A lot of different EU directives and regulations set the targets to decrease greenhouse gas emissions, to increase the share of renewable energy, and to improve energy efficiency. Biofuel usage is directly linked to all of these problems. Since the first generation food-based biofuels should not receive public support after 2020, investigations of next generation biofuels are topical. Hydrotreated vegetable oil (HVO) is one of the most promising next generation biofuels in the near future. This article deals with the results of mathematical modelling to determine the main diesel engine operating parameters (power, torque and fuel consumption) running them on HVO and its blends with fossil diesel fuel. The modelling results of the car Opel Insignia 2.0 CDTi show that every 5% of HVO in fuel blend reduces maximum power and torque of around 0.38% while raising specific fuel consumption by volume of around 0.10%. Analyzing the most realistic scenario in the near future – 7% HVO and 93% fossil diesel blend, the predicted fuel consumption increase (0.14%) and power and torque decrease (0.54%) is inconsiderable for vehicle exploitation, and HVO seems to be a promising biofuel to replace biodiesel in fuel blends and to promote reaching the EU targets.

This experimental study assesses the influence of ignition timing on emissions from a production four cylinder port injection spark ignition engine. The aim of this research was to evaluate the necessity of ignition timing correction when the regular gasoline vehicle is being adapted for the use of E85 fuel. Tests were conducted in the Alternative Fuels Research Laboratory of Latvia University of Agriculture in December 2013. The engine was fuelled with the ethanol-gasoline blend E85 or the commercial gasoline A95. The engine was tested within a vehicle in a chassis dynamometer in steady state conditions, which resemble driving at 50 km hE-1 and 90 km hE-1. The original engine control unit was replaced with a programmable one. Engine-out and tailpipe exhaust gas samples were taken and analysed with a FTIR-type analyser AVL SESAM. Carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), acetaldehyde and unburned ethanol emission volumetric share is presented. CO, HC and acetaldehyde emissions were not affected by variation of the ignition timing within the tested range. NOx and ethanol emissions were reduced with the ignition timing retard. The emissions of CO, HC and NOx were reduced, when the engine was fuelled with the E85 fuel, comparing with the gasoline use. Ignition timing, optimized for the gasoline, was found suitable for the E85 fuel from the emission analyses point.

The paper covers spatial analysis of the Measure “Afforestation of agricultural and other than agricultural lands” implemented in Poland within the framework of the Rural Development Programme 2007 – 2013 (RDP 2007 – 2013). Beneficiaries obtained payments for afforestation based on the commitments made during the programming perspective of 2004 – 2006 or they joined the programme during the perspective of 2007 – 2013. Data obtained from the Department for Direct Payments of the Ministry of Agriculture and Rural Development as of 31 December 2012 formed the base of the analysis. Payments made in the country to the beneficiaries considering their activity and absorption of funds within the framework of the measure are presented. Next, given the disbursements made in voivodships and counties of Poland, the activity of beneficiaries was indicated and average disbursements per beneficiary were determined. The analysis aims at investigating the consistency of the afforestation policy implemented in Poland as of 2004 and showing the role of afforestation projects implemented within the RDP framework. The aim of the article is to show spatial changes in the intensity and dynamics of agricultural land afforestation projects implemented within the framework of the RDP 2007 – 2013 considering natural conditions. The afforestation rate and the ownership structure of the forestland in Poland is diverse. Afforestation allows and rationally manages agricultural land, which is of little use for agricultural production. The utilization of EU funds supporting afforestation of agricultural land in Poland is characterized by spatial variability.

An important factor in the development of forest ecosystem is the ability to regenerate. Natural intensity of self thinning of a forest depends on the tree species and environmental conditions. Due to abiotic and biotic factors in a continuous forest tract, there appears a clearing, which, depending on the size, forms new growth conditions. Over time, the resulting new space is occupied by herbaceous and woody vegetation. Most often regeneration of a new forest depends on the size of the plot. The study was conducted in 2013 during the growing season in a typical broadleaf forest stand. During the study woody vegetation and projection coverage of herbaceous vegetation was registered in large clearings. Light conditions in the plots and under tree canopies, as well as soil parameters were ascertained. Based on the collected data, the view of the structure of woody vegetation, projection coverage of herbaceous vegetation, light conditions, temperature, soil moisture content and pH changes were obtained. In order to clarify the influence of microclimatic conditions on natural forest regeneration, the data on light and soil characteristics were analyzed. The aim of the study - was to determine the changes of woody and herbaceous vegetation in spruce stand clearings and to assess the impact of microclimate. During the study it was found out that in large plots dominated species demanding higher amount of light, while herbaceous vegetation was attributed to the third, fourth groups of aggressiveness. Naturally regenerated seedlings condition was mostly influenced by light conditions and soil moisture content.

This brief review of the recent birch studies is focused on different aspects, such as species distribution, growing conditions, species identification, changes due to environmental factors. All mentioned investigations were carried out in Lithuania. This analytical study summarises the results and increases knowledge dissemination to the international audience. When reviewed and summarized considerable part of relevant literature sources, we realised new problems and challenges; for example, aiming to clarify the peculiarities of the growth and crown condition of the dominant birch species (Betula pendula Roth. and B. pubescens Ehrh.) under the changing climate and anthropogenic pollution.

The aim of the study is to ascertain how different compositions of stand species affect the work of the harvester in commercial thinning under Latvia’s conditions. The data of the harvester – time-tracking files (*.drf) have been used as a basis for the study, where productivity is expressed as the prepared amount of round timber in cubic meters in a unit of time – an hour (m**3 hE-1). The data were collected from 100 commercial thinning areas which were divided into three types depending on the composition of the species: pure pine stands, pure spruce stands and deciduous tree mixed stands (mixed with coniferous trees). All the data for the study were collected in the forests managed by JSC ‘Latvia`s State Forests’. By summarizing the data, it has been established that in pure pine stands the average volume of the stem to be removed is 0.092 m**3, in mixed stands – 0.085 m**3 and in pure spruce stands - 0.068 m**3. The research demonstrates that the harvester showed its highest productivity while working in pure pine stands – 3.96 m**3 hE-1, the second best result was achieved in the mixed stands – 3.67 m**3 hE-1, but the lowest rate was demonstrated in pure spruce stands – 3.09 m**3 hE-1. Significant differences were observed in the productivity of the harvester between pure pine and pure spruce stands. Comparing the calculations of standard deviations in the harvester productivity, it can be seen that they are the biggest in mixed stands, while the lowest rate is demonstrated in pure spruce stands.

Heavy metals as well as other pollutants are widespread and create deleterious impact to the environment and human health. There are different in situ and ex situ technologies of immobilization and removal of contaminants; electrokinetic remediation is one of such technologies. It can be applied for treatment of wide areas, e.g., former industrial and military firing-grounds. Technology is applicable to water soluble contaminants at sites with homogeneous soils that are fine-grained and exhibit both, high permeability and high moisture contents. The aim of the study was to test the efficiency of electrokinetic remediation for copper contaminated clayey soil in laboratory conditions. Pilot scale experiments were applied to test the efficiency of electrokinetic removal of contaminants from soil by application of low voltage direct current (DC). Experimental results show that the use of DC power can be selected for treatment of heavy metal contaminated soils. Batch scale experiments were done by using clayey soil with known physico-mechanical properties, spiked with copper solution of known concentrations. Electric force was changed by varying its parameters. The article gives batch experimental results for diffusion of copper ions in soil under the influence of the external electric field.

Ecological farming is relevant to protected areas. The aim of the study is to perform an analysis of farms applying organic farming measures as well as the analysis of the change of their areas in Aukštadvaris and Krekenava regional parks (RP). The object of the investigation - the farms of Aukštadvaris and Krekenava regional parks. The study is carried out to determine how many farms, forming the regional parks‘ territory, are managed according to the principles of organic farming. The change of the above- mentioned farming area for 2009-2011 is analyzed as well. Paluknys and Naujamiestis subdistricts, not incorporated into the territory of regional parks, were chosen for the comparison analysis. The analysis of the 2009 – 2011 period showed that the declared areas in Krekenava RP have decreased, and the area of farms applying organic measures has increased by 81.69 hectares (nearly 2.5 times). The number of organic farms increased by 1.5 times in Aukštadvaris RP over the period of 2009-2011, and the area has increased by 187.36 ha. The percentage calculations revealed that in 2011 the area of farms applying organic farming measures in Aukštadvaris RP made up 18.89 per cent of the total area declared, the number of farms - 6.61 per cent. The area of farms applying organic farming measures in Krekenava RP was only 1.71 per cent, measures were applied only by 1.89 per cent of all the declared.

The main objective of this research is to find out if quantitative factors describing agriculture have a statistically significant role on the parliamentary election results in Latvia. If this statistical relationship can be proven, then it is important to interpret the causality behind it. 18 agricultural indicators from the 2001 Census of Agriculture were selected to be analyzed with the 8th Saeima political party election results by using multiple linear regression analysis. These 18 parameters are different in their character, and they describe the size of farms, level of education for farmers, land usage statistics, proportion and productivity of certain crops, livestock and the usage of farm machinery. The main hypothesis of this research was that the rural civil parishes with a high intensity of agriculture have a statistically significant difference in election results when compared to the rest of the election results in Latvia. Initial results showed a strong correlation between election results and agricultural indicators, but when the ethnic factor was taken into account in the linear regression model the role of these agricultural indicators was greatly diminished.

This article analyses the elements of R. Hackman’s and G. Oldman’s work characteristics model: the essential work characteristics, critical psychological states, as well as personal and activity results. Research aim is to offer municipal administrative staff innovative elements of the motivation system. The elements of employee motivation are linked with certain work characteristics, distinguishing specific features of the work process that would meet the needs of workers such as the use of self-expression and potential opportunities, ensuring satisfaction with the content of work, independence and recognition. Before suggesting innovative motivation system elements, the factors and motivation measures that most influence municipal administrative staff of Raseiniai, Joniškis, Pakruojis, Akmenė had been found out. Essential elements of work characteristics model (essential work characteristics, psychological states and personal and activity results) among the employees were identified. It presents the characteristics of innovative motivation system elements of municipal administrative staff. Main analysis methods were used: analysis of documents, quantitative research – survey, comparative analyses, methods of statistical and cluster analysis.