During the workshop scientists presented the results of research in the cultivation of crops, plant breeding and disease control, improvement of soil fertility, as well as in livestock husbandry and welfare. Also had been reported (Rivža, B., Rašals, I.) on the results of Latvian Academy of Agriculture and Forest Science (LAAFS) future scientists’ competition in 2023 and the summary of the competition results (2023) of the field trials and laboratory show of scientific institutions organized by the LAAFS Agriculture Department (Alsiņa, I., Rivža, B.). This was followed by a harvest exhibition, tasting of individual exhibits and discussions.

The objective of the research was to study the influence of different rates of the digestate and wood ash mixture fertilizer on the quality of alfalfa (Medicago sativa) yield. Field trials with alfalfa were carried out on sodstagnogley soil. The soil agrochemical parameters were: pH KCl 6.0, organic matter content – 2.2%, phosphorus (P2O5) content – 50–80 mg kgE−1, and potassium (K2O) content – 160–190 mg kgE−1. Fertilizers of the mixtures consisting of pig and cattle manure digestate and woodchip ash in different ratios (digestate to wood ash = 1:0; 3:1 and 4:1) were used for alfalfa fertilisation. The norms of the innovative mixed fertilizer for alfalfa were 15 and 30 t haE−1. Both norms of the pure digestate from pig and cattle manure were used as control. Trials were conducted randomized in three replications. No significant differences between the values of soil acidity were observed at the beginning of the experiment. In the course of the trial, pH KCl increased and varied from 6.6 to 6.8, which was optimal for alfalfa growing. On average, the use of innovative fertilizer contributed to a significant increase in crude protein (CP) content for all variants. A significant (p<0.05) fertilization influence on alfalfa yield was also observed.

The research was started at the end of 2022. The results have been compiled for less than a year. The productivity and keeping of cows from the dairy cow herds of the three farms involved in the study (names of farms A, B, and C) were analysed. The amount of milk yield, fat, protein and urea content, and the number of somatic cells in milk were analysed according to the indicators of the control days in the month. We took saliva samples from individual cows (n = 18 to 20) and determined the cortisol content. The results showed no differences in milk yield, milk components and somatic cell count between horned and dehorned cows. Cortisol levels in cow saliva ranged from 1.38 to 2.71 nmol LE−1. This indicator varied between farms’ cow herds by 24 to 49%. Cortisol content indicators in saliva are temporarily increased in cows by stress factors that occur during various manipulations with animals in barns.

In recent years, the area of Japanese quince (Chaenomeles japonica) plantations in Latvia has increased to 500 ha. There are few studies available about the occurrence of fungi, including pathogens, in Japanese quince fruits. This knowledge is necessary to evaluate the necessity and possibilities of plant protection measures against fungal diseases in quince plantations. The aim of the study was to determine the diversity of fungi on Japanese quince fruits in Latvia. Assessments of diseases were performed in eight commercial Japanese quince plantations during the vegetation periods 2017–2019. Pure cultures of fungi were obtained and sorted by morphological features. The most characteristic ones from each group were selected for molecular-genetic analysis carried out in cooperation with the Latvian Biomedical Research and Study Centre. During the research, 202 fungal isolates were obtained and identified at the genus level. A high diversity of fungi, 28 genera, were found in the Japanese quince fruits. The greatest diversity of fungi, 20 genera, was found in fruit spots. Sixteen genera of fungi were isolated from rotted fruits and 10 genera from mummies. The genera Fusarium, Botrytis, and Clonostachys dominated in quince fruits, while Monilinia, Trichoderma, and Alternaria were slightly less frequent but considerable. Further more detailed studies are needed to find out the pathogenicity of obtained fungi. In order to better understand their biological peculiarities, more detailed molecular-genetic analyses should be performed to identify the detected fungal genera at the species level.

Feed consumption is one of the main cost drivers for fattening animals. In sheep breeding, it depends also on the breed of sheep used. In the study, the results of control feeding of rams accumulated at the control feeding station “Klimpas” between 2020 and 2022 were used. In the control feeding, the male gender offspring were mainly used; they were Apolons0302, Edžiņš0365, Skaris0008, Feirāms0023 and Sīmanis0195 lines’ rams. Three or four offspring of each ram were placed into one pen. The rams were fed unlimitedly (ad libitum) with commercially produced compound feed and self-produced hay. Water was provided automatically. The live weight of the rams was monitored regularly once per week. The average fattening period of the rams ranged from 62 days (lines Feirāms0023 and Sīmanis0195) to 71 days (line Apolons0302); the difference of 9 days is significant (p<0.05). The obtained mean live weight of rams during the fattening period was from 21.06 kg (line Sīmanis0195) to 23.66 kg (line Skaris0008). The highest mean live weight gain during the fattening period was achieved by the rams of the Skaris0008 line, on average 376.4 g per day, which is 55.1 g higher than that of the rams of Apolons0302 line. Rams of the Apolons0302 line consumed significantly less compound feed, (on average 1.474 kg per day), but consumption of hay on average was 612 g. For obtaining one kg of live weight gain rams consumed between 4.538 kg (line Skaris0008) and 5.074 kg (line Sīmanis0195) of forage, the difference of 0.536 kg is economically significant.

Soybeans (Glycine max) are one of the most important and widely cultivated legumes in the world, and used as a high-quality protein source in food and feed production. Soybean development and yield are affected by harmful organisms: weeds, pests and diseases. In recent years, soybean downy mildew caused by Peronospora manshurica has been frequently observed. Disease symptoms are more often observed on the leaves, but seeds can also be affected. The aim of the study is to evaluate the development of soybean downy mildew in the Kurzeme region and to describe the symptoms of the disease and its causal agent. The development of diseases, including downy mildew, was assessed in the vegetation season of 2023 in two different fields – in experimental field where variety ‘Laulema’ (bred in Estonia) was used, and in the production field where variety ‘Erika’ (bred in Poland) was used. First symptoms were observed on soybeans at GS 30 in both places. At the end of the growing season, the severity of downy mildew increased to 50% and 70% depending on the field. Plant rotation is an important disease control measure, as oospores can persist and survive in plant debris.

In recent years, we are increasingly faced with extreme weather conditions, cold and dry spring, long periods of drought and high temperatures during summer, as well as excessive precipitation after long droughts. When root water supply is limited or transpiration is high, plants start to suffer from drought. Potatoes (Solanum tuberosum) have a very shallow root system and big leaf area and are very susceptible to drought and high temperatures, especially during tuber initiation, which can result in limited foliage and plant development, fewer tubers, lower yield, and quality. Recent years with dry and hot periods made us think about the necessity to choose a drought resistant potato varieties and the most appropriate fertilization technology. In conditions of prolonged drought, it is necessary to think about additional provision of plants with nutrients using leaf fertilizers in order to reduce plant stress and to insure the nutrient uptake. One of the most important elements for ensuring photosynthesis process is iron, which affects both the transport of nutrients and the formation of chlorophyll in the leaves of the plant. If the iron is blocked in potato leaves, plants show chlorosis and stop photosynthesis, which can lead to yield losses.

In order to promote a balanced development of agriculture and forestry, scientists of the Latvia University of Life Sciences and Technologies (LBTU) within a cooperation project of nine partners have undertaken to use the by-products of biogas production plants and cogeneration plants for the purpose of soil liming and fertilization, creating a new innovative product from their mixtures. Wood ash was mixed with digestate according to certain proportions, which are based on laboratory studies guided by the chemical composition of the raw materials. The set of machines and aggregates required for the preparation and spreading of the new type of fertilizer on the field was made. Digestate, after complete development in bioreactors, is fed to the mechanical screw press separator, where it is divided into solid (dry matter 25 % <) and liquid (dry matter 3 % >) fractions. The digestate of solid fractions is mixed with wood ash in portions in a screw-type mixer equipped with electronic scales. The ingredients are poured in parts so that the mixer mixes a uniform mass. The mixing process for each batch takes 10–15 min to obtain a perfectly uniform mixture.

Field trials were conducted at the Research and Study Farm “Pēterlauki” (56°53' N, 23°71' E) of the Latvia University of Life Sciences and Technologies in 2022/2023. Soil characteristics: sod calcareous soil with following agrochemical parameters: pH KCL 6.7; organic matter content – 26 g kgE−1; phosphorus content – 60 mg kgE−1 P2O5; and potassium content – 144 mg kgE−1 K2O. Winter wheat (Triticum aestivum) sowings were established using different variants of a fertilizer mix with cattle manure digestate (from “Ziedi JP”, Ltd) (D) and wood ash (P) (from “Gren Jelgava”, Ltd) in different ratios. The norms of the innovative mixed fertilizer from cattle manure digestate and wood ash were 5, 10, and 20 t haE−1. Winter wheat plots fertilized only with digestate were used as control. Variants in the two-factor trial were randomized in triplicate. During the experiment, the influence of the researched factors on winter wheat grain yield, the content of starch and protein in grains, grain volume weight (kg hLE−1), and the mass of 1000 grains was determined. It was established that the average winter wheat grain yield in the control variant (D:P=1:0) was 5.29 t haE−1, which is significantly (p<0.05) lower than the average yield in the variants using fertilizers of digestate and wood ash mixtures (6.05 t haE−1).

Apple scab caused by Venturia inaequalis is the most economically important disease of apples (Malus) worldwide. Recombination and changes in pathogen populations is facilitated by annual sexual reproduction, which results in high pathogen variability and better adaptability to resistant cultivars. Due to rapid evolution, new races of V. inaequalis overcome resistance genes in Malus genotypes. Differential Malus genotypes – apple cultivars and hybrids with a specific R gene – are used to identify the racial composition of the causative agents. Fifteen differential Malus genotypes, obtained within the international “Vinquest” initiative, were planted in the germplasm collection sector of the Institute of Horticulture, in Dobele, Latvia during 2016. Apple scab symptoms on the leaves were scored according to the methodology used in the “Vinquest” network. The aim of the study is to collect the information about V. inaequalis races that occur on the differential Malus genotypes at the orchard established at the Institute of Horticulture in 2023. Four races of V. inaequalis were found to be established in Latvia, and they have overcome the genes Rvi1, Rvi3, Rvi4, and Rvi8.