MEASUREMENT OF CO2 EVOLVED FROM ORGANIC SOIL AT DIFFERENT DEPTHS IN SITU

1981 ◽  
Vol 61 (1) ◽  
pp. 137-144 ◽  
Author(s):  
J. A. CAMPBELL ◽  
L. FRASCARELLI
Keyword(s):  
Soil Column ◽  
Soil Surface ◽  
Organic Soil ◽  
Organic Soils ◽  
Concentration Profiles ◽  
Undisturbed Soil ◽  
Surface Evolution ◽  
Different Depths ◽  
A New Technique

A new technique for measuring CO2 evolved from organic soil at different depths in situ was used to monitor CO2 evolution in four experimental sites in southwestern Quebec and in an undisturbed soil column in the laboratory. The technique can be used in conjunction with in situ measurements of surface evolution of CO2, which are used as indicators of total subsidence by oxidation. Subsurface measurements of CO2 evolution provide more detailed estimates of where oxidation is occurring within the profile in organic soils. It also provides a simpler, more direct way of measuring CO2 fluxes below the soil surface than modelling from concentration profiles.

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.;

scholarly journals Analysis of persistent macroaggregates on the surface of agricultural soils

2021 ◽  
Author(s):  
Tian Tian ◽  
Joann K. Whalen ◽  
Pierre Dutilleul
Keyword(s):  
Soil Moisture ◽  
Digital Images ◽  
Agricultural Soils ◽  
Soil Surface ◽  
Organic Soil ◽  
Organic Soils ◽  
Biological Processes ◽  
Time Intervals ◽  
Natural Rainfall ◽  
Cumulative Rainfall

In humid regions, the number of macroaggregates on the soil surface could decline because of rainfall disturbance, or increase due to rainfall-activated chemical and biological processes. We took digital images of macroaggregates at the surface of clay and organic soils six times during a 68-d period with 264 mm natural rainfall. Based on the constant or increasing number of surface macroaggregates during the five time intervals, rainfall did not disturb macroaggregates. Macroaggregate persistence was positively correlated with cumulative rainfall (both soils) and soil moisture (organic soil), so we infer that rainfall promoted macroaggregate assemblage through chemical and biological processes.

In situ dynamics of recently allocated 14C in pasture soil and soil solution collected with Rhizon Soil Moisture Samplers

Soil Research ◽  
2005 ◽  
Vol 43 (5) ◽  
pp. 659 ◽  
Author(s):  
Bhupinderpal-Singh ◽  
M. J. Hedley ◽  
S. Saggar
Keyword(s):  
Soil Moisture ◽  
Soil Solution ◽  
Soil Surface ◽  
Pulse Labelling ◽  
Short Term ◽  
Microbial Decomposition ◽  
Different Depths ◽  
Non Destructive ◽  
Soil Interface

Information on the dynamics of recently photo-assimilated carbon (C) allocated to roots and root-derived exudates in soils is scarce and experimentally difficult to obtain. We used Rhizon Soil Moisture SamplersTM (RSMS) placed at different depths in soil (20, 40, 80, 120 mm) to monitor short-term dynamics of root and root-derived C at the root–soil interface after 14CO2 pulse-labelling of pasture cores. At the 20 mm depth, 14C activity in soil solution peaked within 2 h of 14CO2 application. The peak of 14C activity took longer to appear and slower to disappear with increased depth. Negligible amounts of 14C as soluble exudates were found in the soil solution. The pattern of initial 14C activity in soil solution, allocation of recently assimilated 14C in roots, and root mass distribution with depth were closely related to each other. This suggested that the rapid appearance of 14CO2 in soil solution is more closely linked to root respiration of recent 14C-assimilates (transferred via shoots to roots) and/or to microbial decomposition of root-released 14C-assimilates than to transfer by diffusion of atmospheric 14CO2 through open soil surface to different depths in soil. The use of RSMS was an effective, simple, and non-destructive method to monitor the dynamics of root-derived 14C by in situ sampling of soil solution.

CHEMICAL, PHYSICAL, AND LAND-USE INVESTIGATIONS OF ORGANIC TERRAIN

1975 ◽  
Vol 55 (3) ◽  
pp. 331-342 ◽  
Author(s):  
M. E. WALMSLEY ◽  
L. M. LAVKULICH
Keyword(s):  
Water Retention ◽  
Particle Density ◽  
Organic Soil ◽  
Surface Expression ◽  
Organic Soils ◽  
Sampling Area ◽  
Temperature Conductivity ◽  
Water Retention Properties ◽  
Physical And Chemical

Chemical and physical properties of selected organic soil samples were studied in relation to the chemical status of the associated ground water. Soil analyses included standard chemical analyses, fibre content, bulk density, particle density, hydraulic conductivity and water retention properties. In situ water chemical analysis included temperature, conductivity, dissolved oxygen and pH. Laboratory measurements of dissolved Ca, Mg, N, K, Si, NO3, F and Cl are also reported. The results are interpreted with reference to the surface expression and overall terrain morphology of the sampling area resulting in the formation of different peat types and associated vegetation. Physical and chemical data indicate a relationship between degree of decomposition and magnitude of various parameters. The distinction between bog and fen areas in terms of the level of dissolved electrolytes permits the prediction of the nature of the material comprising the organic soil. The distinctive properties of organic soils are discussed in terms of some use constraints imposed by the nature of the material in the context of afforestation of this terrain type.

scholarly journals Does <i>Juncus effusus</i> enhance methane emissions from grazed pastures on peat?

2015 ◽  
Vol 12 (11) ◽  
pp. 8467-8495 ◽  
Author(s):  
A. Henneberg ◽  
L. Elsgaard ◽  
B. K. Sorrell ◽  
H. Brix ◽  
S. O. Petersen
Keyword(s):  
Soil Column ◽  
Soil Surface ◽  
Point Sources ◽  
Organic Soils ◽  
Juncus Effusus ◽  
Emission Rates ◽  
Soil Layers ◽  
Local Maxima ◽  
Ch4 Emissions ◽  
Field Campaigns

Abstract. Methane (CH4) emissions from drained organic soils are generally low, but internal gas transport in aerenchymatous plants may result in local emission hotspots. In a paired-sample field study at three different sites we measured fluxes of CH4 with static chambers from adjacent sampling quadrats with and without Juncus effusus during four field campaigns. At all three sites, CH4 was observed in the soil at all sampling depths (5–100 cm), and in most cases both above and below the groundwater table. During spring, local maxima suggested methanogenesis took place above the water table at all three sites. We found significant CH4 emissions at all three sites, but emission controls were clearly different. Across the three sites, average emission rates (±1 SE) for sampling quadrats with and without J. effusus were 1.47 ± 0.28 and 1.37 ± 0.33 mg CH4 m-2 h-1 respectively, with no overall effect of J. effusus on CH4 emissions, but a significant effect at one of the three sites. At this site, local CH4 maxima were closer to the soil surface than at the other sites, and the upper soil layers were dryer. This could have affected both root CH4 accessibility and CH4 oxidation respectively, and together with limited gas diffusivity in the soil column, cause elevated CH4 emissions from J. effusus. We conclude that aerenchymatous plants has the potential to act as point sources of CH4 from drained peatlands, but more studies on the specific conditions under which there is an effect, are needed before the results can be used in modelling of CH4 emissions.

scholarly journals Does <i>Juncus effusus</i> enhance methane emissions from grazed pastures on peat?

2015 ◽  
Vol 12 (19) ◽  
pp. 5667-5676 ◽  
Author(s):  
A. Henneberg ◽  
L. Elsgaard ◽  
B. K. Sorrell ◽  
H. Brix ◽  
S. O. Petersen
Keyword(s):  
Soil Column ◽  
Soil Surface ◽  
Point Sources ◽  
Organic Soils ◽  
Juncus Effusus ◽  
Emission Rates ◽  
Soil Layers ◽  
Local Maxima ◽  
Ch4 Emissions ◽  
Field Campaigns

Abstract. Methane (CH4) emissions from drained organic soils are generally low, but internal gas transport in aerenchymatous plants may result in local emission hotspots. In a paired-sample field study at three different sites we measured fluxes of CH4 with static chambers from adjacent sampling quadrats with and without Juncus effusus during four field campaigns. At all three sites, CH4 was observed in the soil at all sampling depths (5 to 100 cm), and in most cases both above and below the groundwater table. During spring, local maxima suggested methanogenesis also took place above the water table at all three sites. We found significant CH4 emissions at all three sites, but emission controls were clearly different. Across the three sites, average emission rates (±1 SE) for sampling quadrats with and without J. effusus were 1.47 ± 0.28 and 1.37 ± 0.33 mg CH4 m−2 h−1, respectively, with no overall effect of J. effusus on CH4 emissions. However, a significant effect of J. effusus was seen at one of the three sites. At this site, local CH4 maxima were closer to the soil surface than at the other sites, and the upper soil layers were dryer. This could have affected both root CH4 accessibility and CH4 oxidation respectively, and together with limited gas diffusivity in the soil column, cause elevated CH4 emissions from J. effusus. We conclude that J. effusus has the potential to act as point sources of CH4 from drained peatlands, but more studies on the specific conditions under which there is an effect, are needed before the results can be used in modelling of CH4 emissions.

A new technique for placement of radioactive solutions in root studies and a study of root growth of Paspalum commersonii

1967 ◽  
Vol 7 (28) ◽  
pp. 447
Author(s):  
TR Evans
Keyword(s):  
Root Growth ◽  
Soil Surface ◽  
New Technique ◽  
Undisturbed Soil ◽  
Test Species ◽  
Repeated Applications ◽  
A New Technique ◽  
Different Diameters ◽  
Made In

A new technique is described for placement of radioactive solutions for studies on root growth. This technique involves placement of a perforated ring of polythene tubing at a predetermined depth with an access tube leading to the soil surface. Cylinders of 16 gauge galvanised iron and of different diameters are used for placement of polythene rings. Soil is excavated from outside the cylinder as it is forced to the required depth ; the polythene is placed in position and soil back-filled over it as the cylinder is withdrawn, thus leaving an undisturbed core of soil of the same diameter as the cylinder to the depth of placement. Radioactive solution introduced through the access tube from an automatic burette is distributed evenly in the soil by percolation from the perforated polythene ring. Rate of root growth of single plants through the undisturbed soil can be determined from measurement of radioactivity in plant leaves at various intervals of time. The technique was tested using radioactive phosphate (32P) as tracer and Paspalm commersonii Lam. as the test species. Root growth both vertically and laterally was measured. The advantages of this technique compared with others at present in use are : 1. Non-disturbance of the soil through which root growth is being measured. 2. Repeated applications of radioactive solution without disturbance of the system may be made in long-term studies. 3. Soil contamination by 32P solution above the point of placement is eliminated. The technique is well suited for studies on root growth and activity of single plants, or for competition studies.

Passive acoustic emissions: a dynamic tool to monitor soil structure variations?

2021 ◽  
Author(s):  
Marine Lacoste ◽  
Guillaume Giot ◽  
Maud Seger ◽  
Isabelle Cousin
Keyword(s):  
Surface Density ◽  
Soil Structure ◽  
Acoustic Emissions ◽  
Soil Surface ◽  
Agricultural Field ◽  
Undisturbed Soil ◽  
Soil Desiccation ◽  
Acoustic Signature ◽  
Two Samples

&lt;p&gt;The structure of soils, i.e. the macroscopic organization of aggregates and pores, conditions the storage and transport of water and gas in the soil, and strongly determines the physico-chemical environment of soil organisms (plants, micro and macro-organisms). The description of the soils structure dynamics constitutes a major issue in the current context of global change, at the scientific, environmental and agronomic level. However, few tools are available to monitor this dynamic non-destructively and in situ. We therefore propose to develop a new method based on the analysis of acoustic emissions (AE) spontaneously emitted by soils during the evolution of their structure. A laboratory feasibility study was conducted to explore the links between variations in soil structure and the AE emitted during soil desiccation.&lt;/p&gt;&lt;p&gt;Two undisturbed soil columns (8 cm in diameter, 5 cm high) were sampled in an agricultural field (near Chartres in France), in the surface horizon of a Glossic Retisol. These cylinders were air dried (20&amp;#176;C during 9 days), and the AE produced during drying were monitored using piezoelectric sensors place at the soil surface. The concomitant soil structure changes were followed through 3D images, acquired by X-ray tomography (CIRE platform, INRAE, Nouzilly) all along the experiment. These images, with a resolution of 168 &amp;#181;m, were used to characterize the pore network (porosity, surface density, connectivity, etc.).&lt;/p&gt;&lt;p&gt;The dynamics of the EAs recorded during the drying of the samples is comparable for the two samples: the AE rates are maximum at the start of the experiment and then reach a plateau. Changes in soil structure follow the same dynamics, e.g. considering porosity or surface density of the pores. If we analyze the relationship between the signals recorded by the surface sensors (EA rate) and the porosity, we observe a linear relationship (R&amp;#178; of 0.79). This relationship, although encouraging, remains to be consolidated by additional results.&lt;/p&gt;&lt;p&gt;To go further, it is also necessary to define the necessary conditions to perform such a measurement in situ, and to improve the acoustic signal processing to characterize the EA produced during soil desiccation. Indeed, a major objective of our work is to differentiate, thanks to EAs, the various factors responsible for the evolution of soil structure (physical and biological), by determining their &quot;acoustic signature&quot;.&lt;/p&gt;

INEXPENSIVE THERMISTOR SENSORS FOR TEMPERATURE MEASUREMENTS IN ORGANIC SOILS

1981 ◽  
Vol 61 (3) ◽  
pp. 521-524
Author(s):  
JAMES A. CAMPBELL ◽  
LOUISE FRASCARELLI
Keyword(s):  
Stainless Steel ◽  
Soil Temperature ◽  
Organic Soil ◽  
In Situ Measurements ◽  
Temperature Measurements ◽  
Organic Soils

Thermistors were incorporated in stainless steel tubular probes and in CPVC epoxy-filled pioe for accurate periodic and continuous in situ measurements of temperature in organic soil. Temperature can be measured with ± 0.1 °C with portable analog meters and ± 0.01 °C with digital meters.

scholarly journals Determination of Field Capacity in a Florida Sandy Soil and Drainage Time at Different Depths

1999 ◽  
Vol 9 (2) ◽  
pp. 258-261 ◽  
Author(s):  
Mongi Zekri ◽  
Lawrence R. Parsons
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Laboratory Data ◽  
Field Capacity ◽  
Fine Sand ◽  
Degree Of Saturation ◽  
Undisturbed Soil ◽  
Different Depths

The development of improved equipment for measuring soil water content has created the need for a better understanding of soil water drainage and movement. Without this understanding, it is impossible to know if an observed decrease in soil water content at a particular depth is due to evapotranspiration and/or continual drainage. This study was designed to determine the length of time for different soil depths of a Florida Candler fine sand to reach field capacity. A field site with no vegetation on it was saturated with water and covered with a plastic tarp to prevent evaporation. At 6- to 24-hour intervals, soil water content was measured gravimetrically in the top 15 cm (6 inches) and with the neutron probe from 30 to 150 cm (12 to 59 inches). The 15-cm depth reached field capacity after one day, but it took 4 days for the 30- to 150-cm depths to reach field capacity because of rewetting by water draining form higher horizons. The time required for drainage to stop must be considered when evaluating changes in soil water status at a particular depth. This is important for distinguishing between plant water uptake and drainage for different soil layers.Soil water characteristic curves of undisturbed soil samples, bulkdensity, porosity, and field capacity in situ were also determined for this soil. Field capacity values found in situ were compared to those found using the pressure plate technique. Laboratory values were higher than field values because the laboratory data were closer to hydrostatic conditions than the field data and the degree of saturation provided during wetting of the cores was higher in the laboratory. Water was not readily retained in Candler fine sand because the soil was very porous, infiltration rates were high, drainage was rapid, and water storage capacity was limited. Using field measurements, field capacity values of soil at different depths ranged from 4.8% to 6.2% volume for Candler fine sand. These are considered to be low values when compared to other types of soil.

Sign in / Sign up

Export Citation Format

Share Document