Farmers and researchers now have access to a new database of weed species, which can help them gain insights into the management of traditional agricultural systems throughout history.
A collaborative research effort spanning over 30 years by archaeologists and ecologists at the Universities of Sheffield and Oxford University resulted in a comprehensive list of nearly 930 weed species found in Europe, Western Asia, and North Africa. The open-access resource gives researchers around the world the opportunity to compare archaeobotanical data with traditional farming systems as far back as 8,000 BCE.
For researchers like Antonio DiTomasso, a professor of crop science at Cornell University, this database is an eye-opener. Weeds act as living records to provide clues about soil health, biodiversity, and even past climates, which can help farmers select suitable crops and adopt practices that are in line with the unique characteristics of their land.
“By knowing the history of what weeds were grown in the 1100s or in the early years of agriculture, that informs us because we get a clearer idea of what was done for the resiliency of food systems then, since certain weeds grow with certain crops,” DiTomasso said.
Weeds, being the wild relatives of crops, haven’t changed for centuries, while crops have evolved, he notes. “If you know that certain weeds were associated with wet conditions, and other weeds associated with crops grown during drought-heavy years, it gives us an idea of whether those crops could survive today.”
The database, available as an Excel spreadsheet, catalogs a weed species and identifies their type (annual, biennial, wood perennial, etc), thickness, specific leaf area, canopy height and diameter, and World Flora Online number. Analyzing this kind of data provides deep insight into what kind of plants can adapt to, or may be vulnerable to, changing conditions in their habitats.
“The robust data from this years-long research offers the potential for understanding the resilience of food systems in a time of climate change, drought and degradation of land, and the exploration of a narrative for issues the world is facing today in terms of global food production,” plant ecologist and lead researcher John Hodgson, a research associate at Oxford, said in a press release.
Glynis Jones, emeritus professor of archaeology at the University of Sheffield, said in the same release that the research reveals trends in arable agriculture over time and how farming practices have differed in various environments.
“We found that sites from the Iron Age and Roman period that encompassed more extensive areas were less intensively cultivated, so more crops may be grown but they would not be farmed as intensively as before as they covered larger areas,” Jones said.
Understanding historic farming patterns can help agricultural specialists and farmers recognize how weeds respond to various crop rotation and fallowing systems, according to a 2022 paper published by Cambridge University Press. For example, the abundance of thin-leaved species such as common corncockle (Agrostemma githago L.), false thorow-wax (Bupleurum lancifolium Hornem.), and darnel (Lolium temulentum L.) “could reflect a lack of crop rotation in the Roman and Visigothic periods at a site in the northeastern Iberian Peninsula.”
The Sheffield and Oxford researchers point to how valuable this dataset can be for weed ecologists, but DiTommaso highlights how climatologists can also benefit from analyzing the legacy of hundreds of weed species. A 2018 study echoes his claim: Research looking at the Iron Age in northeastern Thailand used weed flora to demonstrate a shift from dryland to wetland rice cultivation, likely in response to an increasingly arid climate.
A weed database this extensive is a goldmine for researchers to “allow us to look into the past to inform the future,” DiTomasso said.