Rapid identification of soil textural and management zones using electromagnetic induction sensing of soils

Soil Research ◽  
2004 ◽  
Vol 42 (4) ◽  
pp. 389 ◽  
Author(s):  
C. B. Hedley ◽  
I. J. Yule ◽  
C. R. Eastwood ◽  
T. G. Shepherd ◽  
G. Arnold

Three surveys of a pastoral–cropping farming system were carried out over a period of 1 year, using an electromagnetic sensor and real-time-kinematic (RTK)-GPS. The maps produced delineated areas of different apparent soil electrical conductivity (ECa). These delineated areas were compared with soil units of a conventional soil map and results showed the ECa map related well to soil-particle-size classes. In addition ECa could be used to predict groupings of soil phases accurately within one soil type.Soil coring to depths of 1 m, to determine soil physical and chemical properties, showed ECa values were moderately well correlated (R2 = 0.72) to soil clay percentage, weighted for the soil profile. Soil fertility indicators, Olsen P (R2 = 0.61), cation exchange capacity (R2 = 0.59), and exchangeable magnesium (R2 = 0.76) also related well. The linear regression (R2 = 0.76) of ECa with exchangeable magnesium is thought to reflect the dominant clay mineralogy of the study area, i.e. chlorites weathering to illites and releasing magnesium to the soil solution. Discriminant statistical analysis of results showed point ECa values could be used to predict 2 major groupings of the mapped soil phases with 100% accuracy. More precise prediction of these mapped soil units is constrained by localised management effects. Elevated ECa values occur at areas of soil compaction, which have been deduced from measurements of soil strength, aggregate size distribution and visual soil assessment.

2005 ◽  
Vol 5 ◽  
pp. 183-194 ◽  
Author(s):  
Tanmoy Karak ◽  
Dilip Kumar Das ◽  
Uttam Kumar Singh ◽  
Debtanu Maiti

Concentrations of total dissolved cadmium (Cd) and activity of its free ions in soil solution are suggested to be influenced by soil pH, organic matter (OM) content, cation exchange capacity (CEC), and clay mineralogy. We investigated the sorption of Cd by taking 25-, 50-, and 100-µM Cd solutions in five noncontaminated soils of West Bengal, India, having differing chemical properties with batch sorption experiments. The charge characteristics and point of zero salt effect (PZSE) of all experimental soils were calculated by the potentiometric titration method measuring the adsorption of H+and OH–on amphoteric surfaces in solutions of varying ionic strength (I). Sorption of Cd was more pronounced at pH levels greater than PZSE for all experimental soils. The CEC, OM content, clay mineralogy, and specific surface area (SSA) also had a great influence on the sorption of Cd from soil solution to soils. The relationships of Cd with those parameters were found to be consistent and the results concluded that Cd sorption in soils is strongly affected by the soil characteristics.


Author(s):  
Dereje Dejene ◽  
Eyob Tilahun

Imprudently disposed and burning of organic wastes have been causing environmental pollution and greenhouse gas emission. The objective of this study was to characterize the biochar produced from different agricultural wastes to explore its potential use as organic soil amendments. The feedstock derived from each of Eucalyptus globules (EG), Acacia decarance (AD), farm yard manure (FYM) and rice straw (RS) were collected and biochar was produced by slow pyrolysis at 300oC in the furnace. The determination of pH, carbon, phosphorus, cation exchange capacity, electrical conductivity and exchangeable basic cations of individual biochar was performed and statistical analyses carried out to compare the means values obtained. Higher carbon content was observed in biochar produced from AD (65.00%) compared with that of biochar produced from other feedstock types included in this study. pH value of Bbiochar produced from EG and RS were moderately acidic (pH 5.94) and neutral (pH 6.6), respectively, whereas biochar produced from AD (pH 8.07 and FYM (pH 8.17) revealed moderately alkaline pH level. High and low EC values were recorded in biochar produced from FYM (4.70 DS m-1) and the low value from EG (0.68 DS m-1), respectively. The maximum concentration of exchangeable magnesium (20.95%), potassium (16.40%) and sodium (1.77%), EC and phosphorous (2288.75 ppm) were testimony in biochar produced from FYM is potential to prove phosphorus fertilizer requirement of a crop but calcium (39.50%) was from biochar produced from AD. Higher CEC (129.75 cmolc kg-1) was detected in biochar produced from EG followed by biochar produced from RS (127.5 cmolc kg-1), AD (117 cmolc kg-1) and FYM (87.25 cmolc kg-1). Generally, the current finding revealed that biochar from different feedstock’s had different chemical properties, so this difference could contribute for soil fertility improvement as the result agricultural wastes is managed without pollution. But, the current work was limited to the characterization of biochar. So, more detailed investigation on the rate and reclaiming the power of the biochar and other issues should be investigated.


Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 915 ◽  
Author(s):  
RF Isbell

Since the first soil map of Australia by Prescott in 1931, acid red soils developed from basalt have been specifically recognized in spite of their very limited area of occurrence in eastern Australia from North Queensland to Tasmania in a rainfall zone of about 1000 to 4000 mm. Until the early 1950s these soils were known as red loams, but the term krasnozem became formalised in 1953 with the publication of Stephen's Manual of Australian Soils. Over the past 40 years, these soils have been extensively studied because their favourable agronomic properties have led to intensive land use. The krasnozems are red to brown, acid, strongly structured clay soils (50-70% clay) ranging in depth from less than 1 m to over 7 m. Their clay mineralogy is dominated by kaolin and iron and aluminium oxides, and this ensures that the soils have variable charge properties with low cation exchange capacity and usually a significant anion exchange capacity. Free iron oxide contents range from about 7 to 18% Fe. Red basalt-derived soils occur in a number of other countries, and the 'typical' Russian krasnozems appear to have similar mineralogical and chemical properties but apparently lack the characteristic strong polyhedral structure of the Australian soils and are only about one metre deep. The Australian krasnozems are mostly classified as Oxisols in Soil Taxonomy and Ferralsols in the FAO-Unesco scheme. In the new Australian classification they are classed as Ferrosols and a more specific definition and subdivision of this class into lower categories is given, together with their relationship to morphologically similar soils.


2004 ◽  
Vol 36 (1) ◽  
pp. 130 ◽  
Author(s):  
P. Tsolis-Katagas ◽  
D. Papoulis

Two widely different kaolin deposits were investigated in order to determine their physical and chemical properties and suggest their possible utilization. Kaolin deposits from Leucogia area, NE Greece, were formed in situ by weathering of gneissic rocks under a temperate climate; they consist largely of halloysite exhibiting different morphological forms, and stacks and plates of kaolinite in various proportions. The kaolin occurrences of Kos island are products of hydrothermally altered rhyolitic rocks of Pliocene age. The highly altered samples contain dickite and kaolinite. Testing included particle size distribution, brightness and whiteness, measurement of CEC (cation exchange capacity) and some ceramic properties including Atterberg limits. The CEC values range between 3.8-8 meq/100 g and 0.8-2.2 meq/100 g for kaolin samples from Leucogia and Kos island respectively and reflect the differences in clay mineralogy and the characteristic kaolin mineral present. Platy halloysite enhances CEC in Leucogia kaolins while kaolinite-rich samples in Kos exhibit higher CEC values than dickite-rich samples. Atterberg limit tests reveal the Leucogia and Kos kaolins to be of low to medium plasticity and to be classified in the category of kaolinitic clays suitable for brick making. The Leucogia kaolin shows relatively higher brightness (47-60%) and whiteness (62-77%) than Kos kaolin (41-48% and 61-66% respectively). These properties are influenced by the type of kaolin mineral present, their relative proportions and the FeaCb content of the samples. The obtained values for brightness and whiteness from both areas are lower compared to the standard commercial kaolins for the paper and filler market. Brightness, however, can be improved by fine grinding and refinement. The physical, chemical and mineralogical properties of Leucogia and Kos kaolins indicate that they are of low grade type. However, kaolin processing from the crude state can optimize some of these highly commercial properties


Soil Research ◽  
2012 ◽  
Vol 50 (1) ◽  
pp. 1 ◽  
Author(s):  
Philip M. Bloesch

The ratio of cation exchange capacity to clay (CCR) has been used as an index of clay mineralogy in subsoils low in organic matter in place of the standard X-ray diffraction measurement. Laboratory determination of this ratio is time-consuming and expensive and involves two analyses. In this paper, the CCR has been successfully predicted from mid-infrared diffuse reflectance spectra using partial least-squares regression (PLSR) with a square-root transformation of the CCR values (R2 = 0.860; root mean squared error of prediction = 0.089; relative per cent deviation = 2.660 for an independent validation set). The most important wavelengths used in the PLSR calibration were identified. The prediction of CCR using mid-infrared spectroscopy provides a cheaper and faster alternative to laboratory determination.


2017 ◽  
Vol 38 (1) ◽  
pp. 143
Author(s):  
Liane Barreto Alves Pinheiro ◽  
Rodrigo Camara ◽  
Marcos Gervasio Pereira ◽  
Eduardo Lima ◽  
Maria Elizabeth Fernandes Correia ◽  
...  

Mound-building termites are important agents of soil bioperturbation, but these species have not been extensively studied thus far. The present study aimed to evaluate the soil particle-size and the chemical attributes of termite mounds and the surrounding soil under different land use strategies. A one-hectare plot was defined for an unmanaged degraded pasture, planted pasture, and for a eucalyptus Corymbia citriodora plantation. In each plot, the top, center, and base sections of five Cornitermes cumulans mounds, and the surrounding soil at the depths of 0-5; 5-10; 10-20 cm, were sampled in the Pinheiral, Rio de Janeiro state. In the three areas, the center of the mounds contained higher clay content, organic carbon, phosphorous, calcium and magnesium, total bases, and cation exchangeable capacity, when compared to the top, base, and the surrounding soils. However, the center had lower values of exchangeable acidity and potassium, of the three areas. In the eucalyptus plantation, the values of pH, total bases, calcium, and magnesium were lower, whereas aluminum, exchangeable acidity, sodium, and cation exchange capacity were higher both in the mounds and in the surrounding soil, in relation to the pastures. There were no differences among the three areas in terms of organic carbon, potassium, phosphorous, and total bases, in the mounds and adjacent soil. Thus, the termite activity altered the clay content and most of the soil chemical properties in all of the studied areas, but only for the center of the mounds. However, the effect of these organisms was different in the eucalyptus plantation in relation to the pasture areas.


Soil Research ◽  
1984 ◽  
Vol 22 (1) ◽  
pp. 59 ◽  
Author(s):  
KJ Coughlan ◽  
RJ Loch

This paper explores the processes responsible for clay dispersion, and the formation of large dry aggregates, in cracking clay soils. It also isolates the soil factors causing variations in dry aggregate size using regression analysis. Twelve cracking clay soil samples were selected on visual differences in dry aggregate size distribution following seedbed preparation, and a range of soil structural and chemical properties were measured. The per cent dry aggregates > 5 mm was found to increase with resistance to mechanical abrasion, stability to wet sieving after capillary wetting, and dispersion ratio, indicating that large dry aggregates are formed as a result of binding by dispersed clay. Both raindrop impact and puddling by cultivation may be involved in dispersion. There was a strong relationship between dry aggregate size in the 0-10 cm layer and salt content in the subsurface (60-90 cm) layer. Coarse surface aggregation is explained in terms of limited profile hydraulic conductivity. For the soils studied, the properties of the surface layer appear to be responsible, at least in part, for the limitation in profile hydraulic conductivity. Dry aggregate size in the 0-10 cm layer was not simply correlated with any of the chemical properties of that layer. However, equations containing two (ESP and CEC per gram of clay) or three (ESP, per cent clay and CEC) independent variables were derived to explain variations in dry aggregate size, both for the 12 soils studied and for a wider range of Queensland cracking clay soils.


2019 ◽  
Vol 14 (1) ◽  
pp. 20-34
Author(s):  
T. G. RYASHCHENKO ◽  
N. N. UKHOVA ◽  
S. I. SHTELMAKH ◽  
N. I. BELYANINA ◽  
P. S. BELYANIN

The article considers the study results of composition, microstructure and physical-chemical properties of the quaternary clays of the Prikhankayskaya depression in district of the lake Khanka (Primorye) on the example of air-dry samples of geological borehole 45-b in the range of 18–62 m. The objective of research was to obtain new information about the properties of widespread clay sediments in this area using geologic-lithological materials and laboratory data. The schematic geologic-lithological column was composed with the selection of various zones in the quaternary clay sediments section and the border with sediments of the Neogene System. The methodological scheme of laboratory studies of clays was proposed. This scheme includes the determination of chemical and microelement composition, clay minerals, contents of carbonates, water-soluble salts, mobile forms of aluminum oxide, humus, as well as microstructural parameters (method «Microstructure») and some physical-chemical properties. Geochemical coefficients (Kz, CIA, CIW, ICV) determined the degree of chemical maturity of clays and confirmed the results of palynological studies reflecting the fluctuations of the climatic conditions of their formation. For the group of toxic microelements for the first time the special indicator (Zc) was calculated. Which was the criterion for a degree of pollution of the clay sediments section. Clay minerals of the quaternary clays are represented by smectite and hydromica. The clear change in the mineral association was found when passing to the Neogene sediments (kaolinite prevails). The method «Microstructure» revealed the aggregated type of clays microstructure, the domination of the particles of coarse dust fraction among the primary (free) particles and the almost complete absence of the particles of fine-grained sand fraction, the participation of various fractions in the composition of aggregates. The variants of the formation of certain types of aggregates (on sizes) in the fluviolacustrine «khankayskiy» clays are presented. Solid part density, water resistance (soaking time), sedimentation volume, plasticity, relative swelling (samples-pastes) were determined using standard methods for clays. By special methods, the cation exchange capacity was measured and the calculated values of the plasticity index were obtained from forecasting formulas using the yield limit. The proposed methodological scheme of complex laboratory studies of clay sediments can be recommended for problematic geologic-lithological and engineering-geological sections.


Author(s):  
Vítězslav Vlček ◽  
Miroslav Pohanka

Soil samples (n = 11) were collected in the chernozem areas of the Czech Republic (the Central Europe) from the topsoil and used as representative samples. All sampling areas have been used for agricultural purposes (arable soil) and they were selected as typical representatives of agricultural soil. These samples represented the soil with same genesis (to reduction differencies between soil types) but with different soil properties (physical and chemical). Complete chemical and physical analyses were made for confirmation of copper adsorption on solid phase: we analysed the particle size distribution, content of oxidizable carbon (Cox), the cation exchange capacity (CEC), supply of exchange calcium, magnesium, sodium, phosphorus and potassium, soil reaction and the total supply of Fe, Al, Mn, Ca, Mg, K, P and N. The strongest simple correlation between analysed soil properties and copper concentration had content of available magnesium (r = 0.44) and available phosphorus (r = −0.51). In the case of multiple correlations (i. e. collective influence of multiple soil properties) had the strongest influence combination of clay, soil reaction, total content of phosphorus, available magnesium and available phosphorus. The main influence of phosphorus and magnesium is evident. We suppose that copper and phosphorus enter into specific complex. Influence of these five soil properties can explain 92.7 % (r = 0.927) changes in the content of copper changes in the experiment.


Author(s):  
C. V. Ogbenna ◽  
V. E. Osodeke

Aim: A pot experiment was carried out to determine the effect of sawdust ash and lime (Ca(OH)2) on soil characteristics and yield of sunflower in acidic soil of southeastern Nigeria. Study Design: The experiment was laid out in split-plot design, using sawdust ash (0, 1, 2, 3, 4 t ha-1) as the sub plot and lime (0, 0.5, 1.0, 1.5 t ha-1) as the main plot. Place and Duration of Study: Study was conducted outdoors at Michael Okpara University of Agriculture Umudike, Nigeria, during the 2010 planting season. Materials and Methods: Treatment combinations were applied to the 60 buckets containing soil, mixed thoroughly and watered adequately. After 1 week of treatment application, two sunflower seeds were planted and later thinned to one seedling per bucket. Plant growth and yield data were collected. Pre planting and post-harvest soil samples were collected and analyzed for soil properties. Results: Results showed that with the exception of organic carbon there was significant effect of treatments on all soil chemical properties. Lime and sawdust ash (SDA) as single and combined treatments significantly increased total nitrogen (P=0.05), available phosphorus (P<0.010), and base saturation (P<0.012). The interaction between SDA and lime significantly (P=0.05) increased total exchangeable bases and effective cation exchange capacity, while soil pH was significantly increased (P=0.05) by single applications. The increases in soil chemical properties led to significant positive response of the sunflower. With the exception of number of leaves, other plant parameters (Plant height, stem diameter, head weight, 50 seed weight, head diameter) had significant increases for sawdust ash alone at P=0.05. Correlation studies showed positive significant relationship between soil pH and sunflower yield. Conclusion: The study showed that sunflower performed best at the combination of 3 tha-1 SDA and 1.5 t ha-1 lime producing a mean head weight of 45.4 g.


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