Small-scale Spatial Variability of Hydro-physical Properties of Differently Degraded Peat

2020 ◽  
Author(s):  
Miaorun Wang ◽  
Haojie Liu ◽  
Bernd Lennartz
Keyword(s):  
Spatial Variability ◽  
Physical Properties ◽  
Bulk Density ◽  
Peat Soil ◽  
Soil Physical Properties ◽  
Small Scale ◽  
Model Parameters ◽  
Strong Positive Correlation ◽  
Undisturbed Soil ◽  
Van Genuchten Model

<p>Spatial variability of soil properties is important for hydrological studies. However, little information is available on the spatial variability of hydro-physical properties of peat soils. Three study sites: natural, degraded and extremely degraded peatland were selected for this study. At each site, 72 undisturbed soil cores were collected from 5m by 5m grid cells in an area of 40m by 45m. The saturated hydraulic conductivity (Ks), soil water retention curves, total porosity, macroporosity, bulk density and soil organic matter (OM) content were determined for all sampling locations. The van Genuchten model parameters (θs, α, n) were optimized using the RETC software package. A strong positive correlation between macroporosity and Ks was observed irrespective of the degradation stage of the peat. However, the relationships between macroporosity and Ks differed for the different sites. The soil physical properties (e.g. OM content and bulk density) exhibited different levels of spatial autocorrelation depending on the soil degradation stage. The cross-semivariograms showed a strong or moderate spatial dependency between soil physical properties and van Genuchten model parameters. The more a peat soil is degraded, the more likely it is that soil physical properties are spatially dependent. In conclusion, degradation stage plays an important role and should be considered more often in spatial analysis. The obtained cross-semivariogram may serve as a basis for 2D and 3D hydrological modelling. </p>

scholarly journals Topography and spatial variability of soil physical properties

2009 ◽  
Vol 66 (3) ◽  
pp. 338-352 ◽  
Author(s):  
Marcos Bacis Ceddia ◽  
Sidney Rosa Vieira ◽  
André Luis Oliveira Villela ◽  
Lenilson dos Santos Mota ◽  
Lúcia Helena Cunha dos Anjos ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Physical Properties ◽  
Bulk Density ◽  
Soil Water ◽  
Water Retention ◽  
Particle Density ◽  
Soil Physical Properties ◽  
Soil Water Retention ◽  
Soil Attributes ◽  
Physical Attributes

Among the soil formation factors, relief is one of the most used in soil mapping, because of its strong correlation with the spatial variability of soil attributes over a landscape. In this study the relationship between topography and the spatial variability of some soil physical properties was evaluated. The study site, a pasture with 2.84 ha, is located near Seropédica, Rio de Janeiro State, Brazil, where a regular square grid with 20 m spacing was laid out and georreferenced. In each sampling point, altitude was measured and undisturbed soil samples were collected, at 0.0-0.1, 0.1-0.2, and 0.2-0.3 m depths. Organic carbon content, soil texture, bulk density, particle density, and soil water retention at 10 (Field Capacity), 80 (limit of tensiometer reading) and 1500 kPa (Permanent Wilting Point) were determined. Descriptive statistics was used to evaluate central tendency and dispersion parameters of the data. Semivariograms and cross semivariograms were calculated to evaluate the spatial variability of elevation and soil physical attributes, as well as, the relation between elevation and soil physical attributes. Except for silt fraction content (at the three depths), bulk density (at 0.2-0.3 m) and particle density (at 0.0-0.1 m depth), all soil attributes showed a strong spatial dependence. Areas with higher elevation presented higher values of clay content, as well as soil water retention at 10, 80 and 1500 kPa. The correlation between altitude and soil physical attributes decreased as soil depth increased. The cross semivariograms demonstrated the viability in using altitude as an auxiliary variable to improve the interpolation of sand and clay contents at the depth of 0.0-0.3 m, and of water retention at 10, 80 and 1500 kPa at the depth of 0.0-0.2 m.

Degree of compactness, soil physical properties and yield of soybean in six soils under no-tillage

Soil Research ◽  
2013 ◽  
Vol 51 (4) ◽  
pp. 311 ◽  
Author(s):  
L. E. A. S. Suzuki ◽  
J. M. Reichert ◽  
D. J. Reinert
Keyword(s):  
Root Growth ◽  
Physical Properties ◽  
Bulk Density ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Soil Physical Properties ◽  
Soil Samples ◽  
Uniaxial Compression Test ◽  
No Tillage ◽  
Undisturbed Soil

The ‘degree of compactness’ is a useful parameter to study soil compaction and represents the current bulk density in relation to the bulk density of the same soil in a reference state. The objectives of this study were to: (i) determine the best compression stress to establish the reference bulk density in the uniaxial compression test using undisturbed samples; (ii) quantify the effect of texture on degree of compactness, and (iii) evaluate the influence of degree of compactness on selected soil physical properties and crop yield. Six soils under no-tillage from southern Brazil were used and the reference bulk density was evaluated on soil samples equilibrated to the matric suction of 33 kPa and subjected to uniaxial compression test. Soil macroporosity, mechanical penetration resistance, root growth, and yield of soybean were also evaluated. For undisturbed soil samples, stresses ≥800 kPa (particularly the stress of 1600 kPa) are appropriate to determine the reference bulk density. Degree of compactness is independent of clay content and is associated with changes in soil physical properties. A degree of compactness ~100% restricted root growth of soybean, whereas the highest soybean yield was obtained with a DC of 82% for Alfisols and Ultisol, and 85% for Oxisols.

scholarly journals Surface lime and silicate application and crop production system effects on physical characteristics of a Brazilian Oxisol

Soil Research ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 778
Author(s):  
G. S. A. Castro ◽  
C. A. C. Crusciol ◽  
C. A. Rosolem ◽  
J. C. Calonego ◽  
K. R. Brye
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Production System ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Crop Productivity ◽  
Soil Physical Properties ◽  
Physical Characteristics ◽  
Forage Crop

This work aimed to evaluate the effects of crop rotations and soil acidity amelioration on soil physical properties of an Oxisol (Rhodic Ferralsol or Red Ferrosol in the Australian Soil Classification) from October 2006 to September 2011 in Botucatu, SP, Brazil. Treatments consisted of four soybean (Glycine max)–maize (Zea mays)–rice (Oryza sativa) rotations that differed in their off-season crop, either a signal grass (Urochloa ruziziensis) forage crop, a second crop, a cover crop, or fallow. Two acid-neutralising materials, dolomitic lime (effective calcium carbonate equivalent (ECCE) = 90%) and calcium-magnesium silicate (ECCE = 80%), were surface applied to raise the soil’s base saturation to 70%. Selected soil physical characteristics were evaluated at three depths (0–0.1, 0.1–0.2, and 0.2–0.4 m). In the top 0.1 m, soil bulk density was lowest (P < 0.05) and macroporosity and aggregate stability index were greatest (P < 0.05) in the forage crop compared with all other production systems. Also, bulk density was lower (P < 0.05) and macroporosity was greater (P < 0.05) in the acid-neutralising-amended than the unamended control soil. In the 0.1–0.2-m interval, mean weight diameter and mean geometric diameter were greater (P < 0.05) in the forage crop compared with all other production systems. All soil properties evaluated in this study in the 0.2–0.4-m interval were unaffected by production system or soil amendment after five complete cropping cycles. Results of this study demonstrated that certain soil physical properties can be improved in a no-tillage soybean–maize–rice rotation using a forage crop in the off-season and with the addition of acid-neutralising soil amendments. Any soil and crop management practices that improve soil physical properties will likely contribute to sustaining long-term soil and crop productivity in areas with highly weathered, organic matter-depleted, acidic Oxisols.

scholarly journals Characterizing Soil Physical Properties for Soil Moisture Monitoring with the North Carolina Environment and Climate Observing Network

2012 ◽  
Vol 29 (7) ◽  
pp. 933-943 ◽  
Author(s):  
Weinan Pan ◽  
R. P. Boyles ◽  
J. G. White ◽  
J. L. Heitman
Keyword(s):  
North Carolina ◽  
Soil Moisture ◽  
Physical Properties ◽  
Soil Properties ◽  
Water Content ◽  
Bulk Density ◽  
Soil Physical Properties ◽  
The North ◽  
Wide Range ◽  
Soil Moisture Monitoring

Abstract Soil moisture has important implications for meteorology, climatology, hydrology, and agriculture. This has led to growing interest in development of in situ soil moisture monitoring networks. Measurement interpretation is severely limited without soil property data. In North Carolina, soil moisture has been monitored since 1999 as a routine parameter in the statewide Environment and Climate Observing Network (ECONet), but with little soils information available for ECONet sites. The objective of this paper is to provide soils data for ECONet development. The authors studied soil physical properties at 27 ECONet sites and generated a database with 13 soil physical parameters, including sand, silt, and clay contents; bulk density; total porosity; saturated hydraulic conductivity; air-dried water content; and water retention at six pressures. Soil properties were highly variable among individual ECONet sites [coefficients of variation (CVs) ranging from 12% to 80%]. This wide range of properties suggests very different behavior among sites with respect to soil moisture. A principal component analysis indicated parameter groupings associated primarily with soil texture, bulk density, and air-dried water content accounted for 80% of the total variance in the dataset. These results suggested that a few specific soil properties could be measured to provide an understanding of differences in sites with respect to major soil properties. The authors also illustrate how the measured soil properties have been used to develop new soil moisture products and data screening for the North Carolina ECONet. The methods, analysis, and results presented here have applications to North Carolina and for other regions with heterogeneous soils where soil moisture monitoring is valuable.

Effect of Nano, Bio and Organic Fertilizers on Some Soil Physical Properties and Soybean Productivity in Saline Soil

2021 ◽  
pp. 44-57
Author(s):  
Kh. A. Shaban ◽  
M. A. Esmaeil ◽  
A. K. Abdel Fattah ◽  
Kh. A. Faroh
Keyword(s):  
Humic Acid ◽  
Hydraulic Conductivity ◽  
Physical Properties ◽  
Bulk Density ◽  
Saline Soil ◽  
Field Capacity ◽  
Soil Physical Properties ◽  
Organic Fertilizers ◽  
Mineral Fertilizers ◽  
Soil Conditions

A field experiment was carried out at Khaled Ibn El-waleed village, Sahl El-Hussinia, El-Sharkia Governorate, Egypt, during two summer seasons 2019 and 2020 to study the effect of NPK nanofertilizers, biofertilizers and humic acid combined with or without mineral fertilizers different at rates on some soil physical properties and soybean productivity and quality under saline soil conditions. The treatments consisted of: NPK-chitosan, NPK-Ca, humic acid, biofertilzer and control (mineral NPK only). In both seasons, the experiment was carried out in a split plot design with three replicates. The results indicated a significant increase in the soybean yield parameters as compared to control. There was also a significant increase in dry and water stable aggregates in all treatments as compared to control. The treatment NPK-Chitosan was the best in improving dry and stable aggregates. Also, hydraulic conductivity and total porosity values were significantly increased in all treatments due to increase in soil aggregation and porosity that led to increase in values of hydraulic conductivity. Values of bulk density were decreased, the lowest values of bulk density were found in NPK-chitosan treatment as a result of the high concentration of organic matter resulted from NPK-chitosan is much lighter in weight than the mineral fraction in soils. Accordingly, the increase in the organic fraction decreases the total weight and bulk density of the soil. Concerning soil moisture constants, all treatments significantly increased field capacity and available water compared to control. This increase was due to improvement of the soil aggregates and pores spaces which allowed the free movement of water within the soil thereby, increasing the moisture content at field capacity.

Long-term effect of biochar on soil physical properties of agricultural soils with different textures

2021 ◽  
Author(s):  
Martin Zanutel ◽  
Sarah Garré ◽  
Charles Bielders
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Water Retention ◽  
Particle Density ◽  
Sandy Loam ◽  
Soil Physical Properties ◽  
Term Effect ◽  
Silt Loam ◽  
Long Term Effect

&lt;p&gt;In the context of global soil degradation, biochar is being promoted as a potential solution to improve soil quality, besides its carbon sequestration potential. Burying biochar in soils is known to effect soil physical quality in the short-term (&lt;5 years), and the intensity of these effects depends on soil texture. However, the long-term effects of biochar remain largely unknown yet and are important to quantify given biochar&amp;#8217;s persistency in soils. The objective of this study was therefore to assess the long-term effect of biochar on soil physical properties as a function of soil texture and biochar concentration.&amp;#160; For this purpose, soil physical properties (particle density, bulk density, porosity, water retention and hydraulic conductivity curves) were measured in the topsoil of three fields with former kiln sites containing charcoal more than 150 years old in Wallonia (southern Belgium).&amp;#160; The fields had a silt loam, loam and sandy loam texture.&amp;#160; Samples were collected along 3 transects in each field, from the center of the kiln sites outwards.&amp;#160;&lt;/p&gt;&lt;p&gt;Particle density and bulk density slightly decreased as a function of charcoal content. Because particle density and bulk density were affected to a similar extent by charcoal content, total porosity was not affected by the presence of century-old charcoal. Regarding the soil water retention curve, charcoal affected mostly water content in the mesopore range. This effect was strongest for the sandy loam. On the other hand, the presence of century-old charcoal increased significantly the hydraulic conductivity at pF between 1.5 and 2 for the silt loam, while no effect of charcoal was observed for the loamy soil.&amp;#160; The study highlights a limited effect of century-old charcoal on the pore size distribution (at constant porosity) and on the resulting soil physical properties for the range of soils and charcoal concentrations investigated here.&amp;#160; Further research may be needed to confirm the observed trends over a wider range of soil types.&amp;#160;&lt;/p&gt;

scholarly journals Relationships between Root Traits and Soil Physical Properties after Field Traffic from the Perspective of Soil Compaction Mitigation

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1697
Author(s):  
Matthieu Forster ◽  
Carolina Ugarte ◽  
Mathieu Lamandé ◽  
Michel-Pierre Faucon
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Soil Compaction ◽  
Root Length Density ◽  
Root Traits ◽  
Air Permeability ◽  
Soil Physical Properties ◽  
Soil Reinforcement ◽  
Soil Functions ◽  
Crop Species

Compaction due to traffic is a major threat to soil functions and ecosystem services as it decreases both soil pore volume and continuity. The effects of roots on soil structure have previously been investigated as a solution to alleviate compaction. Roots have been identified as a major actor in soil reinforcement and aggregation through the enhancement of soil microbial activity. However, we still know little about the root’s potential to protect soil from compaction during traffic. The objective of this study was to investigate the relationships between root traits and soil physical properties directly after traffic. Twelve crop species with contrasting root traits were grown as monocultures and trafficked with a tractor pulling a trailer. Root traits, soil bulk density, water content and specific air permeability were measured after traffic. The results showed a positive correlation between the specific air permeability and root length density and a negative correlation was found between bulk density and the root carbon/nitrogen ratio. This study provides first insight into how root traits could help reduce the consequences of soil compaction on soil functions. Further studies are needed to identify the most efficient plant species for mitigation of soil compaction during traffic in the field.

scholarly journals Variations in selected soil physical properties with landforms and slope within an inland valley ecosystem in Ashanti region of Ghana

2011 ◽  
Vol 6 (No. 2) ◽  
pp. 73-82 ◽  
Author(s):  
S.E. Obalum ◽  
J.C. Nwite ◽  
J. Oppong ◽  
C.A. Igwe ◽  
T. Wakatsuki
Keyword(s):  
Particle Size ◽  
Moisture Content ◽  
Particle Size Distribution ◽  
Physical Properties ◽  
Bulk Density ◽  
Site Selection ◽  
Total Porosity ◽  
Soil Physical Properties ◽  
Silt Fraction ◽  
Inland Valley

One peculiar feature of the inland valleys abundant in West Africa is their site-specific hydrology, underlain mainly by the prevailing landforms and topography. Development and management of these land resources under the increasingly popular sawah (a system of bunded, puddled and levelled rice field with facilities for irrigation and drainage) technology is a promising opportunity for enhancing rice (Oryza sativa L.) production in the region. Information on the variations in selected soil physical properties as influenced by the prevailing landforms may serve as a useful guide in site selection. This is of practical importance since majority of the inland valleys are potentially unsuitable for sawah development and most farmers in the region are of low technical level. Three landforms (river levee, elevated area and depressed area) were identified within a sawah field located in an inland valley at Ahafo Ano South District of Ghana. Each of these landforms was topsoil-sampled along on identified gradient (top, mid and bottom slope positions). Parameters determined included particle size distribution, bulk density, total porosity and field moisture content. The soil is predominantly clayey. There were no variations in the particle size distribution among the slope positions in the river levee. Overall, the river levee had lower silt content than the elevated and the depressed landforms. The bulk density, total porosity, and gravimetric moisture content indicated relative improvements only in the depressed area in the order, bottom &gt; mid &gt; top slope. Irrespective of slope position, the three landforms differed in these parameters in the order, depressed &gt; river levee &gt; elevated. The sand fraction impacted negatively on the silt fraction and bulk density of the soil, both of which controlled the soil moisture status. Despite the fairly low silt content of the soil, the silt fraction strongly influenced the gravimetric moisture content (R<sup>2</sup> = 0.80). So too did the soil bulk density on the gravimetric moisture content (R<sup>2</sup> = 0.90). It is concluded that: (1) since the landforms more prominently influenced the measured parameters than the slope positions, the former should take pre-eminence over the latter in soil suitability judgment; (2) with respect to moisture retention, variations in silt fraction and bulk density of this and other clayey inland-valley soils should be used as guide in site selection for sawah development.

Effects of spent mushroom substrate on soil physical conditions and plant growth in an intensive horticultural system

Soil Research ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 899 ◽  
Author(s):  
D. P. C. Stewart ◽  
K. C. Cameron ◽  
I. S. Cornforth ◽  
J. R. Sedcole
Keyword(s):  
Plant Growth ◽  
Physical Properties ◽  
Water Content ◽  
Bulk Density ◽  
Principal Components ◽  
Crop Yields ◽  
Infiltration Rate ◽  
Soil Physical Properties ◽  
Spent Mushroom Substrate ◽  
Surface Crust

A 2-year field trial determined the influence of applying spent mushroom substrate (SMS) on soil physical properties and the growth of 4 consecutive vegetable crops (sweetcorn, cabbage, potato, cabbage). Treatments comprised 0, 20, 40, and 80 t/ha of moist SMS, both with and without inorganic fertiliser, applied to each crop, giving a range of SMS rates up to 320 t/ha. SMS improved the environment for plant root growth by decreasing soil bulk density (by 0· 05-0·25 g/cm 3 at 100 mm depth), increasing aggregate stability (by 13-16%), reducing clod and surface crust formation (by 16-31 and 18-94%, respectively), increasing the infiltration rate (by 130-207 mm/h), increasing the water content of the soil (by 0-7% w/w), and reducing diurnal temperature changes. Some of these changes were not evident until repeated applications of 80 t/ha SMS had been made. Soil physical properties were related to crop yield, and soil physical properties’ principal components were related to crop principal components using regression analysis (r2 of 0·20-0·60 and 0·16-0·54, respectively). The soil physical properties that had the most influence on plant growth were specific to each crop and included bulk density, water content, surface crust cover, infiltration rate, and aggregate size distribution. Soil physical properties had a large influence on the potato yield irrespective of fertiliser use and on both cabbage crop yields when fertiliser was not used, but not on the sweetcorn yield (the first crop to be grown). The effect of changing soil physical properties on plant growth was most apparent when fertiliser was not used. This was because the improved physical properties increased plant yield (at least in part) because of increased plant nutrient uptake.

scholarly journals Short and long-term effects of tillage systems and nutrient sources on soil physical properties of a Southern Brazilian Hapludox

2008 ◽  
Vol 32 (4) ◽  
pp. 1437-1446 ◽  
Author(s):  
Milton da Veiga ◽  
Dalvan José Reinert ◽  
José Miguel Reichert ◽  
Douglas Rodrigo Kaiser
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Crop Residues ◽  
Total Porosity ◽  
Soil Physical Properties ◽  
Soil Tillage ◽  
Tillage Systems ◽  
Nutrient Sources ◽  
Over Time

Soil tillage promotes changes in soil structure. The magnitude of the changes varies with the nature of the soil, tillage system and soil water content and decreases over time after tillage. The objective of this study was to evaluate short-term (one year period) and long-term (nine year period) effects of soil tillage and nutrient sources on some physical properties of a very clayey Hapludox. Five tillage systems were evaluated: no-till (NT), chisel plow + one secondary disking (CP), primary + two (secondary) diskings (CT), CT with burning of crop residues (CTb), and CT with removal of crop residues from the field (CTr), in combination with five nutrient sources: control without nutrient application (C); mineral fertilizers, according to technical recommendations for each crop (MF); 5 Mg ha-1 yr-1 of poultry litter (wetmatter) (PL); 60 m³ ha-1 yr-1 of cattle slurry (CS) and; 40 m³ ha-1 yr-1 of swine slurry (SS). Bulk density (BD), total porosity (TP), and parameters related to the water retention curve (macroporosity, mesoporosity and microporosity) were determined after nine years and at five sampling dates during the tenth year of the experiment. Soil physical properties were tillage and time-dependent. Tilled treatments increased total porosity and macroporosity, and reduced bulk density in the surface layer (0.00-0.05 m), but this effect decreased over time after tillage operations due to natural soil reconsolidation, since no external stress was applied in this period. Changes in pore size distribution were more pronounced in larger and medium pore diameter classes. The bulk density was greatest in intermediate layers in all tillage treatments (0.05-0.10 and 0.12-0.17 m) and decreased down to the deepest layer (0.27-0.32 m), indicating a more compacted layer around 0.05-0.20 m. Nutrient sources did not significantly affect soil physical and hydraulic properties studied.

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