Turkey has rich inland water sources, about 200 natural lakes, about 750 artificial lakes or ponds, about 193 reservoirs, 33 rivers and streams of 177,714 km length and 8333 km of coastal strips. Some lagoons covering of 70,000 ha in Aegean and Mediterranean coastal strips are very suitable for aquaculture. The main fish species cultured in Turkey are carp (Cyprinus carpio), rainbow trout (Oncorhynchus mykiss), Atlantic salmon (Salmo salar), gilthead sea bream (Sparus aurata), European sea bass (Dicentrarchus labrax), bluefin tuna (Thunnus thynnus), Blackl sea turbot (Pselta maxima), Mediterranean mussel (Mytilus galloprovincialis) and shrimp (Penaeidae spp). Aquaculture production of Turkey has grown steadily over the years from 5,782 t in 1990 to 63,000 t in 1999 and to 79,031 t in 2000. There are 1309 farms in inland water producing approximately 32,466 t of fresh water fish species and 352 farms at sea producing 40,119 t of sea fish species, mainly Gilthead sea bream and European sea bass.

The article discusses investigations in a flat rectangular contact area of two elastic solids (brake friction lining and disc) using a theoretical method. The solids are in free as well as in forced movement. The investigations have resulted in correlations describing deformation and stiffness parameters of solid flat joint in different loads: transference of the centre of cross section delta0 the angle of turning phi of one solid in relation to the other (as a result of friction lining deformation), and tension sigmax in any cross section of the contact area. The results of the investigations make it possible to analyze the stiffness of the contact of solids, test the strength of the contact areas, optimize the contact are of solids, and prognosticate even wear out of friction lining.

Theoretical and experimental investigations are carried out to estimating the impact of the plough body working width on its specific draft resistance, as well as the ploughing efficiency. By using analytical correlations derived as a result of theoretical research, a computer algorithm has been worked out for simulating the functions of the plough body and the forces exerted by soil upon the operating parts, as well as its draft resistance. Specific draft resistance of the plough body, energy consumption, as well as labour efficiency and ploughing costs depend considerably on the working width of the body. By increasing it, the energy capacity, specific fuel consumption and expenditure decrease, but labour efficiency increases.

Biodiesel is renewable and environmentally friendly fuel, which can be used as a substitute for diesel in compression ignition (CI) engines. Nowadays it is also successfully used not only in transport sector, but also in commercial construction equipment and space heating. As the production of biodiesel (rapeseed methyl ester RME) is started now and is planned to grow rapidly, it is necessary to investigate biodiesel impact on engine performance and exhaust gas composition. This paper describes results of the investigation the aim of which was to find out the impact of biodiesel and its blends on an engine's dynamical, economical and ecological parameters in laboratory conditions on an engine test bench. The experimental work was done with an XD2P diesel engine in the Motor testing and biofuels laboratory of the Motor Vehicle Institute of Latvia University of Agriculture. The engine was fuelled on fossil diesel, rapeseed methyl ester (RME) and on blends of 5 (5RME) and 35 (35RME) percent RME/diesel fuel. The results indicated that power for biodiesel and blends was lower than with ordinary petrol diesel on average. 7.9% on 100RME and 3.6% on 35RME. The reduction in torque and increase in fuel consumption was observed. Experimental results showed that the addition of RME to diesel can significantly reduce oxides of nitrogen (NOx), carbon monoxide (CO), and absorption coefficient.

The processing of milk in dairy companies produces a certain amount of wastewater and liquid wastes. During the treatment process of such wastes sludge is accumulated in treatment facilities. The sludge is a rather valuable soil fertilizer; however, apart from plant available nutrients, it also contains large amounts of pollutants. The paper analyzes the quality of wastewater treatment process performed in treatment facilities of dairy companies, and specifies the amounts of plant available nutrients contained in sludge accumulated during the treatment process of wastewater and liquid wastes. The amounts of heavy metals contained in sludge are compared with their maximum allowable concentrations determined in the environmental requirements for soil fertilization (Aplinkosaugos reikalavimai..., 2001). On the basis of the study results and normative documents of environment protection, the article presents optimal rates and regime for sludge fertilization as well as analyzes the agro-technical and qualitative characteristics of sludge spreaders made at the Water management Institute of Lithuanian University of Agriculture and used during the technological process of fertilization.

The paper presents study results on nutrient leaching in crop rotation fields where slurry was applied. The studies were carried out within the period of 2001-2003. As the study results have shown, phosphorus (P) concentrations much depend on drainage runoff. Increasing drainage runoff resulted in decreased P concentrations (r=0.7). P leaching also depends on the precipitation amount (r=0.83). Higher precipitation rates resulted in more intensive P leaching. P leaching more depended on the drainage runoff and the type of cultivated crops rather than on fertilization rates. P leaching also depends on the precipitation amount (r=0.83). Higher precipitation rates resulted in more intensive P leaching. P leaching more depended on the drainage runoff and the type of cultivated crops rather than on fertilization rates. P leaching decreased when higher amounts of phosphorus were accumulated in crop yield; the mineralization process of vegetative residuals that were left in the test field enhanced more intensive P leaching. When slurry was applied on crops of the test field, P concentrations never exceeded maximum allowable rates determined in normative documents of the environment of Lithuania. From the point of view of the environment protection, it is more expedient to apply slurry in spring because in this season of the year the leached amount of total P input into the soil is 37.5% less compared to its leached amount when slurry is applied in autumn.

The studies were carried out in two control profiles of the Graisupis ditch excavated 40 years ago and situated at the distance of 2.4 and 4.8 km from the outlet in the land of intensive farming in Kedainiai district. The study object contained mineral loam/sandy-loam soils on the flat relief. The areas of catchments in control profiles were 12.1 and 5.9 square km, the largest discharges of spring floods were 3.4 and 1.6 m**3sE-1. Cross-sectional parameters, grass characteristics and flow parameters were measured under the conditions of different discharges (6 replications in each control profile during the vegetation period and 4 replications in spring when the channel bed is clean). As the study results show, roughness coefficient of the grass-cowered channel bed increased up to 21 times, water tables were observed to be 20-40 cm higher, the outlets of the drainage were flooded up. Considering the average grass indices determined in control profiles, grass hydraulic resistance was calculated according to 4 formulas based on the scheme when grass cover resistance is estimated as the total resistance of separate obstructions. The difference of 22.3% between calculated results and natural measurements was determined. The formula estimating grass cover parameters as well as flow regime determined to be most suitable.

Latvia has become a fully-fledged Member State of the European Union (EU) and now is a part of the global integration processes. The EU has set a goal to form a knowledge-based society and to become a region with a dynamic economy. For this reason it is necessary to increase scientific research and innovation capacity. The scientific potential is characterized by adequate supply of materials, facilities and equipment. It is a precondition for any kind of productive scientific activity. It must be noted that equipment, along with materials and resources necessary for their maintenance and operation in scientific institutes and by groups of scientists, has not experience any significant improvement since the Soviet period. Since 1990, budgetary funding for science has been sufficient to ensure a mere survival. In 2004, Ministry of Education and Science, together with scientific institutions, drafted the National Programme "Support for Modernization of the Scientific Infrastructure in the State Research Institutions". The funding made available through the EU Structural Funds can be used for purchasing new scientific equipment for the state research institutions.

The research paper summarizes the results of the influencing factors of small and medium enterprises development: government's policy, access to short and long term financing with reasonable interest rate, investments, tax system, geographical environment, business environment and infrastructure, experience and knowledge. Most of all the small and medium enterprises development is influenced by the investments but also other factors have very significant role.

Same public goods can only be produced jointly with private goods. This paper focuses on the biological diversity that could be produced on semi-natural pastures through the assistance of grazing animals. The question that is being investigated is what shapes the total and marginal cost functions for biological diversity production on semi-natural pastures have if private goods are already being produced using livestock at farms near the pastures. The empirical analysis shows that a quadratic function describes the costs well and that the production is characterized by increasing marginal costs.