Main factors raised interest about biomass as the source of energy increase renewable resource demand in the context of Green house gases emissions decrease and the problem of environmentally friendly and efficient waste utilization. Legislation of waste water sewage sludge use is becoming stricter now. After cutting away top peat layer of peat quarry, the owners have two alternatives: the first, to flood the fields and transform them into bogs, the second, to carry out some economic activities - one of which must be field afforestation with traditional or fast growing tree species. Before planting trees it is necessary to fertilize the fields, and waste water sewage sludge will be one of potential fertilizers. Aims of research were to determine the impact of waste water sewage sludge fertilization 10 t haE-1 on tree growth and soil properties. Concentration changes of N, P, K, and Ca, Mg in different depth and concentration of S and total C and heavy metal in soil top layer during the year 2006 were determined. The effect of fertilization on tree growth and stock was determined by the non-destructive method, data were calculated by height and root core diameter of trees. Fertilization stimulates tree growth as weed growth too. On peat areas observed soil acidity decreasing. Despite of sufficient amount of nutrients willows were not suitable for peat fields. To avoid increasing of heavy metals content in soils, only qualitative waste water sewage sludge or waste water sewage sludge composts is acceptable for fertilization.

Wood construction elements are widely used in buildings and they can be used in construction elements such as roofs, floorings, windows and doors. As wood is combustible material, there are lot of fire regulations that should be fulfilled at the design stage of any building project. In Latvia, as in some other countries usage of wood in building constructions is limited. Wood materials are an ecologically friendly material and a renewable resource, and its usage should be promoted. The paper presents an overview of heat distribution in wood floorings exposed to standard heat fluxes which is different compared to wood members exposed to high heat radiation. Fire spread and self-ignition investigation on wood floorings is carried out in this research. The results show different kinds of the temperature distribution in the cross section of the wood member cross section depending on heat radiation and location of the temperature measurement point. Temperature distributions in wood during fire can be completely different in dependence on heat radiation and cross section of the wood member. The wood materials in floorings do not reach the self-ignition temperature during standard heat radiation.

The study focuses on protected landscape aesthetic quality assessment where the main problem is how to associate aesthetical and ecological approaches. High ecological quality does not often correlate with high landscape aesthetic quality, and this relationship may differ depending on specific ecosystem. The landscape aesthetic quality assessment historically developed on two approaches. One of them - expert approach, which has dominated in landscape planning and management practice, and the second - perception approach, which has dominated in research. In protected landscape aesthetic quality assessment traditional approaches will be revised by ecology and green philosophy aspects. The study example regards important natural and protected areas around river Lielupe - from Jelgava city to Kalnciems. This is the landscape with high heritage, natural, biological values and it is also living, recreation place for people. Therefore, cooperation between aesthetic and ecological approaches in landscape assessment is needed. The outdoor investigations were carried out in autumn 2006. There were photographs and video materials on the first stage of investigation. In the second part aesthetic quality of views was analyzed with expert approach. There were three main groups of evaluation criteria of protected landscape aesthetic quality. These covered design and compositional outlines - features, their quality and relationship among these features. The results showed that not all criteria are suitable and effective for evaluation of protected landscape aesthetic quality because of restriction of specific ecological conditions.

The objective of the studies was to evaluate the suitability of sand reed filter for the treatment of wastewater from milk collection post and on the basis of the studies performed to determine the minimal length of filtration path in order to reach the normative wastewater treatment level. In 2003, in Padargupiai village (Ariogala municipality, Raseiniai district) experimental treatment facilities for wastewater from milk collection post were constructed. As the pollution of such wastewater after pre-treatment (primary treatment) is 2 times higher than that of domestic wastewater, the filtration path in constructed wetlands was made 2 times longer (up to 10 m long). On the basis of the study results the dependence equations were made, with the help of which the amounts of the main pollutants contained in wastewater of milk collection posts were calculated, after the wastewater is filtered through the sand layer of different length. As calculations have shown, the treatment of wastewater from milk collection posts until the allowable rates depends on the constructed wetlands with the length of the filtration path of 7 m. The removal of organic pollutants, total nitrogen and total phosphorus from wastewater flowing through such media are 97.2%, 68.7%, and 91% respectively. The studies performed allowed to improve the calculations of the necessary area of constructed wetlands in order to reach the normative treatment level of wastewater from milk collection posts according to the index biochemical oxygen demand (BOD5).

The paper presents the study material and analysis of the distribution of woody vegetation of regulated streams in southeast Lithuania. The studies were carried out in 110 randomly selected slope strips of regulated streams in the Neris River basin in the Baltic Highland within the period of 2005 to 2006. During the studies 32 species of woody vegetation were found, from which 14 species of trees and 18 species of bushes. In regulated streams different species of willows are most common. However their distribution on channel slopes is different. For most species of woody vegetation the conditions are most favourable in the lower and middle part of slopes. Here their density is highest (0.34 +- 0.89 and 0.73 +- 0.139 units mE-2 respectively), the frequency is 0.56 and 0.64 respectively. As it was determined, the frequency of woody vegetation on slope strips of regulated streams is na = 0:61. On the slope the lower overgrowth limit of woody vegetation is ra = 1:58 +- 0:16 m, the upper limit is rv = 4:13 +- 0:22 m. In southeast Lithuania, in discharge network of drainage systems there are more possibilities for planning of ecological means, when trees and bushes are allowed to grow on slopes.

On the basis of this research and the investigations of other authors (1992 - 2002), the paper presents the comparison of the treatment efficiency of domestic wastewater treatment facilities functioning by different natural means. From all the studied three natural wastewater treatment facilities, constructed wetlands are considered as most efficient for domestic wastewater treatment: here the removal of organic pollutants and biogenic compounds is 85-98% and 67-95% respectively. Biological ponds are most suitable for the treatment of domestic wastewater, the discharge and pollution of which is fluctuating within a wide range. However, such ponds do not always ensure the treatment until the allowable rates. Their treatment efficiency according to biochemical oxygen demand (BOD5) is 49.6%. Total nitrogen amount contained in wastewater outflow from the treatment facilities with biological ponds was on the average 22.2 mg lE-1. The biggest problem of those ponds is rather low P removal efficiency (only 29.5%). Therefore wastewater flowing out of the ponds needs additional treatment. The usage of subsoil filtration fields is limited because their arrangement requires light soils. When arranging the distribution pipeline below the freezing zone, in many places the requirement that the pipes must be 1 m above the maximum ground water level is violated. The pipes should be arranged in places where there is no recipient for treated wastewater outflow. The load of subsoil filtration fields should not exceed 300 m**3 haE-1 per month. From the economical point of view, domestic wastewater treatment facilities with flowing ponds require least expenses.

The paper deals with statistic analysis of the relation between variables of cultural heritage and that of regional development in Latgale region. Latgale was selected as the study area - it is one of the five cultural or historical ethnographic regions of Latvia with stable original features, which are formed in the result of the specific historical processes but stands out among other regions of Latvia with the lowest indicators of development. According to the results of analysis of correlation, the number of architectural and archaeological monuments per 1000 people or their density in area have no close correlation with the major part of the parameters under examination. The analysis of regression was carried out between 'the number of architectural monuments against the area', and 'the natural logarithm from the density of population in 2005'. The ratio is expressed by the function y = 0.0339x**2 - 0.1422x + 0.1671, where y is the number of architectural monuments per square kilometre, but x - natural logarithm from the density of population (the number of people per square kilometre). The coefficient of determination for this relation is almost the same as for a functional one - 0.9499. Both for the coefficients of the equation and free member of equation have very high validity (t - empirical respectively 21.7; -11.1; 7.9).

After the regaining of independence in Republic of Latvia, a new period in the structural-politics of national economy, in choice of enterprise forms and business companies, in their foundation and development began. Beginning from the regain of independence, there has been no published research on these issues for about 16 year period. All studies on this topic were dedicated to separate periods, processes or regions. In the Paper format results of original research have been expounded on the development of entrepreneurship content forms in four separate urban, strategic territories: Daugavpils or Southern-Latgale, Rezekne or Eastern-Latgale, Liepaja - Ventspils or Western-Kurzeme and Riga intra-regions. In the research the whole period since regaining of Latvia independence has been analyzed, as well as the adaption of the law package on entrepreneurship and the beginning of the real entrepreneurship activity in years 1991-1992. Substantial differences between the territories (agglomerations) and also conformities of common development have been defined. There are essential differences in the activity efficiency of entrepreneurship subjects and in the results of the work contributed. The urban influence of big cities increases. The subjects and components of logistics systems develop faster.

The aim of this research was to compare effects of fertilization with various ratios of N, P and K (N:P:K) on arbuscular mycorrhizal fungi (AMF) infection in roots of Dactylis glomerata in Ca-carbonate (limed) and non-limed meadow plots at the Research Centre of Skriveri, Latvia University of Agriculture. Dactylis glomerata roots were excavated from variously fertilizer plots, a minimum 3 root samples per plot and analysed for two consecutive years. Arbuscular mycorrhizal fungi infection rates were estimated according to accepted scoring tables used for determination of AMF colonization.

A study was conducted to determine efficiency of an organic acids additive on pigs metabolic processes and diggestive tract microflora. The pigs of control group were fed without an organic acids additive. The feed of the trial group piglets contained 6 kg of organic acids additive per tonne feed, for starter pigs - 4 kg per tonne feed, for finished pigs - 3 kg per tonne feed. The study indicated that at the age of 130 days, pig mass in the trial group was 54.08 kg an average, but in the control group - 51.06 kg, which showed that pigs from the trial group had by 6% higher average mass than in the control group (p is less than 0.005). At the age of 160 days, pig mass in the trial group was an average 94.3 kg, in the control group - 90.63 kg; pigs from the trial group had by 4% higher mass than in the control group (p is less than 0.005). Feed consumption for the trial group was by 1% less than in the control group. Average daily gain for the trial group was 0.663 kg, which was by 6% more than for the control group pigs (p is less than 0.005). Feed conversion in the trial group was 3.06 kg, but in the control group - 3.275 kg, i.e. 6.4% higher than in the trial group. Analyses of Jejunum microflora showed that use of acidifier additive reduced Mould colony formed units - CFU amount in 1 g of the trial group sample by 6%. Staphylococcus species amount in the trial group was 500 CFU in 1 g of sample, but in the control group - 40000 CFU, i.e. 80 times more. In the trial group, Lactic acid bacteria CFU amount in 1 g of sample was by 6% higher than in the control group. The results of Rectum microflora analyses showed that Staphylococcus species amount in the trial group was 12000 CFU in 1 g of sample, but in the control group it was by 34% higher.