A research has been done on the possibility to increase the range of beer drinks by substituting hops with additives of other plants in the wort boiling process. The obtained data present evidence of the possibility of substituting hops by oak bark, yarrow, wormwood and oak acorn.

In order not to decrease the significance of a forest in the environmental maintenance and its role in the national economy, Latvian Forest policy needs to ensure that the existing forest areas are not decreasing, establish forest land transformation restrictions, thus, maintaining a long lasting development of forests. The preconditions for the change of the forest land use is one of the instruments for the state policy realisation, with the help of which a long-term development of forests can be ensured. At the moment working out the land policy in Latvia on a country level is being started. The publication is in the context of setting strategic targets for forestry and human resource development planning strategy, within the framework of Latvian forest and related department national programme. Due to the reasons mentioned, the topic discussed in the article is a problem of the day, and the research in this direction has got both theoretical and practical significance. The author investigate the forest land transformation process, by analysing normative acts and political documents in the article, as well as by summarising statistical data about the relevant processes in Latvia and in the world, during last six years. The issues, related to the forest land transformation process have been covered in the article; it has been analysed whether there are cases when a necessity arises to review the existing normative regulations. The answers have been given how to eliminate identified shortcomings, contradictions or problems.

The task of this paper is to create a simulation model of wood resource flow, enabling analysis of the flow of resources to the customer. The model consists of four modelling steps - the study of the system, the creation of conceptual and logical model, as well as data analysis. The model has been developed in UML (Unified Modelling Language) diagrams and the simulation model has been created using software EXTEND Industry. For the simulation of the model the scenario has been created. Based on this scenario, extended scenarios have been developed. Model of basic simulation represents the loading of resources into the transport, transportation, discharging from the transport and the return to the loading point. Using this basic scenario, the extended scenario has been created. This scenario analyzes the flow of wood resources to the customer, taking into account two criterions restricting the flows - assortment to be processed and the distance from the loading place to the customer's location. Extended scenario allows to analyze the load of each sector, as well as to follow each unit existent in the process of simulation. There are attributes of information (type, assortment etc.) added to the unit equivalent to 1m**3 of wood resources. These attributes can provide information about the unit flow within any part of the process.

Highly polluted wastewater is formed on private farms. The wastewater contains Ntotal and Ptotal concentrations up to 150 mg lE-1 and 30 mg lE-1 respectively, which is 2-3 times higher than that contained in domestic wastewater. During the biological treatment of wastewater the removal of organic pollutants (BOD5- biochemical oxygen demand, and SS - suspended solids) is about 96% and the treatment efficiency satisfies the environment protection standards. However, the removal of biogenic pollutants is only 55%, thus the residual pollution with biogenic substances exceeds the maximum allowable rate according to Ntotal and Ptotal for wastewater released into the environment. Currently, different natural and artificial powdery mineral materials (zeolite, filtralite, etc.) containing metals and carbon compounds are transported into Lithuania. Such materials could be used as Ntotal and Ptotal adsorbing filters. In respect of the filter load with pollutants, biologically pre-treated wastewater treatment efficiency of Ntotal and Ptotal was determined to be from 50 to 91% and from 49 to 90% respectively. Having filtrated to the wastewater through a filter containing 50% of zeolite and 50% of filtralite, Ntotal and Ptotal removal efficiency was fluctuating from 28 to 60% and from 23 to 70% respectively. Having made the investigations with different loads of minerals, it was determined that N removal is more efficient in the zeolite mineral filter, while P removal is more efficient in the filtralite filter. In order to reach the best results of biogenic pollution removal, both mineral mixtures should be used for the load of the filter.

The objective of the present studies has been to estimate peculiarities of nitrogen removal in constructed wetlands of different construction. In limited companies (LTD) 'Pastoge' and 'Nikola', constructed wetlands of vertical flow (VFCW) are arranged, while limited company (LTD) 'Agaras' has two-stage constructed wetlands of horizontal flow (HFCW). In all the objects the supplied wastewater is after primary treatment. Having compared the efficiency of ammonium and nitrite nitrogen removal in two types of constructed wetlands (VFCW and HFCW) it was determined that larger amounts of total nitrogen are removed in HFCW (38.1%) rather than in VFCW (24.4%). However, in VFCW smaller amounts of ammonium and nitrite nitrogen are discharged with wastewater. No significant effect of the fluctuations of ambient temperature on the removal of ammonium and nitrite nitrogen was observed in HFCW (difference in average values of cold and warm periods was 3-8%). A rather reliable relation (R2 = 0:738) was determined between ammonium nitrogen concentrations in wastewater outflow and HFCW load according to total nitrogen, however, ammonium nitrogen amounts in treated wastewater (when filter load according to total nitrogen is 0.3 to 4.6 g mE-2 dE-1) exceeded the maximum allowable concentration (MAC) and were fluctuating from 6 to 32 mg lE-1.

The objective of the present studies has been to estimate wastewater treatment efficiency of surface-flow wetlands for finishing treatment of secondary effluent. The studies have been carried out within the reconstructed wastewater treatment facilities in Babenai (Kedainiai district, Lithuania), where, after the initial wastewater treatment in the septic tanks and biological ponds, a plant filter has been set for finishing the wastewater treatment. The removal efficiency of the main pollutants in the filter like BOD5, suspended solids, total N (nitrogen), and total P (phosphorus) has become the focus of the analysis as well. Wastewater treatment efficiency analysis was done on base measurements taken in all seasons of the year within the period 2003-2006. Surface-flow wetlands are characterised by good removal efficiency of the organic pollutants. At the average load of the examined plant filter - 0.9 mg O2 lE-1 BOD5 (biochemical oxygen demand), the removal efficiency reached up to 61.2%. Low winter temperatures reduce the rate of removal for BOD and the biological reactions responsible for nitrification and denitrification. During the warm period of the year, the treatment efficiency of BOD5 was 70.8%, and during the cold one - 52.4%. However, the total N constituted up to 16.7% and 9.7% respectively. Due to the anoxic and anaerobic conditions in the filter, wastewater after the treatment on average contains 66.0% of ammonium nitrogen of the total N concentration. After a year, with the growth of plants the phosphorus removal efficiency improved and at the average load of the examined plant filter according to P 0.063 g mE-2 dE-1, on average 0.018 g mE-2 dE-1 of the total P was removed, i.e., the removal efficiency constituted 28.6%.

The most urgent environmental problem in cultivated land areas of Lithuanian karst region is the protection of subsurface water from technogenic pollution. In terms of subsurface water pollution, the ambience of sinkholes is considered to be particularly dangerous. The work was carried out in 2004-2006 in the district of Birzai. Having analyzed the regime of sinkhole water formed in the vicinity of sinkholes as well as the regime of ground water of their vicinity it was determined that this regime is different in respect of the local hydrogeological conditions. A common regularity was observed: during the snow thaw period and rainy period sinkholes are fed with water from ambient soil and with shallow ground water, during the dry period water accumulated in peat of the failures of sinkholes flows into the ambience, and during the particularly dry periods subsurface water abates in sinkholes and they start draining the ground water very intensively. Analyzing the interrelations of water quality indices it was determined that in most cases the quality of ground water in sinkholes and in their vicinity is closely related. Sinkholes with water level higher than the ground water level and with higher chemical compounds concentrations make no adverse effect on ground water quality due to comparatively low runoff into the environment. However, such sinkholes are considered to be potential pollution sources of lower aquatic layers. Nitrate nitrogen is one of the most harmful pollutants getting into the sinkholes from agricultural fields and farming land plots where mineral fertilizers are applied. Ground water of higher level polluted with the nitrogen is obviously polluting the subsurface water of the sinkhole as well.

After the private ownership of land was restored and a part of land reclamation structures was given to land owners, the intensity of land use has changed. In the areas of Lithuania, which are less favoured for agriculture, the land is not intensely used. Further financing of land reclamation of such areas from the state budget grants is economically inefficient as the return of relatively high investments is very low. With the changing of land reclamation infrastructure it is necessary to prepare measures which would facilitate rational, regional agricultural specialization corresponding to natural conditions. The routine procedure of financing the land reclamation has to be changed as well. The paper analyses the changes in usage of drained land areas and financing of the land reclamation sector in Lithuania during the last decade (1997-2007). The purpose of this research is to establish the criteria of the economical efficiency of drainage systems and to propose methods how to change the financing of state-owned land reclamation infrastructure. On the grounds of the carried out situation analysis, a methodology of distributing state grants for land reclamation to municipality budgets are presented. To have an efficient use of the state budget funds, the operation and maintenance of shared land reclamation systems have to be carried out according to the maintenance plans approved by municipalities, which would provide for arrangements and compensations due to conflict of interests arising when land plots are used in different ways. Possible ecological measures that could be applied when carrying out repair and reconstruction of drainage systems are discussed.

If among engineering phenomena exist nonlinear interconnections, they are expressed with help of corresponding nonlinear functions. Teaching the regression analysis for the engineering science students one of the important topic is method of Least Square Method (LSM) and their application in the nonlinear regression analysis. Based on experience at Latvia University of Agriculture, the illustrated approach of teaching of nonlinear regression topics for undergraduate students in engineering applications is presented. Teaching statistics on regression analysis, students usually have problems with interpretation of the transformed regression model parameters significance. The tasks of teaching using LSM in the nonlinear regression analysis are discussed. On the figure 1 regression dependence are shown between such sizes as age of pine-tree and his height. The main species in Latvia is pine-tree (47% from total Latvia forest area); growth of trees motion is stipulated by tips of growth circumstances (Statistical Yearbook of Latvia, 2005).

Recently, the graduates should not only be technically competent, but also they should be skilled in communication and team work, have social and global awareness, be self directed and prepared for life-long learning. Knowing of languages contributes to student personal development. However, passivity of the students in the English classroom is among the factors limiting not only active engagement in academic tasks, acquisition of communicative skills but also soft skills needed for future profession. Therefore, at Lithuanian University of Agriculture, where student-active teaching and learning has been applied the study of the most acceptable class work forms for breaking passivity and improving students' motivation in the classroom for learning English as a foreign language was performed. The most persistent problem for the passive students who are afraid of speaking is the inability to find right words to express themselves (31%), and the fear of making mistakes, criticism, and sounding foolish (almost 55%). The application of the active class-work forms seems to behave well over fighting the passivity and enabling acquisition of the most important skills both for foreign language acquisition and becoming perspective future employees. Team work in created by a teacher relaxed atmosphere in the fitted classroom was found to be one the ways for breaking silence and passivity of the students in the English class room.