Although he kept out of the public spotlight, John Dieter Kahlbetzer, 92, accumulated a 430,000 hectare portfolio of NSW properties spanning wool and beef, broadacre cereals, irrigated cotton, rice, and citrus and a cotton ginning and marketing business between 1969 and the early 2000s.

Big name properties owned by Twynam while Mr Kahlbetzer was at the helm ranged from Ramornie Station in the Clarence Valley to Mungadal, Gundaline, Cobran, Merowie and Steam Plains in the Riverina; Jemalong and Buttabone in the Central West, and Boolcarrol and Milton Downs in the North West.

At its peak the company held 44 properties, employed more than 400 staff, was Australia's largest cotton and rice grower and among the top 10 wool and wheat producers.

An early and persistent player in the southern NSW cotton industry, it was NSW's largest private water owner, too.

Twynam also became a significant shareholder in the big northern beef business, Australian Agricultural Company, for a decade from 1985, holding almost a third of AACo's shares by 1990.

The stake was eventually sold in 1995 after Mr Kahlbetzer, frustrated by the pastoral giant's management by Colonial Mutual, supported takeover moves led by Elders, then quit his holding to fund Twynam's purchase of ginner and marketer Colly Cotton.

Colly included northern NSW's Collymongle Station and gin, plus gins at Mungindi and Warren and a half share in Hillston.

John Kahlbetzer's flourishing agribusiness career had followed initial success as a steel exporter and importer which had, in turn, fostered the purchase of "a few hundred acres" south of Sydney, near Picton.

At Razorback the family were among the earliest producers with an interest in the newly introduced Chianina cattle breed from Italy.

Son, Johnny Kahlbetzer, who joined Twynam in the 1990s and eventually took over the Australian business, recalled of all his father's farming interests, beef cattle were his favourite, although he did not persist as a fan of Chianinas.

"We're not really sure what originally attracted Dad to agriculture, but he had the ability to see a lot of productivity opportunities and made the most of them," he said.

Born in Germany, John Kahlbetzer migrated to Australia in 1954 as a 23-year-old oil rig worker in Western Australia, moving to Adelaide to work in the steel market, including later opening an import office in Beijing.

After returning to Australia via the US and South America, he teamed up with his former boss, Rudi Meth, forming a new Sydney-based steel export and import firm, Methco, which generated enough cash to buy in his first pastoral-sized holding, the famed 4270ha Ramornie, near Grafton, in the early 1970s.

That was followed soon after by the first of three Monaro properties which aggregated into the 10,500ha Umerella Station near Cooma, then Gunyerwarildi at Warialda in 1977.

Twynam's big build-up occurred with the acquisition of a swag of former Naroo Pastoral Company stations from Amatil (formerly British Tobacco) in 1979, adding Jemalong and The Mount at Forbes, Buttabone and Oxley on the Macquarie River, Narra Allen at Boorowa and Mungadal and Steam Plains in the Riverina.

Later acquisitions included the Boolcarrol aggregation near Wee Waa in 1982, the Elengerah aggregation at Warren and Gunnee at Delungra in 1987, Hanging Rock at Grafton in 1988, the Merrowie aggregation at Hillston in 1992 and 1994, and the Gundaline aggregation, including Back Gundaline, Cooinbil and Toganmain, then Milton Downs at Narrabri in 1997, and the Cobran aggregation at Carrathool in 2002.

Twynam's livestock interests included Mungadal's Merino stud and a Santa Gertrudis stud, which moved to Jemalong where a Santa-Gelbveih-Angus composite cattle herd established, and an Angus stud was also based.

Angus eventually became Twynam's signature beef breed.

By the 1990s, although his company was growing rapidly in Australia, Mr Kahlbetzer was largely based overseas in South America and later the US or Europe, keeping a surprisingly low profile.

He returned to Sydney permanently a year ago.

The early 1980s saw him in South America investing in farmland via his new business LIAG Argentina, including eventually developing 35,000ha of irrigated cropping country.

Twynam's annual Argentine harvest, of primarily soybeans, corn and wheat, tallied about 300,000t a year and ranked as one of the largest farming businesses in the country.

Less successful were attempts to develop cotton in Argentina, where despite making significant inroads in southern NSW, Twynam's yields on its 5000ha of plantings tended to struggle compared to crops back in Australia.

"Dad saw irrigation as a key requirement for agriculture to grow and was keen to concentrate land purchases in areas which could make use of river water or bore assets," Johnny Kahlbetzer said.

"Prior to buying in the Riverina cotton had only been tried on a couple of places, but we were the first to really work at it on a bigger scale, which did cost us a lot of dollars before we eventually started getting a return.

"Cotton in Argentina was a bit similar to our early southern NSW experience."

Twynam's progressive sell-down of its land assets in Australia followed its momentous and contentious $300m sale of 240,000 megaliters to the federal government in 2009.

The asset sale program, as part of a steady family succession strategy, had begun the year before when Boolcarrol was offloaded, followed in 2010 by Mungadal, Cooinbil and Buttabone, Collymongle in 2012, Gundaline in 2014 and Jemalong and Merrowie in 2018.

Twynam's cotton gins sold to Queensland Cotton, with Namoi Cotton taking full control at Hillston.

Last year, son Markus Kahlbetzer, who has been leading the LIAG Argentina business, offloaded the South American properties for a reported $300m.

- with PETER AUSTIN