Mycorrhizal Tea and Corn Drought Tolerance

ISEF Category: Plant Sciences

Subcategory: Agriculture and Agronomy  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

Corn seedlings can look fine one day and collapse the next when water runs low. Mycorrhizal fungi can help roots pull in water, almost like underground plumbing. Your question is whether a homemade forest-floor brew can do as well as a commercial inoculant. That gives you a real comparison with a clear outcome you can measure.

What Is It?

Mycorrhizae are fungi that live with plant roots. The plant gives the fungi sugar, and the fungi help the plant gather water and nutrients. Think of them as a trade deal under the soil. When people talk about mycorrhizal "tea," they usually mean a liquid made from soil, litter, or fungal-rich material that may carry spores, hyphae, or other microbial bits.

In this project, you are testing whether that homemade brew helps corn seedlings handle drought. You are not just asking if the plants live. You are asking how long they stay upright, how fast they wilt, and whether they recover after stress. That makes the topic more than a yes-or-no question. It becomes a study of plant stress, root help, and water use.

Why This Is a Good Topic

This is a strong science fair topic because you can test a real biological idea with visible results. You can compare a homemade treatment, a commercial product, and a no-inoculant control, which gives you a fair design. The project connects to crop survival, soil health, and water stress, all of which matter in agriculture. You can also learn experimental design, replication, and how to measure a plant trait without fancy gear.

Research Questions

• How does mycorrhizal tea from forest-floor litter affect the wilting point of corn seedlings compared with no inoculant? ?
• What is the effect of commercial mycorrhizal inoculant on corn seedling drought tolerance compared with forest-floor tea? ?
• Does the source of forest-floor litter change how much drought protection the tea provides? ?
• To what extent does mycorrhizal treatment change the number of days until visible wilting in corn seedlings? ?
• Which treatment, forest-floor tea, commercial inoculant, or control, gives the highest recovery after rewatering? ?
• How does mycorrhizal treatment affect leaf droop score during a dry-down trial? ?

Basic Materials

• Corn seeds from the same packet or lot.
• Small pots with drainage holes.
• Potting mix with the same soil blend for every pot.
• Forest-floor litter sample from one location, collected with permission.
• Commercial mycorrhizal inoculant.
• Distilled water or dechlorinated water.
• Digital kitchen scale with 0.1 g accuracy.
• Measuring cups or graduated cylinders.
• Labels and a permanent marker.
• Tray to catch runoff.
• Ruler or caliper for seedling height.
• Smartphone camera for daily photos.
• Notebook or spreadsheet for daily scores.

Advanced Materials

• Corn seeds from a single hybrid lot.
• Autoclaved or pasteurized growth substrate for cleaner comparisons.
• Greenhouse bench space with controlled light exposure.
• Soil moisture sensor or volumetric water content probe.
• Leaf gas exchange meter, if available.
• Chlorophyll fluorescence meter, if available.
• SPAD meter, if available.
• Sterile filtration setup for comparing filtered and unfiltered tea.
• Hemocytometer or microscope for estimating spore or propagule density.
• PCR access for confirming fungal DNA in inoculum, if your lab supports it.
• Balance with higher precision for pot mass tracking.
• Data logger for repeated measurements.

Software & Tools

• Google Sheets: Organizes daily plant scores, pot masses, and treatment groups in one place.
• ImageJ: Measures leaf area, droop angle, or color change from standardized photos.
• R: Runs statistics, plots dry-down curves, and compares treatment means.
• NIH ImageJ macro tools: Help you repeat the same photo measurement steps across many plants.
• QGIS: Maps litter collection points if you compare multiple forest sites.

Experiment Steps

1. Define the exact plant outcome you will measure, such as days to visible wilting, leaf droop score, or recovery after rewatering.
2. Choose one comparison setup, such as forest-floor tea, commercial inoculant, and untreated control.
3. Decide how you will keep soil, pot size, seed lot, and light conditions the same across groups.
4. Plan a dry-down schedule that creates water stress in a repeatable way without drying plants too fast.
5. Build a measurement system for weekly growth and daily stress scoring, then test it on a few plants before the full run.
6. Set up your analysis plan before collecting data, including how you will compare averages and handle outliers.

Common Pitfalls

• Using litter from different forest spots, which changes the microbial mix and makes your treatment inconsistent.
• Letting the homemade tea sit too long, which can favor random bacteria instead of mycorrhizal propagules.
• Comparing plants by visual wilting only, which misses differences in soil moisture and plant size.
• Watering by feel instead of pot mass, which makes the dry-down stress uneven across groups.
• Mixing inoculant into soil unevenly, which leaves some seedlings untreated even inside the same group.

What Makes This Competitive

A competitive version of this project needs more than a simple treatment comparison. You can strengthen it by quantifying drought stress with repeated measurements, not just a final wilt score. You can also compare multiple tea sources, verify whether the inoculum really contains fungal material, or test whether the effect depends on soil type. Strong statistics, clean controls, and a clear mechanism will make the work stand out.

Project Variations

• Test forest-floor tea on beans or tomatoes instead of corn to compare how different crops respond.
• Compare filtered and unfiltered mycorrhizal tea to see whether living particles matter more than the liquid itself.
• Test the same treatments in sandy soil and potting mix to see how soil texture changes drought response.

Learn More

• USDA NRCS soil health resources: Search for pages on mycorrhizae, soil biology, and plant water relations.
• USDA Agricultural Research Service: Search for articles and reports on mycorrhizal fungi in crop production.
• NIH PubMed: Search review articles on arbuscular mycorrhizal fungi and drought tolerance in maize.
• NOAA Climate.gov: Use background material on drought, evapotranspiration, and water stress in plants.
• MIT OpenCourseWare, introductory plant biology materials: Find free lectures and readings on roots, plant stress, and nutrient uptake.