Dear Researcher, please let me know can bulk density of soil determine in the lab with air dry soil packed in to ring? Thanks
Please check the following link.
https://www.quora.com/What-is-the-most-suitable-laboratory-test-to-determine-bulk-density-and-moisture-content-and-dry-density-so-as-to-evaluate-degree-of-comapaction
Dear Manoj, you can do that, but according to my experience, it is better to remove the soil packed inside the ring, dry it in the oven and then weight it again.
I hope this answer will help you.
Best wishes,
Antonio Guerra
Dear Manoj,
Please follow the method mentioned in this PDF attachment.
Good Luck
Dear Manoj,
You can do what you have suggested in the lab and as Arvind has pointed out you can use lab methods to determine the relationship of achieved bulk density with moisture content to work out at what moisture content you can achieve maximum compacted density. This is useful from a geotechnical point of view (when you want to minimise hydraulic conductivity for example or increase bearing capacity). From your workplace however, I assume you are interested in soil physical conditions for plant growth and thus your interest in bulk density is related to soil quality (soil compaction and potential impedance of root growth or oxygen/water transport). If you are interested in soil physical quality for plant growth, the measurement of a bulk density on a reconstituted core made from air dried soil is not going to give you a good estimate of field bulk density and will not help you rate the soil in terms of likely restriction to root growth. It may be able to give you some idea of how susceptible it might be to compaction, but little more. Field methods (either in-situ using volume replacement methods or collection of intact cores) are your best choice.
Dear Manoj Kumar,
See EUROPEAN PHARMACOPOEIA 5.0 (BULK AND TAPPED DENSITY page 65) ;
Please check attached doc.
Good luck.
Best Reagrds
M. Ouhsaine Morocco
Dear Manoj,
Do you mean that air-dry soils collected from field are first brought to laboratory and packed in the ring (in the laboratory) for determining bulk density? That is not the correct procedure. You have to collect the undisturbed soil core from the field using the metal ring, bring that to the laboratory and follow the steps described in 1.pdf provided by Dr. Arvind Singh.
Wish you correct measurements of bulk density of your soils.
You can determine in lab by using Keens Cup method. Keens cups are available in agronomy/soil science/agri. physics lab. take the soil samples and mix thoroughly, assure that it contains sand, silt and clay. Place the filter paper in keens cup, pour the samples and add water upto the neck. alternatively take water in the plastic tub and place the keens cups in the water ensures bottom of the keens cup should touches the water. Then measure the volume of the keens cup using PAI r2 H (sorry PAI symbol is not coming). Then take the oven dry weight of the samples. you can also determine moisture holding capacity, pore space and particle density for the keens cups.
Thank you very much all of ..for you valuable information....
Dr. Dilip, However, we have collected undistributed soil cores 10cm depth samples from the field using agar for several experiments as well as bulk density. Samples are air dried at room temperature for 48h and sieved 2mm and again left for air dry for 24h. Now, air dried soil are packed in to metal ring with 25-30 tapings up to top of fill.
Dear Manoj,
you collected undisturbed soil core from field but subsequently you crushed the soil mass to pass through 2 mm sieve. So it is no more undisturbed. If you repack the processed soil samples in metal rings with tapping for determining bulk density, your recorded b.d. values will not be the actual b.d. of field soils. If your objective is to determine b.d. of the soil, you must determine it using undisturbed core only.
Sometimes our objective is to determine hydraulic conductivity of the soil (using constant head method). In such cases, we need to reconstruct soil core/ column in the laboratory (adjusting bulk density of the packed soil nearer to normal/ field condition) and pass the water through those cores/ columns to estimate hydraulic conductivity (rate of leaching of water per unit time). Bulk density of re-packed soil cores is not actual/normal but nearer to normal.
Hope I have explained the point clearly.
i was worried about the same things but i found my solution from watching countless you tube channels on soil analysis. hope it helps
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