University of Alberta scientists find that promoting biodiversity increases the amount of phosphorus available in soil
Promoting plant biodiversity helps boost phosphorus in soil, a recent study indicates. That is important for agriculture because easily mineable deposits of the nutrient could be depleted in 50 to 100 years.
Phosphorus is difficult for plants to access naturally, said Xinli Chen, the study’s lead author and a Banting postdoctoral fellow at the University of Alberta’s Faculty of Agricultural, Life and Environmental Sciences.
“Sustainable management strategies to better use and increase soil phosphorus are urgently needed to reduce the dependence on fertilizer, and maintaining plant diversity is one way to do that,” he said in a university statement.
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Such methods could include farmers growing more than one crop on the same land at the same time, as well as preserving shelterbelts and windrows around fields, he said. He called it a “win-win situation” because it could reduce the need for producers to buy phosphorus fertilizer.
Other practices by farmers could include crop rotation and growing cover crops, said study co-author Scott Chang, a professor in the faculty’s Department of Renewable Resources.
He said cattle production involving grasslands is the sector that will likely be the easiest in which to promote plant biodiversity, he said.
Chang added that his suggestions about agricultural practices are speculation and aren’t part of the study. Such measures have to make financial sense for producers, “so this cannot dictate how the farmers do their operations over the economic effects.”
The study was recently published in Nature Ecology and Evolution, said Chang.
Local plant biodiversity is rapidly declining globally due to land use and associated changes, said the study. Availability of soil phosphorus in response to changes in plant diversity is not well understood.
However, research has shown that land with mixtures of plants display more benefits of phosphorus compared to ecosystems with a single plant species or crop type. Roots mostly grow in surface soil, which the study found contained 6.8 percent more phosphorus.
There was also an 8.5 percent increase in enzyme activity that makes the nutrient available to plants, along with 4.6 percent more phosphorus that plants could take up, the study said. Findings are the “first to show on a global scale that conserving plant diversity boosts a nutrient crucial for healthy land, including productive croplands.”
The results are based on a review of 180 studies of ecosystems ranging from temperate to tropical zones around the world, with the majority located in Asia and Europe, said Chang. They included land use types ranging from grasslands to cropland and greenhouses.
“The benefit of this study is that it is based on a global data set, so it’s not based just on a single study here in Alberta or in Canada for that matter. If there’s only one study site, what you find in terms of the data and in terms of the results is that really it’s pretty much only applicable for that specific site.”
Researchers found that ecosystems with a higher plant biodiversity can extract phosphorus from deeper deposits within topsoil, enriching the surface soil, said Chang. The increase helps boosts plant photosynthesis and productivity.
Chen said the findings join many other known advantages of preserving plant biodiversity, including the ability to sequester carbon.
“Now we’ve established that improving soil phosphorus availability is an additional benefit that helps sustain our current and future productivity of croplands, forests and other types of terrestrial ecosystems.”
Apart from agriculture, the findings could help guide decisions to protect plant biodiversity across the natural world, Chang said.
“We hope this research helps show the need for policy makers and the general public alike to promote the maintenance of biodiversity in all of our ecosystems.”
