Scientists discovered that tiny fungi living in soil can help plants use fertilizer more efficiently by preventing nitrogen from washing away. In a study of tea plant soil, researchers found that when special fungi called arbuscular mycorrhizal fungi were present, they reduced the amount of nitrogen lost through water drainage by up to 45%. The fungi work by changing the soil structure and helping plants absorb more nutrients directly. This discovery could help farmers use less fertilizer while growing healthier crops, which is better for both their wallets and the environment.

The Quick Take

  • What they studied: Whether special soil fungi can prevent nitrogen fertilizer from washing away in tea plant soil, and how they do it
  • Who participated: A controlled pot experiment with tea plants (Camellia oleifera) grown in soil with and without the special fungi, tested with different amounts of nitrogen fertilizer
  • Key finding: The special fungi reduced nitrogen loss in water by 19-45% when plants received higher amounts of fertilizer, mainly by changing how soil particles stick together and helping plants absorb more nitrogen
  • What it means for you: If this works in real farms, it could mean farmers need less fertilizer to grow the same amount of crops, saving money and reducing pollution. However, this was a lab experiment, so results may differ in actual farm conditions.

The Research Details

Researchers grew tea plants in pots under controlled conditions, creating different scenarios by varying how much nitrogen fertilizer they added (none, low, medium, and high amounts) and whether they added special soil fungi or not. They measured what happened to the plants, the soil, and the water that drained from the pots over time.

The special fungi studied are called arbuscular mycorrhizal fungi—they’re beneficial organisms that naturally live in soil and form partnerships with plant roots. The researchers compared soil with these fungi present versus soil without them to see what difference they made.

They measured several things: how much nitrogen the plants took up, how much nitrogen washed away in the drainage water, how much fungal threads grew in the soil, and how the soil structure changed. They also looked at a sticky protein the fungi produce that helps hold soil particles together.

Understanding how these fungi prevent fertilizer loss is important because it could lead to practical solutions for farmers. Many farms lose 30-50% of their nitrogen fertilizer through water drainage, which wastes money and pollutes groundwater. If we can use natural soil fungi to reduce this loss, we could grow more food with less fertilizer, which helps both farmers’ profits and environmental health.

This was a controlled laboratory experiment, which means the conditions were carefully managed and results should be reliable for those specific conditions. The study used proper experimental design with multiple repetitions. However, because it was done in pots rather than in actual farm fields, the results may not be exactly the same in real-world farming situations where weather, soil types, and other factors vary.

What the Results Show

When the special fungi were present in the soil, they significantly reduced the amount of nitrogen washing away in water—by 19% at medium fertilizer levels and by 45% at high fertilizer levels. This happened mainly because the fungi changed how the soil was structured.

The fungi worked through two main mechanisms: First, they produced a sticky protein called glomalin that acts like a glue, helping soil particles stick together into larger clumps. These larger clumps hold onto nitrogen better and prevent it from dissolving and washing away. Second, the fungal threads directly absorbed nitrogen from the soil, making it unavailable to wash away.

Interestingly, the fungi were most effective at preventing nitrogen loss when plants received the highest amounts of fertilizer. This suggests they’re particularly helpful in situations where excess fertilizer might otherwise be wasted.

The researchers found that the amount of nitrogen dissolved in the soil water was the strongest predictor of how much nitrogen would wash away—and the fungi reduced this dissolved nitrogen by improving soil structure.

The fungi also increased the amount of certain nitrogen forms (nitrate) that stayed in the soil, and they changed the distribution of soil particle sizes. Specifically, they increased the proportion of medium-sized soil clumps (0.05-1.00 mm) while reducing very small particles (0.002-0.05 mm). These changes in soil structure appear to be key to how the fungi prevent nutrient loss.

Previous research showed that these fungi help plants absorb more nutrients, but this study goes deeper by explaining how the fungi also change the soil itself to prevent nutrient loss. Most earlier studies focused on what the fungi do for the plant, but this research shows that the fungi’s effect on soil structure is equally important—perhaps even more important—for preventing fertilizer waste.

This study was conducted in pots under controlled laboratory conditions, not in actual farm fields. Real farm soils have different properties, weather patterns, and microbial communities that could affect results. The study used only one type of plant (tea plants) and one type of soil, so results may not apply to other crops or soil types. Additionally, the study didn’t test how long these effects last or whether they work consistently across different seasons or climate conditions.

The Bottom Line

Based on this research, farmers growing tea plants (and potentially other crops) may benefit from inoculating their soil with arbuscular mycorrhizal fungi, especially if they use higher amounts of nitrogen fertilizer. This could reduce fertilizer waste and environmental pollution. However, more field testing is needed before making widespread recommendations. Confidence level: Moderate—the laboratory results are clear, but real-world effectiveness needs confirmation.

Tea farmers and other agricultural producers using nitrogen fertilizers should find this interesting, particularly those concerned about fertilizer costs or environmental impact. Environmental scientists and soil researchers should also pay attention. However, home gardeners should wait for more practical guidance before trying this approach, as the research is still in early stages.

In a laboratory setting, the fungi showed effects within the timeframe of this experiment (which appears to be a single growing season). In actual farm conditions, it might take one full growing season to see clear benefits, and the effects may vary depending on weather and soil conditions.

Want to Apply This Research?

  • Track nitrogen fertilizer application amounts and measure nitrogen content in soil drainage water monthly (if testing on your own farm). Compare these measurements between treated and untreated soil areas to see if fungal inoculation reduces nitrogen loss over time.
  • If you manage agricultural land, consider testing arbuscular mycorrhizal fungi inoculation on a small section of your field. Start by inoculating soil in one area while keeping another area as a control, then monitor fertilizer use and crop yields over a full growing season to see if you can reduce fertilizer while maintaining production.
  • Over a full growing season, track: (1) amount of nitrogen fertilizer applied, (2) crop yield and quality, (3) soil nitrogen levels (if possible through soil testing), and (4) any visible changes in soil structure or plant health. Compare these metrics between fungal-treated and untreated areas to determine if the practice is effective for your specific situation.

This research was conducted in controlled laboratory conditions with tea plants and may not directly apply to all crops, soil types, or farm conditions. Before implementing fungal inoculation practices on your farm, consult with a local agricultural extension agent or soil scientist who understands your specific growing conditions. This study suggests potential benefits but is not a substitute for professional agricultural advice. Results in actual farm fields may differ from laboratory results due to variations in weather, soil properties, and management practices. Always conduct small-scale trials before making large-scale changes to your farming practices.