Sewage sludge is a specific bulky waste and its utilization is hampered by the presence of the environmentally dangerous contaminated substances in the composition presented mainly by heavy metals, pathogens and coagulants. At the same time sewage sludge may serve as a valuable biological raw material. Utilization of the sewage sludge is crucial environmental and economic challenge. Application of the pneumatic pulse method in the technology of dehydration and utilization of the sewage sludge may allow us to speed up the process of drying, reduce power consumption and capital investment, execute process of dehydration at lower temperatures and in less hazardous explosive conditions. Proposed solution is founded on the use of the compact equipment for dehydration and utilization, including pneumatic pulse drying method. For this purpose the pulser – an airflow feeder with required time intervals or pulses, was included in the technological process. In the process of the drying sewage sludge with the use of pneumatic pulse, there is no need to spend all the energy on evaporation of the water molecules and this fact significantly reduces power consumption. Preliminary calculations, taking into account laboratory data, showed that proposed technology of drying sewage sludge allows to reduce power consumption by 25% upon receipt of the dry sludge. The aim of the study is development of sewage sludge dehydration technology for further utilization of design solutions using the pulse method.

Entrepreneurial activity in various regions of Latvia is one of the most actual topics for politicians at many levels. The aim of this paper is to characterize entrepreneurial activity in the Kurzeme Region in the context of municipalities analysing the accessible statistical data. The entrepreneurial activity in the Kurzeme Region is analyzed both in general and in the context of municipalities in this paper. Analyzing accessible statistical data, one can draw a conclusion that the entrepreneurial activity in the Kurzeme Region is not even. It testifies that the factors which influence entrepreneurial activity development in some areas are to be searched at the level of municipalities. In addition, the analysis of data specifies various correlations. For example, the smallest number of merchants per 1000 inhabitants in Kurzeme region is in relatively small border municipalities, but higher results are in large cities and local authorities who comprise larger cities or in municipalities which border with larger towns. It is similarly discovered that in Kurzeme region there is a smaller amount of self-employed persons in local authorities with a large number of merchants per 1000 inhabitants and vice versa. There are also exceptions, further research is necessary to justify such correlations.

There is a lack of an actual information concerning cultivation of buckwheat (Fagopyrum esculentum), on the best methods of sowing and seeding rates. The aim of the study was to investigate changes in the buckwheat yield forming elements depending on sowing type, time and rate. Trials were established in farm “Araji”, Kraslava area, during 2010. Previous crop was spring barley. Buckwheat cultivar ‘Aiva’ was used in the field trial. Sowing was done on six different dates – May 15, 20, 25 and 30, and June 4 and 9. Two different types of sowing were used – drill sowing, with 4 sowing rates 200, 300, 400, 500 fertile nutlets per 1 m2, and the column sowing with the three sowing rates 150, 250, 300 fertile nutlets per m2. Data analyses were run using MS Excel Two factor analyses of variance. Time of sowing and seed rate had a significant influence on the buckwheat yield forming elements. Evaluating the performance of plant density at column sowing, it was found that plants survival rate was higher than that in drill sowing. The highest individual productivity of the plant was observed in plots sown in columns. The yield of buckwheat was on average 30-50% higher in the plots that were sown from June 4th to 9th if compared to those sown from May 15th to 20th, i.e. earlier sowing times were not the most suitable for buckwheat sowing in 2010.

Chemical composition of crops before winter is important for successful overwintering of plants. The aim of the research, carried out from 2007/2008 till 2009/2010 at the Research and Study farm ‘Vecauce’, was to investigate the influence of agricultural practices (sowing date, sowing rate, and fungicide application) and meteorological conditions during winter on the content of sugar in apical bud and root of two types of winter oilseed rape (Brassica napus L.) cultivars. The content of sugars (monosaccharides) in apical bud and root in autumn and following spring was analysed using the Luff–Schoorl method. Sugar content in apical bud and root of winter oilseed rape in autumn and spring differed depending on the trial year, because of different, even contrary (in season 2009/2010), meteorological conditions. Sugar content was higher in plant parts developed when rape was sowed on earlier sowing dates, but it was substantially influenced by the sowing date only on some occasions. Sowing rate had no impact on sugar content in apical bud and root. Application of a fungicide as a growth regulator had no significant impact on the result, but sugar content decrease during winter 2009/2010 in the root of winter oilseed rape was smaller when fungicide as growth regulator was applied.

To promote the future of abandoned lands management and the reduction of fossil energy consumption in Latvia, the establishment of energy crops plantation facilities, including perennial grasses, was investigated. The objective – suitability of several perennial grasses for bio-energy production under condition of Latvia. The aim of the current research to evaluate the experimental field conditions for the cultivation of perennial grasses. The perennial grasses are modest in terms of soil conditions, they are environmentally friendly, as well as provide high yields of biomass with adequate quality for bio-energy production without large investments. With increasing amounts of bio-energy production the amounts of various by-products which are profitable to utilize as energy crops fertiliser will also increase. It is essential that plant nutrients return back into circulation by creating a complete cycle. In order to test in practice the possibility of creating this complete cycle of growing perennial grasses, an experimental field was chosen at the Research Institute of Agriculture in Skriveri. In the summer of 2011, before trials establishment, the conditions of soil were examined at four depths: 0 – 20 cm; 20 – 40 cm; 40 – 60 cm and 60 – 80 cm. The analyses showed that the experimental field conditions were appropriate for growing of perennial grasses. The results of the soil agrochemical analysis will be a base for future studies of usage efficiency of different fertiliser types on perennial grass productivity and nutrient recycling opportunities in energy crop plantations.

Blueberry cultivation is becoming more and more popular in Latvia, and several commercial plantations have been established recently. Highbush blueberries (Vaccinium corymbosum L.) are perennial and can grow without replanting for 50 years; therefore a choice of soil and its preparation have a great role. This article summarizes results of research carried out in commercial blueberry plantation established in 2004 on loamy Haplic Cambisol. Soil properties, especially reaction and organic matter content, initially were not suitable for blueberry cultivation, therefore deep tillage and application of soil conditioner (acid sphagnum peat) were done before planting and similar peat mulch was applied every second year. Berry yield of 4 blueberry cultivars, soil properties and the nitrogen, phosphorous and potassium content in growing plant leaves were determined. The obtained results showed that sphagnum peat is an effective material for lowering of soil pH in plant root layer (0 – 40 cm). Data about plant nutrient content in topsoil and subsoil as well as in growing plant leaves will help to develop criteria for soil fertility assessment and diagnosis of plant nutrition.

The American cranberry (Vaccinium macrocarpon Ait.) is a perspective and marketable crop both in Latvia and foreign markets, but berries are affected by rot in storage. The aim of the study was to detect the incidence level of cranberry fruit rot at the beginning of storage period in different places in Latvia. In 2007 - 2011, two hundred sound berries (out of 1000) were randomly collected by hand along a diagonal from five different cranberry plantations from locations all over Latvia. Berries were kept in plastic bags for a month and refrigerated at +7 °C. At the end of November, berries were sorted and rotten berries were separated from the sound ones. Over the period of 2007 - 2011, the incidence of storage rot reached 12 - 15% at the end of November, with an upwards trend observed every year, but the hot and rainy summer of 2010 significantly reduced the quality of fruit in storage, peaking on the average 33% of decayed berries. The incidence of fruit rot varied among the inspected cranberry plantations, but a tendency was observed that older plantations produced more rotting fruit and incidence of the disease was 12 - 50% after a month’s storage in the oldest plantation. The application of fungicides during the vegetation season did not affect development of post-harvest rot. Storage rot was a problem in the cranberry samples from all inspected plantations in Latvia, and in future the incidence of fruit rot is expected to increase.

Apple variety influence chemical composition and sensory properties of products obtained from apples. This paper reports the influence of apple varieties on the sensory properties of the cider evaluated by two differently trained panel groups. Juices of five varieties apples (‘Auksis’, ‘Lietuvas Pepins’, ‘DI-93-4-14’, ‘Remo’ and ‘Kerr’) were fermented with Saccharomyces bayanis EC-1118 (Lalvin, Canada). The sensory evaluation of samples was carried out with two panel groups – experts (experienced in the field of beverage technology and evaluation) and trained panellists (finished basic course of sensory evaluation). Experts identified flavours of cider, and evaluated intensity of sensory properties, namely, clarity, aroma (apple, fruit, yeast), taste (apple, yeast, sour, astringent, bitter) using line scale. Trained panellists evaluated the samples only using line scale. Four descriptors were significant for characterization of differences in ciders from various variety apples, namely, sour taste, apple taste, apple aroma and clarity. The research suggests that, varieties with more intense apple and fruit aroma, apple taste and additionally with astringent and bitter taste notes are preferable. Taking into account these results, higher evaluations for cider ‘DI-93-4-14’ were observed, followed by ‘Remo’ and ‘Kerr’.

The rowanberries (Sorbus aucuparia L.) are small orange-red fruits of a rowan tree and belong to the family Rosaceae. These berries have been described as an important source of flavonoids, and their antioxidant activity affects reactive oxygen species and lipid peroxidation; therefore they are suitable for production of health-food products. The ripe wild rowanberries have traditionally been used for jellies and jams, but their use as a food ingredient has been less popular because of their bitter taste. Sweeter and less astringent than wild rowanberries are different cultivars of sweet rowanberries and hybrids with other species. The aim of the current research was to determine physical and chemical parameters and sensory properties of rowanberry marmalades. The experiments were carried out in the Faculty of Food Technology of Latvia University of Agriculture. The purees of wild rowanberry and six different rowanberry cultivars were chosen for the production of marmalades. Chemical, physical and sensory indices of the product – moisture, total carotenoids, tannins, colour, hardness and intensity of sensory properties (flavour, colour, bitterness) – were determined as quality indicators. The results showed large variability in the physical and chemical parameters between the marmalades of different rowanberry cultivars and hybrids. The sensory evaluation of marmalades from rowanberry cultivars ‘Moravica’, ‘Mitchurinskaya krasnaya’, ‘Sorbinka’ and hybrid of rowanberry × hawthorn ‘Granatnaya’ showed that the degree of liking was from “neither like nor dislike” to “like moderately”, and marmalades from wild rowanberry, S. aucuparia var. sibirica and hybrid of rowanberry × pear ‘Alaya Krupnaya’ – from “dislike moderately” to “dislike slightly”.

One of the causes of cardiovascular diseases and overweight problem is a high consumption of sweets. Sugar is traditional food sweet matter. A change of sugar may therefore both change the perception of texture of products. The aim of the research was to evaluate properties of agar-agar jellies prepared with Jerusalem artichoke (Helianthus tuberosus L.) syrup (JAS). Soluble dry matter of experimental samples was determined by Mettler Toledo Refracto, separated sugars - by liquid chromatography, and acidity of jellies - by titration with 0.1 M NaOH. The measurements of pH were made by pH-meter Jenway 3510. Determination of vitamins B1 and B2 was made by the AOAC Official Method 986.27 and 970.65. Texture of samples was determined by using a Texture Analyser (Model TA.XT Plus; Stable Micro Systems), by cylindrical probe (P/25). Colour of jellies was evaluated by using Colour Tec-PCM. The results showed that soluble dry matter decreased from 64.5˚ Brix to 57.5˚ Brix, sucrose decreased by 6%, the acidity increased from 7.2 to 17.8˚, and pH values ranged between 3.8 and 4.5. The hardness of the samples decreased from 50.66N to 40.05N by increasing of added JAS concentration. Adding JAS in jelly, the content of vitamins B1 and B2 increased. Lightness “L” fluctuated between 24.26 and 14.60 with increase JAS concentration. The research suggests that different percents of Jerusalem artichoke syrup could be used as sugar substitute. The product becomes healthier, but the gels obtain a darker colour. Therefore it is recommended to look for other version to improve the colour of experimental jellies.