Search

This paper explores the influence of two thermal loading protocols on the evolutions of stress state and soil consolidation characteristics during subsequent mechanical loading. We employed a specially designed thermal consolidometer to conduct a series of drained heating tests with temperature gradient across a saturated kaolin specimen at different levels of vertical effective stress. The thermal consolidometer accommodated for (1) continuous measurements of excess pore water pressure and temperature at different locations within a specimen; and (2) establishment of a steady nonuniform soil temperature distribution, a condition that often exists in the field. Staged and cyclic thermal loading revealed the influences of vertical effective stress on total and nonrecoverable thermal strain. Continuous measurements of pore pressure and soil volume change traced the evolution of average vertical effective stress with void ratio. While the negative pore pressure measurements at the end of thermal consolidation of normally consolidated clay suggested a pseudo-overconsolidated behavior upon heating at low values of vertical effectives stress, such a tendency diminished with an increase in stress level. A gradual shift in normal consolidation line at ambient temperature suggested continuous hardening of a normally consolidated specimen when subjected to repeated thermal loading cycles in the past. [ABSTRACT FROM AUTHOR]

Aims: Fertilisating crops with zinc (Zn) is considered important to enhance agricultural productivity and combat human Zn deficiencies in sub-Saharan Africa. However, it is unclear on which soils Zn fertilisation can lead to higher yields and increased grain Zn concentrations. This study aimed to find soil properties that predict where soil Zn is limiting maize yields and grain Zn concentrations, and where these respond positively to Zn fertilisation. Methods: Zinc omission trials were set up at multiple farm locations in Kenya (n = 5), Zambia (n = 4) and Zimbabwe (n = 10). Grain yields and tissue Zn concentrations were analysed from plots with a full fertiliser treatment as compared to plots where Zn was omitted. Results: A positive maize yield response to soil Zn fertilisation was found at only two out of nineteen locations, despite soil Zn levels being below suggested critical concentrations at most locations. Soil properties nor plant concentrations were able to explain maize yield response to Zn fertilisation. However, positive responses in Zn uptake and grain Zn concentrations to Zn fertilisation were found at the majority of sites, especially in soils with low pH and organic carbon contents. Labile soil Zn measurements related more with Zn uptake (R2 = 0.35) and grain Zn concentrations (R2 = 0.26) than actual available Zn measurements. Conclusions: We conclude that soil Zn fertilisation did not increase maize yields, but can increase maize grain Zn concentrations, especially in soils with low pH and organic carbon content. Predicting a yield response to Zn fertilisation based on soil properties remains a challenge. [ABSTRACT FROM AUTHOR]

Earth construction results in energy efficient, durable, and beautiful non-toxic structures. Earth walls incorporate remarkable thermal and acoustic properties. They have low maintenance, high longevity, and improve indoor air quality. In addition, they are fire and insect resistant and embody intangible aesthetic qualities. Most importantly, they are environmentally responsible and contribute to sustainable development. With its roots in ancient building techniques, modern earth construction is currently experiencing its reemergence as a valuable building technique. This research takes the form of a field test research report that examines four field tests conducted on three different types of soil, i.e., kaliche, clay, and 50% kaliche-50% clay mix. The four tests include (1) Particle Determination Test, (2) Compaction Test, (3) Cigar Test, and (4) Modulus of Rupture Test. The Particle Determination Test estimates the proportion of major soil constituents (clay, silt, sand, and gravel). The Compaction Test determines the packing quality of the soil. The Cigar Test confirms the moisture content of the soil. The Modulus of Rupture Test verifies the toughness of compressed blocks. The paper concludes that the 50% kaliche-50% clay mix serves as the ideal soil-type for constructing earth walls. The paper also demonstrates that the 50% kaliche-50% clay mix satisfies the conditions of the New Mexico Building Code average Modulus of Rupture. Data generated through the four tests was subsequently utilized to construct an experimental rammed earth wall for demonstration purposes. [ABSTRACT FROM AUTHOR]

Ground improvement was required for construction of the Jaber Al Ahmed New City located about 25 km west of Kuwait City, Kuwait. Loose to medium poorly graded sands and silty sands extended from ground level to a depth ranging from 5m to 9m. Dynamic compaction was employed, as an economic method, to increase the soil bearing capacity and reduce its compressibility for foundation design and construction. The testing program included borings and sampling, Standard Penetration Tests, Cone Penetration Tests, and Pressuremeter Tests before and after dynamic compaction. The area covered in this study is about 31415m² . The results indicated significant ground improvement and satisfaction of the specified acceptance criteria resulting in an allowable soil pressure for shallow foundation design, equal to or exceeding 300 kN/m². [ABSTRACT FROM AUTHOR]

Aims: Many soils in the developed world have been fertilized with phosphate for several decades. Appreciable phosphate has accumulated in such soils. This is referred to as "legacy P". The benefits of legacy P are not widely appreciated. Here, we report the effects of legacy P on buffering capacity and the consequent effects on the effectiveness of plant growth, and its effects on the continuing reaction between soil and P and the consequent effects in decreasing the decline of P effectiveness with time. Methods: We produced five levels of legacy P by incubating the soil with added phosphate at high temperatures for 30 days. We then measured the effect on sorption/desorption and on plant growth in response to further additions of phosphate. Results: Legacy P decreased soil buffering capacity, decreased hysteresis of desorption, and increased the amount of P in a similar state to that of the recently sorbed P. There were analogous effects of plant growth; effectiveness of P fertiliser increased; the decline in effectiveness with time decreased; and the amount of soil P accessible to plants increased. We think that soil tests reflect only the amount of soil P accessible to plants. Soil testing services which include estimates of phosphate buffering reflect its decrease and the consequent increase in fertilizer effectiveness. We propose a simple test to reflect the rate of decline in effectiveness with time. Conclusions: Managing phosphate applications using soil tests alone underestimates phosphate status and leads to over application of phosphate. It is necessary to also include estimates of the change in phosphate buffering and the change in the rate of decline in effectiveness with time. A simple way to estimate the rate of decline is suggested. [ABSTRACT FROM AUTHOR]

The aim of this work is to summarize previously conducted studies on the optimization of the unequal geotechnical testing program and on the selection of the desired calculation indicator based on the results of such tests. The approximate, but quick and cheap tests (“express methods”) are recommended to be performed on a large scale and considered as a means of assessing the geotechnical structure of the site as a whole. It is proposed to carry out expensive “accurate” tests in a reduced volume and to use them as a means of correcting approximate tests. In the article, these issues are considered by the example of determining the bearing capacity of piles according to the data of static sounding (cone penetration testing – CPT), dynamic and static tests of full-scale piles. We propose the mathematical model for evaluating the informative content of the test complex, based on the concepts of information theory. The site is mentally divided into several sections, each of which is characterized by one of the possible values of the ultimate resistance of piles of a certain length. All variants of “placement in the plan” of possible values of pile resistances (“site images”) are considered. Initially, when nothing is known about the true value of the pile resistances in each section, all possible values of the pile resistances are assumed to be equally probable, i.e. the uncertainty of the situation is maximum. In the theory of information, such uncertainty is quantified by the value called entropy. When any test is performed at the site, the uncertainty decreases, and the more accurate the test the more significant is the decrease. The difference in entropy before and after the test represents the amount of information (in bits) that these tests carry. The calculations using this model showed that the information content of a large number of approximate tests can (due to heterogeneity of the soil) exceed the information content of small exact tests. Only one approximate test method can lead to the systematic error (overestimation or underestimation of the average value of the desired indicator). It is necessary to carry out control “exact” tests and approximate tests to eliminate such a danger. A technique is proposed for adjusting approximate estimates based on data from “accurate” tests, which ensures optimal “safety margins” in decisions being made.

The three-year field experiment (2015-2017) with graded doses of magnesium (Mg) and sulphur (S) was carried out at the Humpolec experimental station (49.5546239N, 15.3485489E; Czech Republic). The interactions between boron (B), Mg and S in the soil were studied. No boron was applied into soils. Contents of B, S and Mg in the soil were determined by the Mehlich 3 and NH4 acetate methods. The crop rotation was: spring barley-oilseed rape-winter wheat. Three Kieserite doses (S and Mg fertiliser) were applied. Sulphur treatments were 10-20-40 kg S/ha to cereals and 20-40-80 kg S/ha to oilseed rape. The doses of Mg were: 13-26-52 kg Mg/ha to cereals and 26-52-104 kg Mg/ha to oilseed rape. A significant gradual decrease of B-Mehlich 3 was observed under Kieserite treatments during the experiment (from 1.24 mg B/kg in control in the 1st year to 0.92 mg B/kg in the 3rd year). On the contrary, B-NH4 acetate contents in soils remained similar during 2015-2017 in control soils (0.33-0.39 mg B/kg) and significantly decreased under Kieserite treatments, namely by 55-57% in 2016 and by 43-48% in 2017. A significant decrease of B content in soils was noted since the second year of experiment after oilseed rape. The boron contents in soils were affected in several ways - by adsorption of B on magnesium oxides and other substances, exchange with SO42- anions and possible leaching, and also by the uptake by grown crops, mainly oilseed rape.

• Compliant wheel behavior is captured from full-scale load tests. • Indentation tests show the effect of soil moisture on pressure sinkage curves. • Direct shear test on a flat tire section embedded in soil provide interface strength. • Results are synthesized to set-up a model for two soil types dependent on moisture. • Features of rolling scenarios are elucidated by means of an explicit FEM code. The investigation presented addresses the response of a compliant wheel in interaction with deformable soil dependent on the water content, and accordingly on soil consistency. Two fine soils are considered. The basic soil properties and the soil shear strength are obtained from routine tests. A non-pneumatic Tweel in full size is tested in a loading device against a rigid base and against soil placed in a container in order to assess its stiffness and the compressional behavior of the soil, respectively. The measured pressure sinkage curves are then utilized in conjunction with a standard explicit FEM code to calibrate a hyperelastic model for the Tweel and an elasto-plastic constitutive model for the soil. Soil-tire interface strength is obtained from shear tests on a flat tire section embedded in soil. The numerical model is then applied to investigate how the water content affects the global response of the tire-soil system under different scenarios of free rolling, braking and driving. The methodology followed, complemented by appropriate soil testing, can be used as guide for the implementation of more elaborate models. [ABSTRACT FROM AUTHOR]

Background: Chemical methods allowing a single soil extraction followed by multi‐elemental simultaneous measurement by ICP‐OES are increasingly used to predict plant uptake; however, calibration results against crop response are scarce and contradictory. Aims: Our aims were to evaluate the efficacy of five extractants to predict nutrient uptake by a greenhouse wheat crop, as well as the influence of soil properties on nutrient concentrations in soil extracts and wheat plants. Methods: Unlike other calibration studies, we monitored the pre‐seeding to post‐harvesting changes in soil available Ca, K, Mg, Cu, Fe, Mn, Zn, and Al. We extracted 14 acidic soils (C content: 47–114 g kg−1) with two traditional (AA: ammonium acetate; DTPA: diethylenetriamine‐pentaacetic acid) and three multi‐element extractants (AB‐DTPA: ammonium bicarbonate‐DTPA; Mehlich‐3; AA‐DTPA: ammonium acetate‐DTPA). Results: Relationships between bioavailable and chemically extractable elements were strong for K (R2 = 0.776 to R2 = 0.882; p < 0.001) and Zn (R2 = 0.663 to R2 = 0.721; p < 0.001), especially for AB‐DTPA and AA‐DTPA. Multiple regressions including also soil properties can predict wheat‐Ca (Feoxihydroxides, clay and CaAB‐DTPA; R2 = 0.656; p < 0.001) and wheat‐Cu [Aloxihydroxides and either CuAB‐DTPA (R2 = 0.515; p < 0.01) or CuAA‐DTPA (R2 = 0.472; p < 0.01)]. Pre‐seeding to post‐harvesting changes in KAA‐DTPA and KAB‐DTPA were strongly related with K uptake by wheat (R2 = 0.927 and R2 = 0.949, respectively; p < 0.001); similarly, for wheat‐Zn the best relationships were with ZnMehlich‐3 and ZnAA‐DTPA (R2 = 0.654 and R2 = 0.757, respectively; p < 0.001). Conclusion: Consequently, chemical extractants alone can adequately predict K and Zn bio‐availability, and combined with some soil properties can predict wheat uptake of Ca and Cu, but not that of other nutrients. [ABSTRACT FROM AUTHOR]

Low volume roads in the Czech Republic are roads with lower traffic volume that primarily include forest and field roads, and they are an integral part of the Czech transport network. When building road pavements, we can use processes for surveying, designing, building and inspecting road constructions included in national and international, particularly European, standards. In addition, the roads are evaluated in terms of their environmental impacts, in order to maintain the quality of the environment. However, during the construction of road pavements decisions based on financial, time and other reasons are made. The decisions have impacts on the operation of roads and lead to other measures and additional costs of repairs and reconstructions. The article summarizes the authors' research results from constructions of low volume road pavements and contains evaluations of laboratory and in situ material tests (soils, layers) of installed road pavements as well as evaluations of modelled laboratory and long-term monitored in situ structures.

The pot experiment with graded P doses was carried out in 2015 and 2016 in the Crop Research Institute, Prague – Ruzyně (undermentioned CRI). Three soil types were chosen for the experiment – Chernozem, Cambisol, Haplic Luvisol. The soils were treated by graded P doses (0.3–0.6–1.2 g P/5 kg of soil). The soil without any treatment served as a control. The spring barley (variety KWS Irina) was grown up to the milky ripeness stage. Plants were regularly watered with the deionised water. Two-year results of experiments showed that the increase of spring barley dry matter was noted under graded P doses particularly in the year 2015, whereas in the year 2016 the plant growth despite to increasing trends generaly was not significant. The P-uptake by plants increased in correspondence to graded P doses and correlated with the P contents in soils determined by Mehlich 3 and NH4-acetate soil tests. The proportion of readily available P-NH4-acetate fractions increased in Chernozem and Luvisol in comparison with total available P-Mehlich 3 fractions under graded P doses. No evident increase of P-NH4-acetate fractions was obtained in Cambisol having the lowest CEC from all tested soils. The correlations between P content in plants of spring barley, P-uptake and phosphorus determined by Mehlich 3 and NH4‑acetate methods, with exception of relationship between P-barley and Mehlich 3, showed significant positive relationships. The highly positive relationship between P-Mehlich 3 and NH4-acetate methods indicating the suitability of both tests to predict phosphorus supply in soils.

The three-year field experiment (2015-2017) with graded doses of magnesium (Mg) and sulphur (S) was carried out at the Humpolec experimental station (49.5546239N, 15.3485489E; Czech Republic). The interactions between boron (B), Mg and S in the soil were studied. No boron was applied into soils. Contents of B, S and Mg in the soil were determined by the Mehlich 3 and NH4 acetate methods. The crop rotation was: spring barley-oilseed rape- -winter wheat. Three Kieserite doses (S and Mg fertiliser) were applied. Sulphur treatments were 10-20-40 kg S/ha to cereals and 20-40-80 kg S/ha to oilseed rape. The doses of Mg were: 13-26-52 kg Mg/ha to cereals and 26-52-104 kg Mg/ha to oilseed rape. A significant gradual decrease of B-Mehlich 3 was observed under Kieserite treatments during the experiment (from 1.24 mg B/kg in control in the 1st year to 0.92 mg B/kg in the 3rd year). On the contrary, B-NH4 acetate contents in soils remained similar during 2015-2017 in control soils (0.33-0.39 mg B/kg) and significantly decreased under Kieserite treatments, namely by 55-57% in 2016 and by 43-48% in 2017. A significant decrease of B content in soils was noted since the second year of experiment after oilseed rape. The boron contents in soils were affected in several ways - by adsorption of B on magnesium oxides and other substances, exchange with SO4 2- anions and possible leaching, and also by the uptake by grown crops, mainly oilseed rape. [ABSTRACT FROM AUTHOR]

Purpose.Experimental studies allow determining th estress-strain state or bearing capacity of the tested soil body. A preliminary study of the results of model testing and experimental research allows us to find the optimal solutions and to justify the parameters of the chosen technology. The purpose of this work is to determine the effect of soil cement elements when stabilizing the roadbed on a weak subgrade using the soil tests in laboratory conditions. Methodology. During the development of measures for the reconstruction and consolidation of soil bodies, their strength is tested using many methods. In all cases, we take into account the physical and mechanical characteristics of soils obtained as a result of research, as well as the existing regulatory documents. We performed the experimental studies by model testing in laboratory conditions. The model testing was based on the corresponding relationships between geometric sizes, mechanical properties of materials, loads and other factors on which the stress-strain state depends. During testing, the model was loaded gradually. We maintained each load level up to conditional stabilization of the soil deformation. We took the readings from measuring devices at each stage of loading after achievement of stabilization of soil mass deformations. We fixed the readings in the test journal. Findings. During stabilization with soil cement piles there is an improvement in mechanical properties, which leads to a decrease in deformations by 2…3.5 times. Each test is accompanied with graphs of relative deformations-stress dependence, as well as deformation curves and compression curves. According to the results of experimental stu-dies, it can be seen that when testing a model with cement piles, compared with a model without soil cement piles, the relative deformations of the samples taken prior to the experiment and after the experiment almost coincide, indicating a decrease in deformability under load. Originality. We proved that this stabilization type positively affects the stress-strain state of the soil body, by increasing its physical and mechanical characteristics. The obtained results allow for rational design of subgrade stabilization work with the help of modern technologies.Practicalvalue. The in-depth analysis of the results of experimental studies opens up possibilities for theoretical synthesis and development of theoretical foundations, which will allow in the future avoiding, in the similar cases, the experimental verification of the stabilization type given for the relative type of soil. It is confirmed that this method of stabilization used can be applied in real conditions.

Geotechnical properties of lateritic soil stabilized with ceramic waste dust (CWD) additive was examined. Specific tests conducted on the modified soil samples include grain-size distribution, Atterberg Limits, Proctor Compaction tests, and California Bearing Ratio tests. Lateritic soil obtained from Agbara, South-West Nigeria and pulverized ceramic materials gathered from construction site rubbles were used for the experiment. The Lateritic soil samples were mixed with ceramic dust from 0 to 30% at an incremental rate of 5%. From the analyses of test results, it was found that Liquid Limit, Plastic Limit, Plasticity Index, and Optimum Moisture Content decreased consistently with the incremental addition of ceramic dust up to 30%, whereas, Maximum Dry Density and California Bearing Ratio (Soaked and Un-soaked) increased with CWD additive. Liquid Limit decreased from 59.62% (unmixed laterite) to 35.61% (30% CWD addition). The Plastic Limit decreased linearly from 40.11% (unmixed laterite) to 23.31% (when mixed with 30% CWD). The percentages for both unsoaked and soaked California Bearing Ratio increased from 6.82% to 21.97% and 4.55% to 14.39% respectively for 5% incremental addition of CWD up to 30%. The study concluded that the use of CWD in the stabilization of lateritic soil is recommended for economic, durability, and environmental advantages.

Geotechnical properties of lateritic soil stabilized with ceramic waste dust (CWD) additive was examined. Specific tests conducted on the modified soil samples include grain-size distribution, Atterberg Limits, Proctor Compaction tests, and California Bearing Ratio tests. Lateritic soil obtained from Agbara, South-West Nigeria and pulverized ceramic materials gathered from construction site rubbles were used for the experiment. The Lateritic soil samples were mixed with ceramic dust from 0 to 30% at an incremental rate of 5%. From the analyses of test results, it was found that Liquid Limit, Plastic Limit, Plasticity Index, and Optimum Moisture Content decreased consistently with the incremental addition of ceramic dust up to 30%, whereas, Maximum Dry Density and California Bearing Ratio (Soaked and Un-soaked) increased with CWD additive. Liquid Limit decreased from 59.62% (unmixed laterite) to 35.61% (30% CWD addition). The Plastic Limit decreased linearly from 40.11% (unmixed laterite) to 23.31% (when mixed with 30% CWD). The percentages for both unsoaked and soaked California Bearing Ratio increased from 6.82% to 21.97% and 4.55% to 14.39% respectively for 5% incremental addition of CWD up to 30%. The study concluded that the use of CWD in the stabilization of lateritic soil is recommended for economic, durability, and environmental advantages. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Mining Sciences is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As part of environmental management programs, fruit planting and replanting has been receiving a stronger emphasis. Planning and designing grape and fruit plantations require farmers to use cost-effective technologies and reduce energy consumption. The purpose of this paper is to examine the distribution, area, type and number of plantations in the south-eastern part of Hungary over a period of seven years (2009-2015). The results obtained suggest that vineyards were the most predominant plantation types in the period under consideration, with the exception of 2012. Apricot, cherry and plum plantations were the most prevalent of all the fruit plantations included in the study. The most favourite types of grapes were green (white). In 2013, fruits claimed the highest share in the total structure of plantations examined. The average area of a planned fruit garden was about 33 % larger than that of a vineyard. The number and composition of new plantations in the south-eastern part of Hungary were in accordance with the public regulations.

Low volume roads in the Czech Republic are roads with lower traffic volume that primarily include forest and field roads, and they are an integral part of the Czech transport network. When building road pavements, we can use processes for surveying, designing, building and inspecting road constructions included in national and international, particularly European, standards. In addition, the roads are evaluated in terms of their environmental impacts, in order to maintain the quality of the environment. However, during the construction of road pavements decisions based on financial, time and other reasons are made. The decisions have impacts on the operation of roads and lead to other measures and additional costs of repairs and reconstructions. The article summarizes the authors' research results from constructions of low volume road pavements and contains evaluations of laboratory and in situ material tests (soils, layers) of installed road pavements as well as evaluations of modelled laboratory and long-term monitored in situ structures. [ABSTRACT FROM AUTHOR]

The pot experiment with graded P doses was carried out in 2015 and 2016 in the Crop Research Institute, Prague-Ruzyně (undermentioned CRI). Three soil types were chosen for the experiment-Chernozem, Cambisol, Haplic Luvisol. The soils were treated by graded P doses (0.3-0.6-1.2 g P/5 kg of soil). The soil without any treatment served as a control. The spring barley (variety KWS Irina) was grown up to the milky ripeness stage. Plants were regularly watered with the deionised water. Two-year results of experiments showed that the increase of spring barley dry matter was noted under graded P doses particularly in the year 2015, whereas in the year 2016 the plant growth despite to increasing trends generaly was not significant. The P-uptake by plants increased in correspondence to graded P doses and correlated with the P contents in soils determined by Mehlich 3 and NH4-acetate soil tests. The proportion of readily available P-NH4-acetate fractions increased in Chernozem and Luvisol in comparison with total available P-Mehlich 3 fractions under graded P doses. No evident increase of P-NH4-acetate fractions was obtained in Cambisol having the lowest CEC from all tested soils. The correlations between P content in plants of spring barley, P-uptake and phosphorus determined by Mehlich 3 and NH4-acetate methods, with exception of relationship between P-barley and Mehlich 3, showed significant positive relationships. The highly positive relationship between P-Mehlich 3 and NH4-acetate methods indicating the suitability of both tests to predict phosphorus supply in soils. [ABSTRACT FROM AUTHOR]

The distribution of saturated soft clay is greatly wide in China. The current main measures adopted to deal with soft soil foundations may lead to environmental pollution, even some engineering accidents may happen on soft soil foundations. In order to solve engineering problems of saturated soft soil foundations well, researches of mechanical properties of them are necessary. One of the most important mechanical characteristics of saturated soft clay is its cyclic accumulative deformation under cyclic loadings. For saturated soft clay, the cyclic accumulative deformation is similar to the creep behavior under static loadings. Therefore, the cyclic accumulative deformation is equivalent to the creep, the number of loading cycles is seen as the time, and this study develops a practical method for predicting the cyclic accumulative deformation of saturated soft clay with the creep theory. The method is a pseudostatic elasto-plastic finite element method implemented by ABAQUS software. A fitted equation between cyclic accumulative strain and number of loading cycles and the empirical relationship of parameters of fitted equation were established with a series of cyclic triaxial compression tests. Then with this empirical relationship of parameters, the method developed by this study was employed to predict the cyclic accumulative deformation under cyclic triaxial tension tests. Predicted results were in good agreement with test results, and the effectiveness of this method was thus validated for different stress states. The method was then applied in analyzing the cyclic accumulative deformation for soft soil foundation of a pile-supported wharf structure. [ABSTRACT FROM AUTHOR]

Celem prowadzonych badań było porównanie dwóch testów 1 M HCl i Mehlich 3 do ekstrakcji przyswajalnych dla roślin form miedzi. Podstawą oceny były współczynniki korelacji pomiędzy zawartością Cu podatną na ekstrakcje obydwoma roztworami, a jej koncentracją w roślinie oraz wysokością plonu. Materiał do badań pochodził z doświadczenia mikropoletkowego, założonego na trzech glebach różniących się uziarnieniem, pH oraz zawartością miedzi. Dla każdej z gleb ustalono dwa poziomy pH oraz stosowano pięć różnych dawek Cu: 0, 4, 8, 12 i 16 kg • ha−1. Wyniki wskazują na silną korelację pomiędzy wynikami obu ekstrakcji a także ich podobną przydatność do ekstrakcji fitoprzyswajalnych form miedzi. Osiągnięte współczynniki korelacji Pearsona oraz równania regresji świadczą o nieco lepszej przydatności roztworu Mehlich 3 do ekstrakcji przyswajalnych form miedzi w glebach cięższych o wyższym pH, 1 M HCl natomiast - w glebie lekkiej o kwaśnym odczynie

The objective of the study was to examine a possibility of predicting phosphorus leaching from the top layer of agricultural soils by rainfall simulations by means of three multi-nutrient soil tests: Mehlich 3, NH4-acetate extraction and water extraction (1:5, w/v). Another objective was to determine parameters of maximum phosphorus losses after an extreme load of rainfall on the top layer. Forty soils from different localities of the Czech Republic were used for the experiment. A leaching experiment was conducted in pedological cylinders with a soil layer of about 1 cm and with the bottom from a glass microfibre filter with pores 1.2 μm in size. Within 15 days the soils were flooded ten times with 25 mm of simulated rainfall in a minimum interval of 1 day. The closest regression between the soil test and phosphorus leaching was computed for NH4-acetate soil test (R2 = 0.8831) and Mehlich 3 test (R2 = 0.8572) after the first application of 25 mm of rainfall. In water extraction it was for the mean of 10 simulated rainfalls (R2 = 0.8674). As leaching proceeded, the closeness of regression diminished due to fluctuations of P concentration in leachates (increases and decreases), mainly in soils with higher P-test. The increase in P concentration could be caused by the activation of phosphorus from Fe-phosphates under anaerobic conditions in wet soils. The steepest decrease in P concentration in leachates was observed in light soils with low CEC value and higher initial P-test.

The aim of the paper was to contribute to the acquisition of background data for the specification of safe boron levels in soils in relation to diagnostics by multi-nutrient soil tests and to CEC (cation exchange capacity) value of soil, pH and soil organic matter. The research was conducted on 24 soils. Sorption was determined after 97 days from the application of B at the rates of 0, 1, 2.5, 5 mg B/kg in H3BO3. The closest regression of B-sorption was with the CEC value of soil in NH4-acetate and water tests and it increased with the increasing application of B (regression at a rate of 5 ppm B; NH4-acetate: linear R

The aim of study was to verify a possibility of adding boron to multi-nutrient soil tests: Mehlich 3, water (1:5) and 0.5M NH4-acetate extraction. Thirty-six different soils from topsoils of agriculturally farmed field were used for the study. The basic set of 36 soils was doubled when the same soil samples with gypsum addition at an equivalent dose 2 t Ca/ha were used. The closest correspondence between B in soil (n = 72) and B in plant was found out by the NH4-acetate soil test. This test proved its good universality and independence on a radical intervention in soil chemistry by gypsum treatment. It responded to an increase in B-availability to plants after gypsum treatment of soil. The adjustment of NH4-acetate boron by the percentage difference between the actual and the desired pH of soil improved the closeness of the correlation. Although the H2O soil test showed its lower universality, it is assumed to use the H2O soil test for prediction of B-status in soil when the history of previous fertilisation of the field will be known. The Mehlich 3 soil test did not prove to be suitable for diagnostics of B-status in soil.

Although Ni has been officially recognized as an essential micronutrient for all higher plants since 2004, research on assessing its sufficiency critical levels with different soil tests is missing in the literature. The objective of the study was to determine Ni critical levels in unpolluted cultivated soils utilizing four methods, employing three commonly used calibration techniques. Ten soils with different physical-chemical properties and low Ni content were treated with Ni at rates of 1, 2, 4, and 8 mg kg−1. After equilibration for one month, the soils were analyzed for extractable Ni by four methods, namely DTPA, AB-DTPA, AAAc-EDTA, and Mehlich-3. Response to soil-applied Ni was assessed by a greenhouse pot experiment, with the untreated and Ni-treated soils in three replications, using ryegrass ( Lolium perenne L.). The aboveground biomass of ryegrass was harvested two months after sowing, dry weight of biomass was measured and relative biomass yield was calculated. Nickel's critical levels were determined employing the: (a) graphical technique of Brown and co-workers, (b) Mitscherlich-Bray equation, and (c) Cate and Nelson graphical technique. According to the first technique, Ni critical levels were ≈ 2 mg kg−1 for the DTPA and AB-DTPA methods, and 6.0 and 5.3 mg kg−1 for the AAAc-EDTA and Mehlich-3 methods, respectively. Similar levels were obtained by the Mitscherlich-Bray equation. However, the critical levels assessed by the Cate and Nelson technique were lower and ranged from 0.5 to 1.3 mg kg−1 for all four methods. Conclusively, Ni sufficiency critical levels for all four methods are expected to range at levels of a few mg Ni kg−1 of soil. As far as the three calibration techniques are concerned, a distinct boundary between Ni response and non-response was accomplished by none. However, the fact that 60-74% of the soils were correctly separated into responsive and non-responsive to added Ni by the graphical technique of Brown and co-workers suggests that this is the most suitable technique. [ABSTRACT FROM AUTHOR]

In this study, we compared the size of the mobile Hg pool in soil to those obtained by extractions using 2 M HNO, 5 M HNO, and 2 M HCl. This was done to evaluate their suitability to be used as proxies in view of Hg uptake by ryegrass. Total levels of Hg in soil ranged from 0.66 to 70 mg kg (median 17 mg kg), and concentrations of Hg extracted increased in the order: mobile Hg < 2 M HNO < 5 M HNO < 2 M HCl. The percentage of Hg extracted relative to total Hg in soil varied from 0.13 to 0.79 % (for the mobile pool) to 4.8-82 % (for 2 M HCl). Levels of Hg in ryegrass ranged from 0.060 to 36 mg kg (median 0.65 mg kg, in roots) and from 0.040 to 5.4 mg kg (median 0.34 mg kg, in shoots). Although results from the 2 M HNO extraction appeared to the most comparable to the actual total Hg levels measured in plants, the 2 M HCl extraction better expressed the variation in plant pools. In general, soil tests explained between 66 and 86 % of the variability of Hg contents in ryegrass shoots. Results indicated that all methods tested here can be used to estimate the plant total Hg pool at contaminated areas and can be used in first tier soil risk evaluations. This study also indicates that a relevant part of Hg in plants is from deposition of soil particles and that splashing of soil can be more significant for plant contamination than actual uptake processes. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The study was conducted using a collection of 330 soils taken from the area of 16 Polish provinces. The concentration of B, Cu, Fe, Mn and Zn in the soils was determined using two extractants: 1 M HCl and Mehlich 3. The study revealed that 1 M HCl extracted approx. 5 times more Fe, 3 times more Cu, 2 times more B and Mn, and 1.5 times more Zn than Mehlich 3. Additionally, regression analysis was used to calculate equations allowing conversion of the 1 M HCl results to the Mehlich 3 results. [ABSTRACT FROM AUTHOR]

In an incubation experiment with 36 soils we tested the influence of application of 3.3 g of CaSO4.2 H2O per kg of soil on extractability of nutrients (P, K, Mg, Ca, Mn, B and S). After 134-day incubation of gypsum-treated soils the soils were extracted with water (1:5, w/v), 0.5M ammonium acetate with NH4F addition (pH 7) and by Mehlich 3 method. An ICP-technique was used for nutrient detection and colorimetry on a SKALAR analyser was employed to determine phosphates and sulphates. The most interesting results were measured in phosphorus. P concentration was markedly lower in the H2O extract after gypsum treatment, on average by 69% in ICP detection and by 58% in colorimetric detection of phosphates. A significant depression of P concentration was also measured in the acetate extract, but it was considerably lower (11% in ICP detection, 14% in colorimetry). On the contrary, in Mehlich 3 extraction the concentration after gypsum treatment was higher on average by 31% in ICP detection while colorimetry detection did not show any significant differences. The results indicate that it is necessary to identify the method of soil extraction including the method of analytical determination of the nutrient, when the nutrient status of soils is to be evaluated.

Two simple experiments were carried out to demonstrate two possible ways of environmental impact of element contents in airborne particulate matter. In the first part of the experiment, the response of three rural dust samples applied into the soil were assessed in pot experiment to observe uptake of As, Cd, Pb, and Zn by aboveground biomass of oat (Avena sativa L.). Although the element contents in dust samples exceeded significantly total element contents in soil, the element content in plants was not affected by single-rate soil amendment with rural dust sample. Soil sorption capacity and neutral pH of the experimental soil (7.0) was sufficient for immobilization of the elements. However, potentially mobilizable portions (0.005 mol/l DTPA extractable) of elements significantly increased (Cd by 116%, Pb by 39%, Zn by 50%) in the treated soil, which suggests a possible release of these elements in long-term horizon. On the contrary, high percentages of potentially toxic elements (Cd, Zn, Ni) in the most mobile (exchangeable) fractions were determined in the second part of investigation in two urban dust samples collected in Prague Letná automobile tunnel, and Prague subway station Museum. These results suggest possible direct impact of mobile, and thus potentially bio-available, element fractions on human environment. The results of both particular experiments cannot give complete information concerning behavior of harmful pollutants in airborne particulate matter and their influence on human health. They can however indicate two of possible ways of environmental pollution with this material. Yet, it would require a more detailed investigation in future.

Soil-test crop-response experiments on rice were conducted in the Bastar Plateau Agroclimatic Zone of Chhattisgarh during 2009–2011 to assess yield, soil, plant, and fertilizer nitrogen (N), phosphorus (P), and potassium (K) nutrient relationships and calibrate optimum fertilizer doses for attaining yield targets. Soil fertility status was poor to medium for N (194–283 kg ha−1) and P (7.53–19.66 kg ha−1), and medium to good for K (226–320 kg ha−1). Based on nutrient requirements (NR, kg q−1) and contributions from soil (CS, %), fertilizer (CF, %), and farmyard manure (CFYM, %), optimum fertilizer doses were derived. The fertilizer doses were validated for attaining yield targets of 5000 and 6000 kg ha−1in farmer’s fields. Rice yield within 10% deviation was attained, which indicated that soil-test-based fertilizer dose was superior. This approach could be adopted for regions with similar soil and agroclimatic conditions in other parts of the world to increase rice yields. [ABSTRACT FROM PUBLISHER]

In Poland, assessment of the content of micronutrients in soil is performed using 1 M hydrochloric acid (HCl) as an extractant. The objective of this study has been to check whether 1 M HCl can be replaced by Mehlich 3. In total, 330 soil samples were taken from fields cropped with winter wheat. Each sample was accompanied by a sample of wheat plant. The samples were from four groups of soils having various pH values—from acidic to alkaline soils. The suitability of the extractants was evaluated separately for each soil group based on the significance and power of correlation between soil microelements extracted by both methods, soil and plant microelements, and the bioaccumulation factor. The HCl extractant was a better predictor of the availability of microelements to wheat than Mehlich 3 in all tested soil groups. Mehlich 3 can be applied for extraction of boron (B) and, in some cases, copper (Cu) and manganese (Mn). [ABSTRACT FROM AUTHOR]

Reports of sugarcane yield responses to silicon (Si), coupled with mounting evidence that elevated crop Si levels reduce both biotic and abiotic stresses, account for the interest in the Si nutrition of this crop. In terms of managing Si supplies to sugarcane in South Africa, uncertainties exist regarding, first, the reserves of plant-available Si in soils, and second, the reliability of soil-test methods for predicting Si availability. In this study, extractable Si was measured in 112 soils collected from sugarcane-producing fields in South Africa. Soils were selected on the basis of dominant soil types and included Inceptisols, Alfisols, Mollisols, Vertisols, Oxisols, Entisols, and Ultisols, varying widely in chemical properties, texture, and extent of weathering. Extractants employed were 0.01Mcalcium chloride (CaCl2) and 0.02Nsulfuric acid (H2SO4). Silicon extracted with 0.02NH2SO4ranged from 2 to 293 mg kg−1, whereas with 0.01MCaCl2the range was 5 to 123 mg kg−1. With both extractants, extractable Si decreased significantly with decreasing pH, exchangeable calcium (Ca), and total cations. In soils with potassium chloride (KCl)–extractable Al+H levels of greater than 0.5 cmolcL−1, extractable Si levels were consistently low, suggesting that soluble Al is implicated in reducing plant-available Si levels. Extractable Si levels were not related to the Bache and Williams P-sorption indices of soils. In the second part of the investigation, sugarcane leaf Si concentrations from 28 sites were related to soil extractable Si levels. The CaCl2soil test proved markedly superior to H2SO4as a predictive test for leaf Si levels. [ABSTRACT FROM AUTHOR]

This paper suggests that the isotropic hardening rule with a modified hardening parameter can be used to simulate anisotropic hardening behavior from both theoretical and experimental viewpoints. It is believed that the isotropic hardening rule cannot simulate anisotropic hardening behavior mainly because its yield function is expressed in terms of the principal stresses and its hardening parameter is expressed in terms of the principal plastic strains. Contrary to this belief, the first part of this paper theoretically suggests that the isotropic hardening rule with a modified hardening parameter, expressed in terms of the plastic strains in the coordinate system defined by the principal stress axes, can simulate anisotropic hardening behavior. In the second part of this paper, it is experimentally shown that the isotropic hardening rule with the modified hardening parameter can simulate the actual anisotropic hardening behavior of presheared clay. The second part also discusses the microscopic mechanism of the hardening for the presheared clay with reference to the isotropic hardening rule with the modified hardening parameter. [ABSTRACT FROM AUTHOR]

Although Ni is officially recognized as an essential micronutrient for all higher plants, the majority of the published research on soil availability of Ni focuses on its hazardous role as a heavy metal. The objective of the study was to evaluate certain Ni soil tests in uncontaminated soils for an initial estimation of its sufficiency critical levels. Nickel was extracted from 30 cultivated soils employing the following extraction methods: DTPA, AB-DTPA, AAAc-EDTA, Mehlich-3, 0.1 M HCl, and 0.1 M HNO3. Ryegrass ( Lolium perenne L.) was grown in pots containing the soils, harvested five times, certain plant parameters were determined, and the Cate-Nelson procedures were used for Ni critical levels determination. Among the six methods, HCl was the least reliable extractant for the evaluation of soil available Ni, whereas the most significant ( p ≤ 5%) relationships between Ni concentration or Ni uptake by ryegrass and Ni soil tests were consistently obtained for AAAc-EDTA or Mehlich-3 extractable Ni. In many cases, > 80% of the variability of Ni concentration or uptake by ryegrass was explained by these two soil tests without the inclusion of other soil properties that affect Ni bioavailability. Sufficiency critical levels of Ni in soil were ≈ 2 mg kg-1 for both methods. Consequently, as an initial approach, concentrations of AAAc-EDTA or Mehlich-3 extractable Ni < 2 mg kg-1 are probably a good guide to indicate soils that will respond to Ni fertilization. [ABSTRACT FROM AUTHOR]

Abstract: It is reasonable to expect that compliance with grassland fertilization recommendations in the long run results in optimal soil fertility, and subsequent herbage quality. Here, we evaluate the development of soil, herbage and manure characteristics and their relation over the last decades. We hypothesized that herbage and manure quality are related with soil fertility. We used a large database with results of soil tests, spring forage quality characteristics, and manure analyses, which were made on demand of dairy farmers. We considered the Netherlands as a whole and three selected regions with contrasting soil types (sandy soil, riverine clay, and peaty marine clay). Effects of soil fertility on herbage quality were evident when comparing farms. Farms higher in soil P and K generally have correspondingly higher contents in forage. On average, soil fertility and herbage characteristics were within or just above the agronomical optimal range during the last decades. Herbage crude protein content decreased in all regions during last two decades, which is likely an effect of legislative measures on decreasing the application of N. Selenium (Se) and sulphur (S) contents increased sharply on sandy soils, likely because of increased use of Se and S containing fertilizers. Manure composition did not differ between soil types. In conclusion, at farm level, the element composition of herbage reflected the soil fertility status. The contents of S, P, K, Na, Mg, and Ca in the herbage were all significantly influenced by soil fertility characteristics. Our results emphasize the importance of maintaining soil fertility for high quality roughage production. [Copyright &y& Elsevier]

Copyright of Journal of Elementology is the property of Journal of Elementology - issued by Polish Magnesium Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)