- Field trials in Korea showed that GroMore-Duo achieved the highest grain yield, while GroMore-Star delivered both high productivity and the lowest greenhouse gas intensity per kilogram of grain.
- It reduced total seasonal methane emissions by 10.6% compared to conventional practices and achieved a greenhouse gas intensity of 0.69 kg CO2-equivalent per kg of grain.
- The study highlights the value of evaluating crop protection products for both their agronomic and environmental impacts.
This is good news for agricultural businesses and agrochemical manufacturers, who face mounting pressure to reduce greenhouse gas (GHG) emissions without sacrificing crop productivity. Now, commercial growers and supply chain managers may have a viable pathway to meet stringent climate targets whilst maintaining profitability.
Balancing harvest productivity with environmental efficiency
Flooded rice paddies represent one of the world’s largest agricultural sources of methane. This occurs because traditional cultivation keeps the soil underwater, creating an oxygen-free environment that encourages methane-producing bacteria to thrive. For agribusinesses, finding ways to suppress these emissions without reducing harvested grain volumes remains a major technical challenge.
Researchers from Syngenta and Hankyong National University investigated whether commercial crop protection regimes could solve this challenge. They analysed two variants of Syngenta’s GroMore programme — GroMore-Duo and GroMore-Star — across a commercial paddy field in Pyeongtaek, Gyeonggi Province, during the 2025 growing season.
“Rice production in flooded paddy systems must increasingly balance grain productivity with GHG efficiency,” the researchers stated. The study evaluated two GroMore crop-protection programme variants under two nitrogen input levels in a temperate Korean paddy field to determine whether these treatments could improve yield-scaled climate performance without compromising grain yield.
The GroMore programmes combine traditional insect- and fungus-control ingredients with supplementary amino acids and micronutrients. The two tested variants contain different primary active ingredients to suppress pests, specifically comparing thiamethoxam against pymetrozine.
Higher grain output alongside reduced emissions
To test the programmes under commercial conditions, the research team divided a farmer-managed field into 18 plots separated by physical earth borders and plastic underground barriers. This prevented irrigation water and agrochemicals from leaking between test zones. The scientists tested both GroMore variants against standard conventional farming methods, applying nitrogen fertiliser at 90 kilograms per hectare.
The harvest revealed clear productivity gains for the specialised treatments. Crops grown using conventional methods generated a grain yield of 6.87 megagrams per hectare. In contrast, plots treated with GroMore-Duo reached 9.88 megagrams per hectare, representing the highest harvest volume in the trial.
Meanwhile, GroMore-Star delivered a balanced performance, combining high agricultural output with strong environmental benefits. This group produced 9.05 megagrams per hectare while recording the lowest overall GHG intensity across the trial (GHG intensity measures the warming impact generated to produce one kilogram of harvested grain).
For the GroMore-Star plots, this figure dropped to 0.69 kilograms of carbon dioxide equivalent per kilogram of grain. Furthermore, this treatment reduced total seasonal methane emissions by 10.6% compared to conventional practices.
Shifting the methane accumulation timeline
Beyond measuring final harvest weights and total gas output, the researchers tracked how methane built up in the soil over the six-month growing season. Using mathematical modelling, they identified the specific turning point at which methane gas begins to accumulate rapidly in the flooded earth.
The analysis showed that crops receiving the specialised GroMore treatments reached this rapid methane peak much earlier in their growth cycle than conventionally managed plants. Both the GroMore-Duo and GroMore-Star test groups hit this accumulation turning point at approximately 69 days after transplanting the young rice shoots into the field.
By comparison, the untreated control group reached this turning point at 86 days, while the conventionally managed crops hit it at 89 days.
The researchers linked GroMore’s earlier peak to the way healthy plants manage their internal carbon resources. When rice plants grow robustly, they direct more of their captured carbon into forming the edible grain rather than sending it down into their root systems. Because soil bacteria rely on carbon leaking from plant roots to generate methane, redirecting this energy into the grain cuts off the bacteria’s primary fuel supply.
“Mechanistically, net methane emission in rice paddies reflects the balance between methane production under anaerobic conditions and methane oxidation in aerobic microsites,” the authors explained. “Prior studies further suggest that stronger grain sink formation can reduce methane loss by redirecting assimilated carbon toward grain rather than prolonged rhizosphere supply.”
No disruption to standard farming calendars
Crucially, for commercial farm operations, these biological changes occurred without altering the plant’s natural developmental timetable. Throughout the experiment, the physical heading date — the exact moment the rice head emerges from the stem — occurred at the same time across every test plot.
This confirms that the drop in methane emissions was not caused by the plants maturing faster or slower than usual. Instead, the improvements stemmed from changes in how the plants formed their grain and interacted with the soil during their reproductive phase.
“Heading date was identical across all treatments, indicating that treatment effects were not attributable to phenological shifts,” the scientists confirmed. “Overall, the GroMore programmes were associated with differences in yield components and yield-scaled climate performance under flooded paddy conditions without changing crop phenology.”
Joint assessments required for future product development
For agrochemical suppliers and agricultural planners, the findings underscore the importance of evaluating plant protection products through a wider environmental lens. The research team stressed that future farming strategies must look at crop protection and climate mitigation as a single integrated challenge, rather than separate operational goals.
They concluded: “This study showed that, under the present temperate paddy field conditions, the GroMore® programmes were associated with differences in grain yield, methane-accumulation timing, and yield-scaled climate performance without altering heading date. GroMore-Duo N90 produced the highest grain yield, whereas GroMore-Star N90 maintained high productivity with lower cumulative methane emission and the lowest GHGI.
“These results indicate that treatment differences were expressed more clearly in yield-scaled climate performance than in cumulative methane emission per unit area alone. In this sense, evaluating methane-related climate cost relative to grain yield provided a more useful basis for comparing treatment performance in this study.
“The results also suggest that integrated programme-level crop management may complement conventional fertiliser- and soil-focused approaches in climate-resilient rice production.”
Source: Agronomy
“Rice Growth, Yield Formation, and Methane Intensity Responses to GroMore® Programs and Nitrogen Rate in a Korean Paddy Field”
https://doi.org/10.3390/agronomy16121180
Authors: Maeng Hui-Ju, et al
