Repair technology of canal concrete lining with bitumen-polymer mastic

Purpose: development of technology for repairing canal linings concrete with bitumen-polymer mastic using one- and two-component latex emulsion to reduce water loss through defects in the concrete lining. Materials and methods: the technology of repairing the damaged canal lining concrete coating includes: preparation of the base for the protective coating; preparation of bitumen-polymer mastic for its application (manually) or spraying (mechanized) over the entire repaired area; preparation of equipment, mechanisms and necessary inventory; preparation for the use of material components (reagent (component A) and hardener (component B)) for mechanized application; the process of applying bitumen-polymer mastic to the repaired area. Results: according to the results of a scientific research, when repairing the internal junctions of the bottom and slopes of canal concrete linings, it is necessary to arrange fillets that have a triangle with sides 10–50 mm long in their cross-section. The use of fillets when joining concrete linings will avoid excessive consumption of repair material. The application of a one-component material is carried out manually using a spatula to repair minor damage and reduce losses through them, and the application of a two-component mastic will allow mechanized repair of the largest (areal) damage. Conclusions: the application of one- and two-component cold-curing bitumen-polymer mastic for repairing concrete lining of irrigation canals to various damages on their surface (cracks, shears, concrete scaling, destroyed seams, etc.) is considered. Technological operations for the repair and restoration of canal concrete linings (a technological map for the concrete surfaces repair with a mechanized polymer composite material has been developed), including five stages of work are presented.

WATER SAVING MEASURES SUBSTANTIATION FOR RICE IRRIGATION SYSTEMS

Purpose: analysis of the rice production water intensity and justification of measures for water saving, allowing to reduce the use of water resources for growing rice and companion crops, to reduce water intensity of production of a production unit while maintaining high yields. Materials and methods. Methods of analysis and synthesis to substantiate the rice and companion crops irrigation regime were used. Results. The analysis of long-term studies of the FSBSE “RSRILIP” showed that the water demand design norms for rice irrigation are exceeded by 1.5–2.0 times. For example, in the low-water year 2020, the rice irrigation rates on the rice systems of Rostov region fluctuated in agricultural enterprises from 27 to 47 thousand cubic m/ha. To save water resources, the main measures should be: maintaining the reclamation network and hydraulic structures in good condition, planned water use and water distribution, improving irrigation equipment and technologies. The first place in terms of influence on the value of the irrigation rate is the evenness of the check surface, since if the height in the check is more than 0.03–0.05 m from the design, the irrigation rate can double due to the need to create a given layer of water over the entire check area. It was found that the irrigation rate value is also influenced by the natural moisture content of the territory, the granulometric composition of the soil, the rate of filtration, the depth of groundwater, the degree of soil salinity and alkalinization. Depending on these factors under the conditions of Rostov region, the irrigation rate for rice can vary from 27 to 36 thousand cubic m/ha and more. Conclusions. To reduce the irrigation norms, irrigation regimes of the shortened type of flooding and obtaining seedlings on natural moisture reserves are recommended. The rice and companion crops cultivation using the ridge technology with periodic sprinkler irrigation or check flooding requires study.

LAYOUT SOLUTIONS FOR DRIP IRRIGATION NETWORK MODULES OF IRRIGATED WOOD-FRUIT PLANTS, CULTIVATED IN GARDEN PLANTINGS

Purpose: to develop layout and design schemes for the territorial arrangement of drip irrigated commercial fruit orchards. Materials and methods. When the goal was achieved, the tasks on assessing and choosing the layouts of the garden's plant modules – garden squares, quarters and rows that make up tree-fruit plantations, and the development of irrigation network modules that ensure their drip irrigation were solved. The factual basis of the study was formed by the survey data of wood-fruit orchards and well-known recommendations on the organization of the garden plantings territory. Results. Taking a modular approach to the planning of perennial woody-fruit plantations, implying the arrangement of garden squares, quarters and rows as a basis, the corresponding schemes of the section, irrigation and watering modules ensuring their drip irrigation, were suggested. Taking into account the shapes and sizes of eight-squares garden blocks, two schemes of drip sectional modules were proposed, including a sectional distributor, sprinklers and a system of irrigation pipelines. The irrigation module, which provides watering of the garden quarter, includes an irrigation pipeline and irrigation pipelines fed from it. The watering module provides for irrigation of one row of woody-fruit plants and includes one (for a single-line irrigation module) or two (for a two-line irrigation module) irrigation pipelines with a system of built-in drip micro-outlets, placed taking into account the planting pattern of perennial plants and forming contours or strips of soil moisture in the sub-drip soil space. Conclusions. Rational layout solutions for drip irrigation network modules are proposed, corresponding to garden modules and allowing unifying design solutions for organizing the territory of drip irrigated gardens cultivated according to industrial technologies for planting, maintenance and harvesting operations.

RECONSTRUCTION OF THE NOVOTROITSK RESERVOIR IN STAVROPOL TERRITORY

Purpose: checking the headrace canal to the fall no. 1 for diversion capacity in connection with a change in the canal discharge. Due to the increase in the estimated flow for irrigation and watering, it is planned to build a canal from the reservoir to the fall no. 1. The tasks of the hydraulic computation included the determining of the headrace canal parameters for the intended catastrophic water discharge of 375 cubic m/s, the computation was carried out taking into account the non-steady flow in canal. For effective energy extinction in the tail-race of the fall, it is required to make a constructive decision and carry out a justification taking into account the topographic conditions of the structure's operation. It is necessary to resolve the issue of energy extinction in tail-race of the structure. Calculations of the toothed overfall for energy extinction in the tail-race are presented. Materials and methods. A version of the dissipator with an indented wall which allows dissipate energy in the constraint environment effectively and obtain a favorable distribution of velocities in the flow in tail race of the structure was adopted for the computation. A step-by-step computation for determining the diversion capacity of the fall no. 1 was carried out: first, the diversion capacity of the headrace canal was determined at a catastrophic discharge Q = 375 cubic m/s with a subsequent change in its hydraulic parameters, then the computation for dissipating the flow energy in the downstream of the structure are given. Results: the calculations of the jagged sill for damping the energy in the tail-race are presented, the indented wall of the fall is designed and the corresponding depths in the tail-race are calculated. Conclusions: the performed computation of the headrace canal and fall no. 1 made it possible to ensure the passage of a catastrophic flow rate equal to 375 cubic m/s, under set conditions.

LARGE CANALS RECONSTRUCTION AND THEIR EFFICIENCY ASSESSMENT

Purpose: to define the efficiency of large irrigation canals on the example of the Donskoy main canal and the Bolshoy Stavropol canal during their reconstruction. Materials and methods. The use of geocomposite materials is of interest to creating combined linings of large canals. A geocomposite anti-seepage structure made without a protective layer at the bottom and part of the slope and a concrete-film element in the zone of wave and ice impact is considered. The application of such a combined lining makes it possible to reduce the cost of the anti-seepage screen, to shorten the construction time, to reduce the canal roughness and to increase its water-carrying capacity. The method of hydraulic research is based on the field data of the Bolshoy Stavropol and the Donskoy main canals for average and maximum values of hydraulic parameters. In particular, it was necessary to determine the roughness coefficients of the canal in the area between the sections. Results. A feature of the reconstruction of the most dangerous sections of the Donskoy main canal is the close location of the groundwater level to the surface, which leads to the transition of free filtration to a banked-up one. According to the results of calculations, the total losses are 13.7×10³ cubic meters/day in the section 57–70 km, and with canal lining – 0.504 cubic meters/day, which is 2.09 times less than with banked-up filtration in the earthen bed. Conclusions. The most effective types of linings with the use of geocomposites which, as shown by field surveys, are reliable combined coatings, are presented. Anti-seepage facilities made of concrete and reinforced concrete have high impermeability, though at the same time they are destroyed over time under the influence of water and freezing-thawing processes.

ENVIRONMENTALLY SENSITIVE AREAS OF IRRIGATION LAND USE IN WESTERN SIBERIA

Purpose: to identify the main environmental problems in areas of intensive use of irrigated lands in Western Siberia and to study the relationship between their manifestations and the territorial specifics of the irrigation land use functioning. Materials and methods. The research was carried out on the basis of a systematic approach and comparative geographical analysis. The indicators characterizing the modern structure and territorial specifics of irrigated land use, and parameters reflecting the ecological state of irrigated lands and adjacent territories are studied. Discussions. It was found that the specifics of the identified environmental problems depends not only on type of irrigated lands use but also on the territorial differentiation of irrigated land use and its specialization. For suburban areas with potato and vegetable growing specialization, environmental problems arising as a result of higher intensification of irrigation land use and the proximity effect of Western Siberia metropolis have been identified, which predetermines a high degree of environmental pollution and a high level of land and water resources degradation. For areas with livestock specialization, located in the peripheral and most arid natural and climatic conditions, a great dependence of environmental problems on the irrational structure of irrigation land use and non-observance of norms and technologies for irrigation has been established. Conclusions. For better understanding of the environmental problems causes, it is necessary to study the relationship between their manifestations and the territorial specifics of the irrigation land use functioning. The results of this study can contribute to the search for ways of reducing the irrigation impact on the environment and the development of effective strategies for the sustainable development of irrigation land use in Western Siberia.

THE ANALYSIS OF THE RATIONAL USE OF WATER RESOURCES OF THE CHOGRAI RESERVOIR IN CHERNOZEMELSKY IRRIGATION AND FEEDING SYSTEM

Purpose: to analyze the use of water resources (WR) of the Chograi reservoir (CR) of the Chernozemelsky watering and irrigation system (CWIS). Discussion. The CWIS is currently not working at full capacity: only 25 % of the irrigated area was actually watered in 2020. The main reasons are the lack of irrigation technique, there were 54 units in the Republic of Kalmykia in 2019, as well as the lack of water in the source. A detailed consideration of the latter reason showed that only 17 % of the 291.25 million m³ got from the CR to the CWIS were used rationally (irrigation, watering, fishery needs). The inefficiency of use is expressed by low efficiency of the system (among other things the actual physical deterioration which is 87.49 %), causing the loss of 34 % of water, as well as the consumption of WR for other needs, amounting to 49 %, mainly for feeding the reservoirs, which are the tail escapes of the CWIS. Also, for water users in the CWIS zone, there are difficulties in documents execution aimed at increasing the rationality of the WR use. Gaps are found in the permission documentation when the agency responsible for the water supply is not the water user. Conclusions: to improve the rationality of using WR, it is necessary to consider several options aimed at increasing the system efficiency, including the option providing for the construction of a pipeline instead of the Chernozemelsky main canal (ChMK). It is also necessary to reduce the item of expenditures of WR for other needs or more clearly define the purposes for which water is supplied to the ChMK water bodies.

SURFACE MELT WATER RUNOFF ON THE ARABLE LANDS OF THE LOWER DON

Purpose: to study the indicators of melt water runoff from arable land of various compaction and to assess its quantitative and qualitative characteristics based on long-term data. Materials and methods. Studies of the intensity of melt water runoff were carried out in the Azov zone of Rostov region in the period 1964–2018 by a number of researchers, including the author of the article. Results. The runoff indicators for a 55-year period are characterized by significant fluctuations. Analysis of long-term data revealed that the indicator of melt water runoff rate from loose arable land for the period 1964–2018 averaged 9.0 mm/year and on compacted arable land averaged 17.5 mm/year. On loose arable land, the maximum runoff rate for a 55-year period is 25.3 mm, on compacted arable land it is 47.3 mm. As a result of the analysis of the data, it was revealed that the average water reserve in snow on the surface of the fall-plowed land is 43.7 mm, and 48.7 mm on the winter wheat sowing. In general, for two agrophonies, the runoff indicator for the period 1964–2018 was most often characterized as weak and very weak only on loose arable land. Calculations of statistical indicators of runoff data revealed that they are not uniform, for example, the coefficient of runoff variation from loose arable land was 115.4 %, and from compacted arable land 70.4 %, with a coefficient of variation above 33 %, the aggregate is considered heterogeneous. Rostov region, having a large agricultural potential, is experiencing significant problems from the impact of negative natural processes, among which one of the first places belongs to erosion processes. Conclusions. In the course of generalization of long-term data on melt water runoff from arable land of varying degrees of compaction, indicators that made it possible to plot the flow availability curves were obtained. The use of the results obtained makes it possible to predict the occurrence of runoff of various intensities and thereby prevent its negative impact on agricultural land with the minimal material costs.

THE STATE OF TECHNICAL AND TECHNOLOGICAL CONSTITUENT OF THE AGRO-INDUSTRIAL COMPLEX OF RUSSIA: CHALLENGES AND OPPORTUNITIES FOR DEVELOPMENT UNDER A NEW WORLD ECONOMIC STRUCTURE FORMATION

Purpose: to study and analyze technical and technological constituent of the agro-industrial complex of Russia in the context of a new world economic structure formation and to highlight main issues and development potential. Methods. The monographic, analytical, abstract-logical methods and the method of monitoring studies were used in the course of research. Results. The development of the world economy is characterized by an unsteady and utterly unstable political situation, the “reshaping” of trade and economic relations, the accelerated development of high technologies and their active implementation in the production sphere, which forms the contours of a new world economic structure. As studies show, in our country there is a significant lag in technical and technological provision of the agricultural sector, low innovative activity of agricultural producers in comparison with the advanced agricultural countries, which does not allow fully realize the potential of the industry. If in the developed agrarian countries of the world there is a transition to the sixth technological structure based on the use of science-intensive technologies and innovations, then in Russia there is a simultaneous use of production technologies of the second, third, fourth and fifth technological orders with a predominance of the third and fourth orders, which in its own turn forms a significant lag of our country from the countries – leaders of the agricultural sector. In this regard, the key issues are: technical and technological modernization and digitalization of the agricultural industry, increasing the innovative activity of agribusiness entities, the widespread use of scientific achievements of the fifth technological structure and an accelerated transition to the sixth one. Conclusions. In order to strengthen Russia's position on the international agricultural market by realizing the competitive advantages of domestic goods and industries, it is proposed to develop and implement a unified state policy of the country's agricultural sector modernization.

Drainage and watering systems on even lands with the use of frontal and frontal-circular sprinklers

Purpose: research and development of design solutions for drainage and watering systems using linear and frontal-circular movement sprinkling machines for the effective use of system water resources when draining and moistening reclaimed lands in non-sloping (low-slope) areas and with a slight slope. Materials and methods. During the research, the well-known design solutions of drainage and watering, irrigation and water circulation systems of various scientists were analyzed. In the course of analysis of constructive solutions and methods of movement, analytical, comparative and logical methods were used. When developing (improving) design solutions, the design method was used. Results. During the research, it was found that in the humid zone, due to the decrease in irrigation norms, there is a possibility of increasing the seasonal load of sprinklers. Based on the results of studies of the principles of moving sprinkler machines and currently used design solutions in order to reduce energy consumption and increase the land use coefficient, three design solutions have been proposed for reclaimed lands with different slopes. It is proposed to use frontal and frontal-circular sprinklers in drainage and watering systems. Humidification in these solutions is carried out by accumulated drainage runoff with the possibility of discharging its excess water into a water intake-water source, as well as, additional withdrawal from it in case of necessity. Conclusions. As a result of the research, the constructive solutions for drainage and watering systems have been proposed using frontal-circular and frontal sprinklers on non-slope (low-slope) reclaimed lands, as well as those with a slope, which make it possible to reduce the number of sprinklers due to reduced irrigation norms and the location of the combined drainage-watering and watering networks.