Sources
Brent Rouppet, PhD, is a Sacramento, CA based agricultural consultant with over 20 years’ experience in soils and irrigation on three continents. He is the owner of Fertile Soil Solutions, LLC (fertilesoilsoluitons.com).
Garn Wallace, PhD, is a biochemist and agriculture consultant, and owner of Wallace Labs, El Segundo, CA (wlabs.com).

Endnotes
1 Chen, Liming, and Dick, Warren A., Gypsum for Agricultural Use, 2011, The Ohio State University, Bulletin 945
2 Shainberg, I; Sumner, M.E.; Miller, W.P. ; Farina, M.P.W.; Pavan, M.A.; and M.Y. Fey Use of Gypsum on Soils: A Review 1989 pp. 1-111, Advances in Soil Science, vol. 9. Springer-Verlag, New York.
3 Chen and Dick, 2011
4 Shainberg et al, 1989
5 Chen and Dick, 2011
6 ibid.
7 Norton, L.D.; Shainberg, I.; & King, K.W., Utilization of Gypsiferous Amendments to Reduce Surface Sealing in Some Humid Soils of the Eastern USA, 1993, Soil Surface Sealing and Crusting, Catena Supplement 24:77–92.
8 Shainberg et al, 1989
9 Chen and Dick, 2011
10 ibid.
11 ibid.
12 California Department of Resources Recycling and Recovery (CalRecycle) https://www.calrecycle. ca.gov/condemo/wallboard
13 Klimchouk, Alexander, The Dissolution and Conversion of Gypsum and Anhydrite, International Journal of Speleology vol. 25 3/4, 1996