The Westcountry MP handed the Government's farming brief has vowed to deliver a "fair deal" for rural communities and agriculture.
David Heath, Liberal Democrat MP for Somerton and Frome, secured the promotion as part of major change at the top of the Department for Food, Environment and Rural Affairs (Defra).
Mr Heath, a former Somerset County Council leader, has replaced Jim Paice as Farming Minister. Former Northern Ireland Secretary Owen Paterson will be in charge of the department after Caroline Spelman was sacked.
Mr Heath, who has moved on from Deputy Leader of the House of Commons, yesterday arrived at his new Whitehall office to be confronted with an in-tray that includes tackling tuberculosis in cattle, EU subsidy reform and increasing British food exports.
The ink was drying on a voluntary code of conduct to protect dairy farmers from steep milk price cuts when Lib Dem party leader Nick Clegg appointed Mr Heath to the role.
Mr Heath said: "There is an enormous amount of work to do to ensure a fair deal for rural communities and a fair return for primary producers. At the same time we need to protect rural services, grow the economic opportunities in countryside areas, and balance the needs of often fragile environments."
Mr Heath's office said yesterday his rural Somerset constituency boasts among the largest populations of dairy cows, meaning he sympathises with the problems the industry faces. Somerset-born Mr Heath, 58, was elected in 1997 and was formerly the party's spokesman on agriculture, fisheries and food.
He was among a number of Westcountry MPs given promotions in the coalition Government's first major reshuffle.
Yeovil Lib Dem MP David Laws, who resigned from the Cabinet in 2010 amid a scandal over his expenses, was named a junior Education Minister and a Cabinet Office Minister, and will attend Cabinet.
Jeremy Browne, Lib Dem MP for Taunton Deane, was moved from the Foreign Office to the Home Office.
Hugo Swire, Conservative MP for East Devon, will go from the Northern Ireland Office to become a minister in the Foreign Office.
But Nick Harvey, North Devon's MP, was sacked as Armed Forces Minister. Mr Harvey's departure effectively paved the way for Mr Heath's promotion because of the quota of ministers each party is allowed.
At the Defra helm is Mr Paterson, a Conservative, who is a long-standing critic of the hunting ban and proponent of a badger cull to tackle bovine TB.
He said yesterday: "The department plays a crucial role in many issues that touch people's lives, from producing the food they eat to protecting and managing the land and the seas around them. I look forward to helping to grow a strong rural economy."
The most contentious issue the department faces is the sanctioned pilot culls of badgers, which are set to take place in the South West later this year. Some Lib Dem MPs have indicate their unease at the method to control the disease, which is rife in Devon and Cornwall.
Mary Creagh, Labour's Shadow Environment Secretary, criticised Mr Paterson's appointment. She said: "David Cameron has lurched to the right, appointing a Eurosceptic, climate sceptic, free marketeer as Environment Secretary.
"Farmers and environmentalists alike are deeply worried about Owen Paterson's ability to build alliances to get a good deal for the UK on the Common Agricultural Policy, tackle the food poverty crisis and protect our water, air and countryside here at home."