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.

Re the bulk density, you refer to the dry bulk density or fresh bulk density? I think the value is reasonable if you weighed the soil sample for density calculation after drying.

Generally, loose, porous soils and those rich in organic matter have lower bulk density. Being forest soils, it might have high organic matter, that might have resulted in low bulk density. In western ghats region, we used to get around 1.00, even which is lower that ideal 1.33. Sandy soils have relatively high bulk density since total pore space in sands is less than that of silt or clay soils. Finer-textured soils, such as silt and clay loams, that have good structure have higher pore space and lower bulk density compared to sandy soils

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.

Kishan Bao - bulk density is measured after weight being tat of the oven-dried samples

Surrendra Udayar Pillai - the sample is visibly fine sandy silt, and disturbed by grass roots observed during the sampling, and the sampling area is a man-made community forest under social forestry scheme by the forest department in the lower Gangetic plains.

Dr. Dilip Kumar Pal - Soil organic carbon is yet to be analysed in the laboratory, only the weight is taken of the oven-dried samples, and sampling procedure is followed by the standard methods

As suggested by Dr Dilip Kumar Pal, it has to be done using core method and to confirm, may be it needs to be done in several replicates. Kindly check for SOC also.

Soil organic carbon is yet to be analysed, then it would be more prominent for further interpretation

Generally, the bulk density of a compact soil is greater than the loose or sandy or organic soil. Usually, the forest soil is an organic soil, so its bulk density will be lower. However, the obtained results might be ok.

Thank you Mr. Gautam Kumar Das.

Md. Abul Kalam Azad - Forest soils differ for its different topographic and physiographic set up of the forest floors particularly in West Bengal, as this state of India has the diversity of geographical location from the mountainous terrain of the Himalayas to the coastal areas of the Bay of Bengal, as well as, Gangetic alluvial deltaic plains, plateau and Barindh region and in all these geographical areas, forest stands exist, naturally physico-chemical characteristics and nature of the forest soils are different from each other, that reflects the different values of bulk density as I have analysed forest soils of most of the forest stands, but the value of bulk density of a particular soil sample for a community forest studied for this time astonished me with such a low value, such value for a soil sample of the forest floors stood in the Gangetic alluvial plains is quite rare, never found in my previous studies, even for the remaining samples collected from the same forest floors maintaining a distance of 500 meters.

Bulk density (BD) may vary on the basis of forest types (i.e. coniferous or broadleaf) since they have an implication for organic matter accumulation under the forest floors.

Regardless of the forest types, your BD value 0.81g cm-3 within the range......0.39 to 1.39 g cm-3.

Link:https://www.google.com/search?sxsrf=ALeKk03q67otz8HYZgZeLcFfP0IMccI02A%3A1607188220863&ei=_L7LX7iZNM-M1fAPyfyK6AM&q=forest+land+bulk+density%3F&oq=forest+land+bulk+density%3F&gs_lcp=CgZwc3ktYWIQAzIHCCMQ6gIQJzIHCCMQ6gIQJzIHCCMQ6gIQJzIHCCMQ6gIQJzIHCCMQ6gIQJzIHCCMQ6gIQJzIHCCMQ6gIQJzIHCCMQ6gIQJzIHCCMQ6gIQJzIHCCMQ6gIQJzoECAAQR1DF-VNYh5dVYNGYVWgBcAJ4AIABAIgBAJIBAJgBAKABAaoBB2d3cy13aXqwAQrIAQjAAQE&sclient=psy-ab&ved=0ahUKEwi4h_fXqrftAhVPRhUIHUm-Aj0Q4dUDCA0&uact=5

Gonfa Kewessa - it's the fact that the BD value is within the range, I am just thinking about the low value for the alluvial soils of the forest floors stood in the lower Gangetic deltaic set up, that's all.

Gautam Kumar Das

A soil bulk density value of 0.81 g/cm3 particularly for an alluvial soil is certainly not normal. It is very low. Soil bulk density values of less than 0.90 g/cm3 are common for young volcanic ash soils (Andisols or Andosols) due to the very high soil porosity brought about by the abundance of non-crystalline (amorphous) clay minerals. I suggest that you check again the core sample collection procedure.

Victor B. Asio - you are right, even with the abundant occurrence of soil organic matter in the samples, the bulk density value 0.81 g/cubic centimetre for alluvial soils any how does not show a normal look for the community forest soil sample

In fact, porosity is directly related to bulk density. High bulk density is desirable and is weight of a volume unit and is expressed as g/cm3 / kg/m3 or g/100 ml. Bulk density of 1.6 g/c3 restricts root growth; the same for sandy soils ranges between 1.3 to 1.7 while fine silts and clay is in the range of 1.1.-1.6 g.cm3. Understandably, bulk density increases with compaction.

Dr. A K Shyam - the sample containing low bulk density is physically silty by nature, is there any relationship between silty soils and bulk density ?

This bulk density value of 0.81g/cc translates to a total soil porosity of 69.43% assuming a particle density value of 2.65g/cc. This value is too high for young alluvial soils.

Luz G Asio - Are you sure that the bulk density value of 0.81gm/cc is too high for young alluvial soils of the Gangetic deltaic set up?

Dear Dr. Gautam Kumar Das

Yes, this is the general trend for alluvial soils in different parts of the world (World Soil Resources Report 94, 2001; Soil Taxonomy, 1999). The explanation for this is that alluvial sediments contain mixtures of primary and secondary minerals (3 layer silicates). Exceptions are the acid sulfate soils (Thionic Fluvisols) and organic soils (Histosols) which may have bulk density values as low as 0.6g/cm3 for acid sulfate soils, and 0.1g/cm3 for organic soils. Your study site may of course be different or unique. It is possible that your bulk density values are true values. You only need to double-check if everything went perfectly from sampling in the field to the measurement in the laboratory. Best regards. --Luz

The following is the range and you may please check with reference to this, please.: Clay, silt loam - 1.4-1.55; Silty clay, silty clay loam, silt - 1.4-1.5; clay loam 1.45-1.55; loam 1.45-1.6; sandy clay 1.55-1.65; sandy clay loam 1.55-1.75; sandy loam 1.55-1.75; loamy sand, sand >1.75 ( Ref. Harris 1990 and Morris and Lowery 1988)

Dear Luz, I thought of alike you particularly when I sampled the soil, it's physically supposed like very young with a touch of very tiny and minute organic matter, still I must recheck by sampling from the same spot of the forest floors as per your suggestions, convey my cordial thanks - Gautam

Dr. A K Shyam - I really don't have the idea about the ranges of Bulk density before as I have been working on the sediment textures, Sedimentary structures and other fields and features on Sedimentary environment, but the soil is the new field to me which is comparatively stagnant and older than that of the sediment, naturally, the ranges of Bulk density communicated from your end must be helpful for the further development and progess of the work in the field of forest soils, convey my thanks and regards.

Jeżeli gleba składa się głównie z części organicznych i dodatkowo podczas określania gęstości nasypowej jej wilgotność jest niska (poniżej 20%), to gęstość zawsze będzie poniżej wartości 1g/cm3. Jest to cecha charakterystyczna gleb organicznych, silnie porowatych o niskim stopniu zmineralizowania. Osobiście badam podłoża do produkcji sadzonek, które zawsze są w większości organiczne i ich gęstość nasypowa zależy głównie od wilgotności i stopnia kompresji.

Przykładem może być poster który zamieszczam poniżej:Poster Gęstość objętościowa i zwięzłość substratu torfowo-perlitowe...

Lukasz - do you please communicate your thoughts in English, I can't follow up your write up

If the soil consists mainly of organic parts and, additionally, when determining the bulk density, its moisture content is low (below 20%), the density will always be below 1 g / cm3. It is a characteristic feature of highly porous organic soils with a low degree of mineralization. Personally, I research seedling substrates, which are always mostly organic, and their bulk density depends mainly on moisture and compression.

That is, if the organic soil has low moisture, the bulk density is often lower than 1 g / cm3. Increasing the humidity and compaction causes the approach to the value of 1 g / cm3.

The content of minerals, sand, dolomite dust ... exceeds the value of 1 g / cm3.

Lukasz - right you are, you have nicely highlighted the importance of moisture content in the soil samples that might have controlled the value of bulk density of soils, and it's true that the BD value is low for the soil samples of low moisture content, I appreciate you to remind me such an important role of soil characteristics controlling the bulk density, convey my cordial thanks

Your welcome. I'm glad that I helped ;-)

in Polish:

Proszę bardzo. Cieszę się że pomogłem ;-)

In Polish, I can't even pronounce it, though meaning is translated as you mentioned, thanks

Researchers suggested the core sampling method is needed for obtaining accuracy of the value of bulk density, the bulk density is determined using soil core sampler having a diameter of 5.7 cm, is there any other methods of soil sampling for the analysis of bulk density?

To test the bulk density, you need a container in which to determine it, and you only need to know its capacity and the mass of the sample filling it. The tested material can be downloaded freely, depending on what we want to test. If we test crushed material, we take crushed samples. If we want to test loose, loose material, we have to crush it. We define the mass or the bulk or bulk density for the assumed material size reduction. What we take samples is important only when the fragmentation is to be small. The loose mass depends on the size of the sampled particles. The ideal bulk mass comes from a sample grounded to the atomic scale ;-)

I personally determine the mass and bulk density using a standard cylindrical container with a diameter of 10cm and a height of 15cm and a laboratory scale with an accuracy of 10mg. Cover the container (2) with the loose material to be tested until a dumping cone is obtained, then remove the excess with the scraper (1) flush with the upper surface of the container.

The method of collecting and preparing the sample determines the bulk mass, so we always either assume the degree of fragmentation of the sample or adapt to the requirements of the person ordering the test ;-)

Lukasz - You are right, basics of the science is to be considered first, followed by the methodology