Soil Testing Laboratories Research Articles

Recognition of geological processes in permafrost conditions

Any evaluation of geological processes in the permafrost zone is complicated by the rigorous climate and the general inaccessibility of such areas, which has resulted in insufficient information on territories in permafrost zones. The aim of this study was to delineate areas of geological processes in the zone of the discontinuous permafrost of Western Siberia based on the example of the Beregovoe oil and gas condensate field. An integrated approach using remote materials, the data from a walk-over survey, and laboratory testing of soils for the future pipeline was used. To estimate the prevalence and dynamics of exogenous geological and cryogenic processes, we described the climatic, geomorphic, geological, hydrogeological, and engineering–geological conditions of the territory as the basis of their emergence and development as well as the methodical issues of remote sensing. The recognition of landforms produced by different geological processes depends on the size of the landforms being mapped, their morphological expression, and the contrast between the disturbed landforms and the surrounding undisturbed areas. We defined the interpretive signs of major exogenous processes in the satellite images of the area and created a map on a 1:100,000 scale showing the distribution of geological processes at different geomorphic levels. This approach can be used to assess exogenous processes in other Arctic and Subarctic areas.

Challenges Facing Soil‐Testing Laboratories to Provide Soil Health‐Related Analysis

CSA NewsVolume 64, Issue 4 p. 24-25 Membership Challenges Facing Soil-Testing Laboratories to Provide Soil Health-Related Analysis First published: 18 April 2019 https://doi.org/10.2134/csa2019.64.0423Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume64, Issue4April 2019Pages 24-25 RelatedInformation

Using image analysis to estimate the soil organic carbon content

Soil test for organic carbon content using the Walkley-Black standard method is a laborious task that takes almost 5 working days to report the results. In order to improve lab analysis efficiency, a new analytical method using digital images is proposed. Using multivariate image analysis (MIA) soil organic carbon (SOC) contents can be determined in <3 days. The MIA method for SOC was developed using 177 soil samples collected from 3 regions of Brazil (North, West Central, and Northeast). Digital images of soil samples were correlated with the organic carbon contents determined by the Walkley-Black standard method using multivariate regression algorithms. In the end, MIA model employing a machine learn approach using least squares support vector machine (LS-SVM), presented an excellent correlation, r2 > 0.93, between image data and SOC contents measured by the standard analytical method. The proposed MIA method is eco-friendly, cheap, fast, and a clean alternative that can be employed by soil testing laboratories for measuring SOC contents.

Influence of Depositional Method on Dynamic Properties of Granular Soil

The behaviour of granular soil is mainly dependent upon the nature and arrangement of particles, which in turn affect fabric anisotropy. It has been known for many years that depositional method plays an important role in the results of laboratory testing of granular soils. Despite extensive studies on the dynamic properties of granular soil, previous research has lacked a quantitative study of the effects of depositional methods on the dynamic properties of the granular soil. The primary objective of the current study was to evaluate the effect of fabric anisotropy on the dynamic properties of granular soil for practical applications. The influence of depositional method, mean effective consolidation stress, shear strain amplitude and relative density on the maximum shear modulus (Gmax), shear modulus curve (G-γ), normalized modulus curve (G/Gmax-γ) and damping curve (D-γ) of pure sand, pure gravel and sand-gravel mixtures is investigated. The results of the tests indicate that depositional method has a significant effect on Gmax that this effect was more pronounced for the pure sand specimens than for the pure gravel or sand-gravel mixture specimens. However, the depositional method had no significant effect on the shear modulus at large shear strain amplitudes. The effects of depositional method on the G/Gmax-γ and D-γ curves are dependent on effective confining pressure and relative density.

Yield‐based Nitrogen Management and the ‘1.2 Rule’

Yield‐based Nitrogen Management and the ‘1.2 Rule’

Prediction Method for Overconsolidation Ratio of Marine SoftSoil Based on the Piezocone Penetration Tests

Because of the strong structural and sensitive behavior, the properties of marine soft soil change greatly when subjected to external disturbances, which leads to great difficulty in reflecting its real mechanical properties in the laboratory soil tests. The piezocone penetration test (CPTU) is one of the main technologies for in situ testing of geotechnical engineering. CPTU has the advantages of being fast and convenient, no sampling, low disturbance to soil, large amount of data, and reliable testing. The determination of the overconsolidation ratio (OCR) based on the CPTU results can solve the problems of soil disturbance and stress release, which occur during the consolidation test in the laboratory. However, there are still some problems such as lack of strict theoretical analysis of penetration mechanism and incomplete interpretation theory of in situ test parameters of CPTU. In this paper, the CPTU cone head is assumed to be hemispherical considering the penetration mechanism of CPTU. Moreover, the compaction modes of the CPTU probe penetrating into soil are adopted as spherical and cylindrical cavity expansion modes, respectively. The ultimate expansion pressures of the probe penetrating into soil under the spherical and cylindrical cavity expansion modes are first obtained by virtue of the theory of cavity expansion. Then, two prediction methods for OCR considering the roughness and penetration rate of the cone are proposed by combining the ultimate expansion pressures of the probe penetrating the approximate closed solution of cavity expansion in the modified Cambridge model, which is suitable for predicting the OCR of marine soft clay. Finally, to verify the reliability of the two proposed prediction methods, comparisons with the in situ CPTU tests of marine soft clay in two coastal areas and two existing prediction methods are made. The comparison results show that predictions of OCR of marine soft clay in this paper are close to Wayne’s method and more accurate than Chanmee’s method since the factors such as cone roughness and penetration rate are considered in the new proposed prediction methods. In order to improve the applicability in different cases of the OCR predictions, the average values of the two proposed methods are recommended as the reference value for the OCR of marine soft soil.

Effects of Auxin and Media Additives on the Clonal Propagation of Guava Cuttings (Psidium guajava L.) Var. Chinese Gola

Clonal propagation is a process of asexually reproducing plants by multiplication of one copy to produce several copies that are genetically identical. One of the best methods of clonal propagation is using the cuttings. There are many plants that can be propagated through cuttings and one of them is guava. Guava is popular in Pakistan. To ensure that a guava tree will produce fruits that belong to its original cultivar, this study was conducted. Softwood cuttings of guava were treated with IBA (1600 ppm and 2000 ppm), NAA (7000 ppm and 10,000 ppm) and IBA+NAA (1600+7000 ppm and 2000+10,000 ppm). There were five media used (Soil, Peatmoss+Soil, Sand+Soil, Baggasse+Soil and Soil+Peatmoss+Sand+Bagasse. The experiment was laid out using Completely Randomized Block Design (CRBD) with two-factor factorial arrangement. A total of 105 cuttings were used, each with 12 cm length and with 2-4 nodes. Media samples were collected and physio-chemically analyzed at the Soil and Water Testing Laboratory in Layyah, Pakistan to assess the properties and fertility status. Guava cuttings with 1600 ppm IBA showed the best results in terms of the number of roots, root length and days to sprout, followed by 7000 ppm NAA in Peat moss+soil and soil+peat mass+sand+bagasse. For the combination of growth regulators, the best results were observed in IBA 1600 ppm + NAA 7000 ppm. Poorest result in all parameters (days to sprout, number of roots, and root length) was recorded in control. The 1600 ppm IBA with 10 second dipping time for softwood cuttings of guava yielded best results in peatmoss+soil media for all the parameters tested. Hence, this study concluded that treatment with auxin (such as IBA) can yield best results and can help to solve the problem in propagating guava using cuttings.

Evaluation of a machine to determine maximum bulk density of soils using the vibratory method

Engineering buildings and other structures such as dams and roadways require soil compaction during construction, so as to limit settling of structures after construction. Optimum water content that results in the maximum soil density is normally desired, so that compaction could be done at this water content. This has to be determined by prior laboratory soil tests usually carried out using the standard Proctor test. The design, construction and testing of a vibratory soil machine, which can produce densities and optimum moisture contents that would mimic the Proctor test is described. A mechanism was designed and developed that vibrated the soil at a given time, amplitude and frequency and resulted in compacting the soil. These factors were varied to determine the ideal parameters for operating the vibratory compactor. Results showed that soil densities increased with increasing sand contents in the soils, increasing amplitude, time and frequency of the machine. Results also showed that the vibratory soil compactor would work best at a frequency of 17 Hz and amplitude of 1.17 mm for five minutes. Soil was compacted in three layers. Further, it worked best in sandy soil producing about 98% of the maximum bulk density from the Proctor test and 97% and 96% for the clay loam and clay soils respectively. The major advantage of the constructed vibratory soil compaction equipment is that it would reduce the tedium involved in the standard Proctor soil compaction test.

Peak Friction Angle of Soils as a Function of Grain Size

Numerous studies have attempted to correlate geotechnical properties and to produce semi-empirical methods for estimating geotechnical parameters when sufficient field or laboratory measurements are not available. In the case of Greek soil formations, several studies have been presented that relate in situ tests (standard penetration test, cross-hole, seismocone) and laboratory tests for cohesive soils. Statistical analysis of the data resulted in the formulation of empirical correlations between various soil parameters, often with reasonably high correlation coefficients. However, these relationships refer mainly to cohesive soils, because the majority of tests were carried out in such formations. In this paper, the correlation of the particle size and the peak friction angle for a wide range of Greek soil formations is investigated. A simple, but rational approach for estimating the friction angle is presented, which allows prediction of the shear strength of soil formations. Since this investigation covered a wide range of soils and the number of test results is significant, the obtained empirical correlations can be considered as reliable for Greek soils.

Knowledge of soil test recommendations by the orange growers

The present study on knowledge of soil test recommendations by the orange growers was conducted in Amravati, Chandur Railway and Chandur Bazar talukas of Amravati district. The study was planned to investigate knowledge of soil testing techniques and its recommendations by the orange growers. The exploratory research design of social research was used for the present investigation. The present study was undertaken in Amravati district of Vidarbha in Maharashtra state. The farmers were selected from three taluka Amravati, Chandur Railway and Chandur Bazar, on the basis of having area under orange orchards and orange growers were selected randomly having productive orange orchards. Thus, the total fourteen villages were selected. Data were collected by personally interviewing the respondents with the help of pretested and structured interview schedule. The data collected were tabulated and the statistical tools namely mean, standard deviation, percentage, frequency, correlation co-efficient were employed for interpretation of the findings. Null hypothesis set for the study was tested for its acceptance or rejection. The respondents were selected by proportionate random sampling method to constitute sample size of 80 respondents. The salient findings of the present study revealed that the distributional analysis pertaining to age of respondents indicated that 56.25 per cent were in middle age group, education of respondents indicated that 22.5 per cent of the respondents were studied high school, and 43.75 per cent of the respondents had annual income between 1,00,001 to 1,50,000. From all selected respondents, majority (93.75%) of the respondents were having upto 2 ha area under orange orchard, 62.5 per cent respondents were having orange orchard from 7 to 12 years age. 52.5 per cent respondents availed employment guarantee scheme for plantation of orange orchard. Most (48.75%) of the respondents had deep type of soil. Majority (78.75%) of the respondents had farming experience between 8 to 14 years. More than half (100.00%) respondents have to travel distance upto 50 km from their village for soil testing laboratory. More than half of the respondents (73.75%) had medium level of extension contact, 57.5 per cent of the respondents using drip as a method of irrigation. Out of the total selected orange growers 65.00% of respondents were having medium level of knowledge about soil testing techniques and its recommendations. The variables namely education, type of soil, extension contact and method of irrigation were positively and highly significantly correlated with knowledge of soil testing techniques at 0.01 level of probability. The variable namely age of orchards, annual income, employment guarantee scheme availed and farming experience were positively and significantly correlated with knowledge of soil testing techniques at 0.05 level of probability. Whereas, area under orange orchards, were non-significantly correlated with knowledge about soil testing techniques and its recommendation at 0.05 level of probability. Whereas, age of respondents, distance from soil testing laboratory were negatively and non-significantly correlated with knowledge of soil testing techniques and its recommendation as per the soil test report.

Work-Based Framework for Sample Quality Evaluation of Low Plasticity Soils

AbstractSampling and laboratory testing of soils is often necessary to evaluate site-specific soil properties. Prior research has been primarily performed for clays, producing accepted practices th...

Determination of Physical and Mechanical Characteristics of Macro Sample of Water Saturated Peat

The article reports results of laboratory tests of weak water-saturated soils (remoted from day surface) in stress-strain state under influence of compression with double-sided filtration of pore’s water. The authors suggested the upgraded assembly scheme of the soil pressure sensors (load cells). The laboratory research of the water-saturated macro peat sample was made in compression conditions with “ground lock” and modeling of the experiment with Plaxis 2D software system. The unit deformation-pressure graph and excessive pore pressure against time in different steps of load graph were built and based on this findings. Authors made the new experimental device for research of the water saturated peat mechanics properties with excessive pore pressure

Investigation of physical and mechanical properties of peat

The article describes results of laboratory tests of weak water-saturated soils (remote from day surface) in stress-strain state under influence of compression with double-sided filtration of pore’s water. The experimental device with console-lever system of load transfer and potential of double-sided filtration was made for current research. The compression specification was controlled with the strain gauge sensor element of general pressure (i.e. the load cell).The deformation in sample were measured with the motion detecting transducer that based on indicating gage. The excessive pore pressure was measured with strain gauge sensor elements and digital manometer. Also the plots of compression deformation against pressure and changes of excessive pore pressure during the time on different load degrees were drawn. Although, authors made the new experimental device for research of the water saturated peat mechanics properties with excessive pore pressure.

Geotechnical risks of foundation of warehouses built on brownfields

AbstractThe warehouse halls were founded on backfill sediment, which were 4 to 6 meters thick. Beneath them were the loess and saturated Cretaceous sands. During heavy rains, there were two large landslides that hit the local road. It was therefore necessary to carry out a rapid design of remedial steps (stabilization) without the time to carry out drilling exploration survey. During fieldwork (mapping, geodetic measuring of landslides and sampling of soil) it was found that most of the warehouse halls did not have solved the drainage of rainwater from roofs and roads and there occurred long cracks in the floors of the halls. Laboratory soil tests served as inputs for stability calculations. Reverse analysis (landslide condition) derived residual geotechnical parameters of the soil. The proposal for redevelopment consisted of changing the slope geometry, building a loading bench and brand new drainage of surface water along the slope (it was missing on the top). It was also recommended to replace the subsoil – saturated loess – under the floors of the warehouse halls.

Determination of the shearing behaviour of root-permeated soils with a large-scale direct shear apparatus

Soils with roots or root-like inclusions have often been tested in direct shear to quantify the effects of vegetation on the shear strength of soil, and in turn, the stability of slopes. However, a straightforward evaluation of root reinforcement is challenging due to the complex nature of roots, and the dependency of soil behaviour on many factors. An Inclinable Large-scale Direct Shear Apparatus (ILDSA) was built to study the shearing behaviour of root-permeated soils. Planted specimens, consisting of two different sets of species, were prepared with a moraine, sampled from a recent landslide location, and tested in direct shear subsequent to saturation. Relationships of peak stress ratio with dry weight of roots, maximum dilatancy angle and void ratio were investigated to evaluate the behaviour of root-permeated soil. The combined approach, of taking both presence of roots and dilatant behaviour of soil into consideration, results in a more realistic understanding and quantification of the effects of root reinforcement, at least, for laboratory testing of root-permeated soils.

English

Appropriate quantification of nitrogen availability in soil is the prerequisite for proper implementation of soil-test based fertilizer-application scheme. However, most of the soil testing laboratories use soil organic carbon level to suggest fertilizer dose for nitrogen; hence, the present study has been initiated to develop prediction equation for estimating available nitrogen content of soil from its organic carbon content to facilitate the implementation of soil test based on nitrogen fertilizer application in mulberry garden. A total of 300 soil samples comprising 100 locations from each of Malda, Murshidabad and Birbhum districts have been analyzed for estimation of organic carbon as well as corresponding available nitrogen content. Analytical data was further subjected to regression analysis and district wise working equations were developed to predict nitrogen availability in soil from its organic carbon content. All the equations registered quite higher R2 values, significant at 1% level and thus, considered viable to predict nitrogen availability in soil. Moreover, comparison between predicted and observed values of available nitrogen content in some selected soil samples of each of the districts was done to ascertain accuracy of these equations. The accuracy was found reasonable in terms of &plusmn;10% variation and thus, the developed equations are competent enough to predict nitrogen availability in soil under mulberry vegetation of the districts under investigation. &nbsp; Key words: Available nitrogen, mulberry, organic carbon, prediction, soil-test.

State of the Practice for Laboratory Testing of Soft Soils: It's All in the Details

As with all material testing, soils testing has undergone dramatic advances in technology because of computer automation. In the 1970s, laboratories were filled with dial gages, proving rings, mercury pots, and pressure regulators. It was an environment dominated by manual labor, imposing many constraints on test capability and duration. For example, collecting time-deformation measurements during all the increments of an oedometer test was an expensive venture.

Selecting a reliable soil‐testing lab

Selecting a reliable soil‐testing lab

Association of Soil Parameters with Various Age Classes of Forests of Mukundpur, Satna, Forest Division, Madhya Pradesh, India

Aims: This forest area was susceptible to illicit felling, encroachment and illicit mining. From this problem the forests are changing from stocked - under stocked - blank forests. The majority of the area are blank and under stocked category. To re-vegetate the blank and under stocked area into stocked forests, the soil parameters in the study area were needed to be studied in detail. In the present study the associations of soil parameters like pH, electrical conductivity, availability of major nutrients (nitrogen, phosphorous and potassium) and micro nutrients like (copper, manganese, iron and zinc) with various age classes of forests were analyzed.&#x0D; Study Design: Stratified systematic random sampling.&#x0D; Place and Duration of Study: Study area was the forest area of 111.55 km2 of Mukundpur range of Satna Forest division, Madhya Pradesh, India. Field work was carried out during October 2015 to January 2016.&#x0D; Methodology: The vegetation sampling had been done to assess the forest resource survey. Stratified systematic random sampling method was used for sampling the vegetation. The minimum numbers of sample points were calculated using statistical formula. The 151 sample points at 30”x 30” were selected on safer side with the help of GPS. Half kg of soil sample was collected from central quadrat from the depth of 30 cm from the sample point and air-dried under shade. These samples were sent to soil testing lab Rewa to assess the soil parameters pH, electrical conductivity, organic carbon, available nitrogen, available P2O5, available K2O and micronutrient analysis for availability of zinc, iron, manganese and copper. The Microsoft access program was developed to evaluate the above soil parameters in various age classes of forests. Age classes of forest are defined as, Mature: where average girth of forest trees is more than 120 cm, Middle age: where the average girth of trees of a particular forest stands between 61-120 cm, Young age: where average girth of trees of particular stand is below 60 cm.&#x0D; Results: Results of individual soil parameters on various age classes of forests were summarized below:&#x0D; The average value of pH in different age classes did not change significantly with average value of pH of the study area. The electrical conductivity within encroachment and blank category significantly changed but in medium and young age classes it did not differ significantly with average electrical conductivity of the study area. In encroachment and blank organic carbon content and available nitrogen were significantly higher but in medium and young age classes these parameters did not change significantly with the average value of organic carbon content and available nitrogen of the study area. The average value of available phosphorous in blank and young age classes did not change significantly but in encroachment and medium young age class it was significantly higher than the average value of available phosphorous of the whole study area. The average value of available K2O in encroachment, blank and young age class did not change significantly but it changed significantly in medium age class with average K2O value of study area. Except the encroachment category, the average zinc and iron value in blank, medium and young age classes did not change significantly with average value of the study area. The average value of Mn in encroachment and blank varied significantly but in medium and young category it did not change significantly with the average value of the study area. The average values of Cu with in Blank and young age classes did not change significantly but it had changed significantly in encroachment in medium age class with average value of the study area.&#x0D; The results of combined effects of pH, EC, Organic Carbon and combined impact of nitrogen, P2O5 and K2O (macro nutrients) did not have significant association within various age classes of study area. The results of combined effects of Zn, Fe, Mn and Cu did not have significant association within various age classes of study area.&#x0D; Conclusion: The effects of pH, electrical conductivity and organic carbon were not significant in age classes of study area either individually or jointly. The available nitrogen did not play significant role in age class formation of forest but P2O5 and K2O did make significant impact on medium age classes individually, but the combined effects of nitrogen, P2O5 and K2O (macro nutrients) did not have significant association within various age classes of study area. Individually the Zn, Fe and Mn did not play significant impact on age class formation of the forest, though Cu is significant in medium age classes. The overall impacts of Zn, Fe, Mn and Cu did not have significant association within various age classes of study area.

Stability of Indicators for Net Soil Nitrogen Mineralization in Tobacco Rotation and Tillage Systems

Core Ideas Relative effects of management on net soil N mineralization were stable across three years. Soil C and N fractions contribute variably to predicting N mineralization in different rotation systems. Soil organic C was the overall best predictor for net N mineralization among tobacco rotation systems. Measuring biological net soil nitrogen mineralization (NSNM) can assist nitrogen (N) fertility management in agroecosystems, but the time and apparatus required for this assessment limits measurement frequency. Stable NSNM predictors that could be rapidly measured to compare systems would be extremely useful. We compared the effects of crop and soil management on NSNM from 2011 to 2013 and evaluated several carbon (C) and N indices including particulate organic carbon (POC), particulate organic nitrogen (PON), permanganate oxidizable carbon (POXC), soil organic carbon (SOC), and soil total nitrogen (STN) as NSNM indicators. Soil (0 to 10 and 10 to 20 cm depths) was collected from six long‐term burley tobacco (Nicotiana tobacum L.) tillage and rotation systems. Net soil nitrogen mineralization was estimated by a 120‐d laboratory incubation. The relative effects of management on NSNM among these systems were stable across 3 yr, which suggested NSNM measurement can be reduced to that frequency when NSNM is used to compare different crop and soil management. The soil C and N fractions contributed variably to predicting soil N mineralization in the different rotation systems, but SOC (which can be calculated from soil organic matter, a common index in the routine test package of many soil testing laboratories) was the best overall NSNM predictor in this study.