This research deals with tendencies of growth of Norway spruce Picea abies (L.) Karst. during last 50 years (1960 – 2010) in eastern part of Latvia emphasizing trendal specificity of active periods during the first (t1: 1960-1985) and the second (t2: 1986-2010) time interval. There have been 150 superior stand trees bored in six mixed pine-spruce Pinus sylvestris L. – Picea abies (L.) H.Karst. stands. An active period of factor’s impact is the time span when some meteorological factor (decade average, minimal or maximal temperature and sum of decade precipitation) influences an increase of annual ring width significantly. Comparing average temperatures from two weather stations included in this research the difference between interval t1 and t2 is approximately 1 °C. Active periods of temperature impact on growth of Norway spruce in eastern part of Latvia during last decades have changed not only their location but also an impact direction from positive to negative. Minimal and maximal decade temperatures are those mostly determinating the radial growth of Norway spruce in the eastern part of Latvia. Interval t2 is quite rich in active periods both from minimal and maximal decade temperature. Research results prove hypothesis about trendal shift of meteorological factors’ impact active periods due to climate change. An increase in decade precipitation level in winter caused annual ring growth positively both in the interval t1 as well as in t2.

The aim of this paper is to characterize and ascertain quality influencing factors of wood chips produced from forest residues in clear-cuts. The quality of food fuels varies according to the harvesting season, site characteristics and silvicultural treatment. For this study 89 piles of logging residues from clear-cuts located in Western part of Latvia were used. Piles were stored in different parts of clear-cut according to its direction against nearby stand. Piles of logging residues were pre dried and then chipped. A period of chipping and sample acquisition was from February to May of the year 2012. Results show that chips from forest residues can be successfully used for medium scale boilers. Chips with lower carbon content, calorific value, relative moisture and bulk density of wet chips can be produced in May. Location of the pile in centre and SE part of the clear cuts can decrease resulting ash content in wood chips.

The stump lifting trials were implemented in 5 forest compartments of the JSC ‘’Latvia state forest’’ Vidusdaugava, Rietumvidzeme, Zemgale and Ziemeļkurzeme forestries in autumn, 2012. Total extracted area was 3.5 ha, excluding control. Two stump extraction buckets were compared in these trials – CBI (made in Canada) and MCR-500 (made in Latvia). The scope of the study was to estimate if the prototype of the MCR-500 can compete with stump lifting buckets having positive feedback from industry. Considering that the CBI head cannot prepare soil, this operation was not done by the MCR-500 either. In total 1796 stumps were marked and their main parameters were taken in all trial areas. Extracted biomass was estimated theoretically using biomass expansion factors elaborated in Nordic countries. Allegro CX field computers with SDI software were used in time studies to obtain information about productivity and distribution of productive time in a work cycle. The study demonstrated that productivity of stump extraction with both stump lifting buckets did not differ significantly in 6 cases out of total 10 comparisons.

Heavy metals are worldwide spread pollutants in soils of functioning as well as abandoned industrial territories, landfills, military areas with its historical contamination, and other sites contaminated by industrial activities. Development of soil and groundwater remediation technologies is a matter of great importance to diminish the hazardous impact of pollution to humans and environment. Sustainable solution can be found for remediation of industrial areas using the stabilization/solidification (S/S) technology, which refers to binding of waste contaminants to a more chemically stable form. Geotechnical properties of soil treated with Portland cement (PC) can be improved when municipal solid waste incineration (MSWI) ash is used as the combined additive. Ash is composed mainly of metals, so environmental impact must be evaluated if it is used as amendment in the cement industry. The use of MSWI ash in stabilization of contaminated soils would be useful for the sustainable environmental management in two ways: S/S contaminated soil gains better geotechnical stability and waste incineration industry gets rid of the ash with high metal content. The aim of research is to provide pilot batch experimental results for leaching of heavy metal compounds when S/S technology is used for contaminated soils using PC and MSWI bottom ash additives. Mineral soils were spiked with copper, PC and MSWI were added in known proportions and leaching tests applied. Main results show that PC addition allows to chemically stabilizing soil; thus, heavy metals are not leached out from combined mass of spiked soil and MSWI bottom ash.

Roads play an important role in our daily surroundings and provide access to landscape. Views from the road create the first impression about the country. It is important to pay attention to the landscapes along the roads used by tourists. The purpose of this study was to obtain general overview of the current state, identify existing and disappearing features of the road landscape in Latvia. Research on road landscape perception and design is well developed in the USA and some countries in Europe. The assessment of the current state and proposals for the road landscape development in Latvia are fields which are little discussed and need more attention. The research was carried out in several sections of the main roads and some sections of regional and local roads in July and August, 2011 and August, 2012. Photography method was used. Analysis of the results shows that the main reasons of aesthetic quality loss in road landscapes is lack of planning and management, indicating the necessity to find ways for rural landscape quality enhancement.

Kriging is a method of interpolation, which predicts unknown values from data observed at known locations. This method uses a variogram to express spatial variation, and it minimizes the error of predicted values which are estimated by spatial distribution. The objective of the current work was to investigate how the accuracy of predicted runoff average depth values ranges by applying ordinary Kriging interpolation method when parameters of the method are altered. The simulation was tested by the following method parameters on: fitted semivariogram model, lag size, neighbouring points; the number of sectors of the circle. The best results of the spatial distribution of runoff average depth were received applying the ordinary Kriging method when the exponential variogram is used, the lag size being 27 km while 6 contiguous points and the orbicular scheme divided into sectors in 45° angle are taken. Applying the Ordinary Kriging method having selected all parameters with probability p = 0.95 the model described about 74% of all investigated values.

Utilization of the sewage sludge is pressing and crucial environmental and economic challenge. High moisture content of the sludge is one of the main difficulties during the process of the sewage sludge utilization. Experimental drying module has been designed and manufactured to identify and verify effectiveness of the main parameters of the thermal drying of the sewage sludge with application of the pneumatic pulse method. The pulser is supposed to be part of the technological scheme in order to speed up the process of drying and saving energy. The pulser supplies hot air into the drying chamber with time intervals by pulse. In the drying chamber the airflow dislodges water molecules from the material by means of pulses and then they are taken away from the drying chamber. For the convenience of the comparison and evaluation of the executed experiment the following general characteristics were selected: drying rate – i – kg minE-1; power consumption – q – kWh kgE-1. The greatest effect in application of the pneumatic pulse method for dehydration of the sewage sludge was achieved at the angle of incidence equal to nearly 90° of the airflow on the dried sample and higher temperature. The experiment showed that application of the pneumatic pulse method for dehydration of the sewage sludge allows to reduce power consumption and speed up the process of drying. The process of drying can be executed at lower temperatures.

The paper presents data on the water quality in drainage from manure-fertilized areas in a large livestock company (629 conditional livestock) from 2008 to 2012. The scheme of investigation consists of two field variants: manure fertilized and non-fertilized. Researches are carried out in drained areas, where the drainage water is drained away through outlets. The nitrogen rate 170 kg haE-1 is used annually to fertilize fields in spring. The aim of the research was to ascertain the impact of large livestock company fields fertilized annually with manure on the water quality in drainage. For the purpose of chemical investigations, water samples from drainage were taken once per month. Water analyses were carried out by the accredited Chemical Analytical Laboratory of the Water Management Engineering Institute of Aleksandras Stulginskis University according to specified methods. Investigation results have demonstrated that fields fertilized annually with manure raised the contents of Nmin and P2O5 in the soil by 1.5 and 2.2 times respectively in comparison to the non-fertilized ones. The increase in these contents was conditioned by the higher air temperature and the lower rainfall. The seasonality of Ntotal concentrations in drainage water was discovered: higher concentrations were identified in autumn and winter, lower concentrations – in spring and summer. Due to low dissolubility in the soil, low Ptotal concentrations were identified in drainage water. The highest concentrations were identified with the start of drainage operation.

Most of the regulated rivers are situated in the middle part of Lithuania. Approximately 90% of all agricultural lands are drained in the Basin of Nevezis River, which is one of the most sensitive basins in Lithuania due to the lack of water and potential anthropogenic pollution. The goal of the research is to assess the impact of drainage on Nevezis River flow. Following the data series of 62 years, it was determined that water balance of Nevezis Basin is characterized by negative water balance during May-September due to higher evapotranspiration than average precipitation amount of the same period. It was stated that the average annual flow coefficient of the whole 10th hydrologic region of Lithuania was 0.3 till reclamation. It decreased to 0.28 during the period of intensive reclamation; however, the average annual flow was 0.35 from the year 1980, i.e., it increased in comparison with the period till reclamation. The average flow coefficient of warm period was 0.10 till reclamation, and remained the same during the period of 1956-1980, while the data of 1981-1995 show that the average flow coefficient increased – 0.11. After assessing the meteorological conditions and soil water balance of the Basin of Nevezis River it might be stated that the primary reason of water lack in the basin is climatic conditions. Drainage systems can hardly have a significant impact on wateriness of Nevezis River.

Electronic circulation of documents and electronic services have become the most significant IT development trend in the public sector. During the last few years public sector institutions in all Europe have significantly improved the quality of the provided services. With the evolving options offered by the internet and the digital signature getting more widely used, citizens expect a more up-to-date approach to communications from governmental institutions. Successful operation of electronic services would not be possible without a proper circulation of electronic documents on the national level. This article briefly inspects the history of the electronic service development and analyses the conditions of the development, deals with the experience of different countries with the implementation of e-services. Particular attention has been paid to Latvia, its current situation and historical analysis of e-services. A special part is dedicated to Agricultural Ministry of the Republic of Latvia which is most closely related to national rural development, projects of transition towards electronic document circulation and provision of electronic services.