Latvia at the moment does not have precise data about long-term storage of Scots pine. Long-term storage in warm season may lead to significant damages for high priced timber, income reduction for timber sellers and quality loss risk for timber buyers, therefore, roundwood is transported as soon as possible, because of the risk of blue stain, crooks and insect damages. Results of this study on Scots pine were obtained during summer–autumn season of year 2015. Scots pine timber quality changes in long-term storage were analysed in 4 sample stacks – set up in summer (25 July) and stored for 100 days. In every sample plot there was a control pile, a pile with harvester spike damages, a pile with bark damages and a pile with harvester spike and bark damages. There were 32 timber assortments in every pile in order to determine also the emplacement effect in stack. In this study a high correlation was found between pine timber quality changes and meteorological conditions, side surface damages and storage length. By analysing the proportion of blue stain in cross-section and its changes during storage between control assortments and assortments with bark and harvester damages, significant differences were observed, therefore it can be concluded that not only bark damages influence the proportion of blue stain, but also harvester spike rollers. Based on the results of this study, we can predict maximum storage duration during summer–autumn period in Latvia, and it is set from 9 – 16 days.

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.

Lack of data about effect of meteorological conditions, sowing date, sowing rate, fungicide as growth regulator application and other agroecological factors on rape autumn growth is observed in Latvia. The aim of our research, started in autumn 2007 and continued up to autumn 2010 in Research and Study farm ''Vecauce'', was to investigate the influence of agroecological factors (sowing date, sowing rate and fungicide (as growth regulator in autumn)) application as well as meteorological conditions on autumn plant growth of two types of winter rape varieties. Winter rape biometrical parameters were estimated, and meteorological parameters (hydrothermal coefficient (HTC) and growing degree days (GDD)) were calculated. Four year results showed that winter oilseed rape seed germination was affected by precipitation and air temperature around the sowing time. Calculated GDD correlated with plant biometrical parameters during trial years. HTC showed moisture effect on rape emergence time. Sowing date was important factor which had strong and significant impact on biometrical parameters of rape plants in autumn. Earlier sowing date increased height of growth point, root neck diameter, plant and root mass, and main root length significantly for both cultivars in four trial years. Such agro-ecological factor as sowing rate (plant density) affected plant biometrical parameters only in some trial years. Plant weight was significantly influenced by sowing rate for both cultivars if sowing rates were equal. Other important parameter - height of growth point - was not significantly influenced by sowing rate for both cultivars when similar sowing rates were used in all years; exception was year 2009 for 'Californium'.

The homogeneous and light wood of birch is suitable for different types of treatment processes and is highly valued for products where visual aspect is important, however, birch assortments are highly susceptible to damages caused by fungi during the storage. Such fungal damages cause discoloration of birch roundwood intended for further woodworking. Sapwood discoloration development and its influencing factors for birch roundwood were analyzed in the summer - autumn period of the year 2016 (August, September and October). Control cut for assessment of sapwood discoloration development was made in four birch roundwood stacks in the districts of Auce and Daugavpils. In order to evaluate the influence of harvesting type, side surface damages, placement in pile, storage duration, diameter, distance from the end plane, daily average temperatures, precipitation amount and relative humidity on development of sapwood discoloration, 616 discs from birch log end planes were prepared. After conducting multiple factor linear regression, it was concluded that a significant development of discoloration and its changes for birch roundwood are promoted by harvesting type, placement in pile, distance from the end plane, daily average temperatures and relative humidity (R2 = 0.450). For birch logs that are prepared by harvester with the daily average air temperature + 6 °C, the first signs of discoloration appear after 17 – 18 days, but on all logs stacked in pile they appear after 68 – 69 days. Whereas, with the daily average temperature of + 18 °C, the first signs of discoloration can occur after only six days, but on all logs stacked in pile they appear after 23 days.

The greatest interest in the cultivation of spring wheat is in regions with an increased intensity of late fallow. However, there are also stronger tendencies to limit the area of its cultivation (similarly to other spring cereals), which is mainly due to a lower level of yielding. Farmers decide on the sowing date of varieties mainly after plants that leave the field late, e.g., potatoes, beets and maize. That is why these varieties are usually called „alternative wheat”. The aim of the research was to determine the effect of autumn sowing date on the yield and the technological value of the grains of selected spring wheat varieties. A two-factor field experiment was established using a split-plot design at the Experimental Station of Cultivar Testing (ESCT) in Bezek (51°12′06″N 23°16′06″E), the Lubelskie Voivodeship, Poland (2008/2009, 2009/2010, 2010/2011). Experimental factors were as follows: A) sowing date – I – October, II – November, III – spring, B) spring wheat variety: ‘Tybalt’, ‘Cytra’, ‘Bombona’, ‘Monsun’, ‘Parabola’. It was found that grain yields of spring wheat sown in the autumn were higher than those sown in the spring term. Without regard to the sowing term, the highest grain yields were obtained from ‘Tybalt’ cultivar.

Stable isotope ratios of water (δ2H and δ18O) are important indicators which describe hydrological processes in the environment. These parameters allow to analyse structure, status, migration of pollutants and processes of the groundwater system. Groundwater from dug wells is widely used as a drinking water source highlighting the importance of investigation of water quality and its possible flows and sources. Despite available centralized water systems, there are still wide territories where dug wells are the main source of drinking water supply. Dug wells are recharged from shallow groundwaters which makes them more vulnerable to anthropogenic contamination. Therefore, quality monitoring and estimation of anthropogenic influences are of importance. Quality requirements of drinking water do not provide measurements of stable isotope ratios in drinking water, but the combination of those elements can be valuable for the characterization of impacts on groundwater quality. The aim of this study was to survey 64 dug wells in Eastern Latvia and analyse water quality together with measurements of stable isotope ratios. Measurements were performed twice, i.e., autumn and spring to track water sources in wells and describe the extent of possible impacts. This approach can indicate the magnitude of local factor impacts on drinking water quality. Surveyed wells provide high differences in analysed parameters, for example, nitrate concentrations in autumn varies from 0.44 to 108.26 mg LE−1. Also, other detected parameters are variable; therefore, tracking water flow with stable isotope values gives better insight into the water quality of the studied region.