I was surprised to find Mari pajə̑rka, pə̑jə̑rka and Chuvash payarka ‘small amount’ in Agyagási’s set of shared Mari–Chuvash lexical material of unknown etymology (“Der sprachliche Nachlaß der Spät-Gorodec Bevölkerung in den tschuwaschischen und mariischen Mundarten”, 2000). The words seemed to me like straightforward borrowings of Russian поярок known from Dal’ and glossed ‘шерсть с ярки, первой стрижки, с овцы по первой осени’. When lambs are shorn for the first time, they produce a quite small amount of wool, and the example sentences that Beke’s dictionary gives for Mari pajə̑rka suggest the word was mainly applied to small amounts of material (wool/straw/bast), and so one could readily propose a semantic development ‘small bundle of wool’ → ‘small bundle of any material’ → ‘small thing’.
Agyagási’s ascription of the word to an unknown Middle Volga substrate had the consequence that, first of all, the word was overlooked in her later work Ранние русские заимствовния тюркских языков Волго-Камского ареала, and secondly, the editors of Tscheremissisches Wörterbuch only marked these Mari items “[~ Tschuw.]” I began writing up this Russian loan etymology with publication in mind, so I was rather disappointed to find the etymology had already been presented as an aside in Rédei & Róna-Tas’s 1983 paper “Early Bulgarian loanwords in the Permian languages”, though at the same time it is nice to see my hunch confirmed.
On p. 37 of the article, the authors discuss the mistaken comparison of Komi parga ‘in der Flachshechel zurückgebliebener flockenförmiger, reiner Abfall vom gehechelten Flachs’ with Chuvash parga ‘Büschel’. They write:
The Chuvash parga (Zolotnickij, Čuv.-russk sl.; Paasonen, Csuv. szój) ‘heap, bundle’ is a dialectal form: more exactly, the word is paŕga (Ašmarin IX, p. 117) and is the equivalent of the payărka of the literary language. This word exists in Cheremiss (pajə̑rka, pə̑jə̑rka, Räsänen, Tat. Lehnw., p. 88 Cher. ← Chuv., Etym. Wb., p. 378 Cher. → Chuv.), and also in Tatar (dial. payarka). These words are adoptions of the R poyarok ‘šerst’ jagnjat (pervoj strižki)’ (Vasmer III, p. 351) and the semantic development is ‘small heap of wool’ → ‘small heap, bundle’ (Cf. Cher. miž-pajə̑rka ‘ein wenig Wolle’).