All scientific institutions have worked hard in 2022, continuing to implement various scientific projects. In the articles in the Chronicle section, there is occasional echoes uncertainty about the future due to very rapidly rising resource prices, but there is also a sense of determination to find some solution to this situation caused by the war, not to give up, to continue the industry important studies. The newly formed LBTU council has been actively working since the summer, and most likely, various changes await us in the future. At the Faculty of Agriculture we have received colleagues from the Vegetable and Melon Cultivation Institute of the National Academy of Agrarian Sciences of Ukraine. About individual Ukrainians read the results of colleagues' research and a bit about the institute in this collection.

An evaluation of promising hybrid combinations of cucumber (Cucumis sativus) was carried out according to breading characteristics. It was established that the investigated F1 hybrid combinations belong to the group of medium-early (47–50 days) and medium-ripening (51 day). A high variability of the length of the fruiting period – from 52 to 58 days (s%= 26.80 %) – was noted. The F1 hybrids Anus/No. 11 (24.5 kg mE−2 and 23.1 kg mE−2) and Kuzya/LD (25.5 kg mE−2 and 23.8 kg mE−2) were characterized by the highest total and marketable yields, which significantly exceeded the standard of Crispin (St1) and Nadiya (St2) (p is less than 0.05). The investigated hybrids had a high marketability of products: from 92% in the hybrid Nadiya F1 (St2) to 95% in the hybrid F1 Anus/No. 11. The analysis of the chemical composition of cucumber fruits showed that the content of dry matter was 3.90–8.50%, sugar – 2.20–2.87%, and vitamin C – 6.25–11.61 mg 100 gE−1. The testing of the new hybrid combinations of first-generation cucumbers under protected area conditions demonstrated that according to the values of the general (24.5–25.5 kg mE−2) and marketable (23.1–23.8 kg mE−2) productivity, marketability (95–94%), and the qualitative indicators of fruits and their stability, the best F1 hybrids were Anus/No. 11 and Kuzya/LD.

Green manure is now increasingly used in crop production for many reasons, including its ability to improve soil structure and fertility, and to capture nutrients for the following crop. This study is aimed to determine the promising mixtures of green manure crops in four different organic farms under variable meteorological conditions in 2022. Three different mixtures were grown in four different locations in Latvia: (1) oats (Avena sativa), mustard (Sinapis alba), oil radish (Raphanus sativus ssp. oleiferus), buckwheat (Fagopyrum esculentum) (non-legume), (2) oats, buckwheat, peas (Pisum sativum) (legumes below 50%), and (3) oats, lupine (Lupinus angustifolius), vetch (Vicia sativa) (legumes above 50%). Yield of green biomass in the farms ranged from 14.22 to 26.03 t haE−1. The mixtures with the proportion of legumes below 50% had a significantly (p is less than 0.05) higher yield of green biomass in all farms except “Mazbungas” Ltd with higher yield of mixture with legumes above 50%.

The qualitative indicators of a tillage machine for optimizing a ploughed soil layer, modifying the structure and density of a cultivated soil layer in accordance with agronomic requirements, as well as an effective organic weed-control method have been studied. Physical and mechanical properties of the soil have been studied after spring cultivation in the conditions of bare (black) fallow. Soil structure and aggregate composition depending on the type of cultivation, the density of soil layers at different times, and the dynamics of soil moisture changes in the layers for two months after spring cultivation have been analysed as well. The performance of a soil tillage loosening-separating machine has been studied on a soil layer which was separated after processing into four sublayers: over-seed, seed, under-seed, and subsurface ones. Soil fragments (lumps) of a size larger than 20 mm were completely removed from the overseed sublayer. The most valuable soil structure in agronomic terms was formed in the seed sublayer where the size of individual components did not exceed three times the size of seeds. The experimental machine for optimizing the agrophysical properties of the ploughed soil layer allowed increasing the structural coefficient about 2.5 times as compared with traditional cultivators. It was found that soil cultivation with a loosening-separating tillage machine allows improving the methods of pre-sowing cultivation to improve its agrotechnical characteristics, skip pre-sowing harrowing and cultivation, prepare the soil for sowing in one run, and control weeds without chemicals.

Winter wheat (Triticum aestivum) is the most important and widespread cereal crop grown in Latvia, the production of which is associated with rather large investments for nitrogen fertilization and disease control. The aim of this study was to find out the effect of fungicide application and N topdressing rate on winter wheat grain yield and quality. Field trials were carried out at the Research and Study Farm “Pēterlauki” during four years (2017/2018–2020/2021). Four pesticide treatments (half, full and two full doses during different growth stages) and untreated control, and four N top-dressing rates (N120, 150, 180, 210 kg haE−1) were studied. Winter wheat yield (annual average: 5.23–8.41 t haE−1) and quality depended significantly on the conditions of the study years, as three years were characterized by drought throughout the season or several months. Although any fungicide treatment variant increased the average four-year winter wheat grain yield significantly, the effect of fungicide application in every separate year was different, and it gave an important increase of yield only in 2019/2020. Enhancement of N top-dressing increased grain yield significantly up to the rate N 180 kg haE−1. Although interaction of both studied factors was significant, however, not always usage of higher N rates means that also spraying with fungicides has to be more intensive. The effect of fungicide treatment was observed on 1000 grain weight and hectolitre weight, but it did not affect crude protein and wet gluten content, and ZelenyE index.

Platone Municipality is located on the south of Jelgava town and is a part of the Central Latvian Lowland, which was formed during the Late Weichselian glaciation by the activation of the Zemgale Ice Lobe of the Riga Ice Stream. The diversity of soil cover within the Zemgale Plain south to the Jelgava town was observed. The relatively sharp boundary of the Baltic Ice Lake sand deposits in the north marks off the clayey and silty clayey deposits from the Zemgale Ice-Dammed Plain in the south. Therefore, majority of soils of the research area have been developed from glaciolacustrine deposits with distinct change in soil texture due to the lithic discontinuity. This discontinuity might happen at different depths and effect the water regime. Despite of the congeneric topography – flat or slightly undulating plain –, the heterogeneity of soil parent material and soil cover occurs. Altogether, 55 soil profiles were excavated in the places where soil descriptions were made in 1990. Additional soil profiles were examined during 1997–2017. Data analysis, comparisons between soil classification systems, and the development of Latvia soil classification compatible with the World Reference Base for Soil Resources were the main objectives of the work done in 2022. The project is financed by the Norwegian Financial Mechanism’s pre-defined project “Enhancement of sustainable land soil resource management in agriculture” (E2SOILAGRI).

Fungi from the genus Botrytis are wide-spread and harmful pathogens of legumes. The aim of this study was to summarize the information about Botrytis spp. associated with legume diseases in Latvia. In the present research, the monographic method was used. B. fabae as a causal agent of the chocolate spot of faba beans was first described at the end of the 19th century; later – other species were identified on legumes. Chocolate spot of faba beans is a devastating disease in Latvia. Our research revealed that the disease severity is influenced by cultivars, meteorological conditions, and fungicide application. The diseases of other legumes, possibly caused by Botrytis spp., were observed as well. Molecular genetic methods showed that the diseases were caused by a species complex. Well known and new species of Botrytis (B. cinerea, B. fabae, B. fabiopsis, B. pseudocinerea, B. medusae) were isolated from faba beans and other legumes in Latvia. Also, for some Botrytis strains it could not be identified to which species they belonged. The identified Botrytis spp. was diverse, and their morphological characteristics differed both between and within the species; therefore, these traits cannot be used for accurate identification of Botrytis species. The test of pathogenicity for field beans (Vicia faba), peas (Pisum sativum), narrow-leaf lupin (Lupinus angustifolius), and soya (Glycine max) showed that all the tested Botrytis species were pathogenic to all the tested plants, but virulence was dependent on hosts. Further research is required to describe new species, assess their prevalence in legume sowings, and understand the factors that influence the development of particular species of Botrytis.

The European Union’s Green deal for Agriculture calls for new solutions to replace fertilizers in order to provide plants with the essential nutrients. The course is also focused on the sustainable use and management of water resources (blue bioeconomics policy). These two policies in Latvia can be solved widely by using the algae from sea shore in agriculture as organic fertilizers. The purpose of the study is to find out what is hidden under the term “algae” and how to most correctly determine the sea material washed up on the coast of Latvia; as well as to study the literature to determine whether they are a potential substitute for fertiliser in agriculture, and if their industrial collection and production is possible and justified. According to the literature study, it is acceptable to call the unsorted drifts washed up on the sea coast with the popular term “sea manure”, however, when looking at individual green algae, brown algae, red algae, it is correct to combine them under the term “macroalgae”. Due to the amount of essential plant nutrients in macroalgae, they are not sufficiently effective as a fertiliser in agriculture. Furthermore, macroalgae contain a large number of biologically active substances which make it possible to obtain preparations from algae to promote plant growth; though various factors (heavy metals, plastics, etc.) that limit the use of algae in agriculture must also be taken into account.

Wheat (Triticum spp.) is one of the important and widely grown crops in Latvia and across the globe. Wheat diseases are significant risk factors in wheat production systems, and farmers need knowledge about relevant plant disease control. Tan spot caused by Pyrenophora tritici-repentis is the most severe wheat disease in central parts of Latvia; however, there is insufficient information about the pathogen’s diversity in local conditions. There are three known necrotrophic effectors secreted by P. tritici-repentis – Ptr ToxA, Ptr ToxB, and Ptr ToxC, which induce two types of symptoms – necrosis (Ptr ToxA) or chlorosis (Ptr ToxB and Ptr ToxC). Sequencing of ITS/5.8S region confirmed 21 isolates sampled in Latvia as P. tritici-repentis. The presence of necrotrophic effector encoding genes ToxA, ToxB and toxb was confirmed with specific primers and polymerase chain reaction (PCR). Most of the isolates obtained were from wheat, and 66.6% of isolates from wheat had the ToxA gene that encodes Ptr ToxA production. This effector is causing the formation of necrotic lesions on wheat. Only one isolate obtained from Elymus repens contained genes that encode ToxB genes responsible for protein production that causes chlorosis on susceptible genotypes.

The aim of this study was to compare the welfare in horse breeding stud farms of different sizes in Latvia. The study was performed in six large (more than 10 horses) Latvian Warmblood breed horse stud farms and six small Latvian Warmblood horse breed stud farms. The development of the methodology was based on the Animal Welfare Assessment Protocol for horses, where the authors applied a rating of 0 to 3 points for each horse for each trait. Five groups of welfare traits were evaluated – facial expression, stereotypical behaviour, observance of distances, visual appearance of the horse, place of rest. The study found that large farms, which have smaller rest areas, have better welfare; horses are less likely to distance themselves and have better facial expression than horses in small farms, which are used more intensively.