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Background. Taking into account temperature, soil composition, surface roughness and the dependence of effective dielectric constant on frequency allows a more accurate assessment of soil moisture and other important parameters, which can be used in various fields such as agriculture, geology, ecology and hydrology. Aim. In this work, we calculate the reflection of a linearly polarized electromagnetic wave from wet soil, taking into account such physical factors as heterogeneity of soil structure, surface roughness and dispersion. Methods. Based on a heterogeneous mathematical model of wet soil, taking into account the dispersion of the dielectric constant of water and surface roughness, expressions are derived for the complex reflection coefficients of electromagnetic waves of vertical and horizontal polarization. Results. The model of loose wet soil with the standard deviation of roughness on the surface was chosen as the object of study. An analysis of the frequency and angular characteristics of the modules of the reflection coefficients was carried out at a fixed level of soil moisture. Conclusion. The data obtained as a result of the calculations is a valuable tool for further improving methods of remote sensing of the Earth and contributes to the development of new technologies for monitoring soil parameters using unmanned aerial vehicles, which opens up prospects for more accurate and efficient analysis of the state of land resources and ecosystems.

Studies of the ecological regimes of groundwater and moisture reserves were carried out in the Novgorod Region in 2014–2023 in conditions of arid (HTC 0.9...1.1) and wet vegetation periods (HTC 1.69...2.46) on sod-podzolic loamy soils drained by closed drainage structures: shallow with a depth of 70 cm; two variants of a medium-deep drainage with a depth of 110 cm with filling of the drainage trench with wood chips and sand-gravel mixture; two-tiered, consisting of a lower tier of tubular drains with a depth of 110 cm and an upper tier of tubeless drains perpendicular to it, located at a depth of 60 cm. Analysis of the nature of changes in the groundwater level showed that the minimum depth of groundwater in both wet and dry years was observed at the beginning of the growing season, the second peak of groundwater rise in wet years was observed in August, in dry years it was absent. The highest average seasonal groundwater level was observed in excessively humid 2017 (HTC = 2.46) in the variants of medium–deep drainage with backfilling of chips (30 cm) and shallow drainage (33 cm), the lowest – in the variant of two-tier drainage (58 cm). Analysis of humidity regimes on experimental systems showed that with shallow drainage in a humid year, more than a third, and in an excessively humid year, more than 2/3 of the duration of the growing season, the upper 30-centimeter horizon was in a waterlogged state, and with two-tier drainage, there were no periods of excessive moisture. At the same time, in wet years, the probability of periods with insufficient soil moisture ranged from 8 % (with medium-deep drainage with sand-gravel mixture) to 25 % (with two-tier drainage) In dry years, there was a lack of moisture in the upper soil horizon in the two-tier drainage variant of about 70 %, in other variants this value was slightly lower (62–65 %). The ecological soil regimes formed under the influence of two-tier drainage in modern climatic conditions had a significant impact on the hay yield of perennial grasses (70 % of fodder cereals), which allowed for an average yield increase of 0.9 t/ha relative to the variant with shallow drainage during both wet and dry growing seasons.

Purpose: to determine the share influence of agrophysical, technological, climatic factors and soil moisture on spring wheat grain yield in the arid conditions of the Saratov Trans-Volga region based on a complete correlation analysis of long-term field data. Materials and methods. To achieve this goal, an experiment with basic tillage with various implements according to the following scheme, was carried out: A₀ – with PLN-8-35 plow at 23–25 cm (control); A₁ – with plow PBS-10P at 23–25 cm; A₂ – with deep ripper SSD-4 (2017–2020), chisel plow PChM-4 (2021–2022) at 30–32 cm; A₃ – with a disk header BDM 7×3 PPKShKS at 10–12 cm. The research was carried out over a period of six years using generally accepted methods. Results. A complete correlation analysis of long-term data showed that the most significant influence on the spring wheat yield in the Trans-Volga region is exerted by precipitation during the growing season (24.1 %) and the hydrothermal coefficient (23.6 %). Air temperature determined this indicator by only 12.5 %. The share influence on the yield of soil density in the 10–30 cm layer was 2.9 %. The moisture content of the upper half-meter soil layer during the spring wheat tillering phase determined the yield by 14.8 %, and the lower one (50–100 cm) by 15.6 %. Conclusions. On average, over six years, the maximum yield of spring wheat Albidum 32 variety was obtained in variants with plowing (PBS-10P and PLN-8-35): 1.16 and 1.17 t/ha. Non-mouldboard cultivation with a deep ripper and chisel plow reduced this indicator by 8.5 %. Treatment of dark chestnut soil with a disk header reduced the spring wheat grain yield by 24.8 % relative to the control.

There has been a massive drying out of spruce plantations in recent years. Many versions about the cause of this phenomenon have been put forward by scientists. Despite the active study of the problem of drying out of spruce plantations around the world, a forest management system aimed at reducing the damage from drying out has not been developed yet. Important silvicultural indicators of plantations that can affect their stability are the type of forest growing conditions and the type of forest. The purpose of the study was to establish the influence of the type of forest and the type of forest growing conditions on the resistance to drying out of spruce forests growing in the zone of coniferous-deciduous forests of the Perm Krai. The spruce forests of this territory were the objects of study. The sanitary condition of spruce forests growing in common types of forest growing conditions (B2, C2, C3) and forest types (green moss spruce and pine forest, wood sorrel spruce and pine forest, linden spruce and pine forest, grass spruce and pine forest) of the Perm Krai was determined. The weighted average scores values of the sanitary condition of the spruce forest of the surveyed forest plantations were distributed by forest types and types of forest growing conditions. Statistical indicators of the average weighted scores of the sanitary condition of spruce in different types of forests were obtained. A one-factor analysis of variance was carried out to compare the mean values. It was established that the type of forest and the type of forest growing conditions have an impact on the sanitary condition of spruce stands. The better the forest growing conditions, the more resistant the spruce trees are to drying out, on average. At the same time, soil moisture is more important than soil nutrient status.

Fresh water supplies for irrigation purposes must be used sparingly and judiciously, as water is an invaluable natural resource that is in short supply in much of the Earth. Soil moisture in fields is not uniform everywhere, and deploying thousands of sensors is unnecessarily expensive. The purpose of this publication is to model and predict the relationship between tomato plants leaf color, soil moisture, and thus manage the irrigation process in an optimal manner. The research was conducted using generally accepted methods, the field method, and the method of statistical evaluation of results. Machine learning algorithms (MLA) and data mining are utilized in this paper to model the relationship between RGB color values from tomato leaves and soil moisture and temperature. The color of the leaves of open field tomato plantations grown without stakes is the focus of this study. Three main tasks are fulfilled: to prove that there is a relationship between leaf color and soil moisture, to study its supposedly nonlinear type and to model this relationship with MLA. First, a classifier is trained, and then a model is created and saved. Finally, the efficiency of the chosen model is tested using a different test data set. The name “12-9-6-3” for the methodology of measurements is fgiven. It is proven that the young leaves are more informative about the need for watering. As a result, there is less than a 1% error in predicting soil moisture using the color of tomato leaves considering also soil temperature, using M5P regression model. This predictive model can be used in creation of automated systems for optimal irrigation management and water saving

In this work we calculated the reflection coefficients modules of a linear polarization plane electromagnetic wave depending on soil moisture with a relative complex dielectric constant described by the heterogeneous Maxwell Garnett and Bruggeman models. A comparison is made of the calculated dependences of reflection coefficients for incident E- and H-polarization waves on soil moisture according to the two proposed heterogeneous two-component models. The correctness of the applied models is shown within the soil moisture content up to 10 %. Within the limits of soil moisture change from 10 to 50 %, there are slight discrepancies in the calculation results for two heterogeneous models. The reflection level of an electromagnetic wave from the soil surface in the case of its H-polarization is less than in the case of E-polarization. With an increase in soil moisture, a monotonous increase in the reflection level is observed. The proposed heterogeneous models of wet soil and the calculation method can be used for remote radar sensing of the Earths surface in order to determine the moisture content in the rooted layer of the soil.

In the natural and climatic conditions of the Novgorod region, the ecological regimes of lands drained by various open drainage structures were studied: channels through 70 m (control), runoff hollows in combination with the strips of cultivation, reclamation, and closed drainage. During the operation (1992-2021) of open drainage structures, the agrochemical state of soils changed: the exchange acidity decreased; the humus content increased by 2-3 %, with the exception of a combination of hollows with a reclamation strip (a decrease of 1.5 %); the content of mobile phosphorus and potassium decreased. The formation of groundwater regimes and moisture reserves on drainage systems depends on meteorological conditions, which in the last 5 years have been very diverse: from slightly arid (2020, HTC = 1.1) to excessively moist (2017, HTC = 2.65). The systems of runoff hollows in combination with the reclamation strip provided the lowest groundwater level, while in an extremely wet year they did not rise into the arable horizon. The most favorable moisture regime of the root-inhabited soil layer in excessively humid 2017 and subsequent years was noted on systems of runoff hollows with closed drainage in combination with reclamation strips. During dry periods, which are usually June-July, a lack of moisture in the root layer of the soil was observed on experimental systems of runoff hollows in combination with cultivation and reclamation strips. The most acute moisture deficiency in these periods (0.45 full capacity) was noted on systems combining runoff hollows with cultivation strips. The most favorable soil moisture regime (0.65-0.85 full capacity) was in the combination of hollows with closed drainage and a reclamation strip. The formed new ecological regimes of the soils drained by the hollow-strip method had a significant impact on the hay yield of perennial grasses (Phleum pratense, Festuca pratensis). The increase in yield compared to the control averaged 0.3-0.6 t/ha over 5 years.

In the conditions of the Chuvash Republic, the effect of slottingbetween rowson hop yield and on the water-physical properties of gray forest soil was studied. Soil slotting was used during 2017-2019 in autumn after the completion of harvesting operations (late September-early October) on hop plantations of the Podvyazny variety. Tillage with a SCHX-1.6slotting device (Czech Republic) was carried out to the depth of 50 and 65 cm at different time intervals (annually and three years later). As the control, there was taken the conventional tillage without the use of aparaplow combined with autumn tillage of row spacing to a depth of 20 cm. Studies have shown that the use of aparaplow to a depth of 50 and 65 cm improved the aeration and water permeability of the soil (the specific weight of the 20-25 cm soil layer decreased by 0.1-0.2 g/cm3, the volume weight of the same layer-by 0.1-0.3 g/cm3) and contributed to an increase in hop yield by 1.4-3.1centners per hectare (LSD05 =1.3 centners/ha) compared to the conventional tillage of row spacing (20.9 centners/ha). The content of alpha-acids in hop cones was not affected by slotting between the rows of hops. The specific weight of the 50-55 cm soil layer significantly decreased in all variants in comparison with the control. The highest moisture content of the deep layers of the soil (30-55 cm) was achieved with conventional tillage combined with annual autumn slotting to 50 cm depth. All the studied variants in comparison with the control give a significant increase in the yield of hop cones. For the production, the variant with the lowest costs for deep tillage should be recommended. It is the annual processing of the top soil layer combined with the autumn slotting every 3 years to 50 cm depth.

The article deals with the problem of stable operation of various structures of drainage systems on heavy soils in the natural and climatic conditions of the Novgorod region during the first years after construction and after 30 years of operation. The experiment examines the effectiveness of drainage using shallow drainage structures with the depth of 70 cm and two variants of medium-deep drainage (110 cm) with filling the drainage trench with sand-gravel mixture (PGS) and wood chips to the arable horizon. Analysis of groundwater dynamics showed that the rate of groundwater decline in the early spring period in the first years of operation on all experimental variants was approximately the same: 2.0-2.4 cm/day. In recent years in the shallow drainage variant, the decrease in ground water levels occurred more slowly (2.3 cm/day) compared to the standard drainage variants (3.8-3.9 cm/day). The average humidity of the root layer of the soil during the growing season in experimental closed drainage systems has not increased for 30 years. The average moisture reserves for the growing season in the experimental systems were: 177 mm in the shallow drainage variant in 1991, 168 mm in 2018; 165 and 154 mm for the standard drainage with drainage chips backfill, respectively; 164 and 123 mm in the PGS backfill variant, respectively. The highest reliability and durability were shown by collectors with PGS backfill of the drainage trench, which have maintained a consistently high efficiency over a thirty-year period. During the drought period, shallow drainage systems provided more favorable conditions according to the degree of moisture in the root layer: in 2018, the shortest period of moisture lack in the root layer of the soil (10 days) was observed in shallow drainage systems, and the longest (1 month) - in systems with backfill of the drainage trench with PGS.

One of the most important factors for the development of modern agricultural entrepreneurship is the stable and productive conduct of agricultural production. The main purpose of the article is to study the rate of moisture release after harvesting winter crops and to find the optimal sowing time after harvest. All studies were conducted in real production conditions in accordance with the developed research methodology. Modern devices of different types were used to obtain the most reliable values. An important factor for obtaining high yields is the full disclosure of the potential of available moisture and air in the upper fertile layer of the soil. Gradual movement of climatic zones to the north of Ukraine requires the study of the rate of moisture release from the soil and the determination of the most optimal terms for sowing. In a fairly dry period, the beginning of sowing of winter cereals is necessary immediately after harvest at soil moisture – 17-22%. All necessary agricultural measures to prepare the soil in summer for winter crops (background and main tillage) should be carried out taking into account the basic principles of the theory of "differentiated humidity", according to which the main amount of soil moisture in the range of GWP (marginal field moisture content) is lost due to the upward movement of water through macro- and micro-wells. One of the methods to reduce moisture loss is to create a loose layer on the soil surface, which prevents capillary leakage of moisture and acts as mulch. The loose layer itself significantly slows down the heating of the surface and interrupts the flow of moisture to the evaporation horizon, so it is recommended immediately after harvest to remove straw from the field for loosening the top layer of soil. Significantly reduce the drying of the soil gives some compaction of the soil in its upper layer, which reduces the loss of steam, by moving balers and bales of straw on the surface of the field

Vegetation of oak forests of Polissia is a synthetic and very sensitive indicator of ecological conditions of habitats. After continuous fellings of the main use, there are significant changes in the floristic composition and coenotic structure of vegetation. To preserve biodiversity, the dynamics of soil moisture (Hd), soil acidity (Rc) and the amount of mineral nitrogen in the soil (Nt) were studied on the basis of complete geobotanical descriptions of time series of forest areas with oak forests using phytoindication methods (scoring). It is established that a sharp change in soil parameters occurs immediately after the completion of felling and removal from the plantation of the main edificator - the stand. In the process of vegetation restoration, after the creation of forest oak crops, there is a gradual restoration of soil parameters. Thus, soil moisture (Hd) has the lowest values in plantations before the period of crown closure – 10.70±0.21 points, which increases significantly after the stand formation. The best-formed vegetation in oak forests of wet soils is characterized by 90-year-old cenoses in which there is a decrease in soil moisture to a minimum value – 10.30±0.12 points. The lowest soil acidity (Rc) is characteristic of maternal 120-year-old biogeocenoses – 9.50±0.10 points, the highest – 7.90±0.20 points – for 3-year-old groups. The amount of mineral nitrogen (Nt) in the soil is in the range – from 4.50±0.15 (biennial forest crops) to 4.90±0.15 points (100-year-old and 120-year-old oak biogeocenoses). Thus, during the restoration period of oak forests, the return of soil parameters to the initial values’ level characteristic of the maternal subclimax plantations is observed. In the future, research on the main trends in the restoration of environmental parameters of soils after continuous fellings and the development of methods of their use for practical purposes are promising.

The results of multi-year research on the study of unconventional methods of tillage on fused leached chernozems of the south-foothill zone of Adygea are presented. The following tillage methods have been compared: mouldboard tillage with the PN-4-35 plow, nonmouldboard tillage with the PCh-2.5 chisel plow and the alternation of these methods; single deep slitting, shallow treatment with an anti-erosion KPE-3.8 cultivator – plane cutter; surface treatment with a heavy BDT-3 disk harrow. As a result of the studies the influence of energy-saving methods of tillage on the agrophysical parameters of the soil and crop productivity has been revealed. The content of productive moisture in a meter soil layer on options with constant chisel cultivation is slightly inferior to the options with constant plowing under all crop rotation crops. In the summer growing season a higher moisture content is observed in areas with constant plowing under all crop rotation crops. The bulk soil weight under continuous sowing cultures in a 0-40 cm soil layer is somewhat denser (1.13-1.12 g / cm3) in surface and mouldboard processing than in chisel processing (1.09 g / cm3). The agronomically valuable fraction of soil aggregates (0.25-3.0 mm) is contained in a larger number in crops of row crops, cereal crops, clover in the soil layer of 0-40 cm with constant plowing (26.9 %, 17.0 %, 25,0 %). Excessive crop yields have been noted for variants with permanent chisel processing (275.8 TZE / ha) and at alternating different processing methods compared to the variant with constant plowing (288.3 TZE / ha). In order to reduce erosion processes on sloping lands, when cultivating crops, it is possible to use subsurface tillage: chiseling for six years, shallow and shallow for 2-3 years. According to the results of an economic analysis of the studied methods of soil cultivation, the replacement of the main processing (plowing) with energy-saving methods have provided fuel savings of 20-25 % and an increase in labor productivity by 27-28 %.

The article presents the results of assessing the effect of fine irrigation of tea plantations in the foothills of Adygea on the urease activity of soils. It has been established that the activity of the urease enzyme is an unstable parameter in the dynamics of the leaf collection period of tea and depends on precipitation and, accordingly, on soil moisture. The mathematical model has been obtained as a result of multiple correlation and regression analysis: Y = 0.791 + 1.509 X1 + 0.7344 X2, where Y is the urease activity in mg of NH3 per 100 g of soil; X1 is soil moisture in the layer of 0-60 cm, %; X2 is precipitation, mm.The sample multiple correlation coefficient of Rb = 0.90933 is significant, the relationship between the resultant trait and the totality of factorial traits included in the regression model is close. According to the obtained model, the urease activity increases by 1.509 mg of NH3 with an increase in soil moisture by 1%. A positive correlation has been found with these indicators (the pair correlation coefficient between the urease activity and precipitation is r = 0.89, soil moisture r = 0.68). Irrigation of tea plantations contributes to the activation of the urease enzyme.However, during a period of severe drought, the degree of enrichment of the soil with this enzyme is characterized as poor from 30 to 100 mg of NH3 per 100 g of soil in 24 hours, which indicates the inhibitory effect of the stress factor on the activity of this enzyme.

Copyright of Plant & Soil Science is the property of National University of Life & Environmental Sciences of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plant & Soil Science is the property of National University of Life & Environmental Sciences of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the research was to study methods for increasing productivity, grain quality and adaptation of winter wheat based on agrochemicals application while minimizing the primary soil cultivation under the conditions of Saratov Trans-Volga region. The studies were conducted on the dark chestnut soils of the experimental field of scientific training production association “Povolzh’e” Saratov State Agrarian University in 2016–2018. The two-factor experiment was laid out according to the following scheme: factor A – methods of primary tillage of bare fallow: 1) moldboard cultivation with the PLN-8-35 plow to 23–25 cm (control 1); 2) subsoil tillage with chisel plow SSD-4 to 30–32 cm; 3) minimum tillage with disk harrow BDM 7×3 to 10–12 cm; 4) mixed cultivation with Boykov plow PBS-8M for 23–25 cm; factor B – agrochemicals: 1) control 2 (without fertilizers); 2) AgroVerm – 3 l/ha (fertilizers based on humic acids); 3) Reasil micro (Cu) – 1.5 l/ha (fertilizers based on humic acids); 4) Megamix number 10 – 0.5 l/ha (mineral fertilizer); 5) Microvit – 0.5 l/ha (mineral fertilizer); 6) NanoSilicon – 100 g/ha (mineral fertilizer). The research results showed that minimizing tillage in bare fallow for winter wheat reduces its yield by 13.7 %. A mixed cultivation (2.64 t/ha) provides the maximum yield. The greatest effect from fertilizers application was observed at minimal tillage: the yield increase by 8.8 %, the amount of protein – by 0.5 %, gluten – by 2.2 %. These figures were 5.7; 0.2; 0.8 % at plowing, 4.9; 0.5; 2.1 % at subsoil tillage, 5.5; 0.3; 0.7 % at mixed cultivation. Mineral fertilizers Megamix number 10 (0.5; 2.0 %) and Microvit (0.4; 1.7 %) provided the maximum increase in quality indicators in various methods of primary cultivation from the studied agrochemicals, and the lowest – fertilizers based on humic acids AgroVerm (0.4; 1.2 %) and Reasil micro (Cu) (0.2; 0.8 %).

The effectiveness of the local soil loosening for soya was studied in comparison with soil inversion tillage during a three-year experiment. Experimental design: 4 variants of chisel plow treatment and a conventional moldboard plowing with inversion of the soil layer at the depth of 18-20 cm (control). The task of chisel tines is to provide a predetermined stroke depth in conditions of high soil density, as well as to create conditions for improving the accumulation of moisture and air in the soil. Non-inversion soil tillage creates favorable conditions for the growth and development of soya plants and provides higher grain yield compared with plowing . The soil moisture content by the beginning of spring field works in all areas where local soil loosening was carried out since autumn was 0.4–1.3% higher compared to plowing. The highest field germination (76.4%) and plant density (535 thousand/ha) were in the variant of local soil loosening on a depth of 18-20 cm with a spacing of 0,5 m between tines. The difference in soil moisture content between inversion and non-inversion soil tillage was maintained until the flowering phase. During this period, the moisture content in the areas of local soil loosening was 0.6–4.8% higher in comparison with plowing. This improved the conditions for the growth of soybean plants which height was 2.1–3.8 cm more with local soil loosening. In all variants of non-inversion soil tillage, grain yield was by 0.03-0.07 t/ha more than in the control. The highest yield (1.03 t/ha) was obtained in the variants of soil loosening to a depth of 40 cm.

Geographic information systems are already widely introduced in all spheres of our life as well continue to be actively developing. In the paper, the application of remote sensing methods for determination of soil moisture in combination with the relief plasticity and morphodynamic analysis allowed us to take into account the relief of the earth’s surface. As a result, a guidelines have been developed for precision agriculture. The proposed scheme permits to adjust the amount of fertilizer for distribution in the soil and to develop an irrigation approach to maximize the conservation of natural resources of the used agricultural area.

The article covers the issues of humidity of plants of the miscanthus depending on the MaxiMarin absorbent use during the period of rhyzome seeding. t was established that the absorbent introduction into the soil before planting with rhyzome contributed to a better supply of plants with moisture. In all phases of growth and development of plants, soil moisture in the variant using an absorbent was significantly higher than control - without the use of absorbent for both seasons. There was no significant difference in soil moisture, depending on the type of absorbent, but it was advisable to note that the soil moisture content was significantly higher compared to the control with absorbent granules, and soaking with rhyzomein the gel did not provide a reliable increase in moisture content compared with the control, there was only a tendency to increase it. Over the research years and the stages of growth and development of the miscanthus, the "absorbent" factor has a different effect on soil moisture. But due to the lack of moisture in the phase of the release of the tube in 2017, the impact of this factor was the largest - 61%. During the second planting season, when the average daily air temperature was 10 ° C or more, the soil was well warmed, and the moisture content was lower than during the first period of planting, the effectiveness of the absorbent improved. In all stages of the growth and development of the Miscanthus, the moisture content of the soil was significantly higher than the second seeding period, compared to the first period. The introduction of the MaxiMarin absorbent into the soil before planting with rhyzome contributed to a better supply of plants with moisture not only in the first year of vegetation, but also in the second. In all phases of growth and development of plants, soil moisture content for the application of absorbent granules into the soil and the joint use of granules and gels of absorbent soil moisture was significantly higher than control - without the use of absorbent for both seasons.

Copyright of Plant & Soil Science is the property of National University of Life & Environmental Sciences of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of the research is the development of an algorithm for determining the fundamental operators of irrigation control taking into account the variability of soil moisture reserves. Materials and Methods. The basic tasks of irrigation control such as the need for irrigation and the technological parameters of this irrigation are considered as the fundamental operators. The main research methodological approaches are: the concept of a unified algorithmic construction for determining the main irrigation operators, solving the problem of taking into account the variability of soil moisture content at two levels – on the area and on the soil profile, refusal to use the average humidity of the active soil layer as the main requirement criterion for irrigation. Results. The algorithm solving these problems on the basis of quantitative estimates of average humidity, moisture distribution over the soil profile and variability of moisture reserves over the irrigated area is proposed. The algorithm is presented by three sequentially organized calculation blocks, each of which solves an independent task in accordance with the above mentioned sequence. Computing procedures for solving the tasks in each of the considered algorithmically organized blocks are disclosed. The task based on average estimates of the active soil layer moisture content has a classical solution. The problem based on data on the layer-by-layer moisture distribution in soil profile is solved by sequentially evaluating the layer-by-layer data dispersion as well as the soil layer thickness with moisture below the threshold level. Conclusions: the problem of using the differential precipitation distribution mode is solved on the basis of determining the variability of average estimates of soil moisture by area of the irrigated plot. The result of the algorithm solution is the determination of requirement for irrigation at the estimated date, as well as its main technological parameters, including the irrigation rate and the need for a differentiated precipitation distribution over the irrigated area.

Purpose: to study the impact of the primary tillage methods of dark chestnut soil on the bulk density, water permeability, moisture meter layer and chickpea yield. Materials and methods: studies were carried out on dark chestnut soil in 2016–2019 (Saratov region). The soil density was determined according to GOST 12536-79, soil moisture – according to GOST 28268-89. The trial establishment and the mathematical processing of digital material were carried out in accordance with “Field Experience Methodology” (B. A. Dospekhov, 1985). Results: four-year observations of hydrophysical properties showed that before chickpea sowing, the maximum value of the arable layer density (0–0.3 m) was recorded in the variants with minimal tillage with a disc harrow (1.26 grams per cubic centimeter). The lowest values of soil density were noted in variants with combined and moldboard tillage (1.09–1.10 grams per cubic centimeter, which is 14–15 % less than the minimum tillage). Water permeability of dark chestnut medium loamy soil increased from minimal tillage (71.1 mm per h) to subsurface (107.2 mm per h), combined (126.4 mm per h) and moldboard one (126.5 mm per h). Before chickpea sowing, the highest soil moisture in the meter-long layer was observed during non-mold and combined cultivations (17.5 % of the mass of absolutely dry soil, which exceeded the control by 0.4 % and the minimum by 1.0 %). The least soil moisture was formed in the variant with disking (15.9 %) with the onset of the phenological branching phase in chickpeas. The use of subsurface cultivation increased soil moisture by 0.9 %. Conclusions: combined tillage with a PBS-8M plow to a depth of 23–25 cm contributed to the formation of maximum chickpea yield in four years (1.04 t per ha, which is only 4 % more than the control). Minimization of the primary tillage to 10–12 cm reduced yield by 18 %, subsurface deep loosening (30–32 cm) by 9 % compared with the moldboard cultivation to a depth of 23–25 cm.

Мета. Визначити оптимальні умови зволоження ґрунту для інтенсивного росту та високої продуктивності енергетичних плантацій деяких сортів верби в умовах Київського Полісся. Методи. Об’єктом дослідження були створені у 2009 р. у Боярському лісництві Боярської лісової дослідної станції енергетичні плантації трьох сортів верби: прутовидної (Salix viminalis L.) ‘Тернопільська’, тритичинкової (S. triandra L.) ‘Ярослава’ та шерстистопагінцевої (S. dasyclados Wimm.) ‘Хорс’. Ґрунт – дерновий глинисто-піщаний. Насадження зростали на трьох ділянках із різним ступенем зволоженості ґрунту: слабко-, добре- та дуже зволожений. Результати. Після двох років вирощування найвищий показник збереженості рослин був за доброго зволоження ґрунту: у сорту ‘Тернопільська’ він становив 98,5%, ‘Ярослава’ – 97,1%, ‘Хорс’ – 89,6%. Найбільшу середню висоту дворічних рослин мала верба тритичинкова ‘Ярослава’ на добре зволоженому ґрунті – 3,2±0,06 м. У сорту ‘Тернопільська’ найвищими були рослини, що зростали на менш забезпечених вологою ділянках, тоді як рослини сорту ‘Хорс’ мали приблизно однакову висоту, незалежно від рівня зволоженості ґрунту. Дослідження цих насаджень у 8-річному віці, коли їх наземна частина мала вік 5 років, виявило, що сорт ‘Ярослава’ суттєво перевищує за продуктивністю сорти ‘Тернопільська’ і ‘Хорс’ за зростання на слабко (122,0 т/га) та добре зволоженому ґрунті (128,2 т/гасирої деревної маси). Продуктивність сортів ‘Тернопільська’ і ‘Хорс’ значно зменшується з підвищенням зволоженості субстрату. Зокрема, у першого з них на слабко зволоженому ґрунті за 5 років сформувалося 46,4 т/га свіжозрізаної маси, а на найбільш зволоженому – лише 19,8 т/га. Сорт ‘Хорс’ мав більш вирівняні показники продуктивності в різних варіантах зволоженості ґрунту (від 39,4 до 67,0 т/га). Висновки. Серед досліджуваних генотипів верби найвищими показниками росту й продуктивності на дернових глинисто-піщаних ґрунтах Київського Полісся відзначається сорт ‘Ярослава’. Оптимальні умови для інтенсивного росту енергетичних плантацій цього сорту створюються на добре зволожених ґрунтах, тоді як для верби прутовидної та шерстистопагінцевої – на слабко і добре зволожених. Перезволожені, погано дреновані ґрунти є малопридатними для ефективного вирощування енергетичної вербової сировини

Studies were conducted in 2016-2017 in Nizhny Novgorod region on gray forest soil in a link of "soybeans -spring wheat" crop rotation. The scheme of field experiment included 5 soil tillage systems: 1. Traditional moldboard tilling based on autumn plowing with PN-3-35 at 20-22 cm (control); 2. Non-moldboard "deep" cultivation -autumn plowing with PN-3-35 (without moldboard) at 20-22 cm; 3. Non-moldboard "shallow" cultivation with the Pottinger stubble cultivator to a depth of 14-16 cm; 4. Minimal tillage with the disc harrow XM 44660 NOTHAD to a depth of 10-12 cm; 5. Zero tilling (No-till) with the Sunflower 9421-20 drill. For each soil tillage system, the effectiveness of the action of mineral fertilizers (N60P60K60) and straw in combination with StiMiX®Niva biological preparation (2 l/ha) and mineral nitrogen (10 kg of active matter per 1 ton of straw) was studied. Optimal density of the arable layer of gray forest soil for the growth and development of spring wheat was formed after autumn plowing for all years of the study (2014-2017). By the time of sowing, the bulk weight of the soil in all the studied cultivation technologies under spring wheat in crop rotation increased to 1.41-1.50 g/cm3 in the arable (0-20 cm) soil layer. Soil cultivation regulated the conditions for seeds germination in 0-10 cm soil layer to optimal values (1.29-1.34 g / cm3). No-till technology led to the compaction of gray forest soil both in the initial period of spring wheat vegetation (1.43 g/cm3) and at the end of vegetation (1.48 g/cm3). It negatively affected the growth and development of spring wheat and, as a result, its yield. A higher moisture content in the arable layer of the soil (0-20 cm) at the beginning of spring wheat sowing accumulated in the zero-tilling variant (19.9%). Variants with shallow plowing and minimum tillage with a disc harrow occupied an intermediate position between deep plowing and "direct" sowing as to the content of moisture in the soil. The highest yield of spring wheat of the Ester variety (3.99 t /ha) was obtained against the background of non-moldboard "shallow" tillage by the combined use of mineral fertilizers (N60P60K60) and ammonium nitrate (N10) applied for the decomposition of post-harvest plant residues.

The aim of the research is to increase the water resources use efficiency to obtain the planned yield of carrots (Major F1 hybrid) and table beets (Bordeaux varieties) at the level of 60, 70 and 80 t per ha under the conditions of the Volga-Don interfluve. Material and Methods. The studies were conducted on light chestnut heavy loamy slowly permeable soils of Gorodishchensky district of Volgograd region during 2015–2017. The experiments were carried out according to the generally accepted recommendations by B. A. Dospekhov, G. F. Nikitenko, V. N. Pleshakov. Irrigation was carried out by drip irrigation systems with the maintenance of the predetermined soil moisture thresholds and the designed wetting depth. Results: it was found that maintaining a constant pre-irrigation soil moisture threshold of 80 % minimum moisture-holding capacity and increasing the doses of mineral fertilizers to N₂₁₀P₁₀₀K₂₆₀ made it possible to obtain the highest carrot yield of 81.6 t per ha in the field experiment. This happened simultaneously with the reduction of water consumption coefficients to the minimum values of 72.2 cubic meters per ton, and irrigation water costs – up to 55.2 cubic meters per ton. In variants with a differentiated moisture depth of 0.3–0.5 m at maintaining an optimal irrigation regime of 80 % minimum moisture-holding capacity and increasing fertilizer doses to N₂₃₀P₁₈₀K₁₀₀, beet yield increased to 84.1 t per ha. This caused a maximum reduction of transpiration ratio to 59.8 cubic meters per ton and irrigation water costs to 45.1 cubic meters per ton. Conclusion: the research results proving that water-saving technologies used for light-chestnut soils in the south of Russia, combining the developed irrigation regimes simultaneously with the predicted doses of mineral fertilizers which make it possible to obtain the planned yield of beetroot and carrot with drip irrigation at the level of 60–80 t per ha are presented.

The research was conducted in the Nizhny Novgorod region in 2015-2016 on light gray forest soil in the link of crop rotation “winter wheat-soybean”. The scheme of field experiment included 5 soil treatment systems: 1. Traditional moldboard tilling based on autumn plowing with PN-3-35 at 20-22 cm (control); 2. Nonmoldboard “deep” cultivation - autumn plowing with PN-3-35 (without moldboard) at 20-22 cm; 3. Nonmoldboard “shallow” tilling with the stubble cultivator Pöttinger at a depth of 14-16 cm; 4. The minimum machining with the disc harrow XM 44660 NOTHAD at a depth of 10-12 cm; 5. Zero tilling (No-till) with the Sunflower 9421-20 drill. For each soil treatment system, the effectiveness of the action of mineral fertilizers (N60P60K60) and straw in combination with the bio-preparation Stimix®Niva (21/ha) and mineral nitrogen (10 kg a.i. per 1 ton of straw) was studied. By the time of soybean sowing, only mechanical treatment provided favorable conditions for germination of seeds in the 0-10 cm soil layer (volumetric soil weight 1.25-1.30 g / cm3). The technology of direct seeding led to an increased compaction of the soil already in the initial period of vegetation (1.43 g / cm3). The variants of treatment systems didn’t have a significant effect on the soil moisture. By the time of soybean sowing the moisture content in 0-20 cm soil layer was 14.7-15.5%, and in 0-50 cm layer -16.4-17%. According to the soil treatment systems studied, the highest yield of soybean Svetlaya was obtained on the background of mineral fertilizers (N60P60K60) and straw as well as in variants with bio-preparation Stimix®Niva or mineral nitrogen for plant matter decay. Soybean cultivation by mechanical treatment systems provided grain yields of 1.64-1.761 / ha, and no-till technology reduced it to 0.61 t/ha.

Moisture dynamics of the cultivated soil layer while soybean cultivation The article considers the possibilities of agro technical measures to influence on the dynamics of soil moisture. The article presents the study results of the moisture determination in various soil layers in conditions of insufficient and unstable moistening of the south of Russia. The trials were made in the experimental plots of the NCRIMEA (the structural department of the FSBSI ‘ARC ‘Donskoy’, Zernograd of the Rostov region) in the conditions of long-term stationary experiment when cultivating soybean by various technologies (traditional, zero). The moisture content of the soil was taken into account at a depth of 30 and 60 cm using humidity sensors. The measured relative humidity values ranges from 0 to 100%, the accuracy of measurements is ± 3% at a temperature of 250C for a range of 10-90%, beyond this range, the measurement accuracy is ± 5%. To accumulate data, the registration device (a meteostation) ‘Watch Dog 1400 Micro’ was used. The aim of the research was to determine and compare the influence of soil treatment methods on the moisture index in the soil at various levels. The conducted studies established that soil treatment methods had an effect on soil moisture. The average moisture content of the soil on the untreated background is on 23% lower compared to the moisture content of the soil treated by traditional technology. Soil as a dynamic system converts the input signal (the relative humidity of the surrounding air) so that it decreases in magnitude and in the rate of change (dynamism). These features of the soil are determined both by the methods of treatment and by its composition, since the different structure of the soil and its components that determine this structure have different moisture conductivity, moisture capacity, and moisture retention capacity.

Microbiological concentrates Azoto and phosphate Barvar of Iranian production according to certificate activate azotfixation from the atmosphere and transform complex phosphoric minerals of the soil to forms accessible to the plants. They are introduced into the soil in the form of water solution. In vegetation experiments of row crops the yield of tomato variety Lia in variants with mineral and organic fertilizers (semi-rotten manure, granulatedbird droppings and organomix, ORWACO) according to 3 years’ average data made 475-519, that of the pepper variety Nush 477-500, and in the consentrates of both crops 453 d/pot. In the control variant it was 432 and 418 g/pot, respectively. The content of nitrates in the ripe fruits in all variants of tomato exceeded the MPC (150 mg/kg in open soil) but in the fruits of pepper it was 4 times lower than MPC (200 mg/kg in open soil) which is probably connected with varietal peculiarities. The vegetative mass of the studied crops in the variant of microbiological concentrates has also been the smallest. [ABSTRACT FROM AUTHOR]

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In the territory of the Republic of Crimea, the production of growing cereal crops in arid conditions is becoming topical. The most effective method is the introduction of a system of saving farming. Existing analogues of seeders with disc coulters in conditions of heavy and loamy soils of the arid region of the Republic of Crimea have limited opportunities. A scheme of sowing with rolling out at the level of seed occurrence and a construction of a vomer section with a roller pressing in the seeds is proposed. This scheme includes: cropping of soil; Seedbed formation; Distribution and indentation of seeds into the soil; Transportation and separation of the undercut loose soil layer; Upsetting and leveling of the soil covering the seed. The structure of the proposed vomer section includes a stand on which a seed conduit, a diffuser and a cultivator leg with two flat-cutting knives and a chisel are fixed. A rolling device with a cutter in the form of an ellipsoid of rotation is hinged to the stand. Behind the packing roller to the frame there are attached lamellar tines, made in the form of segments of a logarithmic spiral. At justifying the design parameters and operating modes, methods of theoretical and agricultural mechanics, mechanics of continuum, elasticity theory, integral and differential calculus were applied. Taking into account the need to ensure an even distribution of the sealing action of the paw on the soil, an analytical expression describing the law of distribution of the contact pressure of the cutting edge of the paw on the soil was obtained, which allowed to justify the shape of the cutting edge of the blade of the paw of the vomer section. The shape of the cutting blade is determined taking into account the physico-mechanical properties of the soil: the deformation index, the shear modulus and the friction coefficient of the blade on the soil. The shape of the compacting roller is determined, which ensures the uniformity of indenting seeds into the soil compacted by the blade. The roller must have the form of a truncated ellipsoid of revolution. Covering the dented seeds with a roller is carried out by the guide trays. Overtake is carried out with the final precoating and leveling of the soil surface.

The article presents the results of a three-year study of water and nutritional status of tea plants in Adygea. Deficiency of moisture and nutrients during the crop vegetative period is defined. In bogharic conditions without the use of fertilizers, the yield was 16 ± 5 c / ha. Finely dispersed watering on the background of fertilizers contributed to the increase in the tea yield up to 71.4 c / ha, which is 80% higher than the control. Processes of mobilization of mobile forms of nitrogen, phosphorus and potassium under irrigation conditions take place more intensively, due to the active removal of biogenic elements with the green crop mass and their washing out with irrigation water.

The work objective is to establish the relationship of such soil parameters as soil moisture (SM), penetration resistance force (PRF), and time of the compressed air release. During the investigation, the following tasks are solved: identifying the impact of humidity on the air permeability of various types of soil; establishing the relationship between the soil PRF and the air permeability of the soil types under study; gain in experience of using a penetrometer for measuring the penetration resistance force of different types of soils. The connectivity between humidity and soil penetration resistance force is proved. At that, the highest correlation coefficient is observed in limestone, and the lowest - in alumina and sandy loam. The relationship between the content of pores filled with air, and the air permeability of the soil is determined. The number of pores filled with air ( ) increases with the decreasing of the number of pores filled with water. Whereas the compressed air release time ( ) decreases over the natural logarithm amplitude:

In forest ecosystems, the CO2 efflux from the soil may account for 40–80 % of the total amount of released CO2. Domination carbon breath losses over productivity may change the functional role of the ecosystem and transform it from a carbon sink to source. One of the most important field of study in soil respiration research is to identify a uniform methodology for measuring CO2 fluxes from the soil surface and its standardization. In our study, we assessed the investigation of the temporal and spatial dynamics of CO2 flux from the soil surface using the method based on the dynamic closed chambers in the middle taiga forests of Central Siberia. Soil respiration measurements were carried out during the growing season from June to October 2013. The period, when the soil respiration reached to maximum development – the second half of July to the end of August 2013. The ground cover substantially affected the value of soil respiration. The smallest value observed at the site without any plant cover – pp_sand (0.11–1.24 μmol CO2 m-2 s-1), which is 8 times lower than in the forested areas. The greatest values were attended at the site with mixed forest ranged from 2.31 to 8.41 μmol CO2 m-2 s-1. An important condition to obtain reliable results is the frequency of measurements. It was found that the measurements with a frequency of 5 or more times per month does not exceed the variation coefficient of 10 %, which indicates high reliability of the obtained values

The article presents the results of research related with the study of productivity, water consumption and feasibility of irrigation in flax at different levels of fertility and moisture regimes of drained soil. The experiment was conducted on three backgrounds of agrochemical fertility: 1) control (no fertilizer). 2. The aftereffect of multi-purpose compost (KMN). 3. KMN + NPK (NPK - from 2011 till 2013 in the calculation on the planned crop under the previous culture). Fiber flax is need in irrigation during a dry period of growth to obtain a sufficiently high yield of straw and seeds. Watering with norm of 150 m3 / ha after sowing increased the number of surviving plants till harvesting by 30-35%. Carrying of 3-4 irrigation during growth season increased the straw flax yield from 22.7 to 40.4%, the seeds yield - from 10.5 to 53.2%. In the variant KMN + NPK increments of straw and seeds yields at the expense of irrigation reached 40.4 and 53.2% respectively. Payback additional cost amounted to 2.00 rubles / rubles. In the variant with aftereffect of KMN during the fourth year after the inputting of 15 t / ha under irrigation increase in straw flax yield amounted to almost 30%, seed - 26.7%. Payback costs of obtaining of increases yield was 1.43 rubles per each ruble of costs incurred. The total water consumption of flax without irrigation was about 2000 m3 / ha, at irrigation - more than 4000 m3 / ha. At the growth of flax productivity on the more fertile backgrounds coefficient of water use (Kv) decreases by 29% (non-irrigation) and 40% (for irrigation).

Every ecological group of plants including hygrophytes, mesophytes and xerophytes is characterized by a definite narrow interval of the soil water potential, in which the values of relative transpiration cannot be lower than the optimal level (1.0-0.9). These intervals take into account the influence of soil properties (moisture potential) and meteorological conditions (transpiration) and can be used as optimal indices for the water supply of plants. The peculiar soil water uptake by plants has been studied to show that the soil water and its intensive uptake become increasing but its “dead” reserve decreasing from hygrophytes towards mesophytes and then xerophytes. It is worth emphasizing that the decline in the growth and accumulation of useful products by plants occur due to decreasing the content of soil water to the lower boundary of optimal moistening. The further decrease in soil moisture leads to permanent and then ultimate wilting of plants. Under study were also intervals for soil water potential corresponding to the moisture of ultimate wilting of different ecological plant groups. Lettuce (hygrophyte) is becoming dead when the content of soil water is equal to 1.5, oat (mezophyte) - 1.0 and xerophytes - lower than 1.0 of the wilting moisture. The method of “vegetative miniatures” widely adopted now is imperfect and can be performed only for preliminary notions about the lower limit for plant availability of the soil water.

The authors systematized and comprehensively analyzed the different sources containing the information on surface and underground flooding of soils and lands at the territory of Central Russia. The above processes are observed through their intensive manifestation within the zones of soddy-podzolic, gray forest soils and chernozems in Tver’, Smolensk, Moscow, Ryazan’, Bryansk, Voronezh, Kursk, Tambov, Yaroslavl, Kaluga regions of the studied territory. It is shown that natural events and those induced by human interventions serve as a reason for ccurring and developing these processes in different regions. The soils reveal short-duration flooding and become even waterlogged due to frequent and heavy rainfalls and spring floods taken place almost every year. However, the soils are becoming excessively wet for a long period of time resulted from the groundwater rise due to water engineering constructions and the irrational land use. Being affected by natural and anthropogenic factors, the constant wetting (water-logging and underground flooding) can be also as a consequence of intense urban building accompanying by drainage destruction of the ground water. Special attention is paid to elaborating a complex of measures to prevent the adverse effects of such dangerous natural processes.

The aim of the current study was to assess the extent to which soil mineral fertilization, starter dose, influences the biological potential of soybean rhizosphere under suboptimal soil water content. The experiment was established with 4 replications, in plastic pots (5 kg of absolutely dry soil, carbonate chernozem). The main macro-elements N50P100 (mg/kg) were applied to the soil in the form of Ca(NO3) 2 and P2O5 (KH2PO4). Two soil moisture regimes were examined: 70% and 35% of total soil water capacity. At the budding-flowering stage a reduced soil moisture during 17 days was maintained. Two soybean varieties were subjects for study: Aura (A) and Clavera (C), differing in the degree of drought tolerance (C>A). Control soil without plants was also considered. It was determined that soil biological activity depends on the nutritional and water conditions but not as pronounced lyas plant biomass does.The functional activity of the microbiota (BSR –basal soil respiration) recorded higher values at a lower water content. This could indicate that bacterial community expends additional energy to perform and maintain its vital processes. The biological potential of Aura variety rhizospheric soil was higher compared to the Clavera one and to the soil without plants.

The paper is aimed to consider the theory and methods of determining the coefficients of water conductivity and filtration. Soil columns and lysimeters were used for this purpose. It is shown that even a slightly expressed decrease in the moisture content can lead to decreasing the water conductivity in soil. In the range of high values of the moisture potential the coefficient of water conductivity is significantly higher for light-textured soils, on the contrary, within the range of middle and low values it seems higher for loamy soils. The maximum of water conductivity in any soil is close to filtration coefficients, but its minimum tends to zero. The coefficients of water conductivity and filtration become usually close under conditions of descending flow when the moisture is equal to the maximum water capacity or close to it.

The article presents the study of biochemical indices of strawberry varieties Honeoye, Elsanta, Sharlotte and Betty by improving water quantity management of the drip irrigation system in relation to climatic conditions (rainfall, air temperature, air humidity, evapotranspiration, solar radiation and the presence of wind). Much attention was paid to the main biochemical parameters such as weight of dry substance and carbohydrates content. The best quantitative and qualitative results of strawberries have been obtained in the case of Honeoye variety (variant 1 – maintaining the humidity of 75% of soil’s field capacity).