Trisiloxane ethoxylates (TSEOn) have been found in multiple agro-environmental media due to their pervasive application in agricultural production. While some studies suggested that the differences in the toxicological effects of TSEOn were closely related to their end-capping groups, the environmental behaviors and fate of TSEOn congeners with varying end-capping groups in agroecosystems remain underexplored. This study investigated the dissipation patterns of 39 oligomers across three TSEOn congeners in cucumber, leaves, and soils through field trials, including TSEOn-H (hydroxy, n = 2-14), TSEOn-CH