PREDICTING VOLUMETRIC WATER RETENTIONS FOR SUBSOIL MATERIALS FROM COLCHESTER COUNTY, NOVA SCOTIA

1985 ◽  
Vol 65 (1) ◽  
pp. 233-236 ◽  
Author(s):  
G. J. BEKE ◽  
M. I. MacCORMICK

Relationships between soil water retention and soil properties were developed for subsoil materials from Colchester County, Nova Scotia. The significant variables in the regression equation for soil water content at a suction of 33 kPa were the sand content and the product of silt content and bulk density of the soil. The variables for water retention at 1500 kPa suction were the clay content and the product of organic matter content and bulk density. The multiple correlation coefficients were 0.87 and 0.92 for suctions of 33 and 1500 kPa, respectively. The developed equations were comparable to ones derived elsewhere. Key words: Water retention, texture, organic matter, bulk density

CERNE ◽  
2016 ◽  
Vol 22 (4) ◽  
pp. 381-388 ◽  
Author(s):  
Jonas Elias Castro da Rocha ◽  
Alberto Bentes Brasil Neto ◽  
Norberto Cornejo Noronha ◽  
Marcos André Piedade Gama ◽  
Eduardo Jorge Macklouf Carvalho ◽  
...  

ABSTRACT The aim of this study was to assess organic matter and physical-hydric attributes of an Oxisol under a clonal planting of eucalypt and an abandoned pasture in comparison to a successional forest with its soil under natural conditions at Paragominas municipality, southeast region of the state of Pará. In July 2013, soil samples were collected at the depths 0-0.15 and 0.15-0.35 m, which were used for the determination of the following attributes: organic matter content; soil bulk density; porosity, soil water retention and S index. In field, soil water infiltration tests were performed. The abandoned pasture was the system that presented the greatest contents of organic matter in the soil surface, when compared to successional forest and eucalypt clonal plantation. None of the studied systems achieved a critical level for bulk density and S index values and all systems had water infiltration speed classified as very high. Based on these variables, the soil management with eucalypt cultivation with two years of implantation may be recommended in areas with abandoned pastures.


1988 ◽  
Vol 24 (3) ◽  
pp. 375-384 ◽  
Author(s):  
N. R. Hulugalle ◽  
M. S. Rodriguez

SUMMARYThe soil physical properties of tied ridges were measured in a trial, established in 1983, comparing three treatments: handhoe cultivation and planting on the flat; planting directly without any cultivation on tied ridges constructed the previous year; and handhoe cultivation and remoulding of tied ridges constructed the previous year. Two maize varieties and two management levels were used. The soil properties monitored were particle size distribution, penetro-meter resistance in the surface 20 mm, bulk density, water infiltration, soil water retention and soil temperature.Soil physical properties were affected mainly by the type of seedbed. Clay content in the surface 0.05 m was greater with tied ridging, with that in the furrows being higher than that in the ridge slopes. Daily maximum soil temperature was greatest in the flat planted plots and in the ridge slopes of the tied ridged plots. Penetrometer resistance at a soil water content of 0.05 kg kg−1 was greater in the tied ridged plots. Cumulative infiltration after 2 h was greatest with flat planting. The bulk density of ridge slopes in tied ridged plots was less than that in the furrows and in the flat planted plots. Soil water retention was greatest in the furrows of the tied ridged plots. Clay content was the major factor determining all the soil physical properties measured.


2020 ◽  
Author(s):  
Martine van der Ploeg ◽  
Attila Nemes

<p>Soil hydro-physical properties —such as soil water retention, (un)saturated hydraulic conductivity, shrinkage and swelling, organic matter content, texture (particle distribution), structure (soil aggregation/pore structure)and bulk density— are used in many sub(surface) modeling applications. Reliable soil-hydrophysical properties are key to proper predictions with such models, yet the harmonization and standardization of these properties has not received much attention. Lack of harmonization and standardization may lead to heterogeneity in data as a result of differences in methodologies, rather than real landscape heterogeneity. A need and scope has been identified to better harmonize, innovate, and standardize methodologies regarding measuring soil hydraulic properties that form the information base of many derived products in support of EU policy. With this identified need in mind the Soil Program on Hydro-Physics via International Engagement (SOPHIE) was initiated in 2017. Besides developing new activities that may advise future measurements, we also explore historic data and metadata and mine its relevant contents. The European Hydro-pedological Data Inventory (EU-HYDI), the largest European database on measured soil hydrophysical properties, is – to date – rather under-explored in this sense, which served as motivation for this work.</p><p>From EU-HYDI we selected those records that were complete for soil texture, bulk density and organic matter, and fitted pedo-transfer functions separately for particular water retention points (at heads of 0, 2.5, 10, 100, 300, 1000, 3000, 15000 cm) and saturated hydraulic conductivity by multi-linear regression. We then subtracted the observed retention and hydraulic conductivity values from their estimated counterparts, and grouped the residuals by measurement methodologies. The results show that there can be significant differences between different methodologies and sample sizes used to obtain the water retention and hydraulic conductivity in the laboratory. The results thus show that the EU-data that may underlie large scale modelling may introduce errors in the forcing data that are attributed to a lack of harmonization and standardization in currently used measurement protocols.</p>


1981 ◽  
Vol 61 (2) ◽  
pp. 225-236 ◽  
Author(s):  
C. R. DE KIMPE ◽  
M. R. LAVERDIERE ◽  
J. ZIZKA

Rounding of the lands in a field involves changes in the surface horizons. The thickness of Ap horizons at various sites in corn fields varied from 15 to 41 cm. In these horizons, the organic matter content that ranged between 10 and 250 t/ha influenced the real density of the particles, the bulk density of soils with similar texture, and also the shape of the water retention curves at tensions from 0 to 1.5 MPa. Maximum available water in the Ap horizons between 33.3 kPa and 1.5 MPa varied from 0.5 to 4 cm H2O. Yield differences reached 74% while the standard deviations were generally lower than 15%. Higher yields were observed at higher, intermediate and lower sites of the fields. The differences in the yield were not entirely accounted for by the variations in the chemical and physical properties of the soils.


2018 ◽  
Vol 2 ◽  
pp. 10-22
Author(s):  
Abdulkadir Abdullahi

The study was conducted to investigate if erosion is a major problem and to identify the effect of erosion on some physical properties on selected farmlands on four farms in Gidan kwano. It was done by observation, interview, and questionnaire and soil sample analysis. The infiltration rate, bulk density, porosity, organic matter content, particle size and aggregate stability were determined for all the sample location. The erosion fields results were compared with the results of the non-eroded fields. The results showed that farming was done with simple method and mechanized equipment when available and erosion was considered a major problem in all the farms. The results revealed that bulk density values ranged between 1.475gcm-3and 1.606gcm-3, cumulative infiltration rate fluctuated between 29.75cm/hr and 37.48cm/hr, porosity ranged between 36.49% and 44.34%, organic matter content fluctuated between 0.29% and 0.73% and aggregate stability ranged between 58.00% and 67.60% for the erosion field. The results also revealed that bulk density fluctuated between 1.458gcm-3and 1.544gcm-3, cumulative infiltration rate ranged between 32.19 cm/hr and 40.48cm/hr, porosity fluctuated between 41.73% and 44.98%, organic matter content ranged between 0.30% and 1.09% and aggregate stability ranged between 63.97% and 68.93% for the non-eroded field. From the results, it provides evidence that the effects of erosion on the physical properties were increased bulk density, decreased infiltration rate, organic matter content, porosity, aggregate stability and percentage sand, silt and clay content. Statistical analysis proved that the results were significant (p<0.05) except for the bulk density and porosity which could be attributed to the swelling and compaction characteristics of the soils.


Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 367 ◽  
Author(s):  
Gema Guzmán ◽  
Alberto-Jesus Perea-Moreno ◽  
José Gómez ◽  
Miguel Cabrerizo-Morales ◽  
Gonzalo Martínez ◽  
...  

Soil quality is usually assessed through the measurement of selected soil properties. However, in spite of the diversity of the chosen properties, use of the soil water retention curve, like the pressure head or the specific water capacity at the inflection point, provides relevant information of degradation or improvement of soil. The main aim of this study was to evaluate the methods based on these indices in the evaluation of short-term changes of olive cropped soils under typical Mediterranean agricultural conditions. For this reason, soil properties (bulk density, hydraulic conductivity, aggregates stability, and organic matter content) were measured in a short-term trial settled in two olive orchards under different soil managements: tillage and cover crop. Several sampling areas were also distinguished: (i) along the inter tree row and under the canopies’ projection and (ii) at 0–10 cm and 10–20 cm depth. In addition, water retention curves were determined and fitted using two models (van Genutchen’s and Kosugi’s) in order to obtain the inflection point and therefore the S index. This index is the maximum value of the slope of the soil water retention curve and is related to soil quality. At the two sites, changes in soil management, even after a brief period of two years, had a relatively quick effect, especially in organic matter content along the inter tree row. The use of indices based on soil water retention curves helps to detect soil degradation or improvement changes. Future research, including the inclusion of more soil types and longer time periods, might lead to the development of more refined tools for the assessment of soil health.


Soil Research ◽  
1996 ◽  
Vol 34 (5) ◽  
pp. 679 ◽  
Author(s):  
Z Paydar ◽  
HP Cresswell

Different approaches were investigated for estimating the parameters in the Campbell soil water characteristic (SWC) equation from soil attributes such as particle size distribution (PSD), bulk density, and organic matter content. Predicted soil water characteristics were compared with measured values for soils of the wheatbelt of south-eastern Australia. A method of prediction is proposed incorporating an empirical relationship for estimating the slope of the SWC from the slope of the cumulative PSD. A power-law form is assumed for both the SWC and PSD functions. One measured SWC point is then used to locate and thus define the SWC curve. When SWC points predicted with this 'one-point' method were compared with measured values, the mean absolute value of the difference between each measured and predicted SWC point was 0.016 m3/m3 for the Geeves data and 0.027 m3/m3 for the Forrest data. Eight sets of predictive equations, previously developed using multiple regression analysis, were also evaluated. Whilst the equations predicted the slope of the SWC curves reasonably well, predictions of the air entry potential were poor. Although less accurate, the equations developed by multiple regression are less demanding in data requirement compared with alternative SWC prediction methods. The one-point method gave better predictions than the multiple regression approach but was less accurate than the 'two-point' method proposed in the first paper in this series. The one-point method should be considered where PSD data and 1 measured SWC point are available. In most other circumstances it will be more accurate and cost-effective to measure 2 SWC points to define the soil water characteristic function (the two-point method).* Part I, Aust. J. Soil Res., 1996, 34, 195–212.


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