On a volume basis, water content is expressed as volume per unit total volume of the soil. The mode of expression is useful for calculations of water transport in soils for irrigation and drainage investigation.
Hi Peter,
Indeed soil water in volume unit is more common used in Hydrology and related researches. Soil can keep water until saturation, and the ability to retain water strongly depends on particle size and soil structure. Retrieving satellite-based microwave soil moisture is much easier than dry mass, although there are not big difference in artificial measurements of soil water/dry mass. Additionally, I think soil water is much easier to be accepted by people. Higher soil water values indicate much more available water in soil, yet it is weird a little bit if people see the values for dry mass.
Hope it is useful for you!
Jifu
The volume basis is directly applicable to compute fluxes in water balances (irrigation, evapotranspiration, rain and others). volume ratio is equivalent to depth ratio of soil water.
Volume basis has more relevance , since it takes into account the bulk density and porosity of the soil as well...
Both gravimetric and volumetric water content data provides unique information about the soil being studied. I think they complement each other, however, depth ratio of water per unit depth of soil is more convenient for agronomic purposes.
If we are talking about soil water, soil water is expressed in three ways: Volumetric basis (v/v), Mass basis (w/w) and Equivalent depth (mm or cm or m). It is your preference, the instrument you use, the study/application areas of soil water that determine which method of expression to use. In irrigation, depth could be the most convenient to express soil water. In general, as water is measured in volumetric units (m3 or cm3 etc), we need to convert from mass or depth basis to volumetric units. Volume =Mass * App. specific gravity
Volume= Depth * irrigated area
Hence, a volumetric method is simple /easy for understanding for all people outside of the subject area whether they are educated or not.
- Badges
- Science topic
- Similar topics
- Agricultural Science
- Environmental Science