EARLTON, Ont. - Liberal Leader Michael Ignatieff and Ontario Premier Dalton McGuinty seem to have mended fences over tax harmonization.

The two Liberal leaders had a brief chat Tuesday about the controversial single sales tax at the International Plowing Match in northern Ontario.

McGuinty says he's satisfied that Ignatieff won't block the contentious tax scheme if he becomes prime minister.

The premier stirred up controversy last week when he said he had an agreement with Ignatieff that he wouldn't block the HST.

Ignatieff, who had derided the single tax as the "Harper sales tax" in B.C., was dogged for days about his position on the HST.

He finally cleared things up on Monday by saying a Liberal government wouldn't block the tax harmonization agreements the federal Conservatives have signed with the provinces.

However, the policy isn't going over well with some farmers who gathered at the plowing match, which is widely considered to be the biggest event of the year for rural Ontario residents.

The event attracts thousands of people each year, including federal and provincial politicians who take part in a parade before the festivities begin.

Ignatieff was heckled by a small group of unhappy farmers about the single sales tax as the Liberal float passed by.

John and Lee McIlwraith said they shouted at Ignatieff to stop the tax because they're concerned about the impact it will have on their cattle business.

Both Ontario and British Columbia are moving ahead with merging their provincial sales taxes with the federal GST starting next July.

The move will increase the cost of many items currently exempt from the provincial levy, including heating costs and fuel.

Ignatieff dismissed the heckling, saying it was the sole protest he heard about the HST during the hour-long parade.