In the citrus groves of southwest Florida, a team of researchers is investigating the hidden power of soil nematodes. These tiny organisms with enormous ecological impact offer key insights into soil health. This study investigates how cover crops influence nematode communities and, in turn, impact soil fertility and sustainability. Researchers in the UF/IFAS department of soil, water, and ecosystem sciences (SWES) are leading the study. They include doctoral candidate Yaslin Gonzalez and her advisor, Dr. Gabriel Maltais-Landry, along with their collaborator at the Southwest Florida Research and Education Center, Dr. Sarah Strauss. Their findings could help farmers assess and manage soil health in perennial cropping systems.
Soil health is a crucial factor in sustainable agriculture, influencing everything from crop productivity to nutrient cycling. Traditional assessments focus on chemical and physical properties. However, this research highlights the role of soil biology, particularly nematodes, as sensitive indicators of ecosystem changes.
“Nematodes are important bioindicators,” explains Gonzalez. “Their presence, abundance, and diversity reflect the overall state of soil and ecosystem health. This makes them an invaluable tool for farmers looking to improve soil functions.”
The study took place at two sites within a commercial citrus grove. One site had trees over 20 years old and another with younger trees under 10 years old. Researchers tested three cover crop treatments:
- a mix of legumes and non-legumes
- a non-legume-only mix
- a grower’s standard of bahiagrass that became increasingly weedier with time
They analyzed nematode communities in these different systems over time—six-month intervals from September 2022 to February 2024. The team observed how cover crops influenced food web structure, nutrient cycling, and soil resilience.
Results
Cover crops generally increased nematode abundances across all trophic groups, from bacterivores and fungivores to predators and omnivores. In the older grove, cover crops enhanced soil food web complexity, as indicated by an increase in the Maturity Index (ecological stability). Meanwhile, in the younger grove, cover crops improved nutrient availability and reduced soil perturbations.
“This research reinforces that soil health is a dynamic process influenced by plant diversity,” says Maltais-Landry, an associate professor of sustainable nutrient management systems.
“By integrating cover crops, we can promote beneficial nematode communities that enhance nutrient and carbon cycling and overall soil function,” he added, “which ultimately can lead to healthier citrus trees.”
The researchers hope their work will encourage broader adoption of nematode-based soil health assessments. They hope to share the findings with farmers and land managers, so producers have the tools they need to cultivate resilient agricultural systems.
“Understanding soil biology at this level opens the door to more sustainable farming,” Gonzalez explained. “By paying attention to some of the smallest organisms in our soil, we can take big steps toward healthier crops and ecosystems.”
The research team’s other members include Dr. Sarah Strauss and Dr. Allan Bacon from SWES and Dr. Zane Grabau in the UF/IFAS department of entomology and nematology. The work, which is part of Gonzalez’s dissertation research, is funded by a USDA-NIFA grant, and it is published in the journal Applied Soil Ecology. You can read the full article here: https://doi.org/10.1016/j.apsoil.2025.105917
This work is supported by the Agriculture and Food Research Initiative (AFRI): Foundational Program: Soil Health, grant number: 2021-67019-34240, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture.
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.
Featured image is a UF/IFAS file photo by Thomas Wright.
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