Salinity in the growndwater is due mainly to: a) geochemical degradation of the material underneath and b)quality of the soil through which water travels before reaching the water table. The later is more evident in shallow soils where the aquifer is closer to the surface. Overdraft by pumping accelerates the process.

As the salinity of groundwater is mainly due to the quality of soil above it, can we calculate the salinity of soil profile using the salinity of groundwater through an inverse solution?

Salinity groundwater can be affected by type of soil above the water. if the soil is have Sodium salt or other kind of salt and it has washed up by rain or by Irrigation, and the ground water can be reached from that washing it could be affected

Physical-based answer is that if your problem is a bare soil under steady state condition, let's assume with constant evaporation rate, then the salinity from the water table up to a few cm from the top soil, will be of the ground table. Due to evaporation the salinity of the top soil will be higher, depend on the evaporation rate, soil texture etc.

Nice Question, basically salinity of an particular place directly depends upon the geologic condition of that particular landmass, during various process beneath the soil surface the salt gradient in the groundwater table may increase or decrease. Than the physical chemical and biological means of alterations in the salinity level, seeping from various actions and activities also increase the salt concentration at that particular site.

the salinity of the ground water table directly related with the type of the soil, geomorphology too.

Dear Amir, It is better to find how the groundwater is being recharged and the sources of soluble salts in the groundwater. What is the annual average rainfall and ET?

If the aquifer is closer to coastal area, it may be due to sea water intrusion. Lowering of groundwater level by discharge or heavy pumping or may induce the sea water intrusion.

If it is not closer to the coastal area, the upper soil profile can play a role in different ways. A test for Leaching requirement (LR) may explain the influence of the soil. LR is a ratio between the electrical conductivity (EC) of adding water and drain water through the soil profile. Higher evaporation also causes salinity.

Mowjood

Yes, their is highly correlation between the salinity of the soil and the ground water below, because the salinity of ground water due to 1) the composition the minerals in the rocks which the water percolation in it and dissolve the salts 2) the soil type and its salinity (Ms cm-2), 3) pumping rate 4) water sheds 5) infiltration from saline water

interesting question, but there can be or not be any relationship. The relationship can be quite good but also very minor. Point of course is that as soon as water gets into the equation all will alter. In case you have a good relationship but irrigation water is added from above the relationship may be gone. Or if water comes from below due to rising groundwater tables to top soil salinity may alter. I agree thus an interesting question, but the major point is what do you like to know? If you can estimate the one from the other? Over what time frames? etc. These issues should be clarified before one can address the question posed.

Interesting answer Sir @John Lamers.

In this reference, I like to draw ur attention to my current study. I have done soil salinity analysis and Groundwater analysis for a area, but evidently the saline soils are not exactly superimposed for saline groundwater.

NOTE: The groundwater samples collected mainly belong to shallow dug wells. And Most of the area is fed by river water. My belief is the saline dug wells are acting as SINKs. And mechanism for this unrelated behavior is   agricultural return flows and their quality.

SIR, how can I justify the reasons for distribution of saline and no saline sources in area of say 100 sq Km, and their relation to some of saline areas.

Any clues, like DEM-flow accumulation Index,

Rest of the parameters as crop types, agricultural practices, soil nature, clay content (texture) being same.

Need a method for reclamation of saline soils? Are there modern methods to prevent salinity? Soil changes?

Basically salty ground water makes secoundary salinization. Secondary salinization mostly occurs in low-land areas , where groundwater frequently rises up through the soil profile and the salt lying dormant in the soil mantle dissolves and finally causes salinization of the sub and surface soil by capilary action. In fact, water table depth, is another prime discriminator of saline discharge in the low-land areas. for more Information, I refer you to "Stavi, I., Thevs, N., & Priori, S. (2021). Soil salinity and sodicity in drylands: A review of causes, effects, monitoring, and restoration measures. Frontiers in Environmental Science, 330". , Moreover, please find in attached a Schematic illustration of Capillary action and saline formation in Bajestan Playa, Iran that we are now working about.