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Sorghum out-yields maize in drought
“Switch from maize to sorghum and you will out-yield maize in dry years.”
True below a threshold and false above it. Sorghum wins when crop water use falls under about 250 mm and maize can fail to set grain under 200 mm; with water, modern maize yields around 11.5 t/ha against 8 for sorghum, and modern maize genetics have narrowed the dry-side gap too.
Where it comes from
Sorghum's genuine physiology, deep roots and high transpiration efficiency, and a decade of rapid European expansion driven by dry summers. The crop's promotion body publishes the area figures and the resilience message together.
Who benefits
Sorghum seed companies and the interprofessional body Sorghum ID, which is the source of most European area and yield statistics in circulation and is flagged as an industry source wherever this site quotes it.
What the evidence says
There is a crossover, and it has a number. Crop modelling over 31 years at two sites puts it at about 250 mm of crop water use: below that sorghum out-yields maize, and maize "generally failed to produce any grain" below about 200 mm. Above it, well-watered maize reaches about 11.5 t/ha against 8 for dwarf sorghum (in silico Plants, 2021).
Modern maize has narrowed the dry-side gap. US field data found that modern maize hybrids out-yielded modern sorghum across water levels, and sorghum won under water limitation only against maize genetics from the 1970s or earlier (Field Crops Research, 2024, as reported). Breeders have been selecting maize for drought for fifty years; the comparison in a farmer's memory may be out of date.
Europe is switching anyway, on feed economics. France grew 103,000 ha of grain sorghum in 2024 and exported about 65% of its 2023 crop, mostly to Spain; EU production rose 57% in a decade at 5.62 t/ha (Sorghum ID, industry; USDA GAIN, 2024). Climate projections see sorghum yields falling by up to 1.5 t/ha in southern Europe and rising by up to 3 t/ha in the north by the end of the century (as reported from a 2025 review), which is not the direction the slogan implies.
What to say instead
"Below about 250 mm of crop water use, sorghum; above it, maize." Trial sorghum on your driest field, keep maize where it has water, and remember that most European sorghum is sold as feed. The drought-tolerant varieties page puts the threshold beside the other three things sold as drought tolerance.