Researchers encouraged mung bean plants to take up more phosphorous by applying zinc oxide nanoparticles to their leaves. Photo by WUSTL

ST. LOUIS, April 29 (UPI) -- Researchers at Washington University in St. Louis have found a way use nanoparticles to boost crop production while minimizing fertilizer waste.

They detailed their feat in a new paper published this week in the Journal of Agricultural and Food Chemistry.


As farmers and the agricultural industry work to meet the food demands of a growing populace, more and more phosphorous, the main ingredient in fertilizer, is being dumped into the soil. Unfortunately, crops can only absorb so much phosphorous.

The excess fertilizer gets washed away as runoff, polluting waterways and encouraging large oxygen-sucking, fish-killing algae blooms in the Gulf of Mexico, Great Lakes and waterways all over the world. What's more, the world's supply of phosphorous is finite and shrinking

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"If farmers use the same amount of phosphorus as they're using now, the world's supply will be depleted in about 80 years," Ramesh Raliya, a research scientist at WUSTL, said in a news release. "Now is the time for the world to learn how to use phosphorus in a more sustainable manner."

Raliya and his colleagues created zinc oxide nanoparticles derived from a fungus that helps plant roots take-up phosphorous from the soil. Zinc interacts with three essential enzymes to convert complex phosphorous found in the soil into a simplified version that can be used by the plant.

Overworked soil loses its microflora biodiversity over time, as well the enzymes that aid phosphorous uptake. Dumping more phosphorous into the soil does little good.

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When the nanoparticles were applied to the leaves of mung bean plants, however, researchers observed an 11 percent increase in phosphorous absorption and 84 percent increase in the activity of the three essential enzymes.

"When the enzyme activity increases, you don't need to apply the external phosphorus, because it's already in the soil, but not in an available form for the plant to uptake," Raliya explained. "When we apply these nanoparticles, it mobilizes the complex form of phosphorus to an available form."

Researchers hope to deploy their technology in developing countries, especially in Asia. Farmers in India and China account for nearly half of the world's agricultural phosphorus use.