We spent the year celebrating the State (Latvia 100) and Agriculture higher education (155) anniversaries. We reminded ourselves that life would continue. After the celebrations, and much needs to be done to convince international experts that the importance of agricultural sciences has increased, we are internationally better recognizable, large and powerful in place of many small institutions, their own the articles are submitted to scientific journals and are quoted etc., etc., etc. This year we have collecting all the work done and concluding that the reporting period has indeed been done a lot. The number of publications quoted has increased, the authors have appeared or increased Hirsch Index, foreign colleagues involved to research projects or work in an institution who together make Latvian agricultural science and also scientists more internationally recognizable. The workshop reports presents research results in crop (winter wheat, barley, oregano) cultivation, fertilizers application, plant diseases and pests identification and control. Research in forest stand biomass determination and calculation of carbon sequestration has been viewed. Fertility of Latvian Dark-Headed sheep was analysed. Technology of dehydration of sapropel in geotextile bags has been outlined. Research on influence of soil tillage on clay mineral composition and plasticity has been discussed.

Yellow rust caused by Puccinia striiformis is one of the most harmful diseases in wheat worldwide. It can cause 10–70% yield loss. In Latvia, only periodic observations of yellow rust have been made. In recent years, epidemics of P. striiformis were observed in wheat-growing regions. New aggressive P. striiformisraces were identified. These races are adapted to high temperatures, produce more spores, and have a shorter latent period. This study aimed to identify the races of P. striiformis in Latvia. In 2017–2019, wheat leaves with symptoms of P. striiformis were collected. Wheat samples were sent to the Aarhus University Global Rust Reference Centre in Denmark for race identification with phenotyping and genotyping methods. During the research, the races of P. striiformis – PstS4, PstS7 (Warrior-), PstS10 (Warrior), PstS13 (Triticale2015) and PstS14 were identified.

Heterogeneous populations is one of the ways to increase genetic diversity in varieties of self-pollinating cereals. The aim of this research was to evaluate performance of spring barley (Hordeum vulgare) composite cross population ‘Mirga’ in comparison to three homogenous varieties. Field trials were carried out during 2015–2018 under organic and conventional farming systems. ‘Mirga’ showed a tendency to be more productive under organic conditions and could be characterized as widely adaptable to various growing conditions. Net blotch (Pyrenophora teres) severity was significantly lover for ‘Mirga’ than that of checks under both conditions in most of the cases. Competitiveness against weeds for ‘Mirga’ and checks did not differ.

The study was carried out in a long-term experimental field “Sidrabiņi” where liming and fertilizer usage has been studied since 1982. Field experiment includes 4 plots with different fertilizer and liming rates, which are split in 16 smaller plots, where each plot is unique. Totally, four liming rates 0, 2.85, 5.70 and 11.40 t haE−1 CaCO3 and four rates of mineral fertilizers were used: without fertilizer, N45P30K45, N90P60K90 and N135P90K135 were applied annually. Primary liming was done in 1981 using oil shale ash with neutralizing value 80%, the maintenance liming was performed in 1994 (dolomite flour 97.0%) and in 2014 (limestone flour 97.6%). Soil acidity is one of the most important parameters of soil degradation. Soil pH (soil reaction) affects all stages of plant growth. Besides, soil pH is one of the parameters studied in field experiment. Aim of this study was to evaluate obtained data of soil pH changes from long-term field experiments data base.

Manure Standards is co-funded by the Interreg Baltic Sea Programme project and includes partners from nine countries around the Baltic Sea. The aim of the Project is to develop harmonized methodology and respective tools for calculation of plant nutrients (NPK) excreted by animals and their cycling in agricultural systems depending on livestock operations, farming technology and manure use. Unified approach and implementation methods are crucial for reasonable cooperation within the number of major transnational initiatives like HELCOM nutrient load targets, EU Nitrate directive, mitigation of greenhouse gases as well as ammonia emissions, nitrogen and phosphorous reduction in environment etc. It also addresses the need of plant nutrient (especially nitrogen and phosphorus) farm-specific bookkeeping, including fertilisation plans for the sake of efficient use of local resources with minimum environmental risks.

Accounting of the carbon stock has to be implemented using internationally approved methods that are adapted for local conditions. Previous studies in Latvia on forest biomass and carbon assessment are fragmented and limited to separate biomass components and tree species. The study material included a total of 102 Scots pine (Pinus sylvestris), 81 Norway spruce (Picea abies), 105 birch (Betula spp.) and 84 European aspen (Populus tremula) trees sampled in 124 forest stands, while 37 pines, 29 spruces, 42 birches and 33 aspens are lifted for belowground biomass studies. Wood (14366) and bark (4652) samples have been analysed to study the variation of within-the-stem basic density and to calculate the stem biomass. Study approved that the basic density of stem bark significantly (p is less than 0.001) differed from the stem wood. The use of mean stem wood density instead of whole stem density leads to biased estimation of stem biomass (1.5–4.5% error depending on tree species). Within study equations for estimation of aboveground and belowground biomass were developed. The uses of equations applied for biomass estimation in Fennoscandia in Latvia are creating 4.7–61.7% error depending on tree species and biomass component. Application of default biomass expansion factors and root to shoot ratios for temperate and boreal forests defined in IPCC guidelines creates an overestimation of 36.9% and an underestimation of 5.2%, respectively in comparison to methodology elaborated in this study. According to the forest definition used in national IPCC reports, the forest carbon stock in Latvia in year 2016 was 238.1±3.5 million tonnes.

This study was performed in two biological apple orchards in Latvia to analyse fauna and economic importance of invertebrates trapped by cardboard banding. In cardboard bands assessed, density of predatory invertebrates was twice to nine times higher than of pests of apple trees. Therefore, more detailed studies on usage of cardboard banding as a tool for pest control (its direct and indirect impact on populations of pests) are essential.

The Gross Nutrient Budget (GNB) is a key indicator of relevance for number of agri-environment related policies. It is intended to be a respective indicator of potential threat of surplus or deficit of two major soil and plant nutrients – nitrogen and phosphorus – within the agricultural system. GNB shows the link between agricultural activities and the environmental impact. For annual routine GNB calculation number of input data are required (NP excretion by animals, input by mineral fertilisers, biological N fixation, atmospheric N deposition, seed and planting material, outputs by crop and fodder production, residues removed from the field etc.). These reference values should be unified on the national scale as it is also used to perform other transnational initiatives like HELCOM nutrient load targets, EU Nitrate directive, mitigation of greenhouse gases as well as ammonia emissions, nitrogen and phosphorous reduction in environment etc. It is also used for the fertiliser planning on the farm-scale level. Unification of nutrient budget input values used in Latvia is the main goal of the Project.

Nitrogen fertilizer plays an important role in the production of high yields of winter wheat (Triticum aestivum), but the use of nitrogen amount that does not pose a risk to environment is of constant importance. The aim of this paper is to find out the impact of nitrogen top-dressing rate on winter wheat yield and yield forming components per four year period (2014/2015–2017/2018). The experiment was conducted at the Research and Study farm “Pēterlauki” of Latvia University of Life Sciences and Technologies. Researched factors were eight nitrogen top-dressing rates (N0 or control, N60, N90, N120(90+30), N150(90+60), N180(90+60+30), N210(90+70+50) and N240(120+60+60)), two soil tillage variants(traditional soil tillage with mould-board ploughing at a depth of 20–22 cm and reduced soil tillage with disc harrowing at a depth below 10 cm) and two pre-crops (wheat after oilseed rape (Brassica napus spp. oleifera) and wheat after wheat). Nitrogen top-dressing rate affected average winter wheat grain yield and all tested yield components significantly (p is less than 0.001). Grain yield and 1000 grain weight increased significantly until N top-dressing rate N150. The number of ears per square meter increased significantly until the rate N90, but the grain number per ear and grain weight per ear increased significantly until the rate N120.

By the European Cooperative Programme for the Plant Genetic Resources, oregano (Origanum vulgare L.) is included in the List of “Priority Species”. Wild populations of oregano are too little in Latvia therefore the cultivation is an important step in the conservation of local genetic resources. The aim of this research was to evaluate the differences of oregano accessions by colour of some morphological parts. In August 2019, 44 oregano accessions from an ex situ collection of the Laboratory of Horticulture and Apilogy (Latvia, Jelgava) were analysed, using oregano Draft Descriptor List. By this document, the colour of stem, leaf’s upper surface and petals was analysed, using Colour Chart of the Royal Horticultural Society. In this article, the results were compiled in tables. It is necessary to continue this research for exploring the changeableness of indices and for comparing our results with those from other countries.