Soil Analysis - Science topic

This method typically has the soil samples collected a year (or more) after the imagery date and tissue testing. Site-specific soil test target levels are established for each field and nutrient management plans developed to reach and maintain the target levels. Plant tissue analysis gives a much more direct measure of what the plant is using; the procedures are universally applicable (in contrast to soil testing methodology); and regular plant tissue testing enables plant nutrient status to be monitored. Precision fertilization is applying the Right Input, at the Right Amount, to the Right Place, at the Right Time, and in the Right Manner and help farmers reduce the amount of inputs they use, which can help reduce the risk of environmental pollution. Precision agriculture is the science of improving crop yields and assisting management decisions using high technology sensor and analysis tools. Precision fertilization and precision irrigation are a fertilization technology based on the comprehensive analysis of the yield data of different spatial units and multilayer data, such as soil physical and chemical properties, diseases, pests, and climate. A fertilizer recommendation is the research-based set of guidelines, or management practices, for supplying fertilizer to the crop to achieve yield and quality goals (economic) in a manner that minimizes nutrient losses to the environment. High-spatial-resolution UAS imagery enables much earlier and more cost-effective detection, diagnosis, and corrective action of agricultural management problems compared to low-resolution satellite imagery. Therefore, UAS can address the needs of farmers or other users, enabling them to make better management decisions with minimal costs and environmental impact.

@ Eugenio, the attached file may be useful to you.

There are good published protocols that you will find through Google or Google Scholar

I am discuss about only agriculture economics related topic

There are several methods that can be used to extract polycyclic aromatic compounds (PACs) and other organic pollutants from soil samples. Here are some common methods that you can consider:

Soil sonication: This method involves the use of high-frequency sound waves to break down the soil particles and release the PACs. The soil sample is mixed with a solvent, such as water or methanol, and then subjected to sonication for a specific period of time. The resulting solution is then filtered and analyzed for PACs.

Soil shaking: This method is similar to sonication, but it uses a mechanical shaker instead of sound waves. The soil sample is mixed with a solvent and then shaken for a specific period of time to release the PACs.

Solvent extraction: This method involves the use of a solvent, such as hexane or dichloromethane, to extract the PACs from the soil sample. The soil sample is mixed with the solvent and then agitated or shaken for a specific period of time. The resulting solution is then filtered and analyzed for PACs.

Microwave-assisted extraction: This method uses microwave energy to accelerate the extraction process. The soil sample is mixed with a solvent and then heated in a microwave oven for a specific period of time. The resulting solution is then filtered and analyzed for PACs.

Enhanced solvent extraction: This method uses a combination of solvents and/or additives to enhance the extraction efficiency. For example, a mixture of water and methanol can be used to extract both hydrophilic and hydrophobic PACs.

Soil digestion: This method involves the use of chemicals, such as hydrogen peroxide or nitric acid, to break down the soil particles and release the PACs. The resulting solution is then filtered and analyzed for PACs.

It's important to note that the choice of extraction method will depend on the specific properties of the PACs and the soil sample, as well as the desired purity and sensitivity of the analysis. It's also important to follow proper safety protocols when working with hazardous chemicals and to use appropriate equipment and instrumentation for the analysis.

Different fungicidal compounds act only on certain groups of fungi. When I was doing bacterial isolation from soil samples I used nystatin + cycloheximide. Even then I would get the odd fungus that was resistant to both. Nipagin is also good for stopping fungal growth but it also inhibits bacteria as well. I advise checking your plates 24h after setting them up and using a scalpel to remove any fungi that are persisting.

Enjoyed the response of Kevin very nice.

Trichoderma are a genus of fungi which many are fungal parasites and they form endophytic relation with crop plants.

As a parasite Trichoderma harzianum is a pathogen of commercial mushrooms.

The use of mushroom stalks can be placed in soils and the stalks can elicit the colonizing Trichoderma using a baiting strategy.

Many Trichoderma give biological control activity and plant stimulation.

In the commercial product root shield there ia a well characterized isolate which is known to give positive plant responses.

Get a good monographic treatment for species identification and also use PCR testing to confirm your speciations.

Good luck

If you want to measure natural abundance ratios accurately then you will need to find a lab that has an an ion source and a multicollector MS. If you are spiking it should be possible to use conventional ICP-MS

Aromatic nitriles are versatile intermediates in organic chemistry, serving as precursors to amines, amides, and carboxylic acids among other functional groups. The selective reduction of these nitriles to primary amines in the presence of other functional groups like OH requires careful consideration of reagents and conditions to achieve high selectivity and yield. The challenge is compounded by the resonance stabilization of the nitrile group when attached to an aromatic system, which can impede reduction. Additionally, the presence of an OH group introduces the risk of over-reduction or side reactions, necessitating a strategy that can accommodate both functionalities without necessitating protection of the OH group.

Methodologies for Reduction

1. Catalytic Hydrogenation

Catalytic hydrogenation using hydrogen gas (H₂) and a palladium catalyst (Pd/C) is a widely adopted method for reducing nitriles to primary amines. However, the effectiveness of this method in the presence of an OH group and an aromatic nitrile can vary based on the substrate and catalyst used. Palladium on carbon (Pd/C) under mild conditions can offer a route to selectively reduce the nitrile without over-reducing the OH group, though the reaction may require optimization of pressure and temperature to achieve the desired selectivity (Rylander, 1979).

2. Chemoselective Reduction Agents

Selective reduction agents such as Nickel Boride (Ni2B), formulated by the in situ reaction of Nickel Chloride (NiCl₂) with Sodium Borohydride (NaBH₄), have shown promise in reducing nitriles to amines while preserving other functional groups like OH (Girard et al., 1998). This method leverages the chemoselectivity of nickel boride for the nitrile functionality, potentially offering a viable pathway for selective reduction in complex molecules.

3. Transfer Hydrogenation

Transfer hydrogenation represents an alternative strategy, using formic acid or ammonium formate as hydrogen donors in the presence of a suitable catalyst, such as Ru, Rh, or Ir complexes. This approach has been successful in reducing aromatic nitriles to primary amines under relatively mild conditions, with the potential for high selectivity (Casey et al., 2007). The compatibility of transfer hydrogenation with various functional groups, including OH, makes it an appealing option for selective reductions.

4. Avoidance of Protective Groups

The strategic avoidance of protective groups is a guiding principle in the design of reduction methodologies. While protective group strategies can offer a route to selective reductions, they introduce additional synthetic steps, increasing the complexity and time required for the synthesis. The methods outlined above represent approaches that, in principle, obviate the need for protecting the OH group, thereby streamlining the synthetic process.

References

Your query sounds like an engineering one. If so, try looking at engineering criteria for 'acid sulfate soils'.

Are you asking about establishing CO2 concentrations? This is something commonly done in studying post-harvest storage conditions, e.g., for fruit and vegetables. The concentrations of CO2 etc are monitored and controlled.

PCR purification columns do cause a large loss of product. You can get a better yield by washing the dna off the column with hot 70c water or elution buffer but depending on your next process you may want to exo-sap the product to get rid of primers or just ethanol precipitate the pcr product for later use. Many later stages can take place in pcr buffers ( like restriction digests) so you may want to check what level of purification your samples need

How definitive do you need to be? Are you simply picking all root material from the soil and assuming it is from grass species, or are you identifying each species in the quadrat (the 8.5cm ring), and then following the crown down into the soil and extracting the roots for each plant?

A few questions to help answer your request:

I hope that you have already found your answer ;) but i just found this question.

in any case, the cross section you shoud have used is 0.015 m2 (L x B)

The different carbon fractions of the soil amended with fresh residues showed significantly higher mineralized rates than with same quantity of compost because the higher amounts of humic substances and fulvic and humic acids that serves to support plant life.

First we need to calculate for potassium and then for the rest!

# Because it is in the separate package @! And then diduct the amount of N and p which is in pack with k and then we can Add N and p separately

For exampl

Many commercial laboratories dry their soil at 40 C in a forced air dryer for about 24 hours.

To measure paraffin oil or hydrocarbons in a soil sample:

1. Extract hydrocarbons from the soil using solvents like hexane.

2. Purify the extract using methods like column chromatography.

3. Analyze purified samples using gas chromatography (GC) or high-performance liquid chromatography (HPLC) with appropriate detectors.

4. Create calibration standards to quantify hydrocarbon concentrations.

5. Compare sample peaks to calibration curves to determine hydrocarbon levels in the soil.

Include quality control measures for accuracy and reliability.

ANOVA stands for Analysis of Variance. It is a statistical method used to analyze the differences between the means of two or more groups or treatments. A one-way ANOVA is used when you have three or more categorical, independent groups, but it can be used for just two groups (but an independent-samples t-test is more commonly used for two groups). A two-way ANOVA is used to estimate how the mean of a quantitative variable changes according to the levels of two categorical variables. The sample size should generally be large enough to meet the assumptions of the ANOVA, such as normality and homogeneity of variances. A common rule of thumb is to have at least 20 observations per group in the ANOVA. n=2 is enough for the results to be valid. If your variables do not meet these requirements, then ANOVA may not be the best choice. if you're using multiple different independent variables, a two-way or MANOVA approach might be more useful.

Hydroponics is a method of growing plants without soil. soil gardening uses the natural nutrients present in the soil, whereas hydroponics depends on a nutrient solution to supply the nutrients required for plant growth. soil gardening uses the natural nutrients present in the soil, whereas hydroponics depends on a nutrient solution to supply the nutrients required for plant growth. Hydroponics uses no soil; instead it uses a completely inert, sterile medium. Nutrients in their elemental form are added to the water, and plants are usually watered several times throughout the day. Plant roots absorb these nutrients directly because they are already in their most basic form and dissolved in water. It is simple to test the nutrient solution to find out what concentration of nutrients is available to the plant roots

SILVA has not been updated since 2020, Greengenes since 2013. RDP has most of the sequences with vague taxonomy description.

Check MIMt database that is curated (doesn't contain redundancy) and every single 16S comes from already known complete genomes having full taxonomy description till species level.

I don't think it is not proper to dry soil at 105°C before texture analysis, because some changes may occur in clay minerals during this process. In my opinion it is better to perform soil texture analysis in air-dried soil or, in fresh soil which is neither sticky nor dusty, as it was written by Sritama Chatterjee. But, a different subsample of soil should be dried in owen to determine moisture content. And this moisture content should be considered when weighting the soil sample for texture analysis (better option) or for recalculation of results of particle size distribution determination. E. g. if the soil contain 3% of water, we should weight about 20,6g instead of 20g. If we made analysis on 20g, we must recalculate results, remembering, that it was actually 19,4g of soil.

Arkaprava Roy If you are in initial phase of your work, you may skip the Peterson and Corey method and go for Hedley fractionation / or its modified latest version scheme who is now being widely used .You may also estimate organic P in your soil samples as the samples contain high amount of organic matter.The following reference may be consulted for organic P estimation.There is a new method for organic P estimation based on NMR but facilities may a limitation for you.

Critical evaluation of methods for determination of total organic phosphorus in tropical soils . Soil Sci.Soc.Am.J.54:1261-1266(1990)

This is the metallurgy terms and occurs diopside-fluorapatite based glass-ceramics from blast furnace slag and fluorite tailings the only crystallization product fluorapatite (Ca5(PO4)3F). With respect to thermal behavior of glass, heat treatment of glass with the composition of 40 wt% of blast furnace slag and 60 wt% of fluorite tailings resulted in well sintered glass-ceramics with diopside and fluorapatite as the main crystalline phases. Blast furnace slag (BFS) is a by-product from iron production in blast furnaces, which are fed by a mixture of iron-ore, coke and limestone.

Paul Milham sir, I am extremely glad to receive your reply!

Thanks for reminding me that soil P 'pools' can't be superimposed over soil P 'fractions'. Unfortunately, I'm posted at a very young research institute in India and don't have access to either FTIR or NMR.

I am still curious about what might be the dominant composition of the residual fraction of P because it contributes to almost 40% of the total P content in my paddy soil. The studied soil is clayey Inceptisol with a pH of 7.84, high in amorphous Fe and Al, rich in organic (1.72%) and inorganic C (1.39%), geogenically arsenic-contaminated, and has been regularly fertilized with NPK for the last four decades. The abundance of different P fractions that I found in my study follows: Residual-P>Ca-P>Fe-P>Al-P>Occluded-P>Saloid-P.

If we are using selective extractants to solubilize the elements (Fe, Al, Ca) majorly responsible for binding P to the soil, and if P is never an integral component of resistant aluminosilicate minerals, then where should this high amount of residual P be coming from when our soil is digested with HF? Is it coming from the P:

1. strongly associated with recalcitrant organic matter? However, the soil underwent 17 hours of shaking with 0.1 N NaOH for dissolving Fe-P and Occluded P, and NaOH should dissolve a considerable part of organic matter too.

2. structurally associated with or strongly adsorbed on well-crystalline Ca-, Fe-, or Al-compounds that our extractants are unable to dissolve?

When the probable mineral saturation states were studied in GWB software, it appeared that the discrete P-bearing minerals that could precipitate in our soil are Hydroxyapatite, Whitlockite, MnHPO4 and Strengite. Do these discrete minerals have some contribution to make in the residual pool? Or, do they get dissolved by the selective extractants that we are using?

3. so strongly occluded within Fe and Al oxyhydroxides or CaCO3 that 0.1 N NaOH has failed to solubilize?

4. associated with some other forms?

Until I get access to the relevant instruments to analytically address my doubts, I need the help of your profound expertise in soil chemistry in the form of theoretical insight.

Best regards,

Roy

You need to follow the biosecurity requirements. The receiving laboratory should be able to advise.

Fertilisers can make up 60 percent of the total costs of producing palm oil so it is important to apply fertilisers efficiently.Different fertilisers have different concentrations of nutrients.

The effect of major nutrients on growth and yield of oil palm has been studied in most of the oil palm growing countries in Asia and Africa.

a) Nitrogen: In oil palm, characteristic yellowing symptoms are developed under N deficiency conditions. Nitrogen is found to be essential for rapid growth and fruiting of the palm. It increases the leaf production rate, leaf area, net assimilation rate, number of bunches and bunch weight. Excessive application of nitrogen increases the production of male inflorescence and decreases female inflorescence thereby reducing the sex ratio.

b) Phosphorus: In oil palm seedlings, P deficiency causes the older leaves to become dull and assume a pale olive green colour while in adult palms high incidence of premature desiccation of older leaves occurs. Phosphorus application increases the bunch production rate, bunch weight, umber of female inflorescences and thereby the sex ratio. c) Potassium: When potassium is deficient, growth as well as yield is retarded and it is translocated from mature leaves to growing points. Under severe deficiency, the mature leaves become chlorotic and necrotic. Confluent orange spotting is the main K deficiency condition in oil palm in which chlorotic spots, changing from pale green through yellow to orange, develop and enlarge both between and across the leaflet, veins and fuse to form compound lesions of a bright orange colour.

Have you sorted out the reason?

Start with a soil test to assess the nutrients which are in deficit and look for toxicities while taking in consideration pH and soil organic matter and the soil physical state and if there is profile compaction issues.

Consult this information with experts and get their interpretation.

Together assess a field experiment which could show how the situation might be remediated and design a simple level input trial to find a useful application rate.

not same. A grab bucket sampler is generally used for sampling sludge.

Dear Dr. Suneel Kumar

Shortly: Contact suitable data providers.

In more details. Do you really mean "any", or are you just interested in soil data originating from SW Hungary? In latter case, some soil related geographers from University of Pécs (e.g.: Dénes Lóczy, Szabolcs Czigány), or my institute could help you.

In any case, please specify your demads in more details (e.g: "the reference soil sample" does not exist, there are only observations, which might be representative for a given region, while representativness is also an object- specific feature).

Based on the colony morphology, the plate has two or more fungi.

1. Scrap all the fungi grown on the medium and do the serial dilution again on the primary medium with an antibiotic (to kill bacteria) until you get a single colony.

2. Identify the fungus up to species level by ITS sequencing and phylogenetic analysis.

Soil testing is a crucial practice in agriculture that helps determine the nutrient content, pH level, and other important characteristics of soil. The purpose of soil testing is to assess the soil's suitability for crop growth and to provide recommendations for optimizing crop yields. When we talk about "soil test crop response," we are referring to how the results of a soil test can influence crop management and improve crop yields. Here's how it works:

In summary, "soil test crop response" refers to the process of using soil testing to assess soil nutrient levels and pH, followed by the application of appropriate fertilizers and soil amendments to optimize crop growth and yield. Monitoring the crop's performance helps fine-tune future soil management practices for sustainable and efficient agriculture.

"Brute force" it, i.e., dig your increment and put all the dug out soil into an IKEA bag, weigh it with a luggage scale. For the volume: Put a large trash bag in your hole and fill it with water to determine the volume. Do it for each increment and you should be able to calculate the bulk density for each increment.

Dear Ahmed, the constituent international units are: mmol, c (charge) and the main unit is volume. There may be a valid reason for using volume (L) relating to the method of measurement although this unit is more typically mass (kg), Paul.

Kingsley, although a formula per se is not provided, the graph on page 12 of this document might be useful for you - https://www.hort360.com.au/wordpress/wp-content/uploads/2020/06/Fertcare-Soil-Sampling-Guide.pdf

there are a couple of references that may be worth following up on, although I'm not familiar with either.

kind regards

Murray Hart

From my experience, the 1 year old sample is not a problem.

You might need to adjust your paramters or you can try Dneasy Powersoil pro Kit. I would recommend you to try an experiemnt with fresh soil sample, In which you keep your soil in -80 for 2-3 days, after that you need to try bacterial culture from the soil and at the same time you can go forward with the DNA isolation from soil, changing incubation and lysis time. Perform some experiments then you will find your right conditions.

20 to 3,000 ppm (0.002-0.30 %) the earth crust is about 0.11% of Mn

Syafina Fasya Saiful Anuar ...Can you please add to your question--is this for agricultural use of tilled soils, or grasslands/desert Ecological Restoration? My work is desert/grasslands and is very different than any typical agriculture sampling. Depending on the wild lands species I want to restore, I could take up to 100 samples from one hectare for the first year, and then 30-40 per hectare per year as I monitor my test plot treatments--each treatment minimum size about 3 x 3 meters and the largest about 8 x 8 meters.

I try to do less, but 100 per hectare really give you a good look when you are doing wild lands restoration.

I have very clear black-and-white results and then all sorts of shades of gray in between--when adding fertilizers to get rid of a persistent weed that covers 5 million hectares of California's grasslands, the Yellow Star thistle. In some plots, 99.5% of that weed is gone in only 90 days--pictures attached.

For wild lands, the sampling is always tied to an individual species of plants, and the sampling is always from the top 5 cm only, no deeper. I always add the testing of the percentage organic matter, because a minimum level is needed by each plant, to be able to access the nutrients in the soil and for their seedling's survival in wild lands situations on the natural rainfall.

Please do not use serial dilutions. Please consider the reasons for that suggestion, and consult reference texts. You may take volumes but I suggest that you also measure the SG of the stock standard and measure the masses of the pipetted volumes as a check. You will probably end up using the masses in the calibration.

The international standard for ICP is to measure only between standards, i.e., not below the lowest standard. Look at the residuals of the calibration to determine how well it fits. Have an independent standard to check the calibration and a suitable reference material to check the 'recovery'.

Be aware that matrix matching is necessary for accurate results

Can you use the same extraction technique for all of your compounds? Not enough information is known/provided. "HPLC" is the name of the just the technique. It must be defined. The same is true for the sample prep procedure. For any analysis to be valid, it must be combined with an HPLC "METHOD", fit for purpose, which is shown to be selective for the compound of interest and follows good chromatography fundamentals. *There is no "universal" antibiotic method. Review the different compounds of interest to find out which sample prep techniques are appropriate, then search for an appropriate method to use. The sample (*or sample mixture) should be analyzed using an appropriate method of analysis for all of the compounds present to insure good selectivity and accurate results.

Also, as you are new to liquid chromatography please request help from your teacher and/or a local chromatographer who is experienced using your HPLC system and software.

Dear Kamyar,

It seems impossible from the present perspective, but hopefully, it can be possible in laboratory conditions.

Many fungi and bacteria can digest/degrade/denature microplastics and meso-plastics.

Maybe, those experiments can be prior referred to as those processes.

But, that is for sure it can't be possible on a farm.

Thanks,

@ Cedrick, the attached file may be useful to you.

Joshua Depiver many many thanks sir for your suggestions and help. this article and the method you shared will help a lot.

Regards..

@ Ziqing, It is generally recommended to store soil samples at cool temperatures of 5 or 10°C (Hooper, 1986; Hunt and De Ley, 1996; Oba and Okada, 2008) or room temperature (Mizukubo, 2004) until nematode extraction.

I have successfully extracted RNA from the soil mentioned using the Qiagen RNeasy PowerSoil total RNA kit. Combining the beads and buffers (5 ml Bead sol, 5 ml Phenol mix, 1 ml of SRI & IRS) used for two extractions into a 50 ml capped tube (sterile) you can extract from up to 10 g of soil. Follow the normal protocol but increase the volume of SR3 at step 7 to 3 ml (not 1.5 ml). I also repeated the final incubation and centrifugation step (without inverting or mixing) and then I resuspend the final pellet in 50 uL of water. DNA contamination was present but can be eliminated using a DNase treatment.

Manar Naser If you are not going to change values of predefined field at material (integration) points during simulation, I think you can avoid using USDFLD. Presented .dat file (without lines pertained to USDFLD) is sufficient. From my experience, value of predefined field at any material point is equal to mean of element nodal values.

Hi Mirza, for metagenomics analysis the required edaphic properties may vary based on your specific research question as also mentioned by Pankaj Kumar Singh . Physical parameters such as soil pH, soil moisture or soil water content, bulk density, texture, porosity, water holding capacity, aggregate stability, electric conductivity etc. may be investigated. Further, Soil nutrients in terms of C (organic and inorganic carbon, dissolved organic carbon, total carbon, labile and recalcitrant carbon), N (organic and inorganic, total nitrogen), Phosphorus etc. may be determined. I also suggest to analyze soil microbial biomass carbon to understand the variabilities in the metagenomic data better.

If you want help on how to understand the correlations of these parameters with the metagenomic data please check the following article:

Thanks and all the best in exploring your research.

@ Rajani, actually rhizosphere is the zone of soil surrounding a plant root where the biology and chemistry of the soil are influenced by the root. This zone is about 1 mm wide, but has no distinct edge. To fix the distance for a particular tree rhizosphere we must assured that the volume of soil we are collecting from root zone must be influenced by plant roots and their exudates.

This is traditional just to describe what is happening with depth in soil profiles. The assumption is that most mineral removal by plants is in the surface 10 to 20 cm.

In reality one should not sample across profile boundaries.

Paul Milham thank you for the response. The soil test kit that I used is the one that is commonly used in the garden https://ovcre.uplb.edu.ph/research/our-technologies/article/38-soil-test-kit. I already generated the result of the N, P, and K using the kit. Suppose, I wanted to know if there is a recommended equivalent of the generated qualitative data into quantitative data so that I can compute the amount of fertilizer that I will use using the recommended rate of the crop.

Yes, the difference between soil pH measured in water and CaCl2 can be used to indicate soil buffer capacity, as it reflects the ability of soil to resist changes in pH when acid or base is added. However, it is important to note that this method only provides an estimate of soil buffer capacity and is not a definitive measure.

The smaller the difference between soil pH measured in water and CaCl2, the smaller the buffer capacity of the soil. This is because soils with a lower buffer capacity are less able to resist changes in pH caused by acid or base inputs.

There are several studies that have used this method to estimate soil buffer capacity, and it has been shown to be a useful indicator in many cases. However, it is important to note that other factors, such as soil texture, organic matter content, and nutrient status, can also influence soil buffer capacity and should be considered when interpreting results.

References:

It is best to store soils air-dry. While air-drying, which can be done at room temperature, you should spread the soil as much as you can to create a vast surface. You should use an oven with circulating air. If you're looking for specific organic soil matter components, the temperature shouldn't rise above 35°C.

It is suggested to carry out soil drying by air. Drying at 50°C is stronger and may affect, for example, some labile organic compound.

Well check this link

Hope you will get the info. All the best.

Many analysts do not pay sufficient attention to the predictive quality of their calibration data, especially as Sal suggested, at the low concentration end. Regression fits the bigger values more closely than the smaller values and if the range is large, R2 values can be 0.99 yet therre can be appreciable bias at low concentrations. This shows up in plots of residuals. In addition, some calibration programs 'force' the fits through zero.

In addition, the efficiency of conversion (reduction) of nitrate to nitrate can vary during a 'run' i.e., the sensitivity can change, added to which the instrument can 'drift' over time. To accommodate this a mixed standard of nitrate and nitrite should be measured every few samples, the frequency being based on the actual performance.

My advice is to get the raw instrument data and analyse it yourself. You may hen need to chat with the analyst and arrange to have the instrument operated to meet your requirements.

However, ultimately as the concentration approaches zero there will be small positive and neg values.

Dear Waleed,

The matter is not the soil itself. Curing raw soil has no sense unless, you wish to homogenize humidity in it. However, curing the stabilized soils depends on the type of binder that is used for stabilization. If you use chemical binders that require water for reaction, such as hydraulic binders (cement for instance) or pozzolanic binders (lime for instance), then you'll need to keep water in your specimens as long as possible after for reactions to continue and therefore for better efficiency of the stabilization.

Well, once that is clear, the choice of the curing method depends on the researcher's philosophy. Keeping the specimens for a given period after their fabrication in a controlled Temperature and relative humidity environment may rely on the purpose of comparing various admixtures' performances so that the differences could be assessed with no doubt on any impact of their curing conditions. Finally, some scientists may consider that leaving specimens in varying temperature and relative humidity is more realistic. That is to say that these conditions are like those occurring in the construction site where it isn't possible to apply laboratory curing methods.

regards

Loss on ignition (LOI) is one of the most widely used methods for measuring organic matter content in soils but does not have a universal standard protocol. A large number of factors may influence its accuracy, such as furnace type; sample mass, duration and temperature of ignition and clay content of samples. The Muffle furnace is very hot. For safety, you must use asbestos gloves any time the temperature in the furnace exceeds 100°C. If samples are rich in organics, it is possible that when they burn up, some ash may float between samples and cause cross-contamination. A muffle furnace may be used, if desired, and its use is recommended for the final ignition at 600 ± 50. The minimum ignition temperature is defined in this procedure as being 10°C and 20°C below the lowest temperature that gives flame propagation for furnace temperatures below and above 300°C respectively.

You generally dilute samples to 1) preserve some DNA/cDNA for later use and 2) Lessen the concentration of inhibitors. Regarding "if we dilute DNA concentration by 5:1, after getting the raw number from qPCR machine, should we multiply the received number by 5 to reach exact gene expression copy number?", yes you would have to multiply by the dilution factor to get the quantity in the starting tube (this is assuming absolute quantification method via real time PCR). Alternatively, you can also use digital PCR if you have access to get absolute quantification without the use of standards. Some materials for you to look at:

https://www.gene-quantification.de/strategy.html

The phenomenon in the difference in pile settlement along the length is typical for long piles. Especially this phenomenon occurs in long bored piles.

Definitely you should follow the soil analysis procedure. Biochar is also analyzed using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS) analysis.

EuroVector, the Elemental Analysis Company, is fully dedicated to development of modern Elemental Analyzers (EA) for simultaneous CHNS and O determination.

Soil is not a group of mineral elements accumulated on top of each other, but rather it is a vital medium that contains in addition to the mineral elements a variety of plant and animal organisms that play a major role in soil formation and development. They play an important role in the biochemical reactions that take place in the soil and that result in the transformation of Organic matter into humus and the preparation of nitrogenous materials necessary to feed plants. These reactions are activated when the natural conditions (heat, ventilation, humidity) are suitable for the activity of these organisms.

Try to track your sample in the course of dilution. That is how I do. In your case, you have 0.25g in 20ml solution. In the 1ml you took to dilute, it means you have 0.01g soil (0.25g/20ml). This is also the amount you have in your diluted 10ml solution, despite you added water to the 1ml solution to raise the volume to 10ml. Then, your ICP values were obtained using the 10ml, which is 0.01 L. In this 0.01L, you have 0.01g soil, meaning you have 1g soil in 1L solution. Now, if you obtain a result of, for example, 11.22mg/L Ca, it means you have 11.22mg/g soil or 0.01122mg Ca/kg soil. I hope this helps.

Hi Manar Naser,

This seems like the equation of the sinusoidal wave

where

fo is the initial amplitude at time (t=0) of the wave

Fa is the amplitude of the sinusoidal wave

Formic Acid maybe. It is used in LC-MS.

Check what the project at UC Santa Cruz is doing with their CALeDNA project at https://ucedna.com/

I did some sampling a few years ago, for that project.

It would surprise me if you can pH from spectral data, but it sounds interesting. Could you share some data? I could try and test some models with my software, see: www.lerenisplezant.be/fitting.htm

As per experience, we only did the extraction and PCR in our lab at the Soil Science Department in UPLB. We then did the DGGE at the Molecular Bio Lab of the Animal Science Department.

Thanks for your contribution

Dear Layth Saleem Salman Al-Shihmani ,

You asked an interesting question on the relationship between soil physical appearance and soil fertility. Allow me to proceed as follows:

For a soil to be said to be fertile, it must have a sustainable supply of the right quality and quantities of soil ameliorates which translate to nutrients. There are a number of physical parameters that might indicate fertility status of a soil cohort. However, these factors are not a guarantee that the soil is fertile.

Generally, black -dark colored soils are a positive indicator of the soil fertility status of the soil. They are good absorbers of heat which activates microbial activity hence soil biomass recirculation. This is a common case in 2:1 and 2:2 clay minerals which are generally good nutrient suppliers.

On the other hand,light-bright colored soils such as 1:1 Montmorillonites are generally poor nutrient holders due to poor heat absorption capacity, greater reflection thus poor nutrient churning capacity.

We shall all agree that this can be established by the naked eye.That,large grained soils are generally considered as poor nutrient suppliers as compared to middle grained soil such as Ferrasols,assuming all other factors remain constant. Average soil is directly proportional to water holding capacity, soil Rhizosphere aeration which in turn affects Biota Respiration.

Large grained soils such as sandy soils are loosely attached, prone to erosion. They are also poor water reservoirs due to increased percolation.

Related to point number 1 is vegetative cover. Material cover is directly proportional to soil nutrient fertility status. Such soils might have deeper top layer, zone A and B.A good covered soil shall harbor more soil microbes which accelerates decomposition.Humus,a product of decompostion,makes such soils appear much darker.

Whereas soil physical factors might an indicator of soil fertility status, farmers and researchers should be encouraged to do a completed soil laboratory tests. Some of the physical factors mentioned above could be as a results of other underlying causes such as parent material, soil pollution, environmental degradation etc. Instead of dealing with symptoms which might result to wrong diagnosis/prescription, I recommend soil laboratory analysis.

We can gaze qualitatively (high, medium, low etc.) about the organic matter content in soil according to the soil texture. But we can't quantify the OM content of soil on the basis of soil texture.

What fraction of values below BDL is acceptable.

Why are you making the measurements? The why determines what is acceptable.

If you are concerned about an upper limit, then BDLs are of no concern.

If you are concerned about a lower limit, it will depend upon the nature of your concern.

There is no recommendation. There is no rule of thumb.

You decide from the criteria associated with WHY if you have enough information.

Too many BDLs might mean you need a different technique, but it always returns to WHY.

If , say, a customer wants an answer at each location, use the actual result and note the uncertainty. The result is usually meaningless, because of the high uncertainty.