Thumbnail Image

Degradation of the natural pasturages and quality of the soul in the region Sudan-Guinea of l'Adamaoua and Cameroon

Year of publication 2000

Pages 9

Author Par S. YONKEU, P. M. MAPONGMETSEM et M. B, NGASSOUM;Animal Production and Health Division

Product type Book (stand-alone)

Edition 1

Synopsis (short abstract) The term “soil conservation” is frequently used to mean a variety of activities by humans to control the rate of degradation, loss of soil, and yield of sediment from the landscape by wind, water and gravity (FAO, 1985). Except under forest conditions, surface horizons of most tropical soils having clay and organic matter contents are generally not well aggregated under cultivation. The soil aggregates are weakly developed and unstable to raindrop impact. On quick wetting during rain, these aggregates slake easily to form a surface seal or crust. Such formations occur when the surface ground is bare or incompletely covered by the vegetative canopy or surface mulch. In addition to sealing and crusting, migration of fine soil particles into underlying layers is often observed especially when the soil surface is disturbed by tillage and/or continuous cropping. The loss of pore continuity at the soil surface by sealing and crusting or at the adjacent soil layers by eluv iation of fine topsoil particles causes the reduction of water infiltration. As a result, runoff and soil loss can significantly increase especially on sloppy grounds. Soil erosion is one of the major constraints of agricultural development of the highlands in the tropics. More than 80% of cultivated lands in these regions are prone to severe erosion as a result of improper agricultural practices.

Language English

Also available in:
No results found.

Related items

Showing items related by metadata.

  • Thumbnail Image
    Project
    Report , Working Group on Artisanal Fisheries Statistics for the Western Gulf of Guinea, Nigeria and Cameroon 1993
    Also available in:
    No results found.
    The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organisation or the financing agency concerning the legal status of any country or territory, city or area, or of its authorities, or concerning the delimitations of its frontiers or boundaries.
  • No Thumbnail Available
    Project
    Survey of the Offshore Sub-surface Community from Togo to Cameroon and of the Shelf from Equatorial Guinea to the Congo (August - September 1981) 1981
    Also available in:
    No results found.
    The survey was planned as a 30-days-survey covering the shelf from Togo to Congo with the shelf off Nigeria and Cameroon covered only between 50-200 m depth limit. Due to a breakdown of a generator the survey had to be shortened by over a week, making the sampling intensity less than planned. Generally speaking the findings reveal an area with a very scattered fish distribution, both on small pelagic and demersal species. Dense plankton recordings occurred on most part of the shelf, making an accurate determination of the scant fish resources difficult. The estimates given reflect thus more an order of magnitude than absolute estimates. Both the northern and southern region were estimated to hold an average fish density of 39 tonnes/nm2 .In absolute figures the Togo - Cameroon 50-200 m depth region is estimated to hold 310,000 tonnes of fish while the Equatorial Guinea - Congo shelf region comprise 580,000 tonnes. Of this about 40% is allocated to demersal fish in the northern part a nd 25% in the southern. Only the sardinellas (Sardinella aurita and S. maderensis) off Gabon and Congo seem to form any stocks in terms of resources. The pelagic resources off Gabon and Congo were estimated to 350,000 tonnes of fish in the surveyed area, and about 50% of the biomass should belong to the sardinellas if one should split according to the catches. But this is a weakly based assumption as the hauls were few, the presence of the sardinellas were very concentrated and the trawl-avoidan ce is likely to be species dependent. Furthermore the sardinellas off Gabon - Congo belongs to stocks extending into Angola (TRODEC and GARCIA 1979) and the local abundance is thus heavily influenced by fluctuations according to the migratory pattern.
  • Thumbnail Image
Show more

Users also downloaded

Showing related downloaded files

No results found.