Hi Sakalya,

Are you working on peat soils? Anyway, I try to make things clear. As to details, check my paper.

Liu, H., & Lennartz, B. (2019). Hydraulic properties of peat soils along a bulk density gradient—A meta study. Hydrological Processes, 33, 101– 114. https://doi.org/10.1002/hyp.13314

1, dry bulk density=mass of dry soil/Volume of the soil core. Therefore, for bulk density, the only thing you need is the dry mass of the soil (oven dry for 24 hours at 105 ℃ ). It has nothing to do with the soil moisture or saturation.

2. Total porosity=volumetric water content at saturation=BD* (soil moisture by weight)=BD*(weight of water/weight of dry soil).

So, just measure the soil weight at full saturation and dry weight (oven dry for 24 hours at 105 ℃). The diffence of the two is water weight.

3. I think you mean available water capacity. This parameter is the difference between water content at -60 cm H2O pressured head and -15850 cm H2O pressure head. As far as I know, water content at -60 cm H2O pressure head, you can estimate it using drainable porosity, drain soil core for certain time (please find the litrature). But the wilting point differs between peat types varying from 5vol% to 30vol%.

I suggest you read a soil physics textbook.

If you have any further questions, contact me at [email protected].

Best wishes

I have a large dataset, if you really can not measure the soil water retention curves of other hydraulic parameters, you can use the functions I generated (Liu and Lennartz, 2019; Liu et al., 2020).

Article Hydraulic Properties of Peat Soils along a Bulk Density Grad...

Article Centennial-Scale Shifts in Hydro-Physical Properties of Peat...

Or if you can tell me the BD values, I can provide you a comparable data vlaues for modeling. If the soil bulk density is greater than 0.2 g cm-3. You can use the soil water retention curves I generated. Good Luck.

Dear Haojie Liu Thank you for the detailed answers.

I'm working on burnt rice hull and cedar bark media. I measured their dry bulk densities as you recommended (which was around 0.09- 0.1 gcm-1)

However, the text book I'm referring (mentioned above) suggests taking wet bulk density at a specific pressure. That is why I was wondering.

Anyway, we have a pressure chamber, can I use it instead of a pressure plate?

Thank you for your suggested papers. I will go through them.

Thank you very much!

Haojie Liu , Moreover I calculated the total porosity of some samples through particle density I measured using the pycnometer method (using a volumetric flask). Does it differ from the way you suggested?

Futher, my main concern is that obtaining the saturation point without a pressure level. Since I couldn't find any literature about a method on draining for a certain time.

Hi Sakalya,

1. I read that Chapter again, it is dry bulk density,

BD=SDW/V, SDW is the dry weight of the sample. So, for bulk density determination, you need not consider others.

2, The pressure chamber is the same with pressure plate. You can use it. But double check the pressure range of the pressure plate.

3, you are right, the porosity= 1- BD/Particle density. If you can measure the particle density, then it is fine.

Best

Sakalya, what it the application of rice ash and cedar back media. Does it have some cementitious properties that I can use in a road project. I am directing the questions to Prof. Liu and you Sakalya.

Dear Prof Haojie Liu thank you very much for your answers. It clarified my understanding of many analysis.

Kiprotich Kiptum, Sorry, I don't have any idea about their cementitious properties. I'm using them as growing media