Notts County slumped to their ninth post-war relegation as their late-season slump continued.
Vale took a grip on the game throughout the first-half in which they scored twice, both concessions underlining County's defensive frailties which have seen them concede 76 goals.
Vale, who needed the points to have any chance of finishing in a play-off place, were on the mark as early as the fourth minute.
Notts failed to cut out a long throw by visiting captain Sam Collins, Steve Brooker flicked it on and Steve McPhee finished at short range.
Just past the half-hour mark, Vale doubled their advantage with a gift goal. Goalkeeper Saul Deeney, making his first senior appearance for Notts this season, threw the ball tamely into the path of Mark Bridge-Wilkinson who transferred to Brooker for a decisive finish.
Either side of Brooker's goal, Notts own Steve Scoffham missed with two great chances which could, and should, have hauled his team back into the match.
He was wide on both occasions, first on 15 minutes after a good run down the left flank by Paul Heffernan and then a minute before half time after getting the better of two defenders on the edge of the box.
Notts were booed off at half time and the fans' displeasure was matched by that of manager Gary Mills, who replaced Matty Williams, Simon Baldry and Frazer McHugh, all of whom had made a negligible contribution.
Notts put up a more spirited show in the second half, Scoffham getting on target to force a fine save from Jonathan Brain.
Yet the clearer chances continued to fall to Vale for whom Billy Paynter headed against the inside of a post and Brooker shot tamely wide with a clear opening.
Notts had to wait until stoppage time for Heffernan to claim his 20th league goal of the season, a personal record but scant consolation in view of County's fate.
Mills, who was appointed in January, said afterwards that Notts had flirted with relegation for three seasons and this was the inevitable outcome with a playing staff which was not good enough.
He promised a big shake-up during the close season. His team have won only once in the last ten matches.
Captain Ian Richardson said it was a sombre Notts dressing room, with all the players disappointed.