Morgan Ruelle, an environmental scientist researching food diversity in Ethiopia in 2011, noticed something that didn’t quite fit his framework. Farmers in Tigray cultivated wheat, barley, and other grains in one field, harvested them simultaneously, and treated them as one crop. Duragna was what they called it. Most of the agroecology community had not cataloged it. It had not been discovered by the majority of agricultural researchers. The farmers who had grown it for generations gave straightforward, pragmatic answers when asked why: if one grain fails, the others will survive. Harvesting is always possible.
In the end, Ruelle published research that reinterpreted what Ethiopian farmers had known for centuries. The term “maslin,” which refers to mixed cereal plantings, has been used for over 3,000 years in at least 27 countries. Evidence from Bronze Age and Neolithic sites in what is now Israel suggests that wild barley and wild oats were grown together before either was domesticated. Grain mixtures are millennia older than monocultures. Modern industrial farming reversed a successful practice without understanding why it worked, and the effects of that reversal are starting to be felt.
Roy Steiner, Senior Vice President of Food at the Rockefeller Foundation, compared the results of the 2025 trial directly to those of commercial plant breeding research. It usually takes researchers years to increase yield by 10 or 15 percent. Compared to monocropped barley and wheat, the wheat-barley maslin mixture yielded 1.5 times more than monocropped barley. When farmers measured results in revenue rather than laboratory percentages, the mixture yielded 197.8% of the net benefit over monocropped barley. There are no additional inputs. Seeds do not require any new technology. Chemicals are not used. Throughout agricultural history, two types of grain have been grown together in different combinations for thousands of years.
Examining the mechanism reveals it to be elegantly simple. There are differences in the heights, root depths, and drought and disease tolerance of cereal species. Instead of competing for the same inputs, they rely on different resources at different depths and times when grown together. Wheat often suffers from drought stress, while barley thrives. For that particular season, there is more barley than wheat in the final harvest. Due to the seeds saved for the following year, the crop adapts without the farmer having to make any conscious decisions. An ethnobotanist at the New York Botanical Garden who collaborated with Ruelle says that a diverse mixture can change its effective composition from season to season in response to conditions, whereas a single variety can only adapt across generations. A Georgian priest cultivating the mixture told one of the researchers, “If one fails, at least we have the other.”
Biochar is an equally old and instructive story. Dark earth, or terra preta, was created about 1,500 years ago by pre-Columbian communities in the Amazon basin using charcoal made from bones, bark, and agricultural waste. Terra preta patches in the Amazon are still quantifiably more fertile than surrounding soil even after centuries of no active management. A charcoal’s porous structure provides a home for soil microorganisms that provide nutrients to plants. It prevents fertilizer from washing away in the rain, reducing chemical inputs by up to 50%. It stores carbon instead of releasing it. Modern biochar is made from agricultural waste and applied to fields as a soil amendment, yielding long-term results that synthetic fertilizers cannot.
After reading this research, I feel as if a field is finally realizing what it has been ignoring for far too long. Monocrops selected for maximum yield under ideal conditions, supported by synthetic inputs that replaced what the simplified ecosystem could not provide, was the foundation of the twentieth-century agricultural revolution. The system performed well under stable conditions. There has been no stability in the situation. In dryland farming zones and low-latitude regions, staple crop yields are already declining. Due to lower rainfall, Australia’s yield decreased by almost 30% between 1990 and 2015. There is a fragility to the monoculture model, which was optimized for a climate that no longer exists.
Subsistence farmers in Ethiopia, Georgia, and Greek islands preserved a constantly changing mixed field that adapts without human intervention and yields something harvestable regardless of the season, and it seems much less archaic than the method that replaced it.