Question

vishti a kind of tax which was to be given in the form of physical labour was mainly forced on

Answer 1

It was mainly forced on;
-Artisans,craftsmen,&sudras
-Sudras & Vaisya peasant cultivators
-The whole village population

Answer 2

Vishti, a kind of tax which was to be given in the form of physical labour was mainly forced upon Peasants.

Katuliya also mentions the Vishti. But the Vishti was practiced during the Gupta and post-Gupta period. After the Gupta period, the shudras became peasants as well. So the state forced Vishiti upon shudra and vaishya peasants who had to work in the fields of kings and their fuedatories and for the army without any wages.