Feeding livestock a balanced diet with a differentiated crude protein (CP) content, depending on the lactation phase, can reduce nitrogen emissions from livestock excrement and urine. A higher content of non-starch polysaccharides in livestock diets improves feed absorption in the livestock body and, consequently, nitrogen is emitted more from protein present in livestock manure than from urea acid present in livestock urine. The aim of the study is to calculate the ammonia emission reduction potential in Latvia by optimizing the feeding of dairy cows and ensuring life longevity, as well as provide justification for ammonia emission reduction in dairy farms. Calculations made by using the NorFor Model for optimization of dairy cow (Bos primigenius f. taurus) diets revealed that compared with lowyielding cows, a higher CP content diet fed to high-yielding cows at the beginning of lactation increased the amount of nitrogen (N) in their excrement and urine by 90–180 g dE−1. Reducing the CP content in the cow diet by an average of 10 g kgE−1 dry matter (DM) during mid-lactation resulted in the same trend. Reducing the CP content in the cow diet during late lactation and the dry period by another 20–30 g kgE−1 of DM, N emissions from excrement and urine significantly decreased. Increasing the lifespan of dairy cows also means reducing ammonia emissions from the farm. By increasing the number of lactations per cow on dairy farm, it is possible to reduce the number of heifers per cow. The total reduction of ammonia emissions in Latvia was calculated based on a long-term projection of a decrease of 0.1 heifer per dairy cow. Ammonia emissions could be reduced by 0.051 kt by decreasing the number of heifers by 12.54 thou. at the planned increase in the lifespan of dairy cows by 2030.

Forest mineral soil is one of the terrestrial carbon pools, and changes in forest management practices can affect the carbon stock in forest soil. The purpose of the study is to estimate temporal fertilization impact on mineral soil organic carbon stock, depending on fertilizers applied, forest stand type, different dominant tree species of the stands. Coniferous and birch forest stands with mineral soil in the central and eastern part of Latvia were selected for the experiment. The fertilizers used were wood ash and nitrogen containing mineral fertilizer. No significant differences in organic carbon stock in O horizon were detected 2–5 years after fertilization. A tendency of smaller organic carbon stock in upper mineral soil layers (0–10 cm, 10–20 cm) was found in most part of objects. Significantly smaller organic carbon stock was found in upper mineral soil layers (0–10 cm and 10–20 cm) in birch stands with wet mineral soil treated with ammonium nitrate if compared to the control plots, possibly due to a different soil moisture regime of forest stands. The positive and significant correlations between soil organic carbon and nitrogen stocks were found in most part of the objects.

The Annual 24th International Scientific Conference ‘Research for Rural Development 2018’ was special and dedicated to the Latvia a 100 years since became an independent state, 155th Anniversary of Latvia University of Life Sciences and Technologies (LLU) and 280th Anniversary of Jelgava palace, where is located the main building of university. In the retrospect of four months later, we can count the Conference as a great success as interdisciplinary studies. The theme – Research for Rural Development - attracted participation more than 167 researchers with very different backgrounds. There were 139 presentations from different universities of Estonia, Poland, Kazakhstan, Lithuania, Ukraine, Sweden, South Africa, Indonesia, Russia and Latvia. The interdisciplinary proceedings of the Annual 24th International Scientific Conference ‘Research for Rural Development 2018’ (two volumes since 2010) are intended for academics, students and professionals. The subjects covered by those issues are crop production, animal breeding, agricultural engineering, agrarian and regional economics, food sciences, veterinary medicine, forestry, wood processing, water management, environmental engineering, landscape architecture, information and communication technologies.

The four independent reviewers estimated each paper and recommended 81 articles for publishing at the proceedings consisted of 2 volumes, which started life as presentations at the Annual 23rd International Scientific Conference “Research for Rural Development 2017” held at the Latvia University of Agriculture, in Jelgava, on 17 to 19 May 2017. In the retrospect of four months later, we can count the Conference as a great success. The theme – Research for Rural Development - attracted participation more than 155 researchers with very different backgrounds. There were 124 presentations from different universities of Poland, Kazakhstan, France, Czech Republic, Lithuania, Estonia, India, Russia and Latvia. Thank you for your participation! We are sure that you have learned from the presentations and discussions during the conference and you can use the outcomes in the future. The cross disciplinary proceedings of the Annual 23rd International Scientific Conference “Research for Rural Development 2017” (two volumes since 2010) are intended for academics, students and professionals. The subjects covered by those issues are crop production, animal breeding, agricultural engineering, agrarian and regional economics, food sciences, veterinary medicine, forestry, wood processing, water management, environmental engineering, landscape architecture, information and communication technologies. The papers are grouped according to the sessions in which they have been presented.

Flax (Linum usitatissimum L.) fibre and seeds are widely used to produce healthy and environmentally friendly products. It is known that the main factors that influence flax fibre’ and seeds’ yield are genotype and growing conditions. The main task of the Latvian flax breeding program is to develop flax genotypes that are highly productive (both fibre and seeds) and well adaptable to changing environmental conditions. Goal of this study is to identify high yielding genotypes with good adaptation to local variable agro-ecological conditions. The agronomically important traits, such as yield of stem and seeds, total and technical plant height and fibre content were evaluated for 13 Latvian origin flax lines and standard variety ‘Vega 2’. The field trials have been carried out over the period from 2012 to 2015 at the Agricultural Scientific Centre of Latgale. The regression, correlation, coefficient of variation and cluster analysis between yield and yield provided components were used for identification of high yielding genotypes with good adaptation. On the basis of cluster analysis the genotypes were classified in two groups by lower and higher yield of stem, fibre content, total plant height and technical plant height. The line ‘I18-1’ was identifying as genotype with the highest average yield of stem (751.25 g mE-2) as well as highest yield against other genotypes in moisture and drought years. Most valuable by the average technical plant height was line ‘L26-1’ (73.05 cm).

Since the middle of the last century rapid intensification of agricultural production systems has resulted in dramatic increase in fertilizer consumption as fertilizer has been considered as one of the most important factors for increased yields. However, not all the nutrient ions in a fertilizer applied to soil are taken up by crops, thus certain amount of the applied fertilizer is lost from agricultural fields leading to increases in nitrogen surplus, nitrogen losses to the environment and harmful impacts on biodiversity, air and water quality. This study aims to focus on crop fertilisation planning which is based on the knowledge of physical and chemical properties of soil and involves performing soil tests, designing a fertilisation plan and its practical implementation as well as calculating the balance of N, and to evaluate crop fertilisation planning as a tool for achieving balanced economic and environmental benefits in crop farming, which play an important role in efficient farming. In this study, the authors have analysed current situation in Latvia regarding requirements for fertilization planning in crop farms and have assessed potential costs and benefits from fertilisation planning. The research finds out that total cost of introducing of fertilisation planning ranges from 34 to 22 EUR haE-1, however, fertilisation planning is a neutral measure where costs are compensated by savings from N inputs which ranges from 10 to 40 kg N haE-1.Fertilisation planning generates environmental benefits, i.e. – reduces direct N2 O emissions from agricultural soils by 47 – 187 kg CO2eq haE-1 through reduced N fertilizer inputs.

Artichokes (Cynara cardunculus L.) contain many minerals, vitamins, fibres, and polyphenols. Environmental conditions and climate change on a global scale affects the overall agriculture and food supply. Composition of biological active compounds in plants depends on the climate and growing conditions, cultivar properties, plant development stage, harvesting time and other factors. The aim of research was to evaluate the effect of agroecological factors on yield and flavonoids content of globe artichoke. An experiment was carried out under open field conditions in Institute of Horticulture, in Pūre investigation fields during the vegetation period of 2014 and 2015. The experiment was arranged in two different soils: brown soil with residual carbonates and the soil strongly altered by cultivation. The yield and its quality were analysed during the whole vegetation period. Higher yield was observed in the soil strongly altered by cultivation. The results showed tendency that the higher flavonoids content in artichoke heads was observed in 2014 than in 2015. Significant differences between flavonoid content per harvest time are observed in both soils.

The research was conducted in Latvia University of Agriculture Research and Study Farm ‘Vecauce’ in 600 dairy cows herd, in the period from 2009 to 2013. Within the framework of the research, growth indicators (from birth till the first delivery) of 102 dairy cow calves were analysed. Live weight and hip height of the heifers were found out at birth, at the age of 6 and 12 months, at first insemination and first calving. Heifers born to primiparous cows in both breed groups had notably lower live weight (42.0 and 42.4 kg), as compared to the 4th group heifers born to mature cows (p is less than 0.05). At the age of one year, the greatest weight among the red breed animals was recorded for the 4th group heifers born to mature cows (on average 354.8 ± 7.09 kg), while in Holstein breed those were heifers born to mothers calving on average for the 2nd time (on average 363.0 ± 6.47 kg). The 4th group heifers born to mature Holstein cows had notably greater hip height at birth – on average 78.1 ± 0.9 cm (p is less than 0.05). Heifers of red and Holstein breeds on average were inseminated at the age of 14.6 – 14.8 months as they reached live weight 395 – 396.5 kg. Heifers of red breeds on average calved at the age of 25.8 months, whereas Holstein heifers - of 26.4 months. The research aimed at analysing growth rates of heifers born to dairy cows at different age.

In Latvia, different breeds of beef cattle are grown; therefore, it is important to explain their suitability to organic farming systems, because most Latvian beef cattle breeders work with organic farming methods. The aim of this research was to compare fattening of different beef breed bulls (Bos Taurus) in organic farming system at similar housing and feeding conditions. In the research, there were included Blonde d’Aquitaine (BA), Hereford (HE), Simmental (SI) and crossbred (CB) bulls. Fattening period started after calf weaning from suckler cows at 7 – 8 months of age. Fattening results were significantly affected by factors like breed, live weight and age before fattening, but slaughter results were significantly affected by breed, live weight and age before slaughter. During the fattening period the biggest daily weight gain was showed for SI breed bulls (849 g), but the biggest live weight increase was recognized for BA breed bulls (295 kg). The required slaughter weight the fastest was reached for XG bulls, which average slaughter age was 532 days (p is less than 0.05). The greatest slaughter weight – 342 kg (p is less than 0.05) and dressing percentage (58% (p is less than 0.05)) was recognized for BA breed bulls; also, carcass conformation score in muscle development was the highest for BA bulls (2.0 points (p is less than 0.05)). The greatest economic benefit was from CB bulls, income calculated per one rearing day from CB bulls was - EUR 1.80.

The diversity of non-starter lactic acid bacteria in raw, pasteurised milk and maturated Swiss type cheese was tested. The aim of the present study was to analyse the concentrations and representatives of non-starter lactic acid bacteria in raw milk and to evaluate the changes of their concentrations and representatives during pasteurisation of cheese milk and Swiss-type cheese production. The analysis carried out in the study showed a variation in the microbial composition and quantity of raw milk. The most frequently isolated lactobacilli were found at low level in raw milk (mean 27.5×104 CFU mLE-1) and the most frequently identified species were Lactobacillus brevis and Lactobacillus paracasei. The microflora of raw and pasteurised milk is similar analysing lactic acid bacteria representatives in the samples. Lactobacillus brevis and Lactobacillus paracasei were detected in the same samples in raw milk, pasteurised milk and maturated cheese. Our study showed that lactic acid bacteria concentration was quite low in pasteurised milk (1-12 CFU mLE-1), but they grow rapidly in cheese during ripening reaching 1.1-1.8*106 CFU gE-1. The present study has shown that NSLAB in Swiss-type cheese mainly derive from raw milk, and only a few strains survive the processing conditions and grow during ripening.