In a landmark study published in Applied and Environmental Soil Science, lead author Wang Huang and a team of researchers investigated an innovative strategy to resolve one of modern agriculture’s most pressing dilemmas: balancing high crop productivity with severe environmental nitrogen losses. Conventional farming relies heavily on synthetic nitrogen inputs like urea, yet a massive portion of this applied nitrogen vanishes into the atmosphere through ammonia volatilization or leaches into surrounding ecosystems. While recycling farm waste into composted organic fertilizer offers a promising path toward circular agriculture, conventional organic fertilizers can accelerate urea breakdown and inadvertently spike local ammonia emissions. To overcome this challenge, the research team developed a targeted organic fertilizer co-amended with fifteen percent biochar and half a percent dicyandiamide, evaluating its performance across a continuous two-year rice-wheat crop rotation under a thirty percent reduction in synthetic mineral nitrogen.

The primary success of the study lies in its dramatic mitigation of reactive gaseous nitrogen losses without harming crop performance. Ammonia loss represents the single dominant pathway for nitrogen waste in flooded rice and wheat fields, often exceeding greenhouse gas emissions by several orders of magnitude. Over the multi-year trial, the combined biochar and dicyandiamide organic fertilizer reduced cumulative ammonia losses by 27.1 percent relative to conventional urea application. In stark contrast, standard organic fertilizer and biochar-only organic fertilizer treatments increased ammonia volatilization during subsequent seasons, driven by residual ammonium accumulation and elevated soil pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More. By buffering soil acidity spikes and slowing down the biological conversion of ammonium into volatile forms, the dual-amended formulation successfully retained essential nutrients within the plant root zone. Crucially, overall nitrous oxide emissions remained consistently low across all experimental treatments, proving that the reduction in ammonia gas did not trigger a dangerous secondary tradeoff in greenhouse gas production.

In addition to curbing gaseous losses, the amended fertilizer strategy restructured the underlying biological mechanisms governing soil nutrient cycling. High-throughput genetic sequencing revealed that applying biochar and dicyandiamide organic fertilizer significantly altered the soil microbiome. The treatment favored beneficial stress-tolerant and nitrogen-fixing bacterial groups, such as Firmicutes and Euryarchaeota, while suppressing Nitrospirota, a primary bacterial group responsible for transforming nitrite into nitrate. Suppressing rapid nitrate conversion prevents excessive nutrient leachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil.   More during wet growing phases and optimizes plant uptake. This balanced nutrient release allowed crops to flourish despite receiving significantly less chemical fertilizer. Grain yields for rice and wheat were fully sustained, matching the productivity of full-dose synthetic urea regimes, while kernel nitrogen concentrations in harvested rice grains increased by up to thirty-eight percent.

From an economic and environmental accounting perspective, the dual-amended fertilizer strategy presents an exceptional case for widespread regional adoption. Extensive Monte Carlo financial simulations demonstrated that reducing synthetic urea reliance, mitigating environmental damage, and avoiding human health costs associated with air and water pollution generated substantial monetary returns. The combined biochar and dicyandiamide organic fertilizer reduced total ecological and health costs by 21.8 percent compared to traditional synthetic fertilization. When accounting for reduced fertilizer purchasing expenses and grain market premiums, the intervention delivered an estimated net potential benefit of approximately 36,600 CNY per hectare each year. Scaling this practice across intensive agricultural regions offer a viable pathway toward low-emission, highly profitable sustainable farming.

Source: Huang, W., Wang, L., Gong, X., Bian, R., Lu, X., Bu, Y., Liang, Y., Sun, H., Feng, Y., Xia, C., Jiang, J., & Xue, L. (2026). Ammonia mitigation and economic gains from dicyandiamide and biochar-amended organic fertilizer: a 2-year rice-wheat rotation study. Applied and Environmental Soil Science, 2026, e019.