Constructed wetland (CW) treatment systems are engineered systems designed to treat wastewater with the usage of the same processes that occur in natural wetlands. The full-scale investigations of free water flow surface filters (FWF), subsurface flow filters, including filters of vertical flow (SVF) and horizontal flow (SHF) were carried out in Lithuania. The investigations’ database collected within the study period of 1995-2007 was used for the estimation of phosphorus removal efficiency of different constructed wetlands. It was established that phosphorus removal efficiency depends on construction of filters and the load according to total phosphorus for the area unit of filter surface. Subsurface flow filters are distinguished by better phosphorus removal. At the same load of all filters, i.e., total phosphorus of 0.3 g mE-2 dE-1, the removal efficiency of subsurface flow horizontal, vertical, and free water flow filters reaches 53.0, 46.5 and 28.0%, respectively. The wastewater contains phosphorus in mineral and organic forms. Due to the aerobic conditions in filters of vertical flow, the amount of organic phosphorus removed by SVF is 3 times greater than in horizontal filters. Organic phosphorus in wastewater before the treatment by vertical filters constituted 27% of total P, and after the treatment 21%. In wastewater treated by horizontal filters this ratio was 21% and 31%, respectively.

Highly polluted wastewater accumulates in milk collection stations. Its biochemical oxygen demand (BOD5) ranges from 369 to 1388 mg O2 lE-1. The average contamination was 600 mg O2 lE-1. There was a comparatively small amount of biogenic materials in it: total nitrogen – 27.3, total phosphorus – 5.0 mg lE-1. When variations of wastewater amounts are high, sand filters of vertical filtration are successfully used for the treatment of household wastewater. Model investigations were carried out to establish the possibilities of using these filters in treating wastewater in milk collection stations. The efficiency of wastewater treatment with these filters was 99.3% by BOD5, 99.1% – by suspended solids, 91.2% – by total nitrogen and 98.8% – by total phosphorus. According to the research results dependency equations were made; they were used to calculate the amount of main contaminants in milk collection stations that infiltrated through a layer of silt of diff rent thickness. The calculations showed that wastewater treatment to permissible limits is ensured by filtration through 0.6 m thick layer of sand. The average treatment level by BOD5 in such a filter of vertical filtration would be 20 mg O2 lE-1 and the treatment efficiency – 95.9%. Treatment efficiency of total nitrogen would be 88.1%, total phosphorus – 96.9, suspended solids – 95.5%. Preliminary research in the model showed that sand filters of vertical filtration can be used to treat wastewater from milk collection stations.

The research was made in the Šušvė river basin fertilized with organic fertilizer in the vicinity of a pig complex 'Litpirma' Ltd (25.0 thousand fattening pigs per year), Šiaulėnai local administration, Radviliškis district, in 2001-2006. This article presents total nitrogen concentrations and its amounts leaching from the complex to the basin, in the field drainage water and the Šušvė River (at a distance of 11.6 km from the pig complex). In the investigated Šušvė section, biologically treated wastewater from Šiaulėnai Township and the areas fertilized with organic fertilizers comes into the river. In total, 11.8 t of nitrogen come into the river, of which 4% (0.49 t) come from the township's wastewater, and the rest major part (96% or 11.3 t) is the drainage water coming from fertilized agricultural fields. The dynamics of nitrogen concentrations both in the river and in the drainage outlet is of a seasonal nature: in winter (January – March) concentrations were higher, and in warm season (April – November) – lower. The Šušvė pollution by total nitrogen, both above and below the pig complex activities range, almost all the research period was exceeding the limit (2 mg lE-1). Due to the pig complex activities and intensive agriculture, the runoff of nitrogen pollutants increases from 14.9 to 29.3% in the Šušvė River. This proves that the processes of spontaneous purification are not intensive enough to neutralize completely the pollution from such size pig complex in this particular section of the river.

Use of solar energy increases every year. In Latvia, solar energy is used mainly by solar collectors. The main part of the solar collector is the absorber, but not less important is the covering material which protects the absorber from the cooling impact of the wind. This cover must be transparent for solar radiation, but opaque for thermal radiation of the absorber, which is at greater wavelengths. Therefore it is important to measure absorption spectra of possible covering materials at visible and infrared wavelength ranges. Absorption spectra have been measured for several materials: glass, polythene, Plexiglas, and cells Plexiglas. Absorption spectra for all these materials are measured in three ranges: ultraviolet – visible (UV – VIS): 250 – 1000 nm; near infrared (NIR): 700 – 110 nm; infrared (IR): 1200 – 8000 nm. UV-VIS spectra with the ‘Ocean Optics’ device HR-4000 have been measured, but NIR and IR – with ‘Bruker’ Furje spectrometer EQUINOX 55. Evaluation of absorption spectra showed that the most suitable material (from the considered) for covering of solar collectors is Plexiglas.

Researchers have found that morphology of muscle structure (original or after processing) is closely related to meat tenderness, which is very important attribute for consumer. The aim of the study was to evaluate changes in microstructure of poultry meat during the chilled storage. In the study, the cross-cut microstructure of parents stock hen and broiler muscles were analyzed during the storage at + 1 +- 0.5 °C temperature. The changes were determined for the following muscles: musculus pectoralis and pars praeacetabularis musculus iliotibialis lateralis in seven hours after slaughter and on the 7th day of storage. Parents’ stock (PS) hens were slaughtered on 61st week, but broilers at the age of 42 days (on the 6th week). The decrease in area of muscle fibres of hens and broilers' musculus pectoralis was found in both types of meat when comparing the sample on 7th hour and 7th day, but the smaller decrease was observed in broilers meat. Comparing muscle fibre area of broiler and hen pars praeacetabularis musculus iliotibialis lateralis [musculus biceps femoris] in hen meat it was reduced in higher proportion, but the distance between the fibres was increased reaching similar values for both sample types.

Iodine is a mineral that is added to the table salt and found in a variety of foods. It is important for good health and, fortunately, our bodies require it in minute quantities. Iodine is part of a hormone, thyroxin, which is responsible for maintaining a person’s metabolic rate. Iodine is the basic constituent part of the hormone of the thyreoid gland. On the whole, the amount of T3 and T4 correlates with the number of the iodine atoms. Therefore, without iodine the thyreoid gland cannot synthesize hormones and, therefore, cannot function. The role of iodine intake in both of these conditions was recognized in the 20th century, and since they are fully preventable through diet, public health advocates hope to entirely eliminate them at some point. Many things are natural sources of iodine. Saltwater fish and sea vegetables, for example, both contain abundant amounts of iodine. The material can also be found in plants grown on soil which is rich in sea materials, and in animals grazed on such soils. In some regions of Latvia, however, access to iodine is limited, and conditions like goiter, is realistic of iodine deficiency situations. In Latvia, some fear exists for manufacturers of food who use iodized salt. They are afraid that it will collide with changes of colour or taste of their products and will infringe on interests of the consumer. The main question for such problems is: is it a myth or the truth? In Latvia, starting using iodine salt in manufacturing, the most important question is: ‘What quantity of iodine remains after the technological processing?‘

Annual judging of dairy products including sensory evaluation of local cheese-maker' cheeses proved that the quality of Latvian classical cheeses is various. In fact, in last three competitions three different manufacturers gained the first place in category of Krievijas and Holandes types' cheeses. It indicates instability of Latvian cheese quality. Two types of semi-hard cheeses (Krievijas and Holandes) were selected for testing the quality of Latvian semi-hard cheeses in the beginning of 2008. Krievijas type cheese was selected from three different manufacturers, but Holandes type cheese - from five different manufacturers. Sensory properties such as flavour, structure and colour were measured using line scale method. Statistical analysis of obtained data showed differences between such assessed properties as colour (yellowness), texture (firmness), holes, flavour (acidity and bitterness) in Krievijas type cheese, and colour (yellowness), texture (firmness), flavour (saltiness) in Holandes type cheese.

Understanding the efficacy of organic trace minerals has been increasingly important over the past few years as a result of increased customer awareness of their benefits and the increase in the number of commercial products available to the customer. Organically bound trace minerals of interest in animal nutrition specifically include iron, zinc, manganese, copper, cobalt, and selenium. These elements have been shown to improve reproductive efficiency as measured by conception rate, alleviated calving, and reduced placenta expulsion rate. Additional benefits include improved growth performance of calves. The field trials in the period of 2005 – 2007 with Charolais breed beef cattle cows and calves verified efficacy of the premix PROTRACE G containing Fe, Zn, Cu, Mn, and Co chelates, Se-amino acid (selenomethionine), potassium iodide, and vitamins A, D3 and E. Average calving rate of experimental group cows fed diet with added premix was 20 – 30 min, placenta expulsion time - 28 – 31 min, but in control group fed only basal diet - 2 h 21 min and 1 h 30 min – 2 h 09 min (p is less than 0.05) respectively. Live weight gain of calves and heifers of the experimental group was on 35 – 39% higher (p is less than 0.05) than that in the control group.

In this study the development of meat sector in terms of livestock population, production, farm size and reproductive material, which forms economic basis for effective meat production was analysed. The aim of the study was to investigate main tendencies of meat production sector and development of economic basis in Latvian agriculture. To achieve the set aim following objectives were defined: 1) to analyse concentration and specialization processes of pig breeding farms; 2) to describe restructuring processes of reproductive pig breeding; 3) to investigate restructuring processes of farms producing beef; 4) to characterize concentration and integration processes in poultry production. The study was based on annual statistical data and statistical bulletins covering results of the Farm Structure Survey from 2001 to 2006, scientific publications, special literature and reports of international organizations. To carry out the research adequate research methods were used. The results of this study showed that meat industry has structurally changed in recent years, where the structural change can be defined as the change in the number and size of farms in pig, cattle and poultry sectors. The results also suggested that meat production sector in Latvia has become more intensive, concentrating meat production in large and specialized farms, where this tendency can stimulate the increase of meat production. Therefore, knowledge of the current tendencies and strategies of pig, cattle and poultry sectors is a necessary precondition for the development of the meat sector.

It has been shown in previous studies that transaction costs (TC) of agri-environmental policy measures often are very large both in absolute terms and as a share of payments. As agri-environmental policy measures make up an increasingly large share of agricultural policies, not least within the European Union, it is becoming ever more important to improve the knowledge about the factors determining the level of transaction costs. This paper investigates the TC determinants of one Swedish agri-environmental policy measure. More specifically, it aims to investigate if the level of TC is attributable to economic factors, such as pasture density and distances, or if political factors, such as lobby groups and political majorities at the county level, influence the costs. To evaluate if the results are robust with respect to alterations in model specifications, a version of the extreme bounds analysis is applied. Although initial results indicate that political parties influence the level of transaction costs, the extreme bounds analysis reveals that those results are fragile. It shows that five of the economic variables are robust with respect to model specifications, but none of the political variables is.