According to the article, in the experiment, Wang mixed in powdered dolomitic lime at various rates to the bark/perlite/sphag media before potting and didn't supplement it. After 14 months, he found that the media with 8-16 kg/m3 had a pH of 5.48-5.73 after starting at a pH of 6.18-6.25. The media without lime had a pH of 3.76 after starting at 4.17. The media with lime at 4 kg/m3 started at 6.05, but fell gradually to 3.95.
The lime upped the pH of the media when the plants were first potted and kept the pH in a reasonable range for 14 months.
The plants themselves at all concentrations used "had similar leafspan and leaf number," but "More plants with the highest lime rate produced flowers than those without lime." However, he, "did observe some plants with pale leaves at high lime rates as it was a concern of Larry M. Heuer in his 1977 article in the AOS Bulletin."
My only problem with the study was that it used Maudiae-type hybrids (Laser x Cherry Cider). The barbata species making up this hybrid's background generally aren't calcicolous and grow in acidic media. I'd like to see the study redone with calcicolous species or hybrids with mainly calcicolous species in their background.
--Stephen
source: Wang, Y. Special Report, How Lime and Fertility Affect a Hybrid Paphiopedilum. Orchids 74 (11):814-815, Nov; 2005.
p.s. for a list of calcicolous paphs:
http://www.slipperorchids.info/calcicolous.html