Soil scientists dig for answers after catastrophic Tonga volcano eruption


Photo: Soil scientist survey after eruption


A group of soil scientists have embarked on a quest to determine the impact of the  volcanic ash fall and tsunami caused by the Hunga Tonga Hunga Ha’apai volcanic eruption that occurred near Tonga in January this year.

Funded by the New Zealand Ministry of Foreign Affairs and Trade (MFAT) in partnership with Manaaki Whenua - Landcare Research NZ, the soil survey project saw soil experts travelling the breadth of Tongatapu and Eua islands  to collect more than  100 core soil samples from 25 historic sites and nine tsunami impacted areas. The teams also conducted on-field soil tests to determine soil nutrients.  

Soil experts included those from the  Pacific Community (SPC), the  Commonwealth Scientific and Industrial Research Organisation (CSIRO) Australia and agriculture technical officers from the Tonga Ministry of Agriculture, Forests and Food (MAFF) and MORDI  Tonga Trust. 

“The core soil samples we collected will undergo DNA and chemical analysis at CSIRO’s  Analytical Services Unit laboratory in Australia before being archived and held in trust for the Government of Tonga in the Australian National Soil Archive,” said Dr Ben Macdonald, the Soils and Landscapes Group Leader, Agriculture and Food at CSIRO.

“We are trying to look at how salinity from the tsunami has affected the soil and how the soil has changed since the volcanic eruption by comparing it to some older soil data kept in the  Pacific Soil Portal (PacSoP). We want to also provide some recommendations through MAFF and MORDI on what farmers can do to improve their sustainable production practices.”

SPC Land Resources Division soil scientist Dr Ellen Iramu added that the results will be digitised,  including capturing the soil legacy data, land use and soil type.

 “All the digital soil data generated from this sampling project will be stored in the Pacific Soils Portal  and can be accessed by Tongan  researchers, policy makers and relevant government ministries to guide them on what to grow on their soil .”

“Only countries with data stored in the Pacific Soils Portal can access the detailed digitised data as per the data sharing guidelines endorsed by the Heads of Agriculture and Forestry Services (HOAFS) in 2021.”

MAFF CEO, Dr Viliami  Manu, welcomed the local partnership with MORDI Tonga Trust that will strengthen their service to local farmers.

“MAFF is quite fortunate that NZ Manaaki Whenua – Landcare Research has offered the leading role in this work. This will pave the way for more capacity training of our technical officers who have been accompanying the regional soil experts around the island.”

MORDI Tonga Trust CEO, Soane Patolo agreed, adding their farmers will gain reliable information on the quality of their soil. “Without soil we can’t have sustainable agriculture. This study will guide us in making the right decision on what type of crops to plant or the type of fertilizers to use and so on.

Once the soil analysis data results are out, we will play our role of disseminating this important  information in a language that is easy for our farmers to understand and help equip them with the right science to improve their agricultural  productivity.”

The soil survey team is expected to continue their sampling on Eua Island with plans to explore Vava'u and Ha'api islands groups later this month.

Media contact(s):
Matilda Simmons, Communications Assistant, Land Resources Division, Pacific Community (SPC) | [email protected]
For general media enquiries, please contact [email protected].

About SPC:
The Pacific Community has been supporting sustainable development in the Pacific, through science, knowledge and innovation since 1947. It is the principal intergovernmental organisation in the region, owned and governed by its 27 member countries and territories. 
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