The EU Directive on the promotion of the use of biofuels or other renewable fuels for transport (CO M 2003/30/EC) states that the proportion of biofuels in 2010 must make 5.75% of non-renewable fuels, but in 2020 - 10%. The only way for Latvia to fulfil the Directive 2003/30/EC is to use winter rye because it is one of the oldest cereals grown in Latvia, and Latvia has a long-lasting experience in growing it. A field trial of winter rye (Secale cereale L.) was arranged in the Agricultural Science Centre of Latgale from 2005 to 2007. The influence of four winter rye varieties and five fertilizer rates on grain yield and starch content was researched for three years. The year (factor A), the varieties (factor B), the fertilizer rates (factor C), and the interaction of factors AB, AC , BC, and ABC significantly influenced the yield of grain and the starch content with 95% probability. It is recommended to use good quality grain with high starch content and low protein content for bioethanol production. The varieties of winter rye 'Kaupo', 'Amilo', and 'Walet' are the most suitable for ethanol production in Latgale region.

Cultivation of Christmas trees is not a very common activity in Estonia at the moment. There are about 290 000 hectares of former agricultural and pasture lands, which are out of use in Estonia (Aastaraamat Mets 2007, 2008). Taking into account the knowhow from Europe, the hypothetical plantation was established and calculation of profitability was made. Profitability of Christmas tree cultivation was compared to the other alternative possibilities of land use. Achieving the output of saleable Christmas trees at least 50%, cultivation of Christmas trees is very competitive compared to other possibilities of land use, but at same time it is also the most capital-intensive.

The article presents the part of PhD studies of the energy wood harvesting technologies in thinning, and its development possibilities. A possibility for energy wood procurement and use in Latvia as a good amount of not used energy, including estimation of how much wood for energy purposes could be available in Latvia is analyzed. Research has been made in two parts using forest stands cutting area in three different ages to get an average volume of energy wood per ha. First part of the research has been done in a 60 years old forest stand cutting area in the way that total chips volume is measured and then recalculated to the thinning area. The average volume from studied forest stand was 20.32 m**3 haE-1. The second part of the study shows that from 30 till 45 years old forest stands cutting area by the measuring possible removal tress, the energy wood volume could be 23.74 – 33.5 m**3 haE-1. Including the slash from this forest stands cutting area the possible volume of wood for energy purposes could be ~ 33 – 47 m**3 haE-1. The calculations also have been done to study available energy wood resources from whole forest stands thinning area. Totally the available energy wood volume in Latvian conditions is 0.85 million m3 yrE-1.

Oil-flax has a wide range of utilization possibilities, inclusive of bioenergy production. In our research evaluated out two oil-flax varieties 'Scorpion' and 'Flanders' after the calorific value, oil, lignin, and ash content; and also the chemical composition in 2008 -2010. The results show that oil-flax shoves have a high calorific value and high lignin content but a low temperature for ash fusion. It was established that the growth year and some unexplored factors have influence on the ash content. The oil content in the seeds was 336-458 g kgE-1, depending on the chosen variety. The flax shoves can be used as a supplement for biofuel combustion, as they have a low fusion temperature, a high calorific value, but a comparatively low yield makes oil-flax unprofitable to grow for biofuel production.

This paper discusses some aspects of introducing a new agricultural crop in Latvia – truffles Tuber spp. Truffles are mycorrhiza–forming mushrooms with edible fruit bodies developing in the upper layer of soil. In Latvia, there is a growing interest among farmers to start cultivate truffles. From several cultivated truffle species, the Burgundy truffle Tuber aestivum syn. T. uncinatum is the most suitable to cultivate in Latvia. There are both autochthonous and introduced tree species in Latvia, which are suitable for the Burgundy truffle cultivation and it is suggested to use Quercus robur, Corylus avellana, Tilia cordata and Fagus sylvatica. In order to find the regions in Latvia with the highest potential for successful Burgundy truffle cultivation, climate and soil characteristics had been co-analysed. By superimposing soil and climate maps of Latvia, the most suitable regions for truffle cultivation are situated in the central and southern part of the country. Considering the variability in soil composition even within regions in Latvia, it is thereafter also of great importance to investigate site-specific soil characteristics in order to find the most favourable grounds for truffle cultivation. Other truffle species which might be suitable for cultivation in the future are also discussed, as well as some general recommendations in establishing truffle orchards.

With the increase in demand for renewable energy resources, new studies are carried out about under - utilized resources, namely, stumps. To begin to use stumps in industrial application, it is necessary to find out stump extraction influence on the environment, biodiversity, forest regeneration and other important factors. In Zemgale forestry, Misas and Klīves forest districts managed by Joint stock company “Latvian State Forests” (LSF) study on stump extraction in woodlands where clear-cuttings done in 2006 was carried out in the block No. 177, compartments No. 1 and 5, as well as the block No. 176, compartments No. 3 and 9. In these territories two research objects were made where in November-December 2007 stump extraction as well as soil preparation were performed. Main tasks of the project were to evaluate the results of forest natural seeding and coppice ingrowths in natural regeneration areas and evaluate the use of different methods for artificial reforestation with spruce and pine containerized seedlings. It was observed that more seedlings were cut off in the areas where soil scarification with stump extractor was performed if compared to areas prepared with a disc trencher.

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 research was done to observe open-field cultivation potential for growing melons Cucumis melo L. without covering in two regions of Latvia: Tukums and Cesis. Three varieties of melons 'Zolotistaya', 'Galiley' and 'Kolkhoznica' were used. In all, 15 individuals of each variety were grown at each place - Tukums region and Cesis region. To evaluate growth and development intensity for each variety in each region, the following parameters were measured parameters were measured: length of the main shoot, number of leaves per plant, time of appearance of the first male and female blossom, and number of perished plants. The most suitable variety for the Cesis region was found variety 'Kolhoznica', but for Tukums region - 'Zolotistaya'. The research suggests that variety 'Galiley'is the least suitable for growing in both regions. It was established that successful open-field cultivation of melons in Tukums and Cesis regions is possible only in case of favourable weather conditions. In the year of the investigation, 2004, insufficient sum of effective temperatures limited successful development and yielding of melon.

In 1999-2003, the investigations were carried out in Juodkiskis study object of Water Management Institute of Lithuanian University of Agriculture. Study scheme is composed of three treatments: treatment I -slurry applied, treatment II - mineral fertilizers applied; treatment III - no fertilization. Test field is drained, drain spacing is 15 m; draining depth is 1.2 m. During the crop rotation the following plants were grown: spring wheat with undercrop, red clover (1st year of use), red clover (2nd year of use), sugar beet, and spring rape. The objective of studies was to determine the effect of cultivated crops on drainage water quality. As the study results have show, N total concentrations contained in drainage water increased due to higher fertilization rates and inorganic nitrogen accumulated in the soil. Neither fertilization nor amount of mobile phosphorous contained in the soil made any effect on Ptotal concentrations in drainage water. In arable land, Ntotal concentrations contained in drainage water were 2.3 times higher than those in drainage water of the field, where red clover was grown. Ptotal concentrations were higher in the field with red clover. According to the rates determined in Lithuania, drainage water is not polluted with phosphorus, while average annual Ntotal concentrations exceeded the maximum allowable (MAC) when spring wheat with undercrop and sugar beet was grown.