Deforestation, steep slopes, unsustainable farming practices and reclamation of mangrove swamps are the main drivers of land degradation in Fiji.
The steep topography and highly erosive rainfall contribute to high natural rates of soil erosion. Data on erosion rates is sparse, but a study in a heavily forested area suggests losses of up to 50 tons of soil per hectare each year through run-off, four times the average in tropical areas. From the 1950s a substantial area of sloping land was brought into some form of agricultural production. The impact of this extension of agriculture and increased logging of rainforests on erosion has been considerable. The effects of erosion include: land degradation; loss of soil carbon; decreased productivity; sediment deposition in rivers with subsequent increase in flooding; and damage to coral reefs by transported sediment.
The small size of farm holdings in Fiji (60 percent are less than 3 ha) forces farmers into intensive cultivation (often mono-cropping) for high output, short-term production without (or with only minimal) fallow periods. Furthermore, competition for land is forcing subsistence gardens onto steeper slopes because of the expansion of cash cropping and grazing on the flatter lands. Excessive soil erosion in many sugar cane areas along with the burning of cane trash is resulting in serious depletion of fertility and soil loss on poorly managed farms.
Urbanisation has also led to the capping and sealing of highly versatile land on urban fringes around major centres.
