Exploiting The Wetlands

Wetlands in cool temperate climates are a hindrance to agriculture, particularly in those regions of the world where there is a long winter. In tropical climates wetlands can be used for growing rice and in many areas swamp forests and bottomland forests provide excellent growing conditions for tree growth. In lands where there is a prolonged dormant season waterlogged soils are generally harmful to overwintering crops as well as being an obstacle to tilling and harvesting. Drainage has therefore been the general agricultural solution to the farming of wetlands. The low-lying marshes that surround the mouths and deltas of major rivers are not readily drained due to periodic flooding and tidal activity.

Wetlands can, however, be highly productive with the natural vegetation of reeds, rushes, sedges and willows that colonize the nutrient-rich sediments deposited where major rivers meet the ocean. The oxidation of organic waste by oxygen diffusing out from plant root systems together with the activity of the soil microflora purifies the water. From these wetlands clean water can then eventually recharge underground aquifers causing such regions to be referred to as 'the kidneys of the landscape'. In addition to their nutrient-absorbing capacity they also form land which protects coastlines, and buffers the potentially damaging effects of both flooding and drought. Given these properties it is therefore not surprising that there has been a long history of human usage and occupation of tidal marshes and that they have provided a home since prehistoric times for peoples who could adopt a lifestyle which was not entirely dependent on agriculture and who were prepared to accept the physical risks of their marginal location.

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