System for adjusting the depth of a trench opened by a row unit (10) of an agricultural planter. The row unit (10) includes a trench depth adjustment assembly (90R) configured to modify the trench depth. The trench depth adjustment assembly (90R) includes a depth adjustment body (3044) pivotally connected via a pivot (92) to a frame member (14) of the row unit (10). An electric motor (3030) is operable to cause rotation of a shaft (3034) operably coupled with the depth adjustment body (3044), whereby rotation of the shaft (3034) causes the depth adjustment body (3044) to pivotally move about the pivot (92) thereby changing a position of contact of the depth adjustment body (3044) with a gauge wheel arm (54), thus changing the amount of upward travel of the gauge wheel (50) with respect to a trench opening disc (62) and thus the depth of the trench.