150 years ago, a mishap in an SA paddock revolutionised farming

In 1876 two brothers showcased their stump-jump plough at a country show and solved one of the biggest farming challenges at the time.

The simple invention unlocked previously unviable farmland across the country.

The stump jump plough has been included in a five-coin set released by the Royal Australian Mint.

It has been 150 years since a mishap in a paddock led to a discovery that would forever change agriculture, but at the time the farmer-inventor was dismissed as a "fool and a lunatic".

Before 1876, one of the biggest challenges Mallee farmers faced was scrub stump.

Horse-drawn rollers and fire could flatten vegetation, but the stumps remained stubbornly in place, damaging the inflexible ploughs on the market.

One day, Richard Smith, a blacksmith and farmer at Port Wakefield, was hard at work and broke part of his plough, according to Ardrossan Heritage Museum secretary Brenda Bowman.

"[He] realised through that accident that if the plough shear could move up and down, it could ride over obstacles," she said.

Richard and his brother, Clarence Smith, set about finessing a prototype that was to be unveiled at an exhibition at the Moonta Agricultural Show on November 6, 1876.

The first stump-jump plough was simple, but it would revolutionise Australian agriculture.

By attaching shears to the plough frame with a hinged joint and weight system, the plough could till soil without the scrub remnants being removed.

Despite addressing a common challenge, reactions to the invention were mixed.

"Some people thought it was a great idea and some people just thought it was lazy," said Ms Bowman, the widow of Clarence's great-grandson.

At the 1876 Moonta show, Richard Smith reportedly said: "I don't care what you say or think, I still firmly believe that my plough will open up a new agricultural era in South Australia."

Despite the scepticism the invention became commercially successful and in 1880 Clarence Smith opened a factory in Ardrossan.

The Clarence H. Smith plough factory employed up to 130 people at times, selling ploughs across the country and to New Zealand.

Testimonials in a factory catalogue show just how pleased farmers were with the tool — a Mr John Baker called it "the most perfect plough ever offered".

"Four horses worked it all the season comfortably, and ploughed 220 acres of very rough stump and stony land without bending or breaking anything," he wrote.

The plough remained popular until the Great Depression saw the Ardrossan factory close in 1934.

Though much of it was demolished, part of the building remains and is now home to the Ardrossan Heritage Museum.

In an 1881 paper, the president of the Royal Agricultural and Horticultural Society of SA Sir Robert Ross credited the plough with a drastic increase in farmed land.

Before the invention, scrubland was regularly forfeited by purchasers who found it "almost impossible" to farm.

"In 1873, 4,826 acres were leased, and more than half forfeited: in 1874, 2,183 acres were taken up, and all forfeited," Sir Ross wrote.

As the use of the stump-jump plough increased, so did the amount of land leased, and 285,670 acres were purchased in 1881 in what was "the largest sale that has ever taken place in the colony".

"Both the Government and the farmers of South Australia are considerably indebted to Mr R B Smith for his ingenuity and perseverance in forcing this valuable implement upon the public," Sir Ross wrote.

A lapsed patent meant Richard Smith was not rewarded with riches for his invention, though in 1882 the state government awarded him £500 in recognition of the plough.

Richard and Clarence Smith ultimately had a falling out and Richard relocated to Western Australia.

Though farming machinery looks a little different these days, the principle of the stump-jump plough remains, but with more hydraulics.

This year, the Smith brothers' stump-jump plough featured alongside the jaffle maker and the black box flight recorder in a coin collection chronicling five of Australia's most decorated inventions.