With the weather swinging wildly from blistering sunshine to drenching rain, it was a busy opening day.
Over at the livestock section, RTÉ broadcaster Ryan Tubridy was taking his chances as he milked a cow.
"Amateur hour at the parlour," he admitted, before squirting the photographer with milk in pretty expert manner.
Also doing the rounds of the site in Screggan, Co Offaly, was new Garda Commissioner Drew Harris, shaking hands and receiving many best wishes from people telling him in a mutter that he "has his work cut out for him".
But he was doing no interviews, only making a beeline for the Garda tent where he chatted with officers.
Early to the Ploughing in his perfect country tweed suit, with Sabina in startling purple by his side, Michael D's campaigning was subtle and unofficial - but it was most definitely under way. He fitted in eight separate venues after lunch as the rain poured down in a relentless sheet.
He started with the horses "because that's where it all began", he later explained - remembering his granduncle Patrick who left Ireland for Queensland in Australia in 1862 and found employment as a ploughman. Michael D was not going to talk about the presidential campaign, insisted his press officer - but in reply to a question sprung unexpectedly, he made a brief, steely expression of intent saying that he was "looking forward" to the campaign.
"I'm very much looking forward to the campaign. I've never run away from a campaign in my life," he said.
And in case that wasn't clear enough, he added: "I've been delighted to have answered questions for 30 or 40 years in relation to campaigns."
And he called for "dignity", saying: "Let it be about real issues and let it be dignified."
"Fear uasal," was the verdict of Cian de Butleár from An Cheathrú Rua, Co Galway, after the President had met his daughter Córa (11).
Michael D gave his official opening speech from the bandstand, waxing enthusiastically about the need to support farm families and the particular problems they have suffered over the past year with the wet, cold winter, snow, followed by the heatwave and then Storm Emma.
He told us of the Wexford Star plough that lies in the grounds of the Áras as a symbol of the 1913 Lockout.
And then we noticed Seán Gallagher standing quietly in the wings, dressed not particularly for the Ploughing but in rather more businessy attire.
"He may stay there," breathed a farmer. "Your man here is in again."
Gallagher sang the National Anthem loudly and was quick to shake the President's hand afterwards, having positioned himself strategically.
"He thanked me for a note I sent him," he explained, saying it was to thank him for his seven years in the Áras.
He described the President as an inspirational figure, but felt it was time for "something new and fresh", adding that he did not want to replace Michael D - but that he did want to be his successor.
He claimed it had taken him "more than an hour to walk 300 metres" because of all the people queuing up to meet him.
Gavin Duffy was also doing the rounds, resolutely dressed for the Ploughing in stylish Dubarry leather boots.
"They're not new but they're good," he said, jutting an ankle: "Aren't they nice?"
He said he believed he was "the only candidate who wears wellies a lot" and that though he was known as a businessman, his roots lay in farming.
Sadie Lenihan from Killarney, Co Kerry was a big 'Dragon's Den' fan - but would she vote for him?
"I don't know. I'd have to hear his policies," she considered.
Catherine Plunkett and Maureen Herley from Tullamore, Co Offaly were 'Den' fans too - but also of Michael D. "He's certainly done us proud. But his age is against him," said Catherine.