The Pacific coastline from Peru to Northern Chile is one of the most arid regions in the world, with little rainfall, but considerable amounts of fog produced by the advection of marine clouds towards the continent. This paper describes a project, recently funded by the European Commission, whose objective is to set up a basic plan of sustainable use for the natural resources of the Peruvian coastal desert using collected fog as the only water resource. This plan will be based on the results of a pilot experiment, which is being carried out on the coastal hills of Southern Peru, aimed at verifying the following assumptions: the effectiveness of artificially collected fog water in the restoration of the vegetation in an environment which is undergoing a process of rapid desertification; the ability of plants to sustain themselves by means of the water supply derived from the fog they collect, and with no more need for man made collectors; the possibility that the surplus of water obtained by means of artificial collectors can be used for subsistence agriculture and for pasture growth.

Tropical catfish, Mystus nemurus (C. & V.) (25.89 ± 0.7 g) were stocked semi-intensively in 0.03-ha earthen ponds at the rate of 10 000 ha”-¹ and fed six iso-energetic practical diets ranging from 27% to 50% protein for 8 weeks. Each diet was fed in three replicate ponds twice daily to satiation. Experimental fish were also reared extensively, in control ponds, without supplementary feed. Fish fed the 42% protein diet had the highest standing crop, weight gain and protein utilization values and the differences from other diets were statistically significant (P > 0.05). Protein efficiency ratio (PER) decreased as dietary protein increased. The experiment indicated that natural food organisms contributed to some degree if not significantly to the catfish production. Weight gain, food conversion ratio (FCR). PER and SGR (specific growth rate) indicated that a 42% protein diet with digestible protein-to-energy ratio (D/E) of 27.57 mg kj_¹ produced maximum growth in the static pond system.

This paper uses mechanism design theory to (i) propose a mechanism to price irrigation water when farmers are heterogeneous in their production technologies (adverse selection) and their individual water uses are unobserved (moral hazard) and (ii) discusses briefly when such a mechanism might be economically unreasonable. Unmetered irrigation water is often priced by imposing per-acre fees on cultivated acreage or by charging per-unit fees on observable inputs or outputs. The offered pricing procedure is based on the observed output and achieves a first-best outcome when implementation is free of transaction costs.

[Notes_IRSTEA]car./tabl. [Departement_IRSTEA]GT [TR1_IRSTEA]GT1-Relations entre les écosystèmes et leur utilisation | National audience | The evaluation of water budget of forest sites is a good indicator of forest yield. The goal of this study is to give foresters simple tools for estimating this water budget for any site, as to predict variations of site index. Water-holding capacity of soils is calculated with a simple index, usually used in agronomy : it only takes into account depth, texture and stone content of soil. Another index ("seepage index") evaluates the balance between inputs and outputs of water according to the position of site on slope. These two indices are compared with the site index for Norway spruce and Silver fir in the French Massif Central. This simple test, easy in the field, can be used in wide areas in the French Massif Central. But this method must be used carefully in other conditions : rapid changes of texture, great amount of stones... Then, it seems necessary to take into account other soil variables : stoniness parameters, description of the substratum... | L'alimentation en eau des stations contrôle une part importante de la production forestière. Elle doit pouvoir être évaluée par des indices simples, robustes et facilement mesurables sur le terrain par tout gestionnaire forestier. Cet article montre l'intérêt de méthodes de diagnostic simplifié : la valeur du réservoir en eau du sol (RES) est estimée en prenant en compte uniquement la profondeur du sol (par test-tarière), sa texture et sa pierrosité. Un bilan entre apports et départs d'eau sur le versant complète ce diagnostic. Ces deux éléments sont comparés avec l'indice de fertilité de peuplements d'épicéa commun et de sapin pectiné, qui permet d'estimer leur niveau de production. Cependant, elle ne s'applique en toute rigueur que dans des conditions de relative homogénéité des matériaux parentaux et des sols. Des propositions sont faites pour complèter cette approche dans d'autres contextes édaphiques.