The paper presents the results of the research on the influence of soil and climatic growing conditions on net photosynthetic productivity (NPP) of the early maturing determinate soybean variety Pripyat in the central part of Belarus. During the period of budding-flowering the NPP value is greatly affected by precipitation, during the period of flowering-the beginning of seed filling – by natural soil fertility and the sum of active temperatures. The leaf area at the budding and flowering stage correlates weakly and moderately with the NPP value. In variants with extensive technologies the NPP is not inferior to and exceeds other variants during the period of budding-flowering; during the period of flowering-the beginning of seed filling the NPP is reduced by 1.5 times.

The paper presents the results of the research on the influence of harvesting time on the yield of hulless barley. It was established that for the Adamant variety, when harvested 7 days after the beginning of the full ripeness stage, the yield loss amounted on average 6.3 %, after 14 days – 14.2 %, after 21 days – 21.3 %. For the Deva variety, those figures were slightly higher and amounted to 6.9 %, 17.1 %, 23.5 %, respectively. The husked barley variety Dobra responded to a lesser extent to non-observance of harvesting time in comparison with the studied varieties of hulless barley.

The paper presents the results of the research on silage capacity of newly mown and dried mass of legume grasses and the fermentation coefficient. It’s established that in dried mass (34.8–36.6 % of dry matter) the sugar content increases by 0.1–0.2 percentage points during the stemming stage and by 0.2–0.5 p.p. during the budding stage in relation to newly mown mass. The analysis of the fermentation coefficient level of dried mass of the first cutting both at the stemming stage and the budding stage indicates that this mass is difficult to ensile, since this indicator ranges between 41.7 and 44.4 (below 45). This witnesses that in order to obtain a high-quality preserved fodder without butyric acid from such raw materials, it is necessary to use preservatives.

As a result of assessing the efficiency of various apple tree protection systems from apple leaf midge in 2022–2023, it was established that the systems (chemical and complex) using insecticides from the neonicotinoid group at the beginning of larva hatching (chemical and complex protection systems) were the most effective – 82.7–100 %. That allowed saving 36.3–46.2 c/ha and receiving the net income of 6616.3–8672.2 rubles/ha. The biological efficiency of protection using the agricultural technique (summer trimming) did not exceed 48.7 %, the saved apple yield was 26.4 c/ha, and net income was 4950.0 rubles/ha.

The paper deals with the research results obtained in 2021–2022 under laboratory and vegetation-field conditions, on the effect of the initial invasive load of G. rostochiensis on the final number of nematodes and identifying the possibility to reduce the invasive background when assessing potato hybrids for globodera resistance. Based on the findings it’s established, that the number of formed cysts declines with the increase of the initial invasive load on the potato varieties Briz and Woltman and on the contrary it increases on the Lasunak variety. Besides, when the initial load of golden potato nematode changes from 25 to 15 cysts per plant, the reproductive capabilities of the nematode increase. Thus, depending on the initial load the reproduction coefficient of the nematode increases by 1.3–2.7 times with the decrease of the initial degree of infection under controlled conditions, and by 1.3–2.7 times under vegetative field conditions. Also, in laboratory experiments a strong negative correlation (r = –0.75) is established between the initial invasive load and the reproduction coefficient, which indicates a significant impact of the initial number of golden nematode on the reproductive capability of the phytohelminth. Thus, the obtained data indicate that the initial density of Globodera population has a great effect on the reproductive capacity of phytohelminth. Additionally, it’s established that the assessment of hybrids resistance to nematodes should be carried out under controlled laboratory conditions.

The paper presents the results of the research on biological and economic efficiency of the herbicide Egida, SC (mesotrione, 480 g/l), produced by the company Avgust, Russia. It was established that with pre-emergence application of the herbicide at the rate of 0.2–0.3 l/ha after sowing Phacelia tanacetifolia infestation decreased by 84.1–90.7 % in terms of the number and by 84.1–93.3 % in terms of the weight on average for 2021–2023. Egida, SC destroys quite efficiently annual dicotyledonous weeds (lambsquarter goosefoot, chickweed, bitter winter cress, common spurrey) and increases seed yield by 2.31 c/ha.

The paper summarizes the results of the research on protein accumulation in oil flax seeds of the Belarusian breeding and its amino acid composition, the influence of meteorological conditions and the cultivated variety on formation of the studied indicators. In terms of the maximum amount of protein the varieties Bonus (22.6%) and Ilim (23.1%) were identified. A significant influence of cultivation conditions on the formation of that indicator was noted (58.8%), the share of the variety was 15.3%, the interaction of the studied factors was 21.7%. The protein yield per hectare of crops was 19.4–26.0 c/ha and was determined by the duration of the flowering-ripening period (r = 0.865), as well as the total duration of the vegetation period (r = 0.553). The total amount of amino acids in the protein of the analyzed seeds was 8045.5–17679.7 mg/100 g, with glutamic acid predominance (19.5–28.1%). According to the maximum content of essential acids, the varieties Bonus (46.3%) and Opus (47.2%) were identified. Thus, Belarusian oil flax varieties are a valuable source of oil, polyunsaturated fatty acids and protein, which makes it possible to use them widely in the food industry.

The article deals with the results of the research for 2021–2023 on the influence of the organic matter content in sod-podzolic medium loamy soil (1.5–2.0–2.5 %) on ontogenesis of fiber flax. It’s established that organic matter in soil affects positively the main anatomical indicators of the stem, determining the plant productivity (the area of the completed part of the stem and the central cavity, the power of chlorenchyma, the ratio of bast phloem to wood), the chemical composition of plants at the main stages of their development, which provides the increase of the stem length (r = 0.84–0.90), the number of bolls and seeds per plant (r = 0.94–0.99).

The article presents the results of the field experiments on the influence of cenosis density formed by the seeding rate of 20, 22 , 24, 26 million pcs./ha, on the yield and quality of flax raw materials. The field experiments were conducted under dry and slightly dry weather conditions in 2021 and 2022 and extreme moisture conditions in 2023. Under changing climate conditions with a warming trend in order to obtain competitive flax products, it is advisable to increase the seeding rate up to 24–26 million pcs./ha, which will ensure stem density of 18–19 million pcs./ha, seed yield of 5–6 c/ha, flax straw of 39–40 c/ha and cultivation profitability of 33–36 %.

The addition of various organic materials (high-moor peat, decomposed wood waste and fresh wood sawdust) into low-humus mineral soil before planting highbush blueberry plantations contributed to an increase in the biometric parameters of cultivated plants and an increase in productivity, depending on the method of preparing the soil substrate, by 2,0–2,8 times in the fourth year of cultivation, and as a result, earlier entry into the stage of industrial fruiting.