The veteran competitor left his tractor and plough in Europe after coming sixth in a field of 20 at the last world event in Estonia.
He arrived in Prague with fellow national representative Mark Dillion, from Southland, in early August to prepare for the two-day competition starting on September 5.
They managed to track down a training ground after finding farmers getting ready for harvest and since then have been running straight furrows in daytime temperatures of 30°C.
First impressions were the soils were similar to home country paddocks.
However, team reports indicate the "unforgiving" ground was showing the effects of dry conditions, last interrupted by rain several weeks ago.
Mr Mehrtens’ best result after many efforts on the world stage was runner-up in Kenya in 2017 and he will be aiming to top this performance in Prague.
The seasoned ploughman will not be a competitor [on the world stage] next year because he did not contest the national reversible championships this year due to his tractor being in Europe.
More than 60 ploughmen will compete in the stubble ploughing on day one on cambisol loamy to sandy loam soils in paddocks following winter wheat planted last year.
Mr Dillon is competing in the conventional class again after a repeat performance as the Silver Plough conventional winner.
He said Irish ploughmen would likely be the favourites again.
"The Irish are reigning champions at the moment, but you are competing against the best from across the world so there is stiff competition and everyone here has the same goal."
Republic of Ireland’s Eamonn Tracey, of County Carlow, and Jer Coakley, of County Cork, were both crowned world champions in their classes in Estonia last year.
Mr Coakley has returned for the reversible with Martin Kehoe replacing Mr Tracey in the conventional.
Mr Dillon said he had made modifications to his plough and would be looking to satisfy the judges after getting a feel of the different judging style at the Estonia contest.
The Riversdale cropping farmer was 17th in a field of 24 in the conventional class at Estonia last year. — Additional reporting Shawn McAvinue
