Irrigation is being extended even to the most arid areas changing the age-old ecosystem. The results of all these are yet to be known.
Small and marginal farmers have started leaving the rural areas for their inability to compete with their better off fellow farmers.
The agricultural production has more than tripled but it will have to be further tripled before the population can be hopefully expected to stabilise in the next four or five decades.
Based on the broad foundations of expanding agriculture, we are now busy building a super structure of industry. It has been providing livelihood to a large number of people in the countryside who can no longer be absorbed in farming activities.
Modem commercial agriculture is the most pervasive and environmentally destructive human activity in the sub-Region. Its primary impacts are;
(i) The direct removal of existing ecosystems;
(ii) The reduction of biodiversity;
(iii) Destruction of soils;
(iv) Pollution of the surface and ground waters with agricultural chemicals;
(v) Pollution of wetlands and the marine environment with silt and agricultural chemicals;
(vi) A major contributor to global warming through the loss of trees and generation of methane; and
(vii) A contributor to landlessness.
Agriculture is the leading cause of permanent deforestation, removal of wetlands, and other unique habitats in the Pacific islands.
Habitat removal and replacement with imported “domestic” ecosystems caused serious and permanent loss of biodiversity. Sustainable traditional fanning systems diminished as fanners entered the cash cropping system. Small productive mixed crop gardens with abundant trees were either burned or bulldozed to create large, treeless clearings.
Tractors tilled the soil, chemical fertilisers and poisons were applied with subsidised abandon, fallow times were shortened, sometimes replaced with crop rotation, and mixed crop gardens were replaced with monoculture. Monoculture, growing a dense, single species crop, inevitably leads to outbreaks of pests and application of poisons to control the pests.
Agricultural poisons, used to control pests or clear vegetation, are carried by rain runoff throughout the island ecosystems. Agricultural chemicals adhere to soil particles or are absorbed in organic compounds in the soil. During drought conditions these are blown off the island as dust and settle on the surface of the sea.
The poisons are dissolved in the organic microlayer of the sea and become concentrated in slicks on the sea surface. The slicks are a critical habitat for most species of fish and invertebrates (including sea grasses and corals), and the concentrated poisons endanger the reproductive capacity of marine organisms (Liss and Duce 1997).