Wonder tree keeps on giving

Early tests find benefits extend to root systems

Early tests find benefits extend to root systems

NOT JUST HONEY: Research from the Institute of Environmental Science and Research has found manuka’s anti-microbial properties, well-known in honey and essential oil, are also in the roots, providing a potential option for riparian planting to help clean up the country’s degraded waterways. Picture by Maria Gutierrez-Gines
MANUKA TRIALS: An experiment of manuka roots foraging in a patch of biosolid found manuka roots have the potential to reduce farm run-off contaminants, including nitrates and E. coli. Picture supplied
EXPERT TEAM: Dr Maria Gutierrez-Gines, a post-doctorate fellow at the Institute of Environmental Science and Research.

Picture supplied

MANUKA and kanuka are well-known for their honey and essential oil antimicrobial potential, but they could have an additional benefit — cleaning up waterways. A team of scientists at the government-owned Institute of Environmental Science and Research (ESR), and Lincoln University, have been testing the native trees, which have natural anti-microbial properties, in their potential to disinfect farm run-off.

Initial testing by the Centre for Integrated Biowaste Research (CIBR) has shown E. coli and other pathogens, and nitrates, are reduced at a greater rate in soil with manuka or kanuka roots than in pasture.

“We knew it had those properties in honey so we thought we could try it with leaves and roots,” says Dr Maria Jesus Gutierrez-Gines, a post-doctoral fellow at ESR. In addition to holding more soil and water, we think manuka roots can also affect run-off from farms by decreasing bacteria and nitrates.”

Dr Gutierrez-Gines presented some of the findings of their research at Te Mana o Te Wai freshwater symposium in Uawa/Tolaga Bay earlier this month.

“Planting the edges of rivers and lakes with vegetation is not something new,” Dr Gutierrez-Gines says. “It was there before, and it has been removed.”

Their research has found that the anti-bacterial properties in the trees are not only in the leaves and flowers but also in the roots. One test involved putting manuka and kanuka in pots with E. coli in the soil and comparing it to typical pasture. The time taken to achieve a 90 percent reduction in E. coli was five and eight days for kanuka and manuka respectively, compared with 93 days for rye grass. They have also found the nitrate levels with the trees are much lower than radiata pine.

Two field trials in the North Island, at Lake Waikare near Te Kauwhata in the Waikato, and Lake Wairarapa, will determine how it can be applied in the wider community. At Lake Waikare the community was worried about the state of the lake. With funding from the Waikato River Authority CIBR (led by ESR) is installing a manuka-dominated ecosystem (50 percent) with 25 other species. They are also using manuka specific to that area, which is accustomed to being wet.

“Apart from creating a beautiful ecosystem and trying to reduce sediments and nutrients, we want be able to measure the application and quantify the benefits,” Dr Gutierrez-Gines says.

“We are doing the work so we know how much space is needed to plant manuka and how many plants are needed for the effects.”

Dr Gutierrez-Gines says they are aware how complicated the task of improving water quality is, but hope their research can assist in developing a solution.

“The inputs of nutrients and sediment into lakes and other waterways is a difficult problem. A river is a living thing, from beginning to end, and its degradation is not because of one problem, so there is not one solution. But we know water quality in New Zealand is a big problem, and riparian planting with manuka and kanuka can be a solution to improving it.”

MANUKA and kanuka are well-known for their honey and essential oil antimicrobial potential, but they could have an additional benefit — cleaning up waterways. A team of scientists at the government-owned Institute of Environmental Science and Research (ESR), and Lincoln University, have been testing the native trees, which have natural anti-microbial properties, in their potential to disinfect farm run-off.

Initial testing by the Centre for Integrated Biowaste Research (CIBR) has shown E. coli and other pathogens, and nitrates, are reduced at a greater rate in soil with manuka or kanuka roots than in pasture.

“We knew it had those properties in honey so we thought we could try it with leaves and roots,” says Dr Maria Jesus Gutierrez-Gines, a post-doctoral fellow at ESR. In addition to holding more soil and water, we think manuka roots can also affect run-off from farms by decreasing bacteria and nitrates.”

Dr Gutierrez-Gines presented some of the findings of their research at Te Mana o Te Wai freshwater symposium in Uawa/Tolaga Bay earlier this month.

“Planting the edges of rivers and lakes with vegetation is not something new,” Dr Gutierrez-Gines says. “It was there before, and it has been removed.”

Their research has found that the anti-bacterial properties in the trees are not only in the leaves and flowers but also in the roots. One test involved putting manuka and kanuka in pots with E. coli in the soil and comparing it to typical pasture. The time taken to achieve a 90 percent reduction in E. coli was five and eight days for kanuka and manuka respectively, compared with 93 days for rye grass. They have also found the nitrate levels with the trees are much lower than radiata pine.

Two field trials in the North Island, at Lake Waikare near Te Kauwhata in the Waikato, and Lake Wairarapa, will determine how it can be applied in the wider community. At Lake Waikare the community was worried about the state of the lake. With funding from the Waikato River Authority CIBR (led by ESR) is installing a manuka-dominated ecosystem (50 percent) with 25 other species. They are also using manuka specific to that area, which is accustomed to being wet.

“Apart from creating a beautiful ecosystem and trying to reduce sediments and nutrients, we want be able to measure the application and quantify the benefits,” Dr Gutierrez-Gines says.

“We are doing the work so we know how much space is needed to plant manuka and how many plants are needed for the effects.”

Dr Gutierrez-Gines says they are aware how complicated the task of improving water quality is, but hope their research can assist in developing a solution.

“The inputs of nutrients and sediment into lakes and other waterways is a difficult problem. A river is a living thing, from beginning to end, and its degradation is not because of one problem, so there is not one solution. But we know water quality in New Zealand is a big problem, and riparian planting with manuka and kanuka can be a solution to improving it.”

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