Dear Muthucumaran:

Yes, soil bulk density is affected by soil water content. The physical reasons are evident. You can conduct laboratory experiments using undisturbed soil samples collected in containers with known volume at different water content. You can then correlate BD versus WC. However, be careful with expansive clay soils (for example Vertisols).

Cheers Dr. Millan

Yes I agree with Dr. Humberto Millan that  bulk density is affected by the moisture content of the soil.

Hi Sugirtharan,

yes I agree also with Dr. Humberto Millan and Arvind Singh, but I would describe it converse: the bulk density has an affect on the water content. May be not at the total water content because you weight your soil sample and the bulk density will be determined on an oven-dry sample with know volume. But on the distribution of the

drainage water (from the coarse pores or air filled pores)

plant available water (in the small coarse pores and medium pores)

not plant available water (in the fine pores).

Bulk density of soil is affected by soil compaction, tillage and pedogene effect  ...

With best regards from Osnabrück, Stefan

Dear Muthucumaran,

An interesting question. The impact of soil moisture on the bulk density depends on whether you mean dry or wet bulk density. As Dry bulk density = mass of soil/ volume as a whole and Wet bulk density = mass of soil plus liquids/ volume as a whole, so soil moisture has an impact on the both bulk density. However, I believe that the impact on the wet form is greater since it has the soil moisture on numerator and denominator.

The experiment you mentioned above has been done by several researches and ultimately create equations to calculate bulk density. Hence, you can easily find the impact of soil moisture using these questions.

Hope it helps,

Amir

In general bulk density means mass dry soil divided by bulk volume of soil. Therefore, moisture content has nothing do it. Bulk density is used to calculate the soil porosity. so we should not take moisture content into consideration in determining bulk density. 

Any book on Soil Physics can help. 

Dear researchers, Thank you for the valuable answers

Wet bulk density is a parameter interested to scientists and engineers involved in sedimentology, civil engineering… Wet bulk density is affected by moisture content.

For professions relating to agriculture, forestry, soil science/soil fertility, agronomy, Dry bulk density is what matters.  Moisture content has no influence on dry bulk density except in swelling clay.

thank you very much.

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Dear Muthucumaran Sugirtharan

The density of the soil depends on its humidity. There are numerous works in which graphic representations of this addiction are published, which vary depending on the type of soil and other characteristics. For those who study energy consumption in soil cultivation, the dependence of soil density on its humidity is part of an optimal research.

With great respect,

Cardei Peter

Dear Muthucumaran Sugirtharan, soil moisture has an influence on the rest of the physical, mechanical and hydrophysical properties of the soil, the element with the greatest influence on mechanical resistance, as it directly conditions its cohesion and intergranular or interparticle friction. Within our contributions you can locate various papers where this aspect is answered in various types of soils.

yeah sure i too agree with you all that moisture content is determinant factor for bulk density as is affect by many direct and indirectly affected by soil structure and properties.

Take a look at this useful RG link.

Article Soil moisture and its effect on bulk density and porosity of...