUBSIDENCE-MITIGATING COPPER IN ORGANIC SOILS

1983 ◽  
Vol 63 (3) ◽  
pp. 645-649 ◽  
Author(s):  
SUKHDEV P. MATHUR
Keyword(s):  
Field Experiments ◽  
Organic Soil ◽  
Bactericidal Effect ◽  
Negative Influence ◽  
Organic Soils ◽  
Bacterial Cells ◽  
Old Field ◽  
E Coli ◽  
Rapid Spread ◽  
Mutant Cells

Two poorly humified peat soils, containing 23 or 1207 ppm (wt/wt) Cu, and two well-humified muck soils with 151 or 1264 ppm Cu, obtained from 3-yr-old field experiments on simulated extravagant applications of Cu for mitigation of organic soil degradation and subsidence, were used in this study. The aim was to determine whether the longevity of Escherichia coli (K12 JE 2517-a nonmotile mutant) cells inoculated into the soils would be affected by the soil Cu concentrations. The rapid spread plate method was used for counting viable cells of the coliform. Both microbially active and bromomethane-sterilized soils were aerobically incubated with the bacterium normally alien to the soils for 48 and 168 h, respectively, with or without further additions of 10 ppm Cu to the soils with the bacterial cells. A pulverized quartz sand was included in the experiments to provide comparison. Unlike the immediate and sustained lethality of Cu revealed in sand suspensions, neither the previously nor the newly added Cu had any negative influence on the survival or proliferation of the added E. coli cells. The results thus showed that the soil Cu had no direct bactericidal or bacteriostatic effect. These data were therefore in accord with earlier suggestions that the Cu mitigates decomposition and resultant subsidence by inactivating degradative and accumulated soil enzymes that contribute substantially to the dissipation of their substrate-rich milieux. Key words: Copper, bacteria, organic soils, subsidence

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.

scholarly journals A fertile peatland forest does not constitute a major greenhouse gas sink

2013 ◽  
Vol 10 (11) ◽  
pp. 7739-7758 ◽  
Author(s):  
A. Meyer ◽  
L. Tarvainen ◽  
A. Nousratpour ◽  
R. G. Björk ◽  
M. Ernfors ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Eddy Covariance ◽  
Organic Matter Content ◽  
C Sequestration ◽  
Organic Soil ◽  
Organic Soils ◽  
Indirect Approach ◽  
Short Period ◽  
N2o Fluxes ◽  
C Assimilation

Abstract. Afforestation has been proposed as a strategy to mitigate the often high greenhouse gas (GHG) emissions from agricultural soils with high organic matter content. However, the carbon dioxide (CO2) and nitrous oxide (N2O) fluxes after afforestation can be considerable, depending predominantly on site drainage and nutrient availability. Studies on the full GHG budget of afforested organic soils are scarce and hampered by the uncertainties associated with methodology. In this study we determined the GHG budget of a spruce-dominated forest on a drained organic soil with an agricultural history. Two different approaches for determining the net ecosystem CO2 exchange (NEE) were applied, for the year 2008, one direct (eddy covariance) and the other indirect (analyzing the different components of the GHG budget), so that uncertainties in each method could be evaluated. The annual tree production in 2008 was 8.3 ± 3.9 t C ha−1 yr−1 due to the high levels of soil nutrients, the favorable climatic conditions and the fact that the forest was probably in its phase of maximum C assimilation or shortly past it. The N2O fluxes were determined by the closed-chamber technique and amounted to 0.9 ± 0.8 t Ceq ha−1 yr−1. According to the direct measurements from the eddy covariance technique, the site acts as a minor GHG sink of −1.2 ± 0.8 t Ceq ha−1 yr−1. This contrasts with the NEE estimate derived from the indirect approach which suggests that the site is a net GHG emitter of 0.6 ± 4.5 t Ceq ha−1 yr−1. Irrespective of the approach applied, the soil CO2 effluxes counter large amounts of the C sequestration by trees. Due to accumulated uncertainties involved in the indirect approach, the direct approach is considered the more reliable tool. As the rate of C sequestration will likely decrease with forest age, the site will probably become a GHG source once again as the trees do not compensate for the soil C and N losses. Also forests in younger age stages have been shown to have lower C assimilation rates; thus, the overall GHG sink potential of this afforested nutrient-rich organic soil is probably limited to the short period of maximum C assimilation.

scholarly journals A fertile peatland forest does not constitute a major greenhouse gas sink

2013 ◽  
Vol 10 (3) ◽  
pp. 5107-5148 ◽  
Author(s):  
A. Meyer ◽  
L. Tarvainen ◽  
A. Nousratpour ◽  
R. G. Björk ◽  
M. Ernfors ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Eddy Covariance ◽  
Organic Matter Content ◽  
C Sequestration ◽  
Organic Soil ◽  
Organic Soils ◽  
Optimum Growth ◽  
Indirect Approach ◽  
Short Period ◽  
N2o Fluxes

Abstract. Afforestation has been proposed as a strategy to mitigate the often high greenhouse gas (GHG) emissions from agricultural soils with a high organic matter content. However, the carbon dioxide (CO2) and nitrous oxide (N2O) fluxes after afforestation can be considerable, depending predominantly on site drainage and nutrient availability. Studies on the full GHG budget of afforested organic soils are scarce and hampered by the uncertainties associated with methodology. In this study we determined the GHG budget of a spruce-dominated forest on a drained organic soil with an agricultural history. Two different approaches for determining the net ecosystem CO2 exchange (NEE) were applied: for the year 2008, direct (eddy covariance) and an indirect (analyzing the different components of the GHG budget), so that uncertainties in each method could be evaluated. The annual tree production in 2008 was 8.2 (± 1.7)t C ha–1yr–1 due to the high levels of soil nutrients, the favorable climatic conditions and the fact that the forest was in its optimum growth phase. N2O fluxes were determined by the closed chamber technique and amounted to 3.3 (± 2.4) t CO2eq ha–1 yr–1. According to the direct measurements from the eddy covariance technique, the site acts as a minor GHG sink of −4.1 (± 2.6) t CO2eq ha–1 yr–1. This contrasts with the NEE estimate derived from the indirect approach which suggests that the site is a net GHG emitter of 3.3 (± 10.1)t CO2eq ha–1 yr–1. Irrespective of the approach applied, the soil CO2 effluxes counter large amounts of the C sequestration by trees. Due to major uncertainties involved in the indirect approach, the direct approach is considered the more reliable tool. As the site was in its optimum growth stage, i.e. the rate of C sequestration was at its maximum and will decrease with forest age, it will probably become a GHG source once again as the trees mature. Since forests in their younger stages are usually GHG sources or have no effect on GHGs, the overall sink potential of this afforested nutrient-rich organic soil is probably limited to only a short period.

scholarly journals Water repellency of clay, sand and organic soils in Finland

2008 ◽  
Vol 16 (3) ◽  
pp. 267 ◽  
Author(s):  
K. RASA ◽  
R. HORN ◽  
M. RÄTY
Keyword(s):  
Preferential Flow ◽  
Management Practice ◽  
Soil Surface ◽  
Water Repellency ◽  
Organic Soil ◽  
Water Infiltration ◽  
Organic Soils ◽  
Water Repellent ◽  
Moisture Regime ◽  
Wetting Process

Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

TITRATIONS OF ORGANIC SOILS WITH STANDARD BASE: SOLUBILITY OF IONIZABLE FUNCTIONAL GROUPS AT 25 °C

1989 ◽  
Vol 69 (2) ◽  
pp. 313-325 ◽  
Author(s):  
DONALD S. GAMBLE
Keyword(s):  
Functional Groups ◽  
External Solution ◽  
Organic Soil ◽  
Organic Soils ◽  
Total Acid ◽  
Dissociation Equilibrium ◽  
Carboxylate Anions ◽  
Data Production ◽  
Standard Base ◽  
Automatic Titrator

The conversion of undissolved acidic functional groups into dissolved carboxylate anions has been monitored during potentiometric titration of a Typic Mesisol Peat at 25 °C. The analytical chemical calculations of total acid functional groups and of H+ dissociation equilibrium functions take the dissolution process into account. With 0.05 g of sample suspended in 20 mL of 0.1 N NaCl, the molarity of carboxylate anions in the external solution ranged from 4.3 × 10−4 M at 1 mL g−1 0.1 N NaOH, to 1.5 × 10−3 M at 6 mL g−1 0.1 N NaOH. The corresponding amounts of undissolved carboxyl groups were 5.2 × 10−4 and 1.0 × 10−4 mol g−1. Differential acid constants (KGA) for the undissolved carboxyls were 7.6 × 10−4 (σ 1.4 × 10−4) for αG < 0.02 (0.016 – 0.02) and 1.4 × 10−5 (σ 0.04 × 10−5) for αG > 0.026 (0.026 – 0.60). A substantial increase in productivity was achieved by means of an automatic titrator and a microcomputer with spreadsheet software. Types of data production and processing that were previously labor intensive have now become much more practical. Key words: Organic soils, organic matter solubility, organic soil carboxyls, organic soil ion exchange, organic soil titration, pH dependent solubility

Sign in / Sign up

Export Citation Format

Share Document