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Theme: THE DEGRADATION OF WETLANDS AND ITS SOCIO ECONOMIC AND ENVIRONMENTAL IMPLICATIONS IN NDOP CENTRAL SUBDIVISION, NORTH WEST PROVINCE CAMEROON

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2.2.1.3 The application of chemical fertilizers on wetlands

The change in the water quality (as a manifestation of wetland degradation) is an aspect which is common due to the activities that are practiced on wetlands. The use of chemical fertilizers is a necessity during rice cultivation in order to increase crop yield. This has far reaching effects on the chemical composition of wetland waters. The change in chemical composition has led to the rapid growth of algae in some areas, water weeds in others; and the general tendency is that water is deoxygenated in areas of stagnation e.g. in the Bamendjin reservoir. From interviews with fishermen, 82% of them confirmed that their optimal fishing season is during the weeding season when fertilizers are applied and water weeds/algae bloom rapidly in fishing grounds. These algae act as fish feed which attract fish to the surface and water banks, facilitating their catch. But after a short period, fish become very rare even around areas which once proved to be fertile. Tanten G.C (2004) found out that this occurs because of the deoxygenation of these areas, rendering the area inhospitable to several aquatic organisms.
Several types of fertilizers are used on the rice fields and were readily obtained from the U.N.V.D.A. depot, the local market and from N.W.D.A. These fertilizers are most often compounds of nitrates, sulphates, phosphates and/or uric acid components. To estimate the quantity of fertilizers used in the rice fields in this region on an annual bases, deductions were made based on the average number of farmers, average farm size and a unit measure of fertilizer input being a 15 litter bucket. It was found out that over 81.62 fifteen litter buckets of fertilizers are used over average surfaces of 1632.51 hectares; corresponding to the U.N.V.D.A.s area of intervention. These chemical fertilizers are applied over two periods in the rice fields. Due to the constant flow of water over the rice fields, there is a drift of chemical fertilizers into streams which stagnate into some areas (like in dams); causing the water to change from an oligotrophic to a eutrophic state. This change in state is marked by the rapid growth of green bacteria and algae (See photo 6) which are reputed for deoxygenating fresh water lakes (Green N.P.O; et.al., 1984 and IETC, 2000).

The vegetation cover of Ndop Central Subdivision has been greatly influenced by anthropogenic factors. Following earlier analysis, it can be understood that this region had an immerse flora cover, with several sacred forests. Due to the increasing demand for fuel wood, building materials and farmlands, several wetland forests were cut down. These areas which had a dense ligneous cover, marked by large hard wood species (like the iroko and mahogany)