Dans sa premire partie, cette tude tente de faire le point de la situation de l'effort de pche actuel exerc dans les principaux plans d'caux du Pays. Les seuls paramtres disponibles pour cette valuation datent de 10 20 ans, aucune donne plus rcente n'ayant t recueillie. Cette lacune est due en grande partie la faiblesse de la structure de la Division Pche et Pisciculture de la Direction des Eaux et Forts, reste jusqu'alors au stade embryonnaire, ainsi qu'au manque de budget.

There is a urgent need for a better understanding of the risks of soil degradation and their geographical distribution as well as a better knowledge of where degradation occurs at present. it would be desirable to combine soil conservation activities with other elements for increasing crop production.Erosion, salinity and alkalinity and the loss of soil fertility seriously reduce the natural potential of soils to produce food fibres. During the meeting, many criteria to assess the various types of soil degradation were outlined by the experts.

A major problem facing the areas already under cultivation, is the seriousness of soil degradation and loss of soil fertility due to indiscriminate misuse of agricultural lands, forests and grazing lands. The modern thinking assigns to soil conservation a comprehensive and more positive role than in the past. in that sustained improvement complemented by the preservation of available resources should form the central concept. Soil conservation must not be limited solely to agricultural and grazing lands.

The purpose of this soils bulletin is to summarize the soil erosion problem and to focus attention on remedial measurs available with particular reference to the lands under traditionnal forms of agriculture in the developing countries. It is hoped that the bulletin will be of assistance to fields workers of national, international and bilateral aid agencies working in areas of limited resources.

Este nmero especial de Unasylva tiene dos objetivos principales. Pone a disposicin de nuestros lectores una seleccin de algunos de los trabajos presentados en el importante Cuarto perodo de sesiones del Comit de Desarrollo Forestal en los Trpicos, de la FAO y, de esta manera, pone de relieve la principal preocupacin de la Organizacin en materia forestal: cul es la mejor manera y la ms adecuada para el hombre de utilizar la formacin ecolgica menos conocida, es decir, los bosques tropicales hmedos.

This special issue of Unasylva has two main objectives. It brings to our readers an edited selection of some of the position papers of the important 4th Session of the FAO Committee on Forestry Development in the Tropics and, in doing, this, it emphasizes FAO's principal concern in the field of forestry: how to make the best and wisest use of man's least understood ecological formation, the moist tropical forest.

An international journal of forestry and forest industries

El Código nacional de recursos naturales renovables y de protección del medio ambiente, consta de 340 artículos organizados en dos libros: Del Ambiente (Libro Primero) y De la Propiedad, Uso e Influencia Ambiental de los Recursos Naturales Renovables (Libro Segundo).

Revue internationale des forts et des industries forestires

Land Groups Incorporation Act 1974

Black cotton soils are one of those clays with a high content of montmorillenite. These have a very high plasticity leading to high rates of expansion on wetting followed by shrinkage and considerable cracking on drying. The black cotton soils of Ethiopia have liquid limits ranging between 80 and 120 and plasticity indices of 40 to 80 (see figure l). The activity of these clays is between 0.8 and 1.5. Thus by the Skempton classification the activity of these clays is considerable and, as one would expect, swelling potential is high.

Data will be collected by remote-sensing techniques, through national reports, and by scanning existing inventories. The information would then be collated, analysed and computerized. An effective model would be constrycyed, from which caution and danger areas would be identified, and an alarm system organized for warning governments. Where, for example, the world's thermic balance is altered by the destruction of forest areas, the programme would be in a position to recognize this phenomenon and to adise onh extensive afforestation or reforestation schemes.