The article analyzes the distribution of agricultural land in Belarus by category and type, establishes their area, provides an assessmentof fertility in the republic, regions and districts. Cartograms of plowing and assessing the fertility of arable land arepresented. A close relationship has been established between the points of soil fertility of arable land and the yield of grain crops, which shows the high reliability of the modern assessment of agricultural land in Belarus.

The article presents the results of studies on the dependence of seed productivity of Sudanese grass on hydrothermal conditions that develop during the growing season of crops in sod-podzolic sandy loamy soils of the southwestern part of the republic.

The results of studies using 15 varieties and samples of spring softwheat on 10­day­old hypocotyls length determination in water and nutrient Knop solution and the relative (in %)hypocotyls growth from cultivation in Knop solutionare presented. The tightness and nature of the relationship between the relative growth of hypocotyls and the yield and spring wheat responsiveness tonitrogen fertilizer application is shown.

The article presents the results of studies on the influence of macro­, micronutrient fertilizers, plant growth regulator and bacterial preparation on the yield and quality of millet grain of various varieties.

It was found that the highest grain yield with optimal quality indicators for both the small­ seeded variety Galinka and the large­ seeded variety Druzhba 2 was obtained in the variant where the background of mineral nutrition N₉₀P₆₀K₉₀ and inlaid seeds with a chelated formof copper were used, which amounted to44,0 c/haand 46,5 c/ha, respectively.

This article presents the results of the study of essential oil content in Monarda fistulosa L. plants in ontogenesis for 2012–2013 under the influence of mineral fertilizers on acidic and slightly acidic reaction soils. It was established that the introduction of dolomite flour changes the accumulation dynamics of the mass fraction of monarda essential oil; the highest content of essentiall oil during the application of various doses of mineral fertilizers is observed in the reproductive phase and the vegetative phase, and the highest essential oil yield is in the vegetative phase and the reproductive phase.

Sunflower is a highly profitable and economically profitable crop. This article presents the results of the economic efficiency of the use of mineral fertilizers and growth regulators. The use of mineral fertilizers and growth regulators increased the yield of sunflower seeds by 13,7–24,6 cwt/ha. The maximum net income of 1328,07 rubles/ha with a profitability level of 106,9 % was obtained in the option where the dose of fertilizers was N₉₀P₈₀K₁₅₀. High indicators of economic efficiency were noted in options where boron micronutrients were used against the background of these fertilizers. Net income amounted to 1157,35–1406,51 rubles/ha. The use of growth regulators was less effective due to the high cost.

As a result of the examination, the widespread distribution of Pyrenophora teres f. teres Drechsler in crops of spring barley. A collection of pure cultures was collected in the amount of 62 strains that differ in morphological characteristics of the colonies and growth rate. The most common strains belonging to the D2 and E2 groups were identified, characterized by high dense white mycelium and dense felt mycelium with an olive shade with an average growth rate. The article also presents the results of studies on the cultivation of the pathogen (temperature and light conditions), the selection of a suitable nutrient medium to obtain maximum sporulation. The racial composition of the pathogen is determined. It has been established that in our country there are races 000, 100 and 500.

The article evaluates the existing range of pest control products in onion crops for the period of 2004–2019. The biological and economic efficiency of the recommended by the “State Register … ” preparations to decrease the pests number in common onion crops is given. Itis determined that it is not possible to reduce the number of phytophages to an economically safe level in the crop by the recommended plant protection products, therefore, itis necessary to expand the assortment of insecticides and develop the regulations for their use.

The studies have shown the effect of the intensity of fungicide use in spring durum wheat crops during the growing season on the formation of varietal productivity of agrocenosis. A single use of fungicides provides a significant increase in the yield of crops of the studied varieties. The maximum productivity of agrocenosis is formed during double processing of crops (within of 4,5–5,0 t/ha).

Western corn rootworm is included in the Unified List of quarantine objects of the Eurasian Economic Union. To detect the invasion in Belarus, more than 7 000 hectares of corn crops are controlled. According to pheromone monitoring, the first invasion of the Western corn root worm has been recorded in 2009. Since 2011, foci of invasion have been recorded annually. In 2019, 11 outbreaks have been identified, including 5 outbreaks in the Grodno region. The beetle invades corn crops located along the border with Poland and Ukraine and the Brest – Minsk highway. Over 10 years, foci of invasion have been recorded at a distance of 180–200km along the highway. The main factors contributing to the Western corn rootworm invasion are the territorial location of farms along the borders with the Ukraine and Poland, the cultivation of corn over a large area without crop rotation, spatial isolation in the quarantine zone. Considering the prevailing weather conditions in Belarus, the biology and ecology of the Western corn root warm, the spread of the quarantine pest in the northern and eastern directions is predicted. Only with the strict observance of the recommendations for quarantine, agrotechnical and chemical measures, itis possible to prevent the formation of permanent foci of the Western corn rootworm.

The article presents data reflecting the harmfulness of alternariosis in winter rape plants, which consists in reducing the weight of one pod and the plant as a whole, the weight of 1000 seeds, reducing the number of seeds in the pod and reducing the length of the pod. The data showing changes in the chemical composition of seeds depending on the lesion point are presented. Biological thresholds of harmfulness are determined.

The powdery mildew of the winter rye belongs to dangerous diseases that reduce grain yield and its quality. In the course of investigation between 2016 and 2019 at the ZhNAEU field station, Blumeria graminis (DC.) f. sp. tritici Speer afflicted the winter rye plants within the whole period of vegetation. Itis found out that the disease development was within the range from 4,2 to 18,7 % and depended on the genotype of the variety and weather condition in the vegetation period. Itis established that with the non­resistant variety Dozor yield losses did not exceed 11,8 %, while with the resistant variety Siverskoie they were 2,5 %.

Scientific studies (2016–2018) established that under the conditions of the Right­ Bank Forest­ Steppe of Ukraine to improve the mineral nutrition of soybean plants with nitrogen and phosphorus on gray forests oils and the complex biological protection of the crops of this culture from the main diseases: peronosporosis (Peronospora manshurica Sydow.), septoria (Septoria glycines T. Hemmi), ascocathiasis (Ascochyta sojaecola Abramov.), Pests: acacia moths (Etiella zinckenella Tr.) and mole rats (Adelphocoris lineolatus Goeze), seed treatment with Microgumin (200 ml/gn) + Biophosphorin (1,5 l/t) and conduct treatment of plants in the budding phase by Haupsin (4,0 l/ha) or seed treatment with Rizobofit(2,0 l/gn) + Phytodoctor (1,0 l/t), and during the period of budding Trichodermin (2,0 l/ha), which ensures the preservation of the grain yield of soybean 13–14 %.

The article presents the results of studies (2018–2019) on the effect of doses of nitrogen fertilizer (N₁₈and N₃₅) on samples of Belarusian and French selection of flax (10 samples per group) on the signs of fiber and seed yield. The analysis of productivity indicators allowed to establish the limiting effect of increased doses of nitrogen nutrition on flax samples of different origin. Also, in the group of samples of domestic selection, there was a tendency to increase the interphase period «flowering­ maturation» on an increased background of mineral nutrition (N₃₅), which has an impact on the process of seed formation and maturation.

The article presents experimental data on yield, marketability, nitrate content and biochemical parameters in watermelon fruits, depending on the action of species and doses of trace elements during root dressing according to the phases of plant growth and development.