BYU study researches possible alternatives to plant fertilizer

Rhizobia bacteria may be able to replace nitrogen-based fertilizers. (Mark A. Philbrick)

Some claim that the hundreds of dead zones and oxygen–depleted water areas appearing in the world’s oceans can be linked to the proliferation of common plant fertilizers.

Researchers at BYU are looking for ways to combat this trend by discovering ways to get plants the nitrogen they need without using as much fertilizer.

Problems with fertilizer occur when the nitrogen and phosphorus it contains reach the ocean through agricultural runoff, creating
“dead zones.” Toxic algae fills these dead zones, taking up oxygen and killing fish and plants in the process.

In charge of the BYU study is Paul “Skip” Pricea postdoctoral fellow at BYU. He and his team have found that rhizobia bacteria might be the key in allowing plants to process nitrogen naturally, without nitrogen-based fertilizers.

Price said about 80 percent of the atmosphere is nitrogen, but it is in a form that plants cannot use. However, rhizobia and plants can work together to become mutually beneficial, a process known as symbiosis.

“By doing this and providing nitrogen naturally, you won’t have to add more fertilizers which cause more runoff,” Price said.

The objective of Price’s study is to discover the types of rhizobia that will work in conjunction with plants.

“One of the problems we have now is we don’t know what makes a good rhizobia for the soil,” Price said. “And so that’s what we’re studying, is how to improve the rhizobia for the plant.”

Price has discovered that HrrP, a gene sometimes contained by rhizobia, causes the rhizobia not to cooperate with plants. He said rhizobia with this gene would not generate nitrogen for the plant and would actually harm the plant.

 Map agricultural runoff in the Gulf of Mexico, where there are many dead zones. (
Map agricultural runoff in the Gulf of Mexico, where there are many dead zones.

“When rhizobia is no longer being productive, the plant spends a lot of its resources to try and communicate with the rhizobia,” Price said. “But if it can’t, then it just lost all its nutrients.”

Joel Griffitts, a molecular biology and microbiology professor at BYU, is also involved in the study. He outlined what they are trying to accomplish.

“The two main goals are to understand a complex symbiotic language between plants and beneficial bacteria and to use this knowledge to inform the development of agricultural technologies that will enhance crop yield without as many expensive inputs,” Griffitts said in an email.

Brett Dillon, a BYU graduate who was involved in the study, said that Price has been working on this study for years.

“I think that many people think of research and assume that great discoveries and break throughs are made regularly,” Dillon said.

Price and Griffitts both agree that the future of the rhizobia study is bright.

“If we can discover natural bacteria that can enhance the productivity of these crops while minimizing chemical inputs, it would be a very significant advance,” Griffitts said.

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