This farmers' market is a cash-heavy environment where digital payments are rarely accepted.

cash-heavy 是由名词 cash（现金）和形容词 heavy（重的、大量的）组成的复合形容词，字面意思是"现金很重的"，引申为"以现金为主的"或"现金交易频繁的"。 cash-heavy environment 指的是"以现金交易为主的环境"。