Emergence response of subterranean clover to dissolved gypsum in relation to soil properties and evaporative conditions

Soil Research ◽  
1966 ◽  
Vol 4 (1) ◽  
pp. 55 ◽  
Author(s):  
J Loveday ◽  
DR Scotter
Keyword(s):  
Soil Properties ◽  
Surface Soil ◽  
Subterranean Clover ◽  
Clay Content ◽  
Exchangeable Sodium ◽  
Loam Soil ◽  
Highly Correlated ◽  
The One ◽  
Relationship Of ◽  
Emergence Response

Using small plots set in the earthen floor of an open glasshouse, the emergence response of subterranean clover to dissolved gypsum has been determined on 10 soils covering a range of clay and exchangeable sodium levels. The response on a loam soil of low exchangeable sodium percentage (E.S.P.) has been examined at three times of differing evaporative potential. For loams and clay loams, the appearance of a response depends on the severity of evaporative conditions as well as on the E.S.P. On clay soils not naturally self mulching, some response is probably always obtained but, in general, the higher the clay content and the higher the E.S.P. and evaporative potential, the more likely is an emergence response to dissolved gypsum. Emergence was found to be highly correlated with the matric potential of the surface 1/2 in. at the time emergence began. From a consideration of the relationships between emergence and moisture status, the most significant effect of the gypsum treatment seems to be the delay of several days it causes in the air drying of the surface soil, probably because of improved transmission of moisture from beneath. Parallel effects on surface soil temperature to those on moisture can be explained in terms of differences in amount of evaporative cooling. Relationships found between emergence and emergence response to gypsum on the one hand and clay content and E.S.P. on the other are presumably a reflection of the relationship of these soil properties to porosity and moisture transmission.

Soil properties influencing growth of subterranean clover in the Coleambally Irrigation Area, NSW

1966 ◽  
Vol 6 (22) ◽  
pp. 283 ◽  
Author(s):  
J Loveday ◽  
DS McIntyre
Keyword(s):  
Soil Properties ◽  
Subterranean Clover ◽  
Late Winter ◽  
Soil Factors ◽  
Yield Variation ◽  
Moisture Supply ◽  
Diffusion Rates ◽  
Highly Correlated ◽  
Complete Fertilizer ◽  
Spring Yield

The significance of physical soil factors in controlling the growth of subterranean clover under irrigation was assessed in a field experiment involving small plots scattered over a range of soils. Nutrient differences were reduced by a complete fertilizer dressing, so that as far as possible vegetative growth was controlled only by moisture supply and soil aeration under two watering treatments, one approximating the normal regional practice and the other a more frequent watering. Yield was increased by the latter and variation between sites due to soil differences was reduced. Spring yields from the plots watered at the normal regional level were significantly correlated with water increments at irrigation but not with available water capacity. Fifteen other soil properties showed significant simple correlations with spring yield and in multiple regression relationships a high proportion of yield variation could be accounted for in terms of the variation in selected properties. The best pair of variables for yield prediction, accounting for 59 per cent of variability, were per cent exchangeable sodium at 1-4 inches, and aggregate density at 1-4 inches. These variables were highly correlated with water increment at irrigation. On the more frequently watered plots, waterlogging induced in late winter depressed yield slightly and this, apparently, was not caused by poor aeration, but possibly by leaching of nutrients. Oxygen diffusion rates measured one day after irrigation were negatively correlated with yield. Spring yields from these plots were unrelated to total and air-filled porosity and air permeability. The evidence again pointed to moisture supply being responsible for the yield variation between sites.

scholarly journals USING LEGACY SOIL DATA FOR STANDARDIZING PREDICTIONS OF TOPSOIL CLAY CONTENT OBTAINED FROM VNIR/SWIR HYPERSPECTRAL AIRBORNE IMAGES

2015 ◽  
Vol XL-3/W3 ◽  
pp. 439-444
Author(s):  
C. Gomez ◽  
A. Gholizadeh ◽  
L. Borůvka ◽  
P. Lagacherie
Keyword(s):  
Soil Properties ◽  
Spectral Index ◽  
Near Infrared ◽  
Soil Property ◽  
Clay Content ◽  
Short Wave ◽  
Soil Samples ◽  
Spectral Bands ◽  
Large Sets ◽  
The One

Mapping of topsoil properties using Visible, Near-Infrared and Short Wave Infrared (VNIR/SWIR) hyperspectral imagery requires large sets of ground measurements for calibrating the models that estimate soil properties. To avoid collecting such expensive data, we proposed a procedure including two steps that involves only legacy soil data that were collected over and?or around the study site: <i>1)</i> estimation of a soil property using a spectral index of the literature and <i>2)</i> standardisation of the estimated soil property using legacy soil data. This approach was tested for mapping clay contents in a Mediterranean region in which VNIR/SWIR AISA-DUAL hyperspectral airborne data were acquired. The spectral index was the one proposed by Levin et al (2007) using the spectral bands at 2209, 2133 and 2225 nm. Two legacy soil databases were tested as inputs of the procedure: the <i>Focused-Legacy</i> database composed of 67 soil samples collected in 2000 over the study area, and the No-Focused-Legacy database composed of 64 soil samples collected between 1973 and 1979 around but outside of the study area. The results were compared with those obtained from 120 soil samples collected over the study area during the hyperspectral airborne data acquisition, which were considered as a reference. <br><br> Our results showed that: <i>1)</i> the spectral index with no further standardisation offered predictions with high accuracy in term of coefficient of correlation <i>r</i> (0.71), but also high <i>bias</i> (&minus;414 g/kg) and <i>SEP</i> (439 g/kg), <i>2)</i> the standardisation using both legacy soil databases allowed an increase of accuracy (<i>r</i> = 0.76) and a reduction of <i>bias</i> and <i>SEP</i> and <i>3)</i> a better standardisation was obtained by using the <i>Focused-Legacy</i> database rather than the <i>No-Focused-Legacy</i> database. Finally, the clay predicted map obtained with standardisation using the <i>Focused-Legacy</i> database showed pedologically-significant soil spatial structures with clear short-scale variations of topsoil clay contents in specific areas. <br><br> This study, associated with the coming availability of a next generation of hyperspectral VNIR/SWIR satellite data for the entire globe, paves the way for inexpensive methods for delivering high resolution soil properties maps.

Recognition of gypsum-responsive soils

Soil Research ◽  
1974 ◽  
Vol 12 (2) ◽  
pp. 87 ◽  
Author(s):  
J Loveday
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Canonical Correlation ◽  
Seedling Emergence ◽  
Subterranean Clover ◽  
Response Measure ◽  
Dispersion Index ◽  
Exchangeable Sodium ◽  
Predictive Equations ◽  
Response Measures

Gypsum response for 53 soils has been measured in terms of air-dry crust strength (resistance to penetrometer, Y1) and subterranean clover seedling emergence (Y2) in three glasshouse experiments. It was also measured in terms of hydraulic conductivity (Y3) of samples taken from the treated and untreated soils at the end of the experiments, and this proved to be the most sensitive response measure. Relationships between these response measures and a variety of soil properties have been examined by regression and canonical correlation analyses. A regression of Y3 on three properties, i.e. dispersion index, and percentage exchangeable sodium and magnesium, gives the greatest predictability (R2 86%). Regressions involving a pair of easily determined properties, dispersion index and pH, give reasonable predictability (R2 = 70, 73 and 77% respectively for Y1, Y2, and Y3). Limits to the values of Y1, Y2, and Y3 have been set to provide three categories of gypsum response, viz. strong, moderate and little or no response. It is argued from a general understanding of the ameliorative process that the predictive equations should be of value beyond the areas sampled in the present study.

VARIABILITY OF SOIL PROPERTIES IN RELATION TO SIZE OF MAP UNIT DELINEATION

1982 ◽  
Vol 62 (4) ◽  
pp. 657-662 ◽  
Author(s):  
C. WANG
Keyword(s):  
Organic Carbon ◽  
Soil Properties ◽  
Cation Exchange Capacity ◽  
Surface Soil ◽  
Boundary Effect ◽  
Clay Content ◽  
Soil Characteristics ◽  
Exchange Capacity ◽  
Coefficient Of Variability ◽  
Range Of Variation

The results of a study which compared some selected soil characteristics of small and large map unit delineations are presented. Color, organic carbon, pH, cation exchange capacity and clay content were measured. Properties, such as pH and CEC of surface soil and pH of subsoil, were found to be significantly different between large and small delineations. Although Brandon is selected to be a simple and relatively uniform map unit, the range of variation was wide for all of the selected soil properties. For each property measured the coefficient of variability was always larger in surface soils than in subsoils. However, variance of measured soil properties did not differ between the two groups of delineations. Consequently, the soil boundary effect is considered to be insignificant for the Brandon unit of the Dalhousie association studied.

The strength of remolded soils as affected by exchangeable cations and dispersible clay

Soil Research ◽  
1994 ◽  
Vol 32 (2) ◽  
pp. 185 ◽  
Author(s):  
AR Barzegar ◽  
RS Murray ◽  
GJ Churchman ◽  
P Rengasamy
Keyword(s):  
Tensile Strength ◽  
Clay Content ◽  
Exchangeable Cations ◽  
Rate Of Change ◽  
Exchangeable Cation ◽  
Regression Analyses ◽  
Exchangeable Sodium ◽  
Exchangeable Magnesium ◽  
Highly Correlated ◽  
Dispersible Clay

The tensile strengths of remoulded samples of five Australian soils with differing clay type, texture and shrink-swell potential were measured as a function of exchangeable cations (Na, Ca and Mg) and exchangeable sodium percentage (ESP). Spontaneously and mechanically dispersible clays were also determined as a function of ESP. The tensile strength changed with the nature of the exchangeable cation, clay content and amounts of spontaneously and mechanically dispersible clay. In Ca-soils, the tensile strength was highly correlated with clay content and CEC. Regression analyses of data for soils containing various amounts of exchangeable sodium showed that mechanically and spontaneously dispersible clay were individually correlated with the tensile strength of remoulded soils. However, multiple regression analyses of these data indicated that spontaneously dispersible clay alone was a major predictor of the tensile strength of remoulded sodic soils. This suggests that measurement of spontaneously dispersible clay adequately accounts for the differences in tensile strengths of dry remoulded soils as influenced by ESP values. Analysis of variance of data for all the soils with varying ESP values showed that spontaneously dispersible clay was strongly correlated with clay content. Analyses of data for individual soil type showed that spontaneously dispersible clay was highly correlated with ESP. For each soil studied, increase in ESP resulted in increase of dispersible clay and hence in tensile strength. Although tensile strength increased with ESP, the rate of change of strength with ESP was different for each soil. Soil with the highest clay content gave rise to the greatest rate of change. The effect of exchangeable magnesium on tensile strength was similar to calcium. However, in two of the soils, exchangeable magnesium, in the presence of sodium, increased the strength slightly more than calcium, confirming the ionic radius effect of these elements.

Phytotoxicity and Adsorption of Chlorsulfuron as Affected by Soil Properties

Weed Science ◽  
1985 ◽  
Vol 33 (4) ◽  
pp. 564-568 ◽  
Author(s):  
Wondimagegnehu Mersie ◽  
Chester L. Foy
Keyword(s):  
Organic Matter ◽  
Soil Ph ◽  
Chemical Properties ◽  
Clay Content ◽  
Physical And Chemical Properties ◽  
Highly Correlated ◽  
Relationship Of ◽  
Physical And Chemical ◽  
The Relationship ◽  
And Chemical Properties

The phytotoxicity of chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl] benzenesulfonamide} was compared in six soils, and the relationship of activity to soil physical and chemical properties was evaluated. The influence of soil pH (4.2 to 7.8) on phytotoxicity and adsorption of chlorsulfuron incorporated into high-organic-matter soil was also studied. For the phytotoxicity studies, corn (Zea maysL. ‘Pioneer 3320’) was used as the bioassay plant. Organic matter was the soil variable most highly correlated with chlorsulfuron phytotoxicity. There was an inverse relationship between phytotoxicity and organic matter. No significant relationship between clay content and chlorsulfuron toxicity was observed. The adsorption of chlorsulfuron decreased with increasing soil pH while desorption was greater at alkaline pH. Phytotoxicity of chlorsulfuron increased with increasing soil pH and reached a maximum at pH 6.9.

Pensare Dio. Spunti di riflessione in dialogo con Anca Vasiliu

Elenchos ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 181-194
Author(s):  
Angela Longo
Keyword(s):  
Late Antiquity ◽  
Human Being ◽  
Common Thread ◽  
Critical Issues ◽  
Relevant Topic ◽  
The Common ◽  
The One ◽  
Relationship Of ◽  
The Relationship ◽  
The Trinity

AbstractThe following work features elements to ponder and an in-depth explanation taken on the Anca Vasiliu’s study about the possibilities and ways of thinking of God by a rational entity, such as the human being. This is an ever relevant topic that, however, takes place in relation to Platonic authors and texts, especially in Late Antiquity. The common thread is that the human being is a God’s creature who resembles him and who is image of. Nevertheless, this also applies within the Christian Trinity according to which, not without problems, the Son is the image of the Father. Lastly, also the relationship of the Spirit with the Father and the Son, always within the Trinity, can be considered as a relationship of similarity, but again not without critical issues between the similarity of attributes, on the one hand, and the identity of nature, on the other.

scholarly journals A Comparison, Validation, and Evaluation of the S-world Global Soil Property Database

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 544
Author(s):  
Jetse J. Stoorvogel ◽  
Vera L. Mulder
Keyword(s):  
Comparative Analysis ◽  
Soil Properties ◽  
Soil Property ◽  
Evaluation Criteria ◽  
Clay Content ◽  
Soil Database ◽  
Global Environmental ◽  
Global Soil ◽  
Mean Square Difference ◽  
Methodological Evaluation

Despite the increased usage of global soil property maps, a proper review of the maps rarely takes place. This study aims to explore the options for such a review with an application for the S-World global soil property database. Global soil organic carbon (SOC) and clay content maps from S-World were studied at two spatial resolutions in three steps. First, a comparative analysis with an ensemble of seven datasets derived from five other global soil databases was done. Second, a validation of S-World was done with independent soil observations from the WoSIS soil profile database. Third, a methodological evaluation of S-world took place by looking at the variation of soil properties per soil type and short distance variability. In the comparative analysis, S-World and the ensemble of other maps show similar spatial patterns. However, the ensemble locally shows large discrepancies (e.g., in boreal regions where typically SOC contents are high and the sampling density is low). Overall, the results show that S-World is not deviating strongly from the model ensemble (91% of the area falls within a 1.5% SOC range in the topsoil). The validation with the WoSIS database showed that S-World was able to capture a large part of the variation (with, e.g., a root mean square difference of 1.7% for SOC in the topsoil and a mean difference of 1.2%). Finally, the methodological evaluation revealed that estimates of the ranges of soil properties for the different soil types can be improved by using the larger WoSIS database. It is concluded that the review through the comparison, validation, and evaluation provides a good overview of the strengths and the weaknesses of S-World. The three approaches to review the database each provide specific insights regarding the quality of the database. Specific evaluation criteria for an application will determine whether S-World is a suitable soil database for use in global environmental studies.

scholarly journals One-Dimensional Vacuum Steady Seepage Model of Unsaturated Soil and Finite Difference Solution

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Huang ◽  
Jianguo Lyu ◽  
Guihe Wang ◽  
Hongyan Liu
Keyword(s):  
Finite Difference ◽  
Unsaturated Soil ◽  
Vacuum Pressure ◽  
Vacuum Field ◽  
One Dimensional ◽  
Steady Seepage ◽  
Basic Equations ◽  
The One ◽  
Seepage Law ◽  
Relationship Of

Vacuum tube dewatering method and light well point method have been widely used in engineering dewatering and foundation treatment. However, there is little research on the calculation method of unsaturated seepage under the effect of vacuum pressure which is generated by the vacuum well. In view of this, the one-dimensional (1D) steady seepage law of unsaturated soil in vacuum field has been analyzed based on Darcy’s law, basic equations, and finite difference method. First, the gravity drainage ability is analyzed. The analysis presents that much unsaturated water can not be drained off only by gravity effect because of surface tension. Second, the unsaturated vacuum seepage equations are built up in conditions of flux boundary and waterhead boundary. Finally, two examples are analyzed based on the relationship of matric suction and permeability coefficient after boundary conditions are determined. The results show that vacuum pressure will significantly enhance the drainage ability of unsaturated water by improving the hydraulic gradient of unsaturated water.

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