Heat-Transfer in the Soil During Very Low-Intensity Experimental Fires - the Role of Duff and Soil-Moisture Content

1994 ◽  
Vol 4 (4) ◽  
pp. 225 ◽  
Author(s):  
JC Valette ◽  
V Gomendy ◽  
J Marechal ◽  
C Houssard ◽  
D Gillon
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Temperature Rise ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Dry Weight ◽  
Prescribed Burns ◽  
Low Intensity ◽  
Lethal Temperatures ◽  
Maximum Temperatures

The aim of this study was to analyse the effects of duff thickness and moisture content, and of soil moisture content on the transfer of heat in the soil. The experimental design used intact soil blocks with their duff layer, subjected to controlled fires of variable very low intensities of up to 100 kW m-1. The fuel on the surface was composed of needles and twigs of Pinus pinaster. The maximum temperatures measured within the fuel were of the order of 650 degrees C and were independent of the fireline intensities. For fires with fireline intensity of the order of 30 kW m-1, the presence of the duff layer reduced from 330 degrees C the temperature rise at the soil surface. Duff thickness played only a secondary role, but increasing moisture content reinforced its insulating effect, so that the temperature rise was 2.5 times less at 1 cm depth in the duff when the moisture content exceeded 70% dry weight, than when the moisture content was less than 30%. For more intense fires (> 50 kW m-1) that produced longer-lasting surface heating, duff thickness and moisture content played an important role in significantly reducing the temperature rise at the soil surface (range 140 degrees C to 28 degrees C). Because of low soil thermal conductivity, temperature attenuation with increasing depth was noticed. In the case of low intensity fires (< 30 kW m-1) in the absence of a duff layer, the maximum temperatures were reduced from 350 degrees C at the surface to 7 degrees C at 3.5 cm. The temperature rise in the soil decreased with depth according to a negative exponential relation. The rate constant of this relation was greater when the initial surface temperature and the soil moisture content were higher. For the soil studied, and under the moisture conditions encountered (between 7 and 19% of dry weight), the rate constant could be predicted with acceptable precision (r2 = 0.67), if the surface soil temperature rise and the soil moisture content were known. In these experimental fires, which were carried out when the air temperature did not exceed 20 degrees C, lethal temperatures (> 60 degrees C) were measured in the upper few centimetres of the duff layer in very low-intensity fires, and in the upper few centimetres of the soil (where nutrients are most concentrated and biological activity most intense) in the slightly more intense fires. The fire intensities were always very moderate, and of the order of magnitude df those encountered in the prescribed burns conducted on fuel-breaks of the french Mediterranean area. Their impact on the surface of the forest soil, in terms of lethal temperatures transmitted to the horizon rich in organic matter, are not negligible. In contrast, below 3 to 5 cm depth, prescribed burns, conducted under the conditions of the experiments, would not lead to significant change to nutrients or microfaunal or microfloral activity; in particular, root tips would not be subjected to heat stress sufficient to kill them.

RELATIONSHIP BETWEEN SOIL MOISTURE CONTENT AND SOIL SURFACE REFLECTANCE

2005 ◽  
Vol 48 (5) ◽  
pp. 1979-1986 ◽  
Author(s):  
A. L. Kaleita ◽  
L. F. Tian ◽  
M. C. Hirschi
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Surface Reflectance

scholarly journals The Influence of a Water Absorbing Geocomposite on Soil Water Retention and Soil Matric Potential

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1731 ◽  
Author(s):  
Michał Śpitalniak ◽  
Krzysztof Lejcuś ◽  
Jolanta Dąbrowska ◽  
Daniel Garlikowski ◽  
Adam Bogacz
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Water Retention ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Soil Matric Potential ◽  
Soil Water Retention ◽  
Matric Potential ◽  
Control Samples

Climate change induces droughts that are becoming more intensive and more frequent than ever before. Most of the available forecast tools predict a further significant increase in the risk of drought, which indicates the need to prepare solutions to mitigate its effects. Growing water scarcity is now one of the world’s leading challenges. In agriculture and environmental engineering, in order to increase soil water retention, soil additives are used. In this study, the influence of a newly developed water absorbing geocomposite (WAG) on soil water retention and soil matric potential was analyzed. WAG is a special element made from geotextile which is wrapped around a synthetic skeleton with a superabsorbent polymer placed inside. To describe WAG’s influence on soil water retention and soil matric potential, coarse sand, loamy sand, and sandy loam soils were used. WAG in the form of a mat was used in the study as a treatment. Three kinds of samples were prepared for every soil type. Control samples and samples with WAG treatment placed at depths of 10 cm and 20 cm were examined in a test container of 105 × 70 × 50 cm dimensions. The samples had been watered and drained, and afterwards, the soil surface was heated by lamps of 1100 W total power constantly for 72 h. Soil matric potential was measured by Irrometer field tensiometers at three depths. Soil moisture content was recorded at six depths: of 5, 9, 15, 19, 25, and 30 cm under the top of the soil surface with time-domain reflectometry (TDR) measurement devices. The values of soil moisture content and soil matric potential were collected in one-minute steps, and analyzed in 24-h-long time steps: 24, 48, and 72 h. The samples with the WAG treatment lost more water than the control samples. Similarly, lower soil matric potential was noted in the samples with the WAG than in the control samples. However, after taking into account the water retained in the WAG, it appeared that the samples with the WAG had more water easily available for plants than the control samples. It was found that the mechanism of a capillary barrier affected higher water loss from soil layers above those where the WAG had been placed. The obtained results of water loss depend on the soil type used in the profile.

Ecological studies of hypogeous fungi. II. Sporocarp phenology in a western Oregon Douglas Fir stand

1976 ◽  
Vol 54 (10) ◽  
pp. 1152-1162 ◽  
Author(s):  
Robert Fogel
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Dry Weight ◽  
Douglas Fir ◽  
Total Weight ◽  
Ecological Studies ◽  
Hypogeous Fungi ◽  
Moisture Effects ◽  
Major Species

Sporocarp phenology of hypogeous or subterranean fruiting fleshy fungi was studied between March 1972 and March 1975 in a 40- to 65-year-old Douglas fir stand in western Oregon. Estimates of yearly productivity ranged from 11052 to 16753 sporocarps ha−1 and 2.3 to 5.4 kg dry weight ha−1. The productivity curve was bimodal as a result of temperature and moisture effects, with peaks in May–June and October. Eleven hypogeous ascomycete species and 13 hypogeous basidiomycete species were collected during the study. Major species that each accounted for 5% or more of the total weight were Tuber murinum, Hymenogaster parksii, Hysterangium crassum, H. separabile, and Truncocolumella citrina var. citrina. Sporocarp moisture content as determined for several species presumably varied with sporocarp age and soil moisture content and ranged from 17.4 to 88.6%. Hypogeous sporocarps had substantially higher macronutrient contents of N, P, and K plus the micronutrients Fe and Al than did epigeous sporocarps of Fomes pinicola. Sporocarp numbers increased exponentially with distance from nearest live Douglas fir stem to a peak at 160 to 200 cm, beyond which numbers dropped sharply. The optimum sporocarp zone was slightly less than the average midpoint between tree stems (205 cm).

Microenvironment of Lake Huron sand dunes

1983 ◽  
Vol 61 (1) ◽  
pp. 241-255 ◽  
Author(s):  
K. A. Baldwin ◽  
M. A. Maun
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Transition Zone ◽  
Soil Moisture Content ◽  
Sand Dunes ◽  
Organic Matter Content ◽  
Soil Surface ◽  
Matter Content ◽  
Lake Huron ◽  
Canonical Variate

Measurements were obtained of relative abundance of vegetation, edaphic properties, and microclimate characteristics of some initial stages of the Lake Huron sand-dune sequence at Pinery Provincial Park, Ont. Of the five dune habitats sampled, the oldest (transition zone) was distinguishable from the rest on the basis of greater diversity and abundance of vegetation, higher organic matter content, higher moisture-retaining capacity, enhanced concentrations of available K+ and Mg2+, depleted levels of Ca2+ in the surface soil, reduced air turbulence, and slightly higher air temperatures. The midsummer microclimate of the open dune habitat was characterized by extremely high day temperatures at the soil surface (5 cm) with large diurnal temperature fluctuations. Soil moisture content was generally low in the surface layers of the soil, but at depths greater than 10 cm, it was always plentiful (> 2.5% of soil by weight). Canonical variates analysis showed that the transition zone habitat (800 years old) was separated from younger ones (first dune ridge, slack, high beach) on the first canonical variate (V1), which accounted for about 50% of the total dispersion in the data. The discrimination of the transition zone microclimate on V1 was best characterized by difference in soil moisture content at shallow depths (5 and 10 cm) and wind velocity at 50 and 150 cm above the soil surface.

scholarly journals The Regulatory Mechanism of 2-Acetyl-1-Pyrroline Biosynthesis in Fragrant Rice (Oryza sativa L.) Under Different Soil Moisture Contents

2021 ◽  
Vol 12 ◽  
Author(s):  
Haowen Luo ◽  
Meiyang Duan ◽  
Leilei Kong ◽  
Longxin He ◽  
Yulin Chen ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Growth Parameters ◽  
Oryza Sativa L ◽  
Dry Weight ◽  
Transcript Level ◽  
Fragrant Rice ◽  
Moisture Contents ◽  
Significant Difference

2-acetyl-1-pyrroline (2-AP) is the key compound of rice aroma. However, the responses of 2-AP biosynthesis in fragrant rice under different soil moisture and the corresponding mechanism are little known. The present study evaluated the effects of different soil moisture on 2-AP biosynthesis through a pot experiment. Four soil moisture contents, that is, 50% (SM50), 40% (SM40), 30% (SM30), and 20% (SM20), were adopted, and SM50 treatment was taken as control. The pots were weighed and watered to maintain the corresponding soil moisture content. The results showed no significant difference in growth parameters (plant height, stem diameter, and plant dry weight) among all treatments. Compared with SM50, SM40, SM30, and SM20 treatments significantly (p&lt;0.05) increased 2-AP content by 32.81, 23.18, and 53.12%, respectively. Between 20 to 90% higher proline content was observed in SM40, SM30, and SM20 treatments than in SM50. Enzymes including proline dehydrogenase, ornithine transaminase, and 1-pyrroline-5-carboxylate synthetase exhibited lower activities with soil moisture declined. Higher diamine oxidase activity was observed in SM40, SM30, and SM20 treatments compared with SM50, and real-time PCR analyses showed that transcript level of DAO1 was greatly increased under low soil moisture treatments, especially in SM20 treatment. Transcript levels of PRODH, DAO2, DAO4, DAO5, OAT, P5CS1, and P5CS2 decreased or maintained in SM40, SM30, and SM20 treatments compared with SM50. We deduced that low soil moisture content enhanced 2-AP biosynthesis mainly by upregulating the expression of DAO1 to promote the conversion from putrescine to 2-AP.

scholarly journals Effect of Biochar on Soil Temperature under High Soil Surface Temperature in Coal Mined Arid and Semiarid Regions

2020 ◽  
Vol 12 (19) ◽  
pp. 8238
Author(s):  
Jibing Xiong ◽  
Runhua Yu ◽  
Ejazul Islam ◽  
Fuhai Zhu ◽  
Jianfeng Zha ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Surface Temperature ◽  
Soil Temperature ◽  
Bulk Density ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Soil Bulk Density ◽  
High Soil ◽  
Soil Surface Temperature

High soil surface temperature and loosened soil are major limiting factors of plant productivity in arid and semi-arid coal mining areas of China. Moreover, the extensive and illegitimate burning of crop residues is causing environmental pollution; whereas, these residues could be converted to biochar to benefit soil quality. In this study, the effect of wheat straw biochar (WSB) at rates of 0% (control, CK), 1% (low, LB), 2% (medium, MB) and 4% (high, HB) on soil temperature at different depths (5, 10, 15, and 20 cm) and moisture levels (10 and 20%) was investigated under high soil surface temperature of 50 °C and air humidity of 40%. Our data suggested that soil bulk density was inversely, and soil moisture was directly corelated with soil thermal parameters. Moreover, the increasing rate of WSB addition linearly decreased the soil thermal properties. The maximum decrease in soil bulk density at both moisture levels (10% and 20%) was measured in HB treatment compared to respective CKs. The highest decrease in soil thermal conductivity (59.8% and 24.7%) was found under HB treatment in comparison to respective controls (CK10% and CK20% moisture). The soil volumetric heat capacity was also strongly corelated with soil moisture content (r = 0.91). The WSB treatments displayed differential responses to soil temperature. Under 10% soil moisture, temperature of LB, MB and HB treatments was higher as compared to CK at 5–20 cm depth, and MB treated soil had the smallest increase in temperature. At the 15-cm depth, the MB treatment decreased the temperature by 0.93 °C as compared to the CK20%. Therefore, the effect of WSB on soil temperature was influenced by soil moisture content, soil depth and WSB application rates. It suggested that MB treatment could be a useful farming practice for mitigating soil temperature fluctuation.

scholarly journals Physiology, Growth and Yield of Different Cassava Genotypes Planted in Upland with Dry Environment during High Storage Root Accumulation Stage

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 576 ◽  
Author(s):  
Settawoot Wongnoi ◽  
Poramate Banterng ◽  
Nimitr Vorasoot ◽  
Sanun Jogloy ◽  
Piyada Theerakulpisut
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Moisture Content ◽  
Leaf Area ◽  
Soil Moisture Content ◽  
Starch Content ◽  
Dry Weight ◽  
Storage Root ◽  
Starch Yield ◽  
High Storage

Additional information on the physiological performances for different cassava genotypes would support better decision-making about desirable genetic resources for water-limited conditions. The objective of this study was to evaluate the physiological expression and yield of eight different cassava genotypes grown under a dry environment during high storage root accumulation. The eight cassava genotypes, i.e., Kasetsart 50, Huay Bong 80, Rayong 5, Rayong 7, Rayong 9, Rayong 11, Rayong 90, and CMR38-125-77 were evaluated under rain-fed upland conditions at Khon Kaen University, Thailand, during 2018 to 2020. A randomized complete block design (RCBD) with three replications was used. Soil moisture contents, chlorophyll fluorescence (Fv/Fm and Fv′/Fm′), net photosynthesis (Pn), stomatal conductance, water use efficiency (WUE), relative water content (RWC) for leaf, leaf area index (LAI), specific leaf area (SLA), starch content, crop dry weight, and starch yield were observed at 180, 270, and 360 days after planting (DAP), and weather data during the experimental period were also recorded. The results from both 2018/2019 and 2019/2020 indicated that Pn was positively and significantly correlated with stomatal conductance and Fv/Fm during the high storage root accumulation stage (270 and 360 DAP) with soil moisture content lower than field capacity. CMR38-125-77 had satisfactory performances in Pn, RWC, Fv/Fm, Fv′/Fm′, stomatal conductance, LAI, SLA, WUE, biomass, starch content, and starch yield at a last growth stage with soil moisture content lower than permanent wilting point. Significant association between crop dry weight and WUE at 360 DAP was recorded, and CMR38-125-77 and Kasetsart 50 were classified as favorable genotypes with high WUE and biomass.

scholarly journals Retrieving Photometric Properties and Soil Moisture Content of Tidal Flats Using Bidirectional Spectral Reflectance

2021 ◽  
Vol 13 (7) ◽  
pp. 1402
Author(s):  
Chen Gao ◽  
Min Xu ◽  
Hanzeyu Xu ◽  
Wei Zhou
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Roughness Parameter ◽  
Soil Surface ◽  
Pso Algorithm ◽  
Tidal Flats ◽  
Soil Samples ◽  
Asymmetry Factor ◽  
Equivalent Water Thickness

Moisture content in tidal flats changes frequently and spatially on account of tidal fluctuations, which greatly influence the reflectance of the tidal flat surface. Precise prediction of the spatial-temporal variation of tidal flats’ moisture content is an important foundation of surface bio-geophysical information research by remote sensing. In this paper, we first measured the multi-angle reflectance of soil samples obtained from tidal flats in the northeastern Dongtai, Jiangsu Province, China, in the laboratory. Then, based on the particle swarm optimization (PSO) algorithm, we retrieved the photometric characteristics of the soil surface by employing the SOILSPECT bidirectional reflectance model. Finally, the soil moisture content was retrieved by introducing the equivalent water thickness of the soil. The results showed that: (i) A significant correlation existed between the retrieved equivalent water thickness and the measured soil moisture content. The SOILSPECT model is capable of estimating soil moisture with high precision by using multi-angle reflectance. (ii) Retrieved values of single scattering albedo (ω) were consistent with the variation of soil moisture content. The roughness parameter (h) and the asymmetry factor (Θ) were consistent with the structure and particle composition of the soil surface in dry soil samples. (iii) When the soil samples were soaked with water, the roughness parameter (h) and the type of scattering on the soil surface both showed irregular changes. These results support the importance of using the measured soil particle size as one of the parameters for the retrieval of soil moisture content, which is a method that should be used cautiously, especially in tidal flats.

scholarly journals Remote sensing of surface roughness and top soil moisture of bare tilled soil with an X-band radar.

1979 ◽  
Vol 27 (4) ◽  
pp. 284-296
Author(s):  
A.J. Koolen ◽  
F.F.R. Koenigs ◽  
W. Bouten
Keyword(s):  
Surface Roughness ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Single Frequency ◽  
Agricultural Practice ◽  
X Band ◽  
Top Soil ◽  
Soil Surface Roughness

Using a ground-based radar with a single frequency in the X-band (3 cm wavelength), the feasibility of mapping soil surface roughness and top soil moisture content was investigated. In order to cover the broad range of bare-soil appearances which occur in agricultural practice, the field treatment included a number of tillage types, several degrees of soil structure change which normally occur after tillage, and different soil moisture content. Different angles between the ray beam and the irradiated land (grazing angles) were used. The shape of radar return ( gamma )-grazing angle curves were entirely determined by soil surface roughness, while their positions depended on moisture content. Although this type of radar had limited discrimination ability, mapping of roughness and moisture may be possible under certain conditions. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Phytotoxicity of Triallate Vapors to Wild Oat

Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 134-136 ◽  
Author(s):  
Stephen D. Miller ◽  
John D. Nalewaja
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Growth Inhibition ◽  
Soil Temperature ◽  
Seedling Growth ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Soil Surface ◽  
Avena Fatua ◽  
Wild Oat

Wild oat (Avena fatuaL.) seedlings were exposed to vapors arising from soil treated with triallate [S-(2,3,3-trichloroallyl)diisopropylthiocarbamate]. Vapor from the liquid triallate formulation inhibited seedling growth more than vapor from the granular formulation, and the degree of inhibition was least in Fargo clay, intermediate in Hecla sandy loam and greatest in washed sand. Growth inhibition from vapors of soil-applied liquid or granular triallate increased as soil moisture content and soil temperature increased. The site of effective vapor action on wild oat seedlings was below the soil surface.

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