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Additionally, how to manage P fertilisation in such soils? Continuously apply P fertiliser even though there is a big chance it might be fixed by sesquioxides?
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Portia Phohlo We compared ten P-tests to extract P from acidic soils (Podzol) managed under forest and managed fields with different fertilizer application histories. Water, citric acid, ammonium bicarbonate diethylenetriaminepentaacetic acid (AB-DTPA), Morgan, Olsen, Bray-1, Bray-2, Mehlich-1 and -3 solutions were used to extract and analysed with ICP and colorimetric techniques. The studied soils had a pH range from 3.4 to 6.9; clay contents ranged from 6% to 38%; SOM varied between 0.5% and 47%. We found that Water ≤ Morgan < AB < M1 < B1 < M3 ≤ Olsen << B2 <<<citric acid. B2 extracted 2-folds, and citric acid extracted 4 to 6- folds more P than M3. Proper selection of P-test is required based on the soil properties such as Al, Fe, and SOM content and pH, of course, calibration against nutrient removal or crop yield is very important.
Note: if the acidic soil is currently converted from forest or low in SOM, M3 will overestimate P; if it has been under the management and has higher SOM (5%), M3 might underestimate P.
I will share the manuscript after the final decision of the editor.
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We have Calcium Hydroxide dried sludge in huge quantity as a waste material. How we can make it as an effective soil conditioner. What process you can suggest to convert this waste to an effective soil conditioner. It’s pH >12.5 and EC is >10.
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Such a material can be used for the treatment of Acid Rock/Mine Drainage in mine site remediation. See https://www.imwa.info/piramid/files/PIRAMIDGuidelinesv10.pdf for instance.
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I want to determine low molecular organic acid in Agilent Infinity II HPLC with DAD detector. Can Anyone say what is the detection limit of that instruments? Thanks
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Hi Tamjid, according to my understading, these limits of detection and quantification should be determined for every method, as every method will have different conditions (the column, the analytes to analyze, flow, mobile phase, injection volume, etc). These limits are determined through the validation of the analytical method. After method validation. you can continue and quantify your samples in a reliable way. As an example of method development and validation, you can see this publication. I hope this helps
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Hi,
I am interested about how quickly SOM can deplete over time, and would like to start a discussion on the topic. Please pardon me if my question is broad.
In temperate systems, it is common to find annual decomposition coefficients around 1-3% (i.e., 1-3% of the SOM stock is lost after a year). However, I wonder how quickly can SOM mineralization occur.
While reading the literature on SOM changes after deforestation in the tropics, I found values suggesting that SOM stocks can decline by 10-50% in a few years (5-10 years) after a forest is cleared for cultivation.
Also, while looking at the AMG soil organic matter model, I noticed that the potential (maximum) SOM mineralization rate (k0) was set to 29%!
Have you ever asked yourself this question?
Related to this topic, I was thinking of a simple experiment that could shed some light on this question. Let's imagine pots with freshly collected soil or a plot of land, which is outside, and for which any plant development is precluded (removing seed, young seedlings manually). I would be curious to see how quickly SOM changes over time (considering that we would regularly monitor it or regularly SOM contents), given that no plant can inject organic matter. Of course, this soil would be exposed to environmental changes (such as regular water inputs from rain or manual watering, not to let it dry).
Any thoughts about this?
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Oxidation and microbial proliferation leads to SOM loss. So as long as it is safe from oxidation and microbes there will be no loss of SOM. But still if tillage is done in soil and exposure of surface soil to sunlight is happen then it will take very less time for SOM to loss.
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Hi,
I'm looking to do a study utilizing a pH sensor for soil pH measurments, among other variables. Essentially i want to create a embedded system that automatically takes pH soil measurments of a pot from several angles(4 or 8 points around 360 degrees) and depths, to get a more complete understanding of pH across the pot soil profile.
Reading up about soil chemistry, soil pH measurments and how different pH sensors work i understand that it's quite complex. Initially using a mechanical sensor arm take either in situ soil pH measruments, or take out a small sample(done by the arm) and create soil suspension to measure on.
What complicates things quite quickly given the nature of pH measurments with pH electrodes when it comes to necessary procedures for storage, cleaning and measurment(in situ would be preferable). ISFET sensors would be great for this application they can be stored dry, easier to maintain etc(from what i've read), but they are hard to come by if not expensive.
The idea of measuring pH of soil water drainage from different points across the pot would simplify things alot, the arm and mechanical measurment mechanims could be excluded from the design.
However i can't find littarture or articles covering the relation between soil pH and soil water pH in a clear way. Thinking about it, it would be logical to assume that pH from extracted soil water, would for most soils correlate strongly with pH of soil, but not be exact to soil pH of the same spot.
Could anyone enlighten me about this? Or direct me to research articles or littature clearly describing this relationsship?
Best regards,
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Both are negative logarithm of hydrogen ion. Apparently soil pH is measured with 1:2 ratio soil : distilled water. And soil water pH is directly measured by pocket pH meter in wetted soils. So both are more or less same.
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Hi,
I wonder if it is possible to find natural soil carbonates (calcite, dolomite, etc.), not coming from liming, in soils naturally having a low pH (4-5.5).
Is it possible to find these mineral forms of C in acidic tropical soils?
I am asking because while measuring both total C and inorganic C (after acid dissolution) of tropical soil samples from Indonesia with an Elementar, I sometimes get a gap between the two measurements.
Sometimes the gap is positive (total C > organic C), and other times the gap is negative (organic C > total C !?). Generally, total C is equal to organic C, meaning most samples do not show these confusing 2-way gaps, and suggest the absence of inorganic forms of C.
In both cases, I wonder if discrepancies are just technical (noise), or if the gaps between samples are due to the natural variability of my samples, or in some cases, there could be some carbonates present in those soils (which have a relatively low pH of 4-5).
Best,
Thomas
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Thomas Fungenzi Tough question but i dont think that the carbonates can be found in the acidic soils as it is found or in fact present in the alkaline soils
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There are numerous methods of dry and wet ashing. For plant material – most of them are equally effective. But soil samples are usually a problem. Could you please share the methods of ashing you continuously use in your lab for soil samples and to explain why?
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Extraction of trace elements soluble in aqua regia was used as a decomposition method in accordance with ISO 11466: 1995 E.
1 g sample was weighted accurately in a reaction vessel; 0.5 ml of tri-distilled water was added to obtain a slurry, followed by 9 ml of HCl (12 mol l-1) and 3 ml nitric acid (15.8 mol l-1) .Then 10 ml of 0.5 mol l-1 was added to the absorption vessel which was connected to the reflux condensor. Both apparatus were placed on the top of the reaction vessel. The samples were allowed to stand for 16 h at room temperature in order to reduce the produced during the subsequent heating cycle. They were heated under reflux until boiling for 2 h and allowed to cool slowly at room temperature. The contents and the following rinses of the absorption vessel were passed through the condenser into the reaction vessel. The content of the reaction vessel was transferred quantitatively to a 50 ml graduated flask and filled up to the mark with nitric acid (0.5 mol l-1). After the undissolved material has settled, the supernatant solution was subjected to analysis by ICP-AES.
A blank sample containing the acids used for digestion was prepared in the same way.
In general wet digestions excluding hydrofluoric acid do not attack the silicate matrix. Hence, the separation of the silicate matrix as an insoluble residue from the soluble elements lead to both lowering the dissolved solid concentration in solution and the detection limits for analytes, respectively.In addition, the procedure is carried out in closed system and losses of volatile elements can be eliminated.
With kind regards, N Daskalova
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I have been incubating soils with increasing doses citric and oxalic acids. The general case is that the addition increasing organic acid doses is related to a progressive decrease in soil pH. We had a strange case, for one of our soils the pH increased at low doses of citric acid and only started decreasing at doses higher than 4mMol kg-1. Any ideas of what mechanisms might be involved in this pH increase at low citric acid doses?
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Calcium oxalate
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Sulphate composts are useful for alkaline soils. There are huge amount of sulfur production during refinery processes. Sometimes these amounts of sulfur can not be directly used and should be converted into some other by-products. What is the easiest way to convert organic S into SO4 compost?
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Please find the attachments.
Regards.
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Hi
can anybody please tell me what is  the value (-0.157) next titanium concentration in my soil sample means?
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This is a good question.
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It is a famous model which can be used to calculate the critical load of acidity for forest soils
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Visual Minteq and PhreeqC
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Hi everyone,
I am trying to look for the maximum trace element concentrations that are allowed in soils in the USA. Do you know if such a regulation exist at the federal level?
Thank you immensely,
Xavier
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Of course, the EPA website (U.S. Environmental Protection Agency
) will help you find what you are looking for.
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Hello,
I am looking for the average trace element concentrations in agricultural soils around the world. Do you know of a good place to start?
Thank you all immensely,
Xavier
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They are indeed available for this as this is a very important sector. Although they have been depleted in a few cases, they are being revived with the traditional methods.
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Released phosphorus (P) from fertilizers form initial reaction products after reaction with active cations present in soil, and P release rate and amount from those initial reaction products is very  slow. Also, phosphatic fertilizer cost depend on its P release capacity from initial reaction products not on its nutrient content.
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I think phosphatic fertilizers are very slow in nature and hardly achieve 20% PUE in Indian condition. Facts, under acidic soil availability may be higher. Their losses or adsorb on soil particles are very common. This may be applicable for highly water soluble fertilizer using in drip or sprinkler irrigation. Do work and Good Luck for this.
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How can I calculate lime requirement for increasing soil pH without Lab determine? or which methods are faster and easier than woodruff buffer solution?
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I'd recommend the answer of Salvatore S. Mangiafico
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Soil chemical analysis for various studies shows the impact of Sulphur in crop production particularly in the field of agriculture, and a better result even obtained for the combined effect of Sulphur, Boron and Copper, though Sulphur is a macronutrient whereas Boron and Copper. In my present study, Sulphur concentration of the sampled forest soils varies from 0.28 to 16.53 kg/ha, whereas, Boron content 0.90 to 1.39 kg/ha and Copper from 0.31 to 8.98 kg/ha, are they standard values for the forest soils? Are they working well in combined form for the growth and vegetation of the forest soils?
Moreover, substrate soils are lacking Sulphur almost all over world including Indian subcontinent due to emission of Sulphur compounds to the atmosphere that reduces its concentration in the soils of the forest floors. On contrast, Copper present in the substrate soils as a component becomes retarded very quickly in the soil and that are not available as nutrients for the plants easily, then what contents of Sulphur, Copper and Boron availability are to be considered as the standard values for the forest soils in the forest patches in the south west forest patches of West Bengal?
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@ Gautam, as your soil pH value is low, at that pH soil bacteria may change the sulphur to sulphuric acid, resulted further lowering of soil pH.
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Generally forest ecosystems are often developed on poorly fertile soils where the plant available pools of nutrient cations are frequently very low, but the content of available potassium for a natural terrestrial forest stand shows a very high value of 671.89 kg/ha using the standard method for the soil chemical analysis, is it natural for the soils of a terrestrial forest patch?
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Excellent, do you find any distinct variation in soil test values as per stand of different forest species , let us look at the root density vis-a- vis root education dictating such variation in soil test values , including K...
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Our method consists of a potentiometric titration of a soil plus an electrolyte solution (0.01, 0.1 and 1.0 M KCl). Soil is stabilised during 1 hour and then HCl or NaOH is added in order to modify pH to 4.0 or 12.0 respectively. PZC should be found in the intersection of the three curves, but we are getting unexpected results. Could you recommend another method or a modification of the one I am performing. Thank you very much.
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Video link for determination of Point of zero charge (PZC)
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Totally I have 7 boreholes for soil, each was dug to the depth of 60 cm (10 cm intervals). I've got to compare the differences in chemical parameters among each of the six layers. So, what statistical test are most suitable for this kind of data ? 
I consider using Dependent T-test for the data set. The reason is, for each depth (of all boreholes), soil data are completely independent. However, within a profile, soil sample of any specific depth is closely linked to its upper/lower samples. Is that appropriate ?   
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Dear Nguyen,
Among the variables analyzed, the compatibility with normal distribution of all variables analyzed can be evaluated using the Kolmogorov–Smirnov test.
Differences between groups can be established by Student’s t -test for normally distributed values and by Mann-Whitney U-test for nonparametric values.
Pearson's correlation coefficient can be searched to examine the relation between normally distributed variables.
Spearman’s correlation coefficient can be used for nonnormally distributed values. Statistical significance was defined as P <0.05 or <0.01 etc...
Best regards...
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Almost all the literature shows that the vertical distributions of soil organic carbon (SOC) & available nitrogen (N) is found decreasing with increased value of bulk density with respect to depth and all those values show uniformity in each layer of 20 cm and up to 1m depth, increasing or decreasing of such values are uniformly distributed for the soil samples found in the literature, is that uniformity maintained at every where, soil layer of the mother earth is so unique and maintain such identical uniformity, though I am waiting for the report for the values of distribution of these chemical parameters from the soil test laboratory, if the obtained values are uniformly distributed with depth, it will be really unique and identical.
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Dear Gautam,
In the case of this discussion, I am totally in agreement with the statements and thoughts of Shubham. He explained the issue as well. I am specifically a soil ecologist and zoologist and I am also concerned about issues related to physical and chemical properties of soil. Thank you for your precision. Good luck.
Best, Elaheh
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Sediment is relatively younger than the soil in the depositional environment as the sediments are consequence of the accretion of particles transported either by waters or by winds, whereas, soil profile is stable lacking any sort of movement. Soil profile is developed with time span which is a stable one, but the movement of the sediment particles developed those soil profiles in so many physiographic set up, are they (soils and Sediments) differed chemically, do they possess different chemical environment?
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yes its do it
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Bulk density of a forest soil sample in a community forest created under social forestry scheme in the district of Nadia, West Bengal is obtained as 0.81 gm/ cubic centimetre, comparatively too low from the other samples of the same forest stands collected from 500 meters distance, visibly the sample is silty in nature, and the implanted trees of the said community forest are mostly of teak categories, the forest stood in the alluvial plains of the lower Gangetic deltaic set up, is the obtained value of bulk density normal for the physical nature of the soils of the forest floors?
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Bulk density (BD) measurement needs to be done by core method for any comparison to other soils' BD. If the SOC is very high in soils under forest for a long time, BD may be really low.
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Just read out a paper on C:N ratio of the soils of Sal (Shorea robusta) forest in Terai region of Nepal, in that paper the author has shown the data for organic carbon (C) for all the soil samples is higher than that of the available nitrogen (N), and the content by percentage of both C & N reduces with the depth increment up to 1 meter from the surface layer, contrastingly, the obtained results from the surface soil samples of the forest floors of West Bengal shows that the available nitrogen is higher than that of the organic carbon in each and every samples collected either from the mangroves soils or from the soils of the terrestrial natural forests comprising with the tree lines of Sal, is it normal for the luxuriant occurrences of the Sal forest in two different soil chemical environments?
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The scenario of C:N in WB forest soils is difficult to explain as C always shows higher values than N. If this is a truly real situation, it is intriguing in Soil Science and needs to be probed with great care.
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Available nitrogen, phosphorus and potassium (NPK) content data are correlated applying with the multiple correlation coefficients formula, the obtained values are approaching 1 that indicates a strong positive relationships with each other, but each variable of the soil nutrients is considered to be dependent on the other variables changes, governed by the extraneous factors, that badly needs the regression fit line, but how could I couldn't find any formula for the calculation of the regression fit line for the multiple variables, is it available where two variables are independent and one is dependent, or is the regression fit line for the multiple variables relevant at all?
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@Dipankar Bera
Yes, you are right. Only solution is to plot such q-q plot, residual vs best fitted and etc. Regression fit line for multiple variables is not possible but #Goutam Kumar Das sir you can use MLR model using R-Stat software to show plot in a single frame that helps to fit the regression line for each (One X as dependent variable and one Y as independent variable).
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Mangroves have the ability to absorb up to four times more carbon dioxide by area than upland terrestrial forest ecosystems, carbon dioxide is stored as blue Carbon in the sediment of the mangroves swamps and marshes and green carbon in the soils of the terrestrial forest floors, and that carbon sink forms the carbon pool, but the result obtained from the analysis of the sediment samples of both types of ecosystems doesn't reflect that quantity, the organic carbon of the mangroves swamps ranges from 36 to 69%, whereas, the organic carbon content of the soils of the terrestrial forest ecosystems varies from 16 to 66%, then where and how the extra carbon stored in the mangroves sediments as blue Carbon which is four times more than that of the green carbon of the forest soil?
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Convey my thanks for such a relevant article that nicely elaborated of the carbon draining from the terrestrial forest floors arrested in the mangroves ecosystems and that is seen at a glance, I will go through the paper later on and use as citation in my work
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The content obtained for the C & N in the soil samples of the forest floors is increased this time and in 2020 is 5 times more than that of the C & N obtained in 2008, simultaneously the same forest stands in four districts is increased by areas observed in the India State of Forest Report 2019, not only that the forest canopy is much lush green in comparison to 2008, is this change be considered as the evidence of the climate change, though the time span of only 12 years is very short for interpretation of the evidence of the climate change.
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I totally agree with Fazel Mohammadi-Moghadam that we need more studies to be done around the world to repeat the idea and evidence. It is a very interesting discussion we are countering here. During my PhD study, I have done a long-term research investigating the effects of 20 years climate influence on soil fauna and vegetation. I think 12 years can also be considered as a long-term research and these discussed obtained results maybe show the effect of higher temperatures on increasing the decomposition rates. Although this is a perception and it really needs to be studied in detail.
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Hi,
I'm working with a set of soil analyses obtained from an external laboratory.
Studying the results, I am highly confident that one of the analyses gave incorrect results because the values are extremely unlikely (in total disagreement with what is normally naturally occurring).
Besides, I have conducted additional analyses to triple-check this analysis.
The results I have obtained contradict, as I expected, the anomalous data.
The problem is, that the method I used is not the same as the initial method (unavailable at my lab), but is supposed to measure the same variable.
Now that it is time to write a research article, what would you do to overcome this problem?
Should I explain that for this particular analysis, results were abnormal and were not considered further?
Should it be done early in the results section, or later in the discussion section?
How have you dealt with unexpected/erroneous data with your research, when you cannot repeat the same analysis?
Will a journal accept to publish results which include one bad apple, while the rest of the basket is fine?
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First thing, I would present this to the external lab. Perhaps they can look back at notes, strip charts or other outputs to check for mistake. Then if that fails, present the truth with the possible erroneous value and cross checked with other methods, and discuss briefly in findings. Like suggested, if the whole journal paper has no value with this issue included, then you will probably get some bad marks from editor or reviewers, possible suggestions to recover. When you say the value from lab is extremely unlikely or unnatural, it is likely the lab just made a mistake, it happens. It would be better for them to review the circumstance and your cross checking, and agree there was a mistake and then use your value based on their agreement, with a footnote perhaps briefly mentioning this attached to the value. Other issues can develop such as if your cross checking followed much later in time and samples were not preserved and/or stored properly. You may have to justify your work too.
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After soil chemical analysis, obtained result for the content of organic carbon and nitrogen in kg/ha shows 0.00, whereas potassium content is 55.20 kg/ha for a surface soil sample collected in the Panagarh forest patches under the Bardhaman Forest Division of West Bengal, the soil was collected in the depth of 15 cm and the bulk density of the soil is 1.3 gm/cubic cm, visibly the sampled soil is the admixture of Alfisol and lateritic combination, is it possible for the soil sampled in the natural forests lacking both organic carbon and nitrogen, though the nature of forest vegetation is quite normal in the sampling spot?
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That might be anomalous, I will repeat the analysis for the particular Sample.
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I would be interested to know how wildfire influence on soil environment in forests (cf. OM, TN, CEC, AP, Al, pH, K+,Na+,Ca+,Mg2+, Soil class), especially after surface fire.
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I think the suggested paper is interesting but it focuses on hydrology.
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Negative emissions technologies used in agricultural settings have the potential for synergistic effects improving soil health and promoting carbon capture and storage. Are there any significant interactions or positive/negative impacts expected when applying both biochar and crushed silicate rocks (for enhancing weathering) to the same cultivated soil? What would a reasonable application rate (or ratio) be?
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biochar
How does biochar transform acidic soil into acidic
→What does alkaline or acidic really mean? Free hydrogen ions H+, more acidic means more H+. Hydrogen ions are positively charged and biochar pores are negatively charged. So the H+ ions will be bound by the biochar which decreases the free H+ ions in the soil. Less H+ means more alkaline.
The ash in biochar makes the soil even more alkaline (be carful when using ash in soils that are already alkaline). Ash has potassium carbonate,I am not sure how much you like the chemical side of things... but it is the same idea, potassium carbonate ans silicate ions can react with H+ and form bonds with it.
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Hi,
After some research, I have found recommended soil potassium to magnesium ratios ranging from 0.25 to 0.7 in agricultural soils (ratios calculated from CEC concentrations). Which one do you use or recommend and why ?
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The K/Mg ratio can be indicative of how available the potassium and magnesium are in the soil. If for example your ratio is less than 0.25, it typically indicates that the magnesium in the soil is over powering the potassium in the soil making it harder for the plants root system to uptake potassium. If the ratio is >0.35 it can indicate that the plant may have trouble accessing magnesium.
High potassium demand crops also require attention to K:Mg balance and as we increase potassium application we must pay attention to Mg balance. The ideal K:Mg ratio in meq is 0.2 to 0.35 for most crops and crops such as potato 0.3 to 0.4. Often times in trying to satisfy a crops K requirements yield loss is experienced with over application of K by inducing Mg deficiency. Percent saturation levels of K and Mg in the soil are key to understanding when Mg needs to be applied with K to avoid this K:Mg imbalance in a fertility program.
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Dear Sir/ Madam,
Greetings of the Day.
Hope you all are doing well. As a beginner I want to know the what are the recent development made by soil scientist in the 21st Century ? Specifically in the field of Soil Fertility, Soil Chemistry, Soil Microbiology. Out of which how efficiently such Novel practice adopted by farmers. Although its contemporary debate but as per your expertise and field experience please share your views.
Thanks in advance
With Regards
Hanuman Singh Jatav
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Dear Jatav,
In the last decade or so, there have been remarkable advances in our knowledge of various topics in soil science. It is not possible to list all of them, so I will try to recall some based on what has been discussed in conferences, and what has been published in soil science journals. These include the fate and effects of antibiotics in soils, 4 per mile initiative, clay-organic matter interactions, soil change due to anthropogenic impact, biological soil health indicators, biochar effects on soil properties, soil variability at the aggregate and soil profile scales, use of non-invasive techniques for soil research, nano-fertilizers, temporal and spatial variability of soil properties, factors controlling nutrient availability in soils, the role of dust deposition on soil development, silicon dynamics in soils and ecosystems, pedometrics, pesticide transport in soil, indicators of soil development, the genesis of technosols, fate of heavy metals in soils, new methods of soil analysis, and many others.
Keep safe,
Victor Asio
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Soil pH
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1. Take 10 g of soil sample in 50 ml or 100 mL beaker (1:2.5 Soil water suspension ratio)
2. Add 20 or 25 mL of distilled water, stir well for about 5 minutes and keep for half an hour.
3. Again stir just before immersing the electrodes and take the pH reading by using pH meter.
NOTE: Prepare standard buffer solutions of 4.0, 7.0 and 9.2 in distilled water.
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throughout phosphorus status analyses I noted that the sandy soil always have a higher phosphorus fixation rate. I would like to confirm this.
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Clay particles tend to retain or fix phosphorus in soils. Consequently, fine-textured soils such as clay loam soils have a greater phosphorus-fixing capacity than sandy, coarse-textured soils. Clays of the 1:1-type (kaolinite) have a greater phosphorus-fixing capacity than the 2:1-type clays (montmorillonite, illite, vermiculite). Soils formed under high rainfall and high temperatures contain large amounts of kaolinitic clays, and therefore have a much greater fixing capacity for phosphorus than soils containing the 2:1-type clay. High temperatures and high rainfall also increase the amount of iron and aluminum oxides in the soil, which contributes greatly to the fixation of phosphorus added to these soils.
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For the analysis of soil organic carbon by WB method,I have used 1 g soil with 10 ml of 0.1667M K2Cr2O7 solution, 20 ml concentrated H2SO4,200 ml water for dilution,10 ml H3PO4,10 ml of NaF solution,diphenylamine as an indicator,0.5M FeSO4 solution as a titrant.
During dilution,different soil sample shows a variation in colour i.e. some are orange and some are dark green,but with the same end point of light greenish colour after titration.Why is this colour variation takes place in different soil samples,Is this not an appropriate procedure for soil organic carbon?
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1) Take 0.5 or 1.0 g 0.2 mm sieved soil sample into a 500 ml capacity conical flak.2) Add 10 ml of 1 N potassium dichromate solution and 20 ml of concentrated sulphuric acid, gently mixed and keep the contents for 1/2 hour.3) After 30 min, add 200 ml distilled water, 10 ml phosphoric acid, about 0.2 g NaF and 8 to 10 drops of diphenylamine indicator.4) Titrate the contents against the standard ferrous sulfate or ferrous ammonium sulfate till it becomes bright green in colour.5) Run a blank titration by following all the above steps without soil.6) After noting down the burette readings of both blank and sample titrations, calculate the organic carbon present in the soil using the following formula
  1. % OC = 10 x 1 (Blank value - T.V of sample) x 0.003 x 100 / Blank value x weight of soil (g)
  2. % OM = % OC x 1.724
  3. % N (Total) = % OC/10 or %OM/20
  4. NOTE: Before transferring 0.5 or 1 g soil sample into conical flask take about 2 g of 2 mm sieved air dry soil, grind and passed through a 0.2 mm sieve separately.....Thanking you...@
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Are there any tools or innovative ways in measuring the amount of neonicotinoids, in particular Imidacloprid in the soil?
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How Can I neonicotinoids usage Statistical data?
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There are several method for determining organic matter in soil such as black and walkley and Tyurin method. Among them which on gives the most reliable results?
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Walkley-Black chromic acid wet oxidation method (1934) is best method.
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I would like to have silicic acid by passing sodium/potassium silicate through cation-exchange resin (Amberlite IR-120B, H+ form). Not sure about the procedure of this method. Should I wash the resin with HCL before passing the sample?
Thank you.
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Hi Paul, he want to make colloidal silica, the main method is using cation exchange resin to remove sodium or potassium from sodium and potassium silicate.
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It is intended to determine the possible maximum loss of natural carbon in the upper soil. In this condition, the carbon should be stable. But researches in Germany showed, the amount of carbon is decreasing on farmland. The highest losses are observed on areas with pure corn production where the soil is exposed to sun, water, and wind.
The loss has in my opinion two main factors: erosion and oxidation.
I'm quite familiar with erosion but I need some input about the chemical component.
What triggers the oxidation of carbon and what soil related catalysts are possible? (UV-light, ions from artificial fertilizers, water, higher temperatures from sun radiation)
Thank you for your collaboration!
Steffen
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Excellent answer given by Paul Reed Hepperly.
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What are the phosphorus release strategies installed from the soil?
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1) By adding organic matter humus can form phosphohumic complexes which is easily assimilated by plants, humate ion can replace phosphate ions and humus can form coating around the Fe and Al ions so that coating prevent P from fixation....
2) There are P - solubilizing organisms a) Bacteria - Pseudomonas and Bacillus
b) Fungi - Aspergillus and Pencillium
3) VAM Fungi can increase the absorption of P from soil by extension of root system
4) Placement (Band placement) of fertilizers (Placing the fertilizer below the seed can reduce the fixation of P by reducing the contact between the soil and fertilizer)
5) Liming of acid soils also release fixed P from Fe and Al compounds
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I came across a confusing concept in a reference and was wondering wether increasing CEC, increases the preference of adsorb sites to bind with cations with higher valence ? For example divalents over monovalents. If yes, does this mean that dry soils (with their double layer and pKa of OH groups decreased and their CEC increased)adsorb more divalent cations?
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@ Kamyar, many minerals in soils are negatively charged and, as a consequence, can attract and retain cations such as calcium , magnesium, sodium, potassium and ammonium etc. Cation exchange is a reversible process, in which elements or nutrients that can held in the soil and lost through leaching can subsequently be released for crop uptake. Certain organic compounds also contribute to cation exchange capacity. Additionally CEC is influenced by soil pH. A certain portion of the total negative charge is permanent, while a variable portion is pH dependent. Values of cation exchange capacity are in the range of 1.0 to 100 cmol (+)/kg, least for sandy soil and high for clay soil. Similarly, higher CEC value reflects the dominance of 2:1 clay minerals, and lower value reflect the presence of 1:1 clay minerals.
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Hi -
Has anyone ever had the issue when they are doing Loss on ignition analysis in a muffler oven at 1000C? Previously I worked with a newer muffler oven and had no issues weighing and baking soils at 1000C. I recently started using an different muffler oven which is a little older, but is properly functioning. I baked my soils and crucibles at 550C and it was fine. I then turned it up to 1000C and baked it at 1000C for 6 hours and turned it down to 105C to take the crucibles out after cooling. However, after I took the crucibles out all of them seemed to be changing colors from neutral ceramic white to green from the bottom up. Also it looks like there are small crystals or precipitate forming on the crucibles, more densely from the bottom up. Attached are a couple of pictures. Does anyone have any experience with this or have any suggestions on how to get to the bottom of this or fix it?
Edit: I just want to note I tried to clean these crucibles with an HCl acid bath, and the greenness did not go away and the precipitate crystals seems to arise once it is fully dry again.
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I have also observed this. At elevated temperatures, some elements will dissolve into the solid solution of the crucible. Look into the ceramics literature on vitrification. I would not worry about the color change, nor would I be concerned about contamination unless you are ashing a sample for subsequent digestion and quantification of elements in the ash. If you're simply looking at soil carbon, the altered crucibles will continue to be fine. Disregard the etching and color change. Keep in mind though that some elements like potassium volatilize at high temperatures (> 500 C).
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I am removing carbonates from clay and sand samples. So, I treat the sediments with H2O2. I need to wash the sediments to remove acid residues. I am thinking of heating the sediments with ultra-pure water over hot plate and subsequent evaporation. The process can be repeated for 3-4 times over hot plate. Will it work and act as an alternative method of centrifuge washing?
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Ashok - H2O2 is used to remove organic matter from sediments - not carbonates. If you are trying to remove carbonates, but wish to leave any clay minerals unaffected, you should use a buffered sodium acetate/acetic acid solution (pH 5.3). If you aren't concerned about the clay minerals, dilute HCl would be fine. E-mail me if you would like the method.
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Which are the key publications for understanding the fate, dynamics and effects on agricultural production of biochar from different sources and with different chemical properties in tropical savanna climate areas with a distinct wet and dry season (roughly Aw in the Köppen-Geiger climate classification)? Especially publications from comparative field experiments with a focus on agriculture like e.g. Cornelissen et al. 2013 (10.3390/agronomy3020256) are most welcome - thanks a lot!
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Here is an article on the subject, unfortunately from pot experiments.
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Are there publications on field trials to determine the effects of moderate fertilizer application rates on yields under small-scale farming in tropical savanna climate?
The main focus crops are soy, groundnuts, beans and cowpeas.
Moderate fertilizer rates mean rates that are in the range of what small-scale farmers might afford (such as e.g. 50-100 kg NPK fertilizer per hectare). Thanks a lot!
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All your main focus crops are legumes: it means that they will not react to N fertilizers doses (except if soils are deprived in organic matter and by the way in symbiosis bacterias). Then the difficulty in testing low doses o P and K (and have significant effects) is due to the interference of P and K soil reserves and exchange capacities! Soil nature and soil analytical chemical status will indicate if there is any interest in testing low doses of P or K fertilizers for a "short" term response i.e. their effects could be "medium" or "long" term !
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Which are the key publications for understanding soil organic matter dynamics in tropical savanna climate areas with a distinct wet and dry season (roughly Aw in the Köppen-Geiger climate classification)?
Main interests are SOM contents (e.g. labile SOM/active pool, resistant SOM/intermediate pool) and turnover times under different land use forms (e.g. natural vegetation, conservation agriculture, tillage).
Any of the combinations of the above topics are most welcome - thanks a lot!
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Organic matter of the soil is associated with the climatic factor and the microbiological sphere of the soil. And also contacted with chemical absorption of the soil.
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I want to set up a pot experiment of which phytoremediation techniques should be used as to remove metals. So, which plant I should use or who are the most effective accumulators.
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Brassica juncea is the most suitable plant for phytoremediation of heavy metals.
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In one of my experiment, some adsorbent is used for the removal of heavy metals from water. Now I want to recover the metal from residues.
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First of all, It depends on the type of adsorbent material that you used.
In heavy metal removal processes, desorption/regeneration of adsorbents is one of the essential aspects as it controls the economy of water treatment technology.
For effective regeneration of adsorbents and metal recovery, acids (such as HCl, H2SO4, HNO3, HCOOH and CH3COOH), alkalis (such as NaOH, NaHCO3, Na2
CO3, KOH and K2CO3), salts (such as NaCl, KCl, (NH4)2SO4, CaCl22H2O, NH4NO3, KNO3 and C6H5Na3O72H2O), deionized water, chelating agents and buffer solutions (such as bicarbonate, phosphate and tris) were used in various studies.
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Several methods are available such as phytoremediation, washing, eletrokinetic treatment, and vitrification etc. So, which technique is more feasible and effective?
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I think phytoremediation is the most feasible method for removal of heavy metals from contaminated soil.
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I am using SWAT 2012 New Delhi conference data. when I am using HWSD (FAO) type it is showing that the raster layer hwsd.bil doesn't have attribute table just after its loading ( before defining look up table) as shown in fig 1. and when using SOIL_WATERBASE (faosol.img) it is showing that "I-Ne-3729" doesn't exist in user soil database but it exist (as shown in fig 2.). If I replace it (I-Ne-3729) with some other soil from SWAT default soil of USA, it is showing that - some of the user soil can't be detected by SWAT, should be corrected SWAT RUN.
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Make sure swat is accessing the correct SWAT2012.mdb database. This file should be in your ArcSWAT project folder. When you create an ArcSWAT project, before doing anything, go to "Edit SWAT Input" ---> "Database" and make sure your soil and landuse and other databases are all there and are correct.
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The aim of speciation procedures is to maintain the integrity of heavy metals species and minimise sample preparation procedures that may alter heavy metals speciaton. There is a tendency for laboratories to choose methods they are familiar with rather than the most appropriate procedures likely to obtain accurate and unambiguous speciation data.
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Chemical Speciation and Potential Mobility of Heavy Metals ...
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Especially in metropolitan areas.
Which one has the highest impacting today?
Which heavy metal have the highest pollution rate in urban soils todays?
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Excellent question and answers, according to our team study in Iran: lead in water pipes , traffic intensity , residential wastes , vehicles and urban industries !
Please kindly see the attached article!
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Soil is an important source for heavy metals in crops and vegetables since the plants’ roots can absorb these pollutants from soil, and transfer them to seeds which through this can effect on humans, but what about soils in urban areas?
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Human Nutrient Supply from Soils
A mere 11 elements constitute 99.9% of the atoms in the human body. These are typically divided into major and minor elements. The four major elements, H, O, C, and N, make up approximately 99% of the human body, and seven minor elements, Na, K, Ca, Mg, P, S, and Cl, make up another 0.9% of the body (Combs 2005). Approximately 18 additional elements — called trace elements — are considered essential in small amounts to maintain human life. However, human health experts do not universally agree on the exact number and identity of these trace elements. Out of the approximately 29 elements considered essential for human life, 18 are either essential or beneficial to plants and are obtained from soil, and most of the other elements can be taken up from the soil by plants (Brevik 2013a).
Negative Health Effects
Heavy Metals
Exposure to heavy metals through soil contact is a major human health concern. Arsenic is a metalloid, but it is commonly grouped with the heavy metals. The heavy metals of greatest concern for human health include: As, Pb, Cd, Cr, Cu, Hg, Ni, and Zn (Fergusson 1990). Heavy metals enter soils naturally through the weathering of rocks, but they have also been introduced into soils through human activity. Heavy metals are the by-products of mining ores, and they are present in mine spoils and in the immediate surroundings of metal processing plants. Heavy metals are released into soils from landfills that contain industrial and household wastes and from sewage sludge that comes from wastewater treatment plants. E-wastes, or wastes associated with electronic appliances, are an increasing source of Pb, Sb, Hg, Cd, and Ni in the soil (Robinson 2009). Urban soils are particularly susceptible to significant accumulations of heavy metals from automobile exhaust, coal burning, erosion of metal structures, and refuse incineration. In agricultural settings, the use of fertilizers, manures, and pesticides has also contributed to the accumulation of heavy metals in soils (Senesi et al. 1999). Arsenic has been used in pesticides, and the build-up of arsenic in orchard soils is problematic since it may persist for decades (Walsh et al. 1977). The heavy metals with the most toxicity in humans, including Cd, Pb, Hg, and As, are those with no biological function that disrupt enzymatic activities commonly affecting the brain and kidneys (Hu 2002).
Organic Chemicals
Organic chemicals have been deposited into the soil both naturally and anthropogenically, and many of the organic chemicals deposited into the air and water eventually end up in the soil. Soil contamination with organic chemicals is a serious problem in all nations (Aelion 2009). A large amount of these organic chemicals come from the agricultural application of herbicides, insecticides, and nematicides (Figure 2). Soil pollution with organic chemicals is not limited to farming areas. Soils in urban areas are also polluted with organic chemicals as a result of industrial activities, coal burning, motor vehicle emissions, waste incineration, and sewage and solid waste dumping (Leake et al. 2009). Both farming and urban areas have soil contamination that includes a complex mixture of organic chemicals, metals, and microorganisms caused by municipal and domestic septic system waste, farm animal waste, and other biowastes (Pettry et al. 1973). A more recent health concern includes pharmaceutical waste derived from antibiotics, hormones, and antiparasitic drugs used to treat humans and domestic animals (Albihn 2001).
The most common types of organic chemicals found in soil include polyhalogenated biphenyls, aromatic hydrocarbons, insecticides, herbicides, fossil fuels, and the by-products of fossil fuel combustion (Burgess 2013). These organic chemicals are highly diluted in the upper layers of the soil, and they form chemical mixtures used in reactions involving microorganisms. We have very little toxicological information about the health effects of these chemical mixtures (Carpenter et al. 2002). Studies of the health effects of low concentrations and mixtures of these chemicals in soil have been very limited (Feron et al. 2002). Due to the very long half-lives of many organic chemicals, they are referred to as "persistent organic pollutants." These persistent organic pollutants are organic chemicals that resist decomposition in the environment and bioaccumulate as they move up the food chain. An example of this is 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), which was shown to disrupt the hormonal systems of raptors (Vega et al. 2007).
Airborne Dust
Airborne dust can impact human health, especially when the particles are less than 10 microns in size (Monteil 2008). The main direct health effect of inhaled dust is irritation of the respiratory passages and diseases, such as lung cancer. However, airborne dust can carry additional materials, such as pathogens, harmful gases, organic chemicals, heavy metals, insects, pollen, and radioactive materials, that can cause other health problems (Bartos et al. 2009). Humans can breathe airborne dust containing toxicants into the lungs, where the toxicants may enter the bloodstream. Cultivation for agricultural production and deflation (wind erosion) from unpaved road and work sites and denuded fields can introduce dusts into the atmosphere. Airborne dust from Africa is a significant health concern for North American soils. Clouds of dust from the Sahara and Sahel deserts follow the trade winds across the Atlantic Ocean, and African dust has been linked to elevated levels of Hg, Se, and Pb in North American soils (Garrison et al. 2003). The number of asthma cases in the United States more than doubled between 1980 and 2000, and asthma rates have also increased in the Caribbean (Brevik 2013a). Airborne dust from Africa has been tentatively linked to increased asthma in North America (Monteil 2008).
Soil Pathogens Although most organisms found in soil are not harmful to humans, soil does serve as a home for many pathogenic organisms. Bacteria are the most abundant type of organism in soil, and they are found in every soil on Earth. Most fungi are saprophytes that absorb nutrients by aiding in the decomposition of dead organisms, but approximately 300 soil fungi species out of the more than 100,000 total fungi species are known to cause disease in humans (Bultman et al. 2005) (Figure 3). For example, the soil fungus Exserohilium rostratum was responsible for the 2012 fungal meningitis outbreak in the United States (Brevik & Burgess 2013a). Protozoa are single-celled eukaryotic organisms. Most protozoa found in soil feed on bacteria and algae, but some cause human parasitic diseases such as diarrhea and amoebic dysentery (Brevik 2013a). Helminths are parasites that may inhabit the human intestines, lymph system, or other tissues. Diseases caused by helminths require a non-animal development site or reservoir for transmission, and the soil is a common development site. Billions of people are infected by helminths worldwide each year, with an estimated 130,000 deaths annually. Helminth infections generally occur through ingestion or skin penetration, and in most cases involve infection of the intestines (Bultman et al. 2005). The soil is not a natural reservoir for viruses, but viruses are known to survive in soil. Pathogenic viruses are usually introduced into soil through human septic or sewage waste. Viruses that cause conjunctivitis, gastroenteritis, hepatitis, polio, aseptic meningitis, or smallpox have all been found in soil (Hamilton et al. 2007; Bultman et al. 2005).
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The mineralisation rates or soil organic matter are influenced by temperature and moisture.
I am trying to classify climates, using associations between cumulated annual rainfall and annual average temperature.
Has anyone ever tried to study how soil organic matter or carbon levels where related to the combination of these two easily accesible climate parameters (temperature and rainfall)?
Observed level of SOM or SOC is distinct from the rate of mineralisation of course.
But using climate data is could be interesting to estimate mineralisation rates using only rainfall and temperature (if the relationship is good, and perhaps adjusting with soil texture).
Any ideas?
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Temperature, rainfall got definite relationship with vegetation and soil organic matter and soil organic carbon. These are long established phenomenon.
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I am looking for large datasets including information on soils (texture, depths, carbon , etc.) and their location (GPS coordinates or climates data).
Any suggestions?
Any large studies which would have left their data available for free in repositories?
My objective is to help people find time series on soil carbon on this thread (easily find this discussion with a google search). Thus it could a great reference and link list.
Thanks!
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Dear Dr Fungenzi
You may have seen my response to your first question. One of the attached papers (the first one) was based on a publicly available time series of samplings. We used 41 years and by now there should be data for another 10 years available. The samplings and storage of data takes place at the Swedish University of Agricultural Sciences, Uppsala, Sweden. In case you want a contact I will be happy to support you.
Best regards
Björn Berg
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I am analyzing soil samples from a volcanic area (relatively young), formed by Andosols (non-allophanic), I have run all the routine analyzes (oxalate, DCB, pyrophosphate extractions, CEC....) however I've realized that the Alo content is smaller than the Alp for some samples (all of them A horizons with high organic matter content while for the 'less' organic horizons the Alo is always higher than the Alp). As far as I understand the Alo content represents the organic-bounded + the amorphous Al content, while the Alp represents only the organically-bounded Al, hence the Alo content should be higher than the Alp. Is there any mechanism that could help me explaining this behavior?
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Dear Marlon
Andisol with a high content of humic compounds, the majority of the proportion of Al-amorphous will be complexed to Al-humic, so it makes sense that in Andisol with high organic content, Al-humic> Al-amorphous. Conversely, at andisol with low OM content, only a small portion of Al-amorphous complexed to Al-humic so that Alo> Alp content
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I am doing a column experiment in saturated porous media, using different P concentration effects on the transport of ferrihydrite colloids. I got a 5 ml effluent for every sample. I divided that in two parts. The 2.5 ml I used for measuring soluble P after centrifuge and filtration with 0.22 um filter membrane and measured via Murphy and riley method. while for TOTAL PHOSPHORUS, I took 1 ml of effluent and digested with 4 ml of 6M HCL for 24 hrs as per the digestion process for ferrihydrite colloids described in literature and then I used p-nitrophenol indicator (yellow indicator) and neutralized sample with 4M NaOH and 0.1 HCl. and then after neutralizing the sample I measured total P with murphy and riley (1962) method. My question is that, Is that the right way of measuring total P? I got good results by the way but need opinion from experts...
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Veli Uygur Yes Sir, I prepared ferrihydrite with different concentrations of P, and confirmed. but I didn't find a suitable reference for my work i.e. the digestion of P sorbed iron colloids, the way I did.
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I am trying to estimate phytate-P from soil by enzyme addition method. I consulted several papers and most of them had use malachite green for P determination. I followed the method described in Jarosch et al., 2015 and tried several time for estimating MRP from NaOH-EDTA extract of different soils, after and before enzyme incubation. But I failed to develop color in every cases. Rather I ended up with greenish precipitate inside glassware. I am unable to understand the problem, can anybody please help me?
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any methods to reduce NH4OAc background for IC analysis? or any alternate soil extraction procedures available for cation analysis with IC in order to determine CEC?
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Hi Nitish,
A soil sample is extracted with an excess of 1 M ammonium acetate solution. The amounts of exchangeable sodium, potassium, calcium and magnesium in the extract are determined by flame photometry (Na and k) and by atomic absorption spectrophometry (ca and Mg). lanthanum or strotium is added as a releasing agent to prevent formation of refractory compounds which may interfere with determinations (e.g. phosphate),
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I want to extract soil nitrogen using KCL and use IC for analysis of Nitrate. In most of the protocols that I found so far 1 M KCL is used for extraction. However, IC's are not able to handle such high concentration of chlorides, neither are Hach kits. Any suggestion would be helpful to proceed further.
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follow
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Thanks.
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Recommend Manohar Sehgal answer
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How many gm of salt (sodium chloride) need to create an EC value of 10 dSm-1 in 10 Kg soil?
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Never, never and never try to create an artificial salinity in a normal soil as it does not represent a typical salt affected soil. It is a wastage of time, energy and resources. Instead, you collect soil which is naturally saline or sodic or saline-sodic. You can get the information from soil test laboratories there about the locations in Bangladesh where such problem soils exist naturally. Good Luck.
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I need to get the details of the electro-ultrafiltration method of potassium determination and its efficiency as compared to the other most commonly used methods.
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Following
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The problem we face in gypsiferous soil is how to accurately estimate the texture when gypsum reaches more than 50% and often as much as 70% . I think when the ratio reaches this limit, the texture can not be properly estimated , If the gypsum is washed there will be a difference In the soil texture field and laboratory ... I hope to see your views and suggestions?
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Hello,
I have a question regarding the CEC of organic matter. I have read that its functionnal groups can get protonated or deprotonated with pH but I cannot find anywhere at which pH its CEC is equal to zero.
Thank you all a lot in advance for your help,
Xavier
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Dear Xavier Dupla
Have a look at this published paper. hope be useful.
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Many researchers stated that Low bio-availability is restricting factor to uptake metals. On the other hand side, people try to control high bio-availability or mobility of metals.if they try to control then it will be limited, then phytoextraction potential will be less now which one is good?
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It depends on the toxic metal concentration of the soil and plant type, if the toxic metal content was below than tolerable level of certain plant, no need to control the availability of toxic metals.But, In the case of toxic metal surpassed tolerable level, you need to control the mobility in order to let the accumulation plants live in the substrata. no need to much worry about metal availability after the treatment, only the accumulation plant grow relatively well, plant rhizosphere will mobilize the metal
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Need to understand that till date is there any research has been carried out for soil science of organic farming. What are the soil chemistry, what are the microbial interaction in organic farming soil?
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Currently, only 1.2% of the world agricultural land is under organic farming. However, because of increasing consumer preference for organic products, organic farming has been increasing steadily. India has 9th largest agricultural land area (1.5 M ha) used for organic farming by in excess of 800,000 producers. The largest land mass used for organic farming is in Australia (27 M ha), much of which is under extensive grassland.
There is plenty of literature available on organic farming soil quality, mostly comparison between soils from conventional farming versus organic farming. One example is Y. Ikemura and Manoj K. Shukla, Journal of Organic Systems – Vol.4 No.1, 2009.
Many studies have also shown, nitrate leaching losses have been lower from organic farming compared to conventional systems. Studies have also found, generally while crop/animal product yields have been lower in the organic systems, it has been offset by the higher product price fetched by the organic systems. Interestingly, it has been found organic systems also emit lower greenhouse gases (GHGs).
To date, organic farming studies have shown, highly improved physical, chemical and biological properties of soils which have resulted in better water holding capacity, soil fertility and lower environmental impacts.
A review on organic farming could help to highlight the above findings (K.S. Lee et al. / Journal of Environmental Management 162 (2015). I suggest you search for more open access papers.
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Soil infertility, soil chemistry, physical chemistry, Soil physics
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Mr. Phogat,
Via MS.
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"The C/N ratio of soils is about 10–12:1." ( Donald L. Sparks, in Environmental Soil Chemistry (Second Edition), 2003)
I know, the wording of my question is very strange, but that is to provoke you.
This homogeneity does not sound astonishing to you?
From a soil organic matter perspective, wouldn't it be normal to find different C/N ratios depending on the decomposition/humification stage?
Are soil scientists generalizing or is it really a natural property of soils?
Do most soils tend to reach a C/N = 10 ?
It sounds like a very interesting "universal limit" to me.
What is your take on that? ;)
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I have had a significant amount of experience with prairie soils in the north central US (mostly mollisols). In my evaluation of cropland soils, grassland soils, and wetland soils, I have found the C:N ratios almost always at about 11:1 +/- 1 which is at the 10:1 value. This is assuming that the soils are in equilibrium with their management and environment. This can vary, usually when additional plant/animal biomass is added but due to the microbial equilibrium reestablishing shortly after the biomass is added, returns to near the equilibrium level.
An interesting sidelight of evaluating soil C:N ratios is their usefulness in evaluating environmental pollution or contamination. Contamination from hydrocarbons will widen the C:N ratio due to the excess C while fertilizer contamination will narrow the C:N ratio due to excess N. the rebound from each of these types of contamination take some time to rebound and evaluating C:N on a periodic basis can be used to evaluate effectiveness of remediation.
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The terminology like retention, fixation, sorption, and adsorption are used in soil chemistry and material sciences. These terminologies always confusing. For example, the using this term in P nutrient, we found some scientists think the retention or fixation of phosphorus involves both adsorption and precipitation reactions. And they define the adsorption as the fixation of solutes from a solution on the surface of a solid. Other think, P fixation or sorption, retention (the three terms are frequently used interchangeably). The differentiate between phosphate retention and fixation some authors think retention is easy to remove even by dilute acid, while the fixation phosphate anion held by the soil clay cannot be removed by the treatment of the soil clay with the same acid. Therefore, the distinct between fixation and retention need more explanation.
Therefore, we are looking more detail and explanations of these issue, lecture note, e-book, literature review, articles, and technical report explanting these issue, also are needed.
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*The retention is the presence of ions on the surfaces of ion exchange complexes called the image available.
*The fixation is the capture of ions between the inner layers of clay minerals or other soil particles or enters into the chemical formula of the crystal structure called an image that is not available.
*Adsorption is the retention of ions on the surfaces of the ion exchange complexes in a readily available form.
*Absorption is the process of penetration of ions into the structural structure of clay minerals, especially montmorillonite.
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By best, I mean which could easily extract out soil organic matter such as amino acids plus which could easily be available or synthesised using basic chemicals.
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A new soil extractant (H3A) with the ability to extract NH4, NO3, and P from soil developed and tested against 32 soils, which varied greatly in clay content, organic carbon (C), and soil pH. The extractant (H3A) eliminates the need for separate phosphorus (P) extractants for acid and calcareous soils and maintains the extract pH, on average, within one unit of the soil pH. The extractant is composed of organic root exudates, lithium citrate, and two synthetic chelators (DTPA, EDTA). The new soil extractant was tested against Mehlich 3, Olsen, and water for extractable P, and 1 M KCl and water‐extractable NH4 and NO2/NO3. The pH of the extractant after adding soil, shaking, and filtration measures for each soil sample.
1. Morgan Extraction Reagent which was introduced in 1941
2. Mehlich introduced an universal extractant, frequently referred to as the Double Acid extractant, for assaying acid sandy textured soils.
3. The ammonium bicarbonate‐DTPA extraction reagent for use on alkaline soils was introduced.
4. Wolf modified the Morgan extraction reagent by adding DTPA to it. In 1984, Mehlich described his Mehlich No. 3 extraction reagent for use on a wide range of acid soil types.
All above extraction reagents can be assayed using a multielement analyzer such as the inductively coupled plasma emission specterometer for both the major elements and micronutrients in the obtained extractant.
The soil extract can be prepared by mixing 5g of soil in 1L H2O mix well, filter and then autoclave.You don't have to use soil extract to isolate Actinomycetes you can use any other medium that contained two different antibiotics for inhibition of fungi such as nystatin and streptomycin for inhibition of bacteria.
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Dear Experts,
kindly suggest me a best method to estimate the percentage of potassium sulphate in the organic fertilizers.
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Hi Karuppiah, the easiest way is to dissolve a certain amount of fertilizer in water, filter the solution if necessary and then determine the sulphate content in the solution (http://www.merckmillipore.com/DE/de/product/Sulfate-Test,MDA_CHEM-110019). You can then calculate back to potassium sulphate and with the weight of the dissolved fertiliser you can calculate the mass percentages.
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Hello everybody,
As we know that the shear strength values in the soil are suppose to be similar or close to each other in shear strength tests, 
I had tested a punch of samples but there are differences in the shear strength values. 
Now, I'd like to ask about the causes behind the difference in the strength between UU TrI axial and UCS for the same soil sample ?
Also, is there any relationship between the liquid  limit of the soil  and its strength  ? 
Thank you. . 
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  1. a sample is tested without any confining pressure, i.e. sigma3=0, and hence it can be done only on clayey soil.
  2. It is a quick test and hence undrained test (no time for water to come out of the sample during the test).
  3. Irrespectively the number of soil samples tested, the value of normal stress at failure (i.e. sigma1) is same and hence the corresponding Mohr’s circle of stress at failure is same for all the samples.
Usually the test is done on saturated sample of clayey soil. As the test is undrained, the frictional component of shear strength will not be mobilized. The Mohr-Coulomb failure envelop will be horizontal and so
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What types of organic matter increase the salinity of the soil and what types of organic matter that reduce salinity؟
i want to make compare between two types of O.M to give me different results :
first : decrease Electrical conductivity for soil
second : increase Electrical conductivity for soil
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Dear Diaa Fliah Hassan, there are several way of managing salinity. However, as your question is specified to only organic material, I have tired to highlight in alignment of your specific question.
1) Large quantity plant material left on field, lime, legumes in mature root zone are good for increasing soil salinity by increasing soil pH. A common method for increasing soil pH is to lime soils with calcium carbonate, calcium oxide (CaO), calcium hydroxide (Ca[OH]2), or calcium containing by-products such as sugar-beet lime.
2) Legumes on soil surface, Sulfur, leaf and stem harvest are good for decreasing soil salinity by decreasing soil pH: Among these, sulfur is a common amendment used to lower the pH of basic soils. Elemental sulfur is oxidized by microbes to produce sulfate (SO4 2-) and H+ , causing a lower pH.
3) Addition of Organic material (SOM): SOM buffers the soils pH. Soil organic matter offers many negatively charged sites to bind H+ in an acidic soil, or from which to release H+ in a basic soil, in both cases pushing soil solution towards neutral.
Please go through the attached interesting article for your further information.
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Every month thousands of soil sample we are receiving to soil testing laboratory for preparation of soil healthcard. It is difficult to determine the available nitrogen in conventional alkaline permanganate distillation method (Subbaiah & Asija ,1956) and new modified  kjeldahl method. Hence we require few novel technique or option to determine the soil available N.
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Before you think about conversion, I would suggest that you should study critically about the usefulness of available nitrogen in the soil. To my knowledge and experience, there is hardly any utility of quantifying available nitrogen in the soil. No good correlations have been reported between available nitrogen in the soil and response to fertilizer nitrogen.
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What is the best protocole to measuring phytase enzyme in soil with high organic matter?
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Dear Mostafa
This paper is having information required by you.I hope it might be helpful for your work.
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i want to know if soil sterilization can change C/N ratio ,N ,P and k content of soil
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While solarisation, we expect changes in DOC, which will changes many of the soil physical properties like Soil aggregate stability , aggregate size, AWC rtf, in addition to other soil chemical and biological properties as we discussed previously...
In fact we were looking at , how to arrive at critical time of exposure of soil to different solarisation treatments ...
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Best protocol to measuring soluble phosphate in NBRIP broth medium
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