Atkin, Muriel. "Tajikistan: Status of Islam Since 1917." Encyclopaedia Iranica Online (July 20, 2005), http://www.iranicaonline.org/articles/tajikistan-01-status-of-islam-since-1917.

Muriel provides a short overview of Islam in Tajikistan from 1917 to 2005.  While her review of the post-Soviet period discusses mostly political aspects of Islam, her discussion of the Soviet period does review popular Islam as in the following quote:

Despite the Soviet regime’s efforts to eliminate religion from the public’s consciousness, some measure of Islamic practice and belief survived among the indigenous inhabitants of Tajikistan. Given the political constraints, there are no reliable public opinion surveys that show how many people considered themselves Muslims or the degree to which they were observant. Still, some people continued to pray, observe the Ramadan fast at least partially, celebrate major religious holidays, and perform life-cycle rituals (Atkin, 1989a, p. 25). Even though there were few legal mosques in the republic, people contributed money to build unregistered ones. They adapted other buildings, such as teahouses and clubhouses, for use as mosques, sometimes festooning them with photographs of Soviet leaders and placards bearing Soviet slogans to camouflage the places’ religious function (Atkin, 1989a, pp. 13-15). By the early 1980s, there were said to be more than 1,000 covert mosques in Tajikistan. Believers also went to pray at saints’ tombs and numerous natural settings that had a popular reputation as holy places. Pilgrimages to religious sites converted to secular use by the Soviets could be disguised as tourism (Atkin, 1989b, p. 615). Family dwellings provided a venue in which unregistered Islamic figures conducted ceremonies and preached (Atkin, 1989b, p. 612). Folk Islamic practices, including Sufism, played an important role in sustaining religion among ordinary people (Atkin, 1989a, pp. 23-24).
Covert religious instruction existed apart from the two legally recognized facilities in Uzbekistan. Families were an essential venue for passing on knowledge of Islam from generation to generation. Some families managed to preserve religious books despite Soviet campaigns to destroy them and used these in the religious instruction of their children (Subhon, p. 4; Atkin, 1989a, p. 32). Family-based instruction usually covered the central tenets of the faith, some prayers, and the rites associated with the main holy days. In addition to the dissemination of religous information within families, mullahs taught small groups of local children in underground schools (Atkin, 1989b, p. 612).
Descriptors: 2000s, A, bibliographic, e-article, history, overview, post-Soviet, Soviet, Tajikistan