By Eleanor Gee

World Soil Day was marked for the first time in Tonga with a small ceremony held today, 6 December at the MORDI Tonga Trust complex in Havelu.

The ceremony was part of a three-day soil and water management training attended by 21 participants from MORDI Tonga Trust, Tonga National Youth Congress, Ministry of Agriculture, Food and Forestry and Nishi Trading.

The day highlights the importance of soil to our survival as 95% of our food comes from the soil.

With soil erosion the number one threat to soil functions in many regions of the world, this year’s theme was ‘Stop soil erosion, save our future’.

Assistant FAO Representative to Tonga, Paumolevuka Likiliki, said in his key note address that coastal erosion is a significant problem in the Pacific islands.

“Soil is a finite resource, meaning its loss and degradation is not recoverable within a human lifespan.”

“It can take up to 1000 years to produce 2-3cm of new top soil,” he said.

“Every 5 seconds the equivalent of a football field of soil is eroded globally. Approximately 33% of our global soils are degraded.”

He said soil erosion could occur on various scale, from the eroding hill tops, to the paddocks, to minor gullies, in major creeks and rivers and our coastal shores.

“It can be caused by wind, water and tides, animal tracking and poor land management decisions.”

However, he added that scientific findings presented by FAO showed agriculture systems and agro-ecological practices that dedicate great care to nurturing soil biodiversity, such as organic farming, zero-tillage, crop rotations and conservation agriculture, could sustainably increase farm productivity without degrading soil and water resources.

Tongan soil

Soil consultant, Dr Siosiua Halavatau, said Tongatapu soil is formed from two different ages of volcanic ash.

During the three-day training program, he showed participants how to test soil from Lapaha and Vaini using a soil kit.

He said the soil in Lapaha has less than 40% young ash which gives the soil fertility and in Vaini, there is more than 40cm. In ‘Utulau, the whole soil is young ash and “when you dig down, you reach the base of limestone.

Dr Halavatau believes commercial farmers should invest in a soil testing kit which would tell them how healthy their soil is. It is particularly useful when a farmer wants to know how much nutrients are required for a large harvest of any crop.

The soil kit costs around AUD$2,200 and can test 50 soil samples. It can also be restocked, said Dr Halavatau.

“If you send a soil sample to New Zealand for testing, you could pay around NZD$500 just for one sample to be tested.”

For subsistence farmers, a lower grade soil tester is more ideal.

Soil tests can also determine if a farmer is looking after the soil properly.

The World Soil Day is an annual event run by the UN Food and Agriculture Organization (FAO), to raise awareness of the importance of soil quality for human wellbeing, food security and ecosystems.