The importance of the agricultural sector and its reliance on the fertility of the soil was recognised by the Tongan government in the 1960's, when it requested the New Zealand government to conduct a reconnaissance soil survey of the country, including assessment of the fertility of the major soils.
Tonga Soil and Land Use Programme (1975-78)
- Gibbs. H.S. (1976). Soils of Tongatapu, Tonga. New Zealand Soil Bureau Report 35, 15p.
- Wilde, R. H. Hewitt., A.E. (1983). Soils of 'Eua Island, Kingdom of Tonga. NZ Soil Survey Report 68. DSIR Soil Bureau, Lower Hutt, New Zealand.
- Wilson, A.D. Beecroft, F.G. (1983). Soils of the Ha'apai Group, Kingdom of Tonga. NZ Soil Survey Report 67. DSIR Soil Bureau, Lower Hutt, New Zealand.
- Orbell, G.E., et al. (1985). Soils of Part of the Vava'u Group, Kingdom of Tonga. NZ Soil Survey Report 66. DSIR Soil Bureau, Lower Hutt, New Zealand.
- Cowie, J. D., et al. (1991). Soils of Tongatapu, Kingdom of Tonga. DSIR Land Resources Scientific Report 21. DSIR Soil Bureau, Lower Hutt, New Zealand.
Soil Fertility Factors on Root Crop Production in Tonga
In 1998 Siosiua Halavatau completed his PhD at the University of Queensland which included a reconnaissance survey of the soils of Niuafo'ou and Niuatoputapu that had not been part of the DSIR Soil Survey project.
Tonga Agriculture Sector Plan 2016-2020
The Tonga Agriculture Sector Plan 2016-2020 is a comprehensive plan that includes extensive discussions and planning around the state of Tongan soils and land use and how this should be managed in the future. Funded by FAO and World Bank.
