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In areas with shallow saline groundwater, soil salts inevitably accumulate in the root zone during the growth period due to irrigation and upward movement of salts from the groundwater. In Northern China, autumn irrigation (AIR) with large amounts of water is commonly employed post-harvest to mitigate soil salt stress on crop growth in the subsequent year. Optimizing the total irrigation depth during both crop-growth and non-growth periods is challenging because of the movement of soil salts, which is influenced by their two-dimensional distribution around drippers and the impact of the winter freeze-thaw cycles, significantly affecting water flow and solute transport during winter. In this study, the HYDRUS-1D and HYDRUS-2D models were integrated and calibrated using experimental data collected from 2021 to 2023 in China's Ordos south bank irrigation area. This model integration was conducted to assess soil water and salt dynamics during the non-growth and corn-growth periods under different irrigation strategies: a) AIR with high (AH) and low (AL) irrigation depths, and b) drip irrigation (DIR) with high (DH), medium (DM), and low (DL) irrigation depths. The results indicated that HYDRUS effectively modeled the electrical conductivity of the saturation paste extract (ECe) across different irrigation strategies, yielding an average coefficient of determination (R2) and the root mean square errors (RMSE) of 0.87 and 0.53 dS m−1, respectively. Generally, ECe increased during the growth period with DIR and decreased during the non-growth period with AIR. For the 0–40 cm soil layer, ECe decreased by 5.7 % and 12 % for every 100 mm increase in the AIR and DIR depths, respectively. Compared with the AHDM and AHDL treatments, reducing an AIR depth and increasing a DIR depth resulted in lower ECe in the 0–40 cm layer during the growth period and higher crop yield (CY) and irrigation water productivity (WPI). Specifically, the average ECe in the 0–40 cm layer decreased by 4.8 % during the growth period in the ALDH treatment compared to the AHDM treatment, and CY and WPI increased by 7.2 % and 10.3 %, respectively. Additionally, the irrigation strategy was the most effective in reducing ECe when AIR accounted for 35 % of the total irrigation. This study suggested that combining low AIR and high DIR could enhance water and field productivity.

Purpose: to state hydraulic characteristics and determine priority directions for improving the irrigation module design for combined drip and micro-sprinkler irrigation. Materials and methods. The study is based on the joint use of theoretical methods – a well-known mathematical model for calculating the hydraulic characteristics of the irrigation module and experiment, which allows assessing the problem state and scale solutions in any necessary proportions. Results. According to calculations, the uniformity of watering is maintained at an acceptable level at a lower head level in the range of 1.56–1.68 atm when installing six microsprinklers on a drip line. When installing eight sprinklers, the water head along the length of the drip pipeline decreased to an unacceptable 1.39–1.40 atm. Experimental studies have shown that there is only an option with two sprinklers installed on the pipeline above the level of 1.5 atm. Already with the installation of four sprinklers, the water head along the length of the pipeline decreased to 1.45–1.47 atm. At the same time, the variation in the actual microsprinkler performance reached 16 % or more. The discrepancy between experimental and model data is explained by the fact that the calculation model does not fully take into account local resistances that arise when connecting sprinklers. Conclusions. Two main reasons of the increased uneven distribution of irrigation water over the irrigated area have been identified. The first reason is a significant increase in water flow in the irrigation pipeline when emitters and sprinklers work together. The solution to this problem is to develop structures that make it possible to separate the water flow through emitters and through sprinklers in time. The second reason is an increase in local resistance in the water diversion units to the sprinklers. The solution to this problem is to develop special water diversion structures that would be characterized by minimal local resistance.

The article presents materials on subsoil irrigation (SSI) systems. The advantages and disadvantages of SSI systems, as well as recommendations for their use, are considered. New technical SSI solutions protected by Russian patents include the joint use of SSI and drip water supply, as well as the combination of SSI with sprinkler systems. The methods of using SSI for the utilization of livestock wastewater in compliance with sanitary and hygienic standards, as well as an SSI system for perennial plantations with salt water, are considered. [ABSTRACT FROM AUTHOR]

【Objective】 In northwestern China, freshwater resources are scarce while saline water is abundant. Irrigation using mixed fresh and saline waters has been adopted as an improved practice to maximize water resource use and sustain agricultural production in this region. This paper is to study the effect of mixed saline and fresh water irrigation on CO2 emissions from cotton fields. 【Method】 Saline waters with salt concentration of 2 (S1), 3 (S2), and 5 g/L (S3) were used in the experiment. Each saline water was mixed with freshwater at four ratios (saline water/freshwater): 1∶1 (P1), 1∶4 (P2), 4∶1 (P3) and 1∶0 (P4). The mixed waters were used to drip-irrigate the cottons. The emission of CO2 from soil irrigated by different mixed waters was measured daily using static headspace-gas chromatography method. 【Result】 Compared with freshwater irrigation, irrigation with mixed saline and fresh waters reduced average daily CO2 emissions from the soil by 12.64% to 28.57% (P

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office 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.)

In areas with shallow saline groundwater, soil salts inevitably accumulate in the root zone during the growth period due to irrigation and upward movement of salts from the groundwater. In Northern China, autumn irrigation (AIR) with large amounts of water is commonly employed post-harvest to mitigate soil salt stress on crop growth in the subsequent year. Optimizing the total irrigation depth during both crop-growth and non-growth periods is challenging because of the movement of soil salts, which is influenced by their two-dimensional distribution around drippers and the impact of the winter freeze-thaw cycles, significantly affecting water flow and solute transport during winter. In this study, the HYDRUS-1D and HYDRUS-2D models were integrated and calibrated using experimental data collected from 2021 to 2023 in China's Ordos south bank irrigation area. This model integration was conducted to assess soil water and salt dynamics during the non-growth and corn-growth periods under different irrigation strategies: a) AIR with high (A H) and low (A L) irrigation depths, and b) drip irrigation (DIR) with high (D H), medium (D M), and low (D L) irrigation depths. The results indicated that HYDRUS effectively modeled the electrical conductivity of the saturation paste extract (EC e) across different irrigation strategies, yielding an average coefficient of determination (R 2) and the root mean square errors (RMSE) of 0.87 and 0.53 dS m−1, respectively. Generally, EC e increased during the growth period with DIR and decreased during the non-growth period with AIR. For the 0–40 cm soil layer, EC e decreased by 5.7 % and 12 % for every 100 mm increase in the AIR and DIR depths, respectively. Compared with the A H D M and A H D L treatments, reducing an AIR depth and increasing a DIR depth resulted in lower EC e in the 0–40 cm layer during the growth period and higher crop yield (CY) and irrigation water productivity (WP I). Specifically, the average EC e in the 0–40 cm layer decreased by 4.8 % during the growth period in the A L D H treatment compared to the A H D M treatment, and CY and WP I increased by 7.2 % and 10.3 %, respectively. Additionally, the irrigation strategy was the most effective in reducing EC e when AIR accounted for 35 % of the total irrigation. This study suggested that combining low AIR and high DIR could enhance water and field productivity. • Drip irrigation (DIR) during growth period and autumn irrigation (AIR) during non-growth period were evaluated. • Salt dynamics were analyzed using HYDRUS model (autumn irrigation, freeze-thaw, and growth periods in a sequence). • Soil water-salt balance and water productivity were analyzed under different irrigation strategies. • The strategy of low AIR and high DIR is recommended when irrigation water is limited. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Water & Soil Conservation is the property of Gorgan University of Agricultural Sciences & Natural Resources 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 this study is to develop combined irrigation systems for effective regulation of the hydrothermal regime of soil, plants, and the surface layer to create optimal conditions for plant growth and development. The fundamental methodological approach to creating combined irrigation systems is the combined use of different irrigation methods and their implementation in a special regime within a single technological process. Another key point is that irrigation is carried out in different ways on the basis of a single technical system, which is an independent design solution. The creation of these engineering systems is the starting point for the transition to new reclamation technologies providing an integrated regulation of life factors and an extended protection of agricultural crops from climate risks in open ground conditions. The research substantiates the necessity and technical feasibility for combining fine sprinkling irrigation of agricultural crops with other known methods of irrigation, such as drip, sprinkling, subsoil, and surface irrigation methods. Fine sprinkling covers the vegetative organs of plants with 100–400 μm drops, followed by their evaporation and the absorption of latent vaporization heat, which makes it possible to effectively regulate the microclimate in the sowing medium. During evaporation, water cools the leaf surface by 5–7°C and increases the actual humidity of the surface air by 14–16%, thereby removing peak temperature stress and improving the physiological state of the plants. However, under arid climate conditions with a severe shortage of natural moisture supply, fine sprinkling does not make it possible to compensate the demand of plants for water and does not regulate soil moisture reserves. This makes it necessary to combine the use of fine sprinkling with irrigation methods for soil moisture regulation. [ABSTRACT FROM AUTHOR]

There are no doubts about the advantages of using drip irrigation, however, it does not solve the problem of regulating plant phytoclimate in open ground during periods of high temperatures in the Lower Volga region when the biological development of vegetable crops is inhibited, which leads to a decrease in yield. The use of combined irrigation in the combination of drip and fine solves the problem of reducing thermal stress and increases moisture on the soil surface. Based on the research and publications of Russian scientists, the main requirements for the functioning of combined irrigation systems have been identified. These include the provision of drip and fine (aerosol) irrigation, the system should work both jointly and separately, the regulation of plant phytoclimate, the possibility of using foliar feeding and chemical protection, etc. To solve this problem, a number of technical solutions have been considered, which will allow to partially or fully satisfy all the requirements for the stability of the technological process of growing crops under combined irrigation and eliminate the above-mentioned negative environmental conditions of the Lower Volga region. The FGBNU VNII “Raduga” developed the KAU-1M aerosol humidification kit, and the scientists of the Volgograd State Agrarian University developed technical solutions Spray Nozzle of the Combined Irrigation System for Cultivation of Vegetable Crops). The proposed technical solutions for the combined irrigation system will improve operational reliability, provide the plants with soil moisture, control the temperature, nutritional regime of the plants, which will make it possible to obtain stable yields of agricultural crops and environmental safety of the environment.

Purpose: development of a computer algorithm for a quantitative assessment of the hydraulic parameters of an irrigation and drainage system with the possibility of integrating different irrigation methods. Materials and methods. The design of structures for combined irrigation is based on hydraulic calculation. A feature of such systems is the ability to change irrigation methods, which is associated with a significant change in hydraulic parameters and the complication of hydraulic design of structures. Automation of hydraulic calculations based on a universal computer algorithm is the most acceptable way to solve the problem and the basis for designing combined irrigation systems. Results. A feature of the proposed algorithm for determining the quantitative parameters of the combined irrigation system is the use of a step-by-step approach followed by the formation of a generalized hydraulic screenshot of the entire structure. A screenshot of hydraulic parameters here means a quantitative assessment of hydraulic indicators for all nodal points of a structure, implemented by a calculation method for given, stationary modes of system operation. A set of this kind of static screenshots allows you to evaluate the process in dynamics, as well as to carry out comparative assessments of hydraulic parameters under different operating modes of the combined irrigation system. The algorithm offers an original way to identify objects based on the use of a linear coordinate system. The method makes it possible to organize an enumeration of the structural elements of the system and a step-by-step calculation of hydraulic parameters from the inlet section of the design segment to any given nodal point. Conclusions. The calculation results according to the proposed algorithm make it possible to form a specially organized data array, which is a set of symbolic-numeric values that determine the pressure level and water flow rate and identify them with the nodal point of the system.

Objectives The purpose of this study was to evaluate the temperature changes during implant osteotomies with a combined irrigation system as compared to the commonly used external and internal irrigation under standardized conditions. Material and methods Drilling procedures were performed on VII bovine ribs using a computer-aided surgical system that ensured automated intermittent drilling cycles to simulate clinical conditions. A total of 320 drilling osteotomies were performed with twist (2 mm) and conical implant drills (3.5/4.3/5 mm) at various drilling depths (10/16 mm) and with different saline irrigation (50 ml/min) methods (without/external/internal/combined). Temperature changes were recorded in real time by two custom-built thermoprobes with 14 temperature sensors (7 sensors/thermoprobe) at defined measuring depths. Results The highest temperature increase during osteotomies was observed without any coolant irrigation (median, 8.01°C), followed by commonly used external saline irrigation (median, 2.60°C), combined irrigation (median, 1.51°C) and ultimately with internal saline irrigation (median, 1.48°C). Temperature increase with different drill diameters showed significant differences ( P < 0.05) regarding drill depth, confirming drill depth and time of drilling as influencing factors of heat generation. Internal saline irrigation showed a significantly smaller temperature increase ( P < 0.05) compared with combined and external irrigation. A combined irrigation procedure appears to be preferable ( P < 0.05) to an external irrigation method primarily with higher osteotomy depths. Conclusions Combined irrigation provides sufficient reduction in temperature changes during drilling, and it may be more beneficial in deeper site osteotomies. Further studies to optimize the effects of a combined irrigation are needed. [ABSTRACT FROM AUTHOR]

Objectives Based on a novel standardized bovine specimen, the aim of this study was to investigate thermal effects of different irrigation methods during intermittent and graduated drilling. Material and methods Temperature changes during implant osteotomies ( n = 320) of 10 and 16 mm drilling depths with various irrigation methods were investigated on manufactured uniform bone samples providing homogenous cortical and cancellous areas and analogous thermal conductivity comparable to human bone. Automated sequences were performed with surgical twist drills of 2 mm ∅ and conical drills of 3.5, 4.3 and 5 mm ∅. Real-time recording of temperature increase was done using two custom-built multichannel thermoprobes with 14 temperature sensors at a predefined distance of 1 and 2 mm to the final osteotomy. The effects of drilling depth, drilling diameter and irrigation methods on temperature changes were investigated by a linear mixed model. Results Using this uniform bone specimen, the greatest temperature rise was observed without any coolant supply with 29.87°C, followed by external with 28.47°C and then internal with 25.86°C and combined irrigation with 25.68°C. Significant differences ( P ≤ 0.0156) between drill depths of 10 vs. 16 mm could be observed with all irrigation methods evaluated. With each of the irrigation methods, significantly higher temperature changes ( P < 0.0001) during osteotomies could be observed between twist drills of 2 mm ∅ and conical drills of 3.5, 4.3 and 5 mm ∅. During 10 and 16 mm drilling osteotomies, external irrigation showed significantly higher temperatures ( P < 0.05) for all conical drills compared with internal or combined irrigation, respectively. Significantly lower temperatures ( P < 0.05) could be detected with internal or combined irrigation for the use of conical drills with various diameters and drilling depths. Conclusions This fully standardized bone model provides optimized comparability for the evaluation of bone osteotomies and resulting temperature changes. As regards the efficiency of the various irrigation methods, it could be demonstrated that internal and combined irrigation appears to be more beneficial than external irrigation. [ABSTRACT FROM AUTHOR]

Summary: The commonly used irrigation system in the irrigation districts (with a combined irrigation area of 3.334×106 ha) along the lower Yellow River of China is canal network. It delivers water from the Yellow River to the fields, collects surface runoff and drainage from cropland, and stores both of them for subsequent irrigation uses. This paper developed a new combined irrigation, drainage, and storage (CIDS) module for the SWAT2000 model, simulated the multiple roles of the CIDS canal system, and estimated its performance in improving water reuse in the irrigation districts under different irrigation and water diversion scenarios. The simulation results show that the annual evapotranspiration (ET) of the double-cropping winter wheat and summer maize was the highest under the full irrigation scenario (automatic irrigation), and the lowest under the no irrigation scenario. It varied between these two values when different irrigation schedules were adopted. Precipitation could only meet the water requirement of the double-cropping system by 62–96% on an annual basis; that of the winter wheat by 32–36%, summer maize by 92–123%, and cotton by 87–98% on a seasonal basis. Hence, effective irrigation management for winter wheat is critical to ensure high wheat yield in the study area. Runoff generation was closely related to precipitation and influenced by irrigation. The highest and lowest annual runoff accounted for 19% and 11% of the annual precipitation under the full irrigation and no irrigation scenarios, respectively. Nearly 70% of the annual runoff occurred during months of July and August due to the concentrated precipitation in these 2months. The CIDS canals play an important role in delivering the diversion water from the Yellow River, intercepting the surface runoff and drainage from cropland (inflow of the CIDS canal) and recharging the shallow aquifer for later use. Roughly 14–26% of the simulated total flow in the CIDS canal system recharged shallow aquifer through canal seepage. The water flowing out of the canal system accounted for approximately 32% of the water in the CIDS canals. The storage capacity of the CIDS canals is negatively correlated to the precipitation. In years with abundant precipitation, the volume of the surface runoff and drainage from the cropland may surpass the storage capacities of the CIDS canals, while in years with less precipitation, partial storage capacity of the CIDS canal may be occupied by the diversion water from the Yellow River. Proper maintenance of the storage capacity of the CIDS has the potential in improving the efficiency of reusing the surface runoff and field drainage for irrigation practices to mitigate the increasing water shortage along the lower Yellow River. [Copyright &y& Elsevier]