COLLEGE STATION — Before conclusions can be drawn in any research project, a scientist has to get to the root of things. For Dr. Fred Davies, Texas Agricultural Experiment Station horticulturist, that’s fairly literal.
Davies studies fungi that partner with plant roots to help them become more efficient. His work has taken on such international importance that Davies is spending a year in Peru, where potatoes originated, to examine native strains of the fungus.
“Mycorrhizal fungi are not a panacea,” he said, “but they can help cut costs and provide for a better environment.”
Mycorrhizae (pronounced my-co-RISE-ay) are microorganisms found in soil. They are beneficial because upon entering a plant’s root system, the roots become more efficient in picking up water and nutrients. The majority of important crops can partner with mycorrhizae.
“Phosphorous doesn’t move well in the soil,” Davies said, for example. “Mycorrhizae are a biofertilizer because they enable elements with lower solubility to be picked up more easily.
“They are essential for making lower level of nutrients available,” he added.
Davies said the fungi are important for sustainable agriculture systems, whether low tech as in less-developed countries or high tech operations such as U.S. plant nurseries which are increasingly facing water shortages, high input costs and government controls for managing fertilizer runoff.
“The fungi can work in nurseries that are sophisticated but sustainable in that they have to collect and recycle irrigation water,” he explained.
When mycorrhizae fungi are used in fields or containerized plant production, he said, lower levels of slow release fertilizer can be used because the fungi in the roots enable the plant to use the elements more efficiently.
Mycorrhizae are commercially available, typically in premixed media.
Here’s why it works: mycorrhizae are living organisms that form a symbiotic relationship with plants. That’s necessary because fungi are not capable of performing photosynthesis to make life-sustaining sugars and carbohydrates. Plants provide carbohydrates for the fungi in return for the fungi picking up more nutrients from the soil, Davies said.
“Mycorrhizae have been around a long time and are becoming more commercially available,” Davies said. “But it is industry driven. To some extent, environmental regulation has brought on the use of mycorrhizae because in the long run, the environment is healthier if we use less water and less fertilizer to grow plants.”
A nursery cannot risk skimping on inputs such as fertilizer and pesticides because the resulting poor quality plants wouldn’t be purchased by consumers, he noted. But if a natural system such as the mycorrhizae can be used to produce healthier plants from less water and chemicals, the impacts would be more money for the grower and a better environment, Davies explained.
Plus, nursery plants grown with the mycorrhizae would go to the consumers’ yards or pots already containing the beneficial fungi in their roots which means a more stress-resistant plant and less pesticide, fertilizer and water use by the homeowner, Davies noted.
International interest has grown in mycorrhizae fungi. Davies six years ago did research under a Fulbright fellowship in Mexico to examine mycorrhizae in chili peppers. In Peru, his work will turn to potatoes, one of the most nutritious vegetable crops and a worldwide favorite.
“Potatoes are high in protein, vitamins and antioxidants, and they store well,” Davies said. “The only problem with potatoes is what condiments you add to them before eating.”
Because potatoes are native to the Peruvian region, Davies plans to look at the potato and native mycorrhizae fungi to see how the two have evolved together.
“Potatoes have high nitrogen and phosphorous fertilizer requirements,” Davies explained. “So there is big interest for all of agriculture in looking at them to understand the mycorrhizae fungi better.”
One thing Davies hopes to learn is how mycorrhizae fungi can be more effective. In subsistence and large-scale agriculture production, he will be testing an experimental compound that is available to stimulate the fungi.
Seed potatoes (potato tubers that are diced rather than seed collected from the top of the plant) are coated with an isoflavonoid (a naturally occurring plant chemical) to boost the mycorrhizae fungi that are already in the soil in the field, Davies explained.
“But we need to know how to do it efficiently, commercially or on a large scale,” he said, “and also in the greenhouse — to treat the roots as we want them to grow.”
Both the labor intensity and the cost will be considered in the study, Davies noted.
In the United States, he pointed out, fertilizer costs are only about 2 percent of the cost of production, but in a country such as Peru, it can be as high as 25 percent.
“So, anything you can do to use less will save money while putting less inputs into the environment,” he said. Because they are naturally occurring biological organisms that can save money and the environment, Davies said, mycorrhizae fungi have widespread global interest.
His work in Peru, at National Agrarian University (La Molina) and the International Potato Institute in Lima, is funded by a Guggenheim Fellowship and a Senior Fulbright Fellowship.
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