Low rainfall and harsh, mainly snow-free winters are the main climate constraints to production on farms supplying the Könnern sugar beet factory.

Privately owned by Pfeifer & Langen and built in 1993, the factory replaced 10 ancient ones run by the state before German unification, said the firm’s Hermann Keutmann. It processes about 1.5m tonnes of beet a year from 900 growers, whose average farm size is 920ha (2275 acres).

Normally, the area between Leipzig and Berlin receives only 465mm (18in) of rainfall a year, which can have a big impact on yields, said Mr Keutmann.

Compared with parts of West Germany, which get nearly twice as much and where the mean yield is 54t/ha (22t/acre), Könnern’s growers average yields of only 45t/ha (18t/acre).

To conserve moisture, most growers refrain from ploughing, noted Syngenta’s Ralf Brune.

The upside is that sugar contents are higher, averaging 17.9%. “It’s very dry here,” said Mr Keutmann. “Last year we got only 340mm, so there was a shortage. But this year we’ve had 650mm and the average is 57t/ha with 17.4% sugar.”

On the Quellendorf unit, which supplies three factories, Günther Fischer said his yield averaged 60t/ha (24t/acre) at 19% sugar. But falling prices were hard to live with.

They had dropped from E45/t to E29/t in three years and were set to slip to E25/t next year, he pointed out.