Early results from WorldVeg field trials in Taiwan suggest that regenerative farming practices could encourage naturally occurring beneficial fungi that help crops access nutrients and withstand environmental stress.
The research is examining how practices including reduced tillage, cover cropping and organic fertilizer affect arbuscular mycorrhizal fungi (AMF) – microscopic organisms found naturally in soil that colonize plant roots, helping plants absorb nutrients and water in exchange for carbon and energy.
Some farming practices – including tillage, excessive fertilizer use, and leaving soil without a cover crop – can reduce AMF populations and disrupt their symbiotic relationship with crops. WorldVeg trials are exploring how different regenerative practices can encourage these “friendly” fungi and whether this, in turn, can improve crop performance and nutritional quality.
The experiment uses mungbean – a crop WorldVeg has been breeding for more than five decades, with improved varieties now adopted in 35 countries – grown under different combinations of practices: conventional or no tillage; chemical or organic fertilizer; and with or without a cover crop. For the latter, researchers planted sunn hemp, a fast-growing, high-biomass species that forms strong associations with mycorrhizal fungi, and which is well suited to Taiwan.
As part of a World Food Prize Foundation Borlaug-Ruan International Internship, Emily Eayre spent the summer examining mungbean root samples to determine how these treatments affect AMF colonization, and whether colonization is associated with crop yield and the mineral composition of the grain.
The experiment forms part of a WorldVeg project on regenerative fortification, funded by the Rockefeller Foundation and the Foundation for Food & Agriculture Research (FFAR), which is exploring links between soil health and crop nutritional quality.
In the laboratory, Emily stained the harvested mungbean roots with a blue stain that binds to chitin, a structural material in fungal cell walls. This makes the fungal structures visible under a microscope, revealing the extent to which AMF have colonized the roots. Early results suggest that mungbean grown after a sunn hemp cover crop had greater AMF colonization, although analysis is still underway and it is too early to draw firm conclusions.
One possible explanation lies in the way AMF survive. The fungi depend on living plant roots for carbon, so leaving a field fallow between crops removes their food source. Growing sunn hemp between mungbean crops keeps living roots in the soil, potentially allowing native AMF populations to persist and leaving more fungi available to colonize the next mungbean crop.
The trial is now helping researchers investigate a broader question: whether farmers can deliberately manage their fields in ways that encourage beneficial native AMF, and whether greater colonization translates into measurable benefits for the crop. Preliminary analysis suggests some correlation between the AMF root colonization and higher mungbean yield, and greater zinc and iron content in the grain, especially under no-till conditions, though it is not considered statistically significant. Further research is therefore needed to separate the effects of AMF from other changes that regenerative practices can make to the soil.
The answer could have important practical implications. Farmers can buy commercial products containing AMF to add to their soils, but these can be costly and may not work reliably. If management practices such as cover cropping can consistently support native AMF – and greater colonization improves crop performance – farmers could potentially harness some of the same benefits without purchasing an additional input. This could also save on water use and sequester more carbon.
While commercial products containing AMF are available, their cost can put them beyond the reach of many farmers, particularly those in developing countries. Encouraging the beneficial fungi already present in the soil could offer a more accessible and sustainable alternative.
Looking at the pros and cons
The ongoing research is also examining possible trade-offs. For example, the team observed increased nitrous oxide (N₂O) emissions in plots where mungbean followed a cover crop. Emily and WorldVeg researchers have piloted a new laboratory-based soil-incubation system to investigate whether different bacteria and nitrification inhibitors could help reduce these emissions from decomposing cover crop residues in the soil.
Interestingly, the soil incubation pilot found that both bacteria and nitrification inhibitors can play a role in N₂O reduction, with their co-application resulting in the lowest release of N₂O compared to the residue alone. However, a longer experiment is needed to capture the full picture of nitrogen cycling.
Since the mungbean field trial is only in its second season, more research could help to explain how the effects develop over time. One question is whether management practices that encourage AMF can gradually build fungal populations in the soil and provide increasing benefits across successive seasons.
For Emily, who came to WorldVeg to gain research experience in an international setting and learn from agricultural scientists, the work has also offered an opportunity to explore the breadth of plant and soil science. Alongside her work with the agroecology team, she has spent time with WorldVeg researchers working in areas including entomology and biotechnology.
The mungbean trial has provided a particularly close look at an agricultural resource that is easy to overlook: the complex community of organisms already beneath farmers’ feet – and how managing that community differently could help make farming more productive and sustainable.
This work aligns with the Action Area on Climate Resilience in the WorldVeg Global Strategy 2026-2033. (Download｜Flipbook)
