Questions related to Soil Chemistry
In a simple experiment, I measured the pH of Tween 80 solutions and observed that the pH decreased. investigation results :
3 ppm tween80 = 8.43
6 ppm tween80 = 8.24
12 ppm tween80 = 7.51
15 ppm tween80 = 7.31
1780 ppm tween80 = 4.22
3560 ppm tween80 = 4.05
7120 ppm tween80 = 4.09
Solutions were made in distilled water. It seems that pH increased first and then increased with increasing concentration.
How does polycoated urea respond in texturally divergent soils under different agro-climatic conditions?
How can we diagnose the soil in the laboratory through its appearance that it is fertile or not fertile without conducting an analysis on it?
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?
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.
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
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?
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?
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).
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?
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?
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?
It is a famous model which can be used to calculate the critical load of acidity for forest soils
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,
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,
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.
How can I calculate lime requirement for increasing soil pH without Lab determine? or which methods are faster and easier than woodruff buffer solution?
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?
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?
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.
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 ?
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.
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?
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?
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?
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?
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?
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.
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?
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?
I'm dealing with Upper Cretaceous microfossil association that consists of ostracods and foraminifera. Source material – sandstone and marly limestone – was disintegrated in water with some Hydrogen Peroxide (30%) added to solution. The problem is that microfossils are not totally liberated from the rock and still have pieces of it attached to their carapaces and tests.
Can somebody please give me some hints on how to remove unwanted material?
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.
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?
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
Hanuman Singh Jatav
throughout phosphorus status analyses I noted that the sandy soil always have a higher phosphorus fixation rate. I would like to confirm this.
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?
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?
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!
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?
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.
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?
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!
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!
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!
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.
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.
Several methods are available such as phytoremediation, washing, eletrokinetic treatment, and vitrification etc. So, which technique is more feasible and effective?
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.
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.
Especially in metropolitan areas.
Which one has the highest impacting today?
Which heavy metal have the highest pollution rate in urban soils todays?
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?
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).
I am looking for large datasets including information on soils (texture, depths, carbon , etc.) and their location (GPS coordinates or climates data).
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.
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?
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...
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?
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?
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.
How many gm of salt (sodium chloride) need to create an EC value of 10 dSm-1 in 10 Kg soil?
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.
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?
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,
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?
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?
"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? ;)
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.