Please check the following link.

https://www.researchgate.net/publication/5881465_In_Situ_Soil_Water_Extraction_A_Review

Article In Situ Soil Water Extraction: A Review

ftp://ftp.fao.org/agl/agll/docs/misc28.pdf

http://manuals.decagon.com/Application%20Notes/UMS_Soil-Water-Extraction-Methods.pdf

- Intercomparison of soil pore water extraction methods for stable isotope analysis

Natalie Orlowski, Dyan L. Pratt and Jeffrey J. McDonnell

HYDROLOGICAL PROCESSES Hydrol. Process. 30, 3434 – 3449 (2016)

Dear Arvind, Firoz, and Issam. Thank you very much for your suggested bibliography.

Firoz, thanks for those manuals, unfortunately, in my context (semi-arid) vacuum methods don't work (soil water content usually below 5% for most of the year).

Arvind, I found this paper very nice and I think it will help me in some other studies. But I'm afraid they are not suitable for soils as 'dry' as the ones I'll study.

Issam, the paper you sent me is very useful! It also opened my horizons for further references. I guess the vapor equilibration method is the most suitable for my context.

By now I found a couple of interesting papers on the specific topic of soil water extraction for isotope analysis I think might be useful and/or interesting. Here I list them:

Review on soil water isotope-based groundwater recharge estimations (pages 2817–2834) Version of Record online: 13 APR 2016 | DOI: 10.1002/hyp.10775

Kindly,

Guilherme Sobrinho.