Irrigation Rates Research Articles

Change in renal blood flow in response to intrarenal pressure alterations induced by ureteroscopy in an in-vivo porcine model.

High irrigation rates are commonly used during ureteroscopy and can increase intrarenal pressure (IRP) substantially. Concerns have been raised that elevated IRP may diminish renal blood flow (RBF) and perfusion of the kidney. Our objective was to investigate the real-time changes in RBF while increasing IRP during Ureteroscopy (URS) in an in-vivo porcine model. Four renal units in two porcine subjects were used in this study, three experimental units and one control. For the experimental units, RBF was measured by placing an ultrasonic flow cuff around the renal artery, while performing ureteroscopy in the same kidney using a prototype ureteroscope with a pressure sensor at its tip. Irrigation was cycled between two rates to achieve targeted IRPs of 30mmHg and 100mmHg. A control data set was obtained by placing the ultrasonic flow cuff on the contralateral renal artery while performing ipsilateral URS. At high IRP, RBF was reduced in all three experimental trials by 10-20% but not in the control trial. The percentage change in RBF due to alteration in IRP was internally consistent in each porcine renal unit and independent of slower systemic variation in RBF encountered in both the experimental and control units. RBF decreased 10-20% when IRP was increased from 30 to 100mmHg during ureteroscopy in an in-vivo porcine model. While this reduction in RBF is unlikely to have an appreciable effect on tissue oxygenation, it may impact heat-sink capacity in vulnerable regions of the kidney.

ზედაპირული მორწყვის მათემატიკური მოდელი

Sustainable growth and development of a plant is a function of interacting factors. In irrigated farming, water consumption, irrigation dates, irrigation norm, equal distribution of water on the irrigated area, under conditions of unchanged soil structure belong to the category of difficult tasks of irrigation. In the case of irrigation area usage close to one, the consideration of seepage and discharge conditions is an urgent issue. In the paper, based on the even distribution of water, a prediction model of the free surface is provided. In particular, the equations, describing the length of the irrigation strip, irrigation rate and irrigation water flow, are derived.

Intrarenal pressure study using 7.5 French flexible ureteroscope with or without ureteral access sheath in an ex-vivo porcine kidney model.

7.5F digital fURS and 9.5/11.5F ureteral access sheaths (UAS), both conventional (cUAS) and vacuum-assisted (vaUAS), are commercially available. Irrigation increases intrarenal pressure (IRP). This study analyzes the IRP with various irrigation rates using 7.5F fURS without UAS or with either cUAS or vaUAS in an ex-vivo porcine model. Pyelo-tubular backflow was also studied during these experiments. 11 porcine kidneys were used. 7.5F digital fURS was tested without UAS and with 9.5/11.5F cUAS and vaUAS. 6F pressure monitor catheters were placed into the upper and lower calyces. IRPs were recorded under different irrigation rates. When vaUAS was used, the air vent was either open or closed. 300mmHg aspiration pressure was chosen. Lastly, contrasted irrigation fluid was delivered until IRP reached above 30mmHg. Fluoroscopy images were obtained at 5mmHg intervals over this threshold to study the pyelo-tubular backflow. Using cUAS, IRP reached 30mmHg with irrigation rates between 60 and 70cc/min. Using vaUAS with vent closed, IRP never exceeded 10mmHg with irrigation up to 120cc/min. vaUAS with vent open performed marginally better than cUAS. fURS without UAS performed better than cUAS. Pyelo-tubular backflow became prominent at 40mmHg. In an ex-vivo porcine model, 7.5F fURS could be used safely without UAS with irrigation rates up to 120cc/min. The safety margin dropped to 60-70cc/min with cUAS. vaUAS with vent closed maintained IRP < 10mmHg with irrigation rates up to 120cc/min. Pyelo-tubular backflow was observed with IRP > 35mmHg.

Effects of different irrigation methods on regional climate in North China Plain: A modeling study

Agricultural irrigation is important in boosting crop yields in especially water-stressed regions, but little is known about the distinct climatic effects induced by different irrigation methods, particularly in the North China Plain (NCP) where irrigation is applied extensively. Here we examine the climatic effects of flood (FI), sprinkler (SI) and drip irrigation (DI) over NCP during the growing season using dynamic irrigation schemes implemented into a coupled land-atmosphere model. The model generally captures the spatial distribution of surface temperature, relative humidity and precipitation. The changes in regional average surface temperature induced by FI, SI and DI are –0.43, –0.53 and –0.19 °C, respectively. The relatively larger cooling effect for SI than that for FI is associated with enhanced cloud formation. By shifting the surface energy balance, FI and SI cause a wet, cool, cloudy and shallow planetary boundary layer, while DI exhibits the smallest effect and indeed inhibits cloud formation. The increases in convective available potential energy and precipitable water induced by FI and SI enhance convective precipitation over NCP by 0.8–1.2 mm d–1. In contrast, the reduced precipitation due to surface cooling within DI leads to a warmer and drier surface from June to August, which likely increases upper-level geopotential heights and in turn suppresses precipitation in a series of climate feedbacks. The distinct hydrometeorological interactions and feedbacks arising from different irrigation methods are likely related to different irrigation rates, frequencies and approaches of water application. While DI is recognized as the most water-saving method, it also generates the least surface cooling among the three methods and is thus less effective in safeguarding grain yields against rising temperatures. Our study emphasizes the need for more sustainable and adaptive irrigation methods to ensure food security, water conservation and climate stability in the face of climate change.

Development of a program for calculation of irrigation rates by available moisture reserves

The article presents the development of a program for calculating irrigation rates using available moisture reserves.

Modelling the scale-up of the iodine-assisted chalcopyrite leaching in ferric sulfate media from reactors to columns and simulating heap operations

The iodine-assisted heap leaching of chalcopyrite involves the addition of iodide in ferric sulfate media to accelerate the dissolution of chalcopyrite at ambient temperature. The previous studies using reactor leaching tests identified the solution potential, the amount of iodide added, and temperature as the factors controlling the process performance. In the present study, the iodine-assisted chalcopyrite leaching process was scaled up from reactors to 1-m and 6-m columns to further understand how these parameters control the process performance at a larger scale. This is essential to optimize the process in industrial-scale heap leach pads. The HeapSim-2D model was calibrated with the 1-m and 6-m column leach tests together with the kinetic parameter values obtained in the previous reactor leaching tests. When the iodine-assisted chalcopyrite leaching was scaled up from reactors to 1-m and 6-m columns, the leaching became slower because the ore used in the column leaching tests had larger particle sizes with partially-liberated chalcopyrite particles. The calibrated model was then used to carry out the sensitivity analyses to assess the response of the process performance to key design and operating variables, including irrigation rate, ferric concentration, total iodide concentration, temperature, and heap height. The analyses show that the copper extraction could be optimized by adjusting these key design and operating parameters.

On-farm water energy food carbon-footprint nexus index for quantitative assessment of integrated resources management for wheat farming in Egypt

To improve the farming efficiency, Egypt has been struggling to narrow the water, energy, and yield gaps owing to exacerbated water shortage. For quantitative diagnosis of farming performance, the paper presented an on-farm water, energy, food, and carbon-footprint (WEFC) nexus index made up of four equally pillars. The arithmetic average preserved the multi-centric approach and equal importance of the four pillars. The index was applied to test and rank 2,042 wheat-based farmer fields in Egypt representing diverse inputs, agronomic and irrigation practices, soil types, and agroecological conditions. The water metric was the ratio of saved water, difference between maximum water consumption recorded in the country and actual water consumption, to the maximum water consumption. Likewise, the energy metric was obtained. The food metric was the ratio of actual yield to maximum yield in the country. The carbon-footprint metric was the ratio of difference between maximum CO2 emission in the country and actual emission to the maximum emission. The index values showed a wide range from 18.69% to 87.33% with a high standard deviation emphasizing the diversity of farming practices, soil types, and agroecological conditions. The highest ten values were recorded in fields with sandy soils, relatively large area, drip irrigation, recommended seeding and fertilization rates, well drainage, weeds removal, and tillage. The drip irrigation system in 51 out of 52 fields had above average value. The lowest ten values were in fields with clay soils and flood irrigation, where 18.7% of 1,780 fields exceeded the above average value. Raised beds with furrow irrigation in 83.15% of 184 fields exceeded the above average value. Fertilization rates of nitrogen and phosphorus in 61% and 53% of fields respectively exceeded the recommended rates with no significant reflection on the food metric. The low index values in fields with flood irrigation were attributed to high water losses causing high water consumption, energy consumption, and CO2 emission. The index was a good indicative of input resources consumption and output production as it varied inversely with water and energy consumption and CO2 emission and proportionally with yield. Since the high-water consumption was the main entry point for low index values in fields with flood irrigation, changing the irrigation to drip system or revisiting the irrigation scheduling and the estimated applied irrigation water amount were recommended. The index can be utilized to quantify the effectiveness of both recommendations and further new site-specific interventions and to assess their impact at scale. The index also recommended land use consolidation where farmers retain ownership of their lands but with cooperative farming.

Soil respiration under different N fertilization and irrigation regimes in Bengaluru, S-India

Rapid urbanization in many countries of the Global South has led to intensification of urban and peri-urban agriculture (UPA) whose effects on the soils’ physical, chemical, and microbial properties have been hardly studied. We therefore investigated the effects of different intensity levels, exemplified by three rates of mineral nitrogen (N) addition and irrigation on CO2 emissions in typical crops during the wet (Kharif) and dry (Rabi) season on a Nitisol in Bengaluru, S-India. Respiration data were collected from 2017 to 2021 in two two-factorial split-plot experiments conducted under rainfed and irrigated conditions. Test crops were maize (Zea mays L.), finger millet (Eleusine coracana Gaertn.), and lablab (Lablab purpureus L. Sweet) under rainfed and irrigated conditions, as well as the vegetables cabbage (Brassica oleracea var. capitata), eggplant (Solanum melongena L.), and tomato (Solanum lycopersicum L.) or chili (Capsicum annuum L.). Carbon dioxide (CO2) emissions were determined using a Los Gatos Research (LGR) multi-gas analyzer whereby under our study conditions CH4, NH3 and N2O were negligible. Measurements were conducted from 7:00 am to 11:30 am and repeated from 12:30 pm to 6:00 pm. Irrespective of irrigation, season, crops and N fertilizer level, CO2 emission rates during afternoon hours were significantly higher (2–128%) than during morning hours. In the irrigated field diurnal emission differences between afternoon and morning hours ranged from 0.04 to 1.61 kg CO2-C ha−1 h−1 while in the rainfed field they averaged 0.20–1.78 kg CO2-C ha−1 h−1. Irrespective of crops, in the rainfed field CO2 emissions in high N plots were 56.4% larger than in low N plots whereas in the irrigated field they were only 12.1% larger. The results of a linear mixed model analysis indicated that N fertilization enhanced CO2 emissions whereby these effects were highest in rainfed crops. Soil moisture enhanced emissions in rainfed crops but decreased them under irrigation where crop-specific CO2 emissions within a season were independent of N application. Soil temperature at 5 cm depth enhanced CO2 emissions in both fields. Overall, higher N and soil temperature enhanced CO2 fluxes whereas effects of soil moisture depended on irrigation.

Effects of Different Irrigation Regimes, Nitrogen Levels and Storage Conditions on Volatiles of 'Gala' Apple.

With a characteristic flavour and aroma, "Maçã de Alcobaça" are apples produced in the western region of the mainland of Portugal. Given the known influence of pre-harvest cultural techniques and post-harvest conservation methods on fruit quality, this work evaluated the effect of cultural factors and conservation methods on the volatile profile of 'Gala' apples. Tests were carried out during four seasons (2018 to 2021) in two 'Gala' apple orchards (F and S) maintained with different irrigation rates and nitrogen fertilisation [normal irrigation and normal nitrogen (Control, NINN), normal irrigation and excess nitrogen (NIEN), excess irrigation and normal nitrogen (EINN), excess irrigation and excess nitrogen (EIEN)], and under three storage conditions [Controlled Atmosphere + 1-methylcyclopropene (CA+1-MCP), Dynamic Controlled Atmosphere (DCA) and DCA+1-MCP]. The intact fruit volatiles were isolated by headspace solid-phase microextraction (HS-SPME) and analysed by Gas Chromatography with Flame Ionisation Detection and Gas Chromatography-Mass Spectrometry at harvest (T0) and after 8 months of storage (T8). HS-SPME volatiles from 'Gala' apples, obtained at T0 in control conditions, were characterised by trans,trans-α-farnesene dominance (36-69%), followed by hexyl acetate (5-23%) and hexyl hexanoate (3-9%). The four irrigation and nitrogen treatments did not evidence main changes in the apple volatile profile. Instead, storage conditions changed the ratio between compounds; previously undetected compounds attained high percentages and decreased the intensity of the dominant compounds in the control conditions. Although all storage conditions tested changed the volatile profile and emanation intensity, the effect was more accentuated in storage for 8 months with DCA+1-MCP.

Impact of rice farming on the state of land and water resources of Kuban

The article underlines that rice growing in the Kuban is an important strategic direction for the development of the agro-industrial complex, since rice is the most profitable crop among all grains. However, the active development of this industry has led to significant ecological problems. One of the problems is irrational water consumption. The analysis of the distribution of irrigated agricultural lands in the Krasnodar Territory by the depth of groundwater level, humus content in the rice-growing regions of the Krasnodar Territory, the irrigation rate of water consumption and the reclamation state of irrigated agricultural lands made it possible to establish that today less than half of rice fields in the Kuban is in satisfactory conditions, but the rest of the region can have swamp processes and secondary salinization of soils leading to a decrease in soil fertility. In addition, the risk of fresh water scarcity is increasing. Based on the conducted studies, the author identifies the need to develop measures to reduce the water consumption of rice systems and improve the management of land and water resources, and also proposes such measures for rational water consumption, taking into account scientifically based crop rotations and the organization of a special water regime. It has been established that rice production with rational water consumption creates an opportunity to preserve the entire ecosystem of the region.

Effects of Different Irrigation Rates on Remontant Strawberry Cultivars Grown in Soil

The present study assessed the responses, in terms of vegetative, productive, qualitative, and nutritional features, of plants and berries of three remontant strawberry cultivars cultivated in soil and irrigated using three irrigation regimes: standard irrigation regime (W100), 20% (W80) less irrigation than the standard irrigation, and 40% (W60) less irrigation than the standard irrigation. The tested plants were “Albion”, “San Andreas”, and “Monterey”, which were cultivated in the east coast area of Marche, Italy. Specifically, the study examined the response of the genotype to irrigation deficit, highlighting the performance of the “Monterey” cultivar, which showed improvement in terms of fruit firmness, folate content, and antioxidant capacity at the W80 irrigation regime without a significant yield reduction. In all the cultivars, when irrigation was reduced by up to 20% of the standard irrigation regime (W100), there were no significant losses of yield or reduction in the fruits’ sensorial quality or antioxidant activity. The results showed that the standard irrigation regime (W100) commonly adopted by the farmers in the Marche area uses more water than necessary. With more accurate water management, it will be possible to save almost 226 m3 of water per hectare per cultivation cycle.

Optimizing water and nitrogen management strategies to improve their use efficiency, eggplant yield and fruit quality.

With improvement in living standards, consumer preferences for vegetables are changing from quantity- to quality-oriented. Water and nitrogen supply, as two major determinants of vegetable crop yield and quality, can be optimally managed to improve the yield and quality. To evaluate the response in yield, fruit quality, and water and nitrogen utilization of eggplant to different water and nitrogen management strategies, a 2-year (2021 and 2022) field trial under mulched drip irrigation was conducted. The growth period was divided into seedling, flowering and fruit set, fruit development, and fruit ripening stages. Three irrigation levels were applied during the flowering and fruit set stage: W0, adequate water supply (70%-80% of field water capacity, FC); W1, mild water deficit (60%-70% FC); and W2, moderate water deficit (50%-60% FC). In addition, three nitrogen application rates were applied: N1, low nitrogen level (215 kg ha-1); N2, medium nitrogen level (270 kg ha-1); and N3, high nitrogen level (325 kg ha-1). The irrigation and nitrogen rates were applied in all combinations (i.e., nine treatments in total). Adequate water supply throughout the reproductive period in combination with no nitrogen application served as the control (CK). The yield of the W1N2 treatment was significantly increased by 32.62% and 35.06% in 2021 and 2022, respectively, compared with that of the CK. Fruit soluble protein, soluble solids, and vitamin C contents were significantly higher under W1 than W2. Fruit quality was significantly higher under the N2 rate compared with the other nitrogen rates. The W1N2 treatment showed the highest water productivity, with a significant increase of 11.27%-37.84% (2021) and 14.71%-42.48% (2022) compared with that under the other treatments. Based on the average water-deficit degree and nitrogen application rate, W0 and N1 had the highest partial factor productivity of nitrogen. Assessment of the results using the TOPSIS (technique for order preference by similarity to an ideal solution) method indicated that mild water deficit in combination with the medium nitrogen application rate (W1N2) was the optimal water and nitrogen management strategy for cultivated eggplant. The present findings contribute novel insights into the sustainable cultivation of eggplant in an oasis arid environment.

Management Soil Zones, Irrigation, and Fertigation Effects on Yield and Oil Content of Coriandrum sativum L. Using Precision Agriculture with Fuzzy k-Means Clustering

Precision agriculture (PA), management zone (MZ) strategies at the field level, soil analyses, deficit irrigation (DI), and fertilizer Variable Rate Application (VRA) are management strategies that help farmers improve crop production, fertilizer use efficiency, and irrigation water use efficiency (IWUE). In order to further investigate these management strategies, the effects of four soil MZ treatments, which were delineated using PA with fuzzy k-means clustering, two irrigation levels [IR1:FI = full drip irrigation (&gt;90% of θfc), IR2:VDI = variable deficit drip irrigation (60–75% of θfc)], and four VRA fertilizations were studied on coriander yield and essential oil content in a two-year research project in Greece. A daily soil-water-crop-atmosphere (SWCA) balance model and a daily depletion model were developed using sensor measurements (climatic parameter sensors as well as soil moisture sensors). Unbalanced one-way ANOVA (p = 0.05) statistical analysis results revealed that correct delineation of MZs by PA with fuzzy k-means clustering, if applied under deficit irrigation and VRA fertilization, leads to increased essential oil content of coriander with statistically significant differences (SSD) and lower fruit yields; however, without SSD differences among management zones, when appropriate VRA fertilization is applied to leverage soil nutrient levels through the different fuzzy clustered MZs for farming sustainability. Moreover, VDI compared to full irrigation in different MZs yields 22.85% to 29.44% in water savings, thus raising IWUE (up to 64.112 kg m−3), nitrogen efficiency (up to 5.623), and N-P-K fertilizer productivity (up to 5.329).

Exploring deficit irrigation as a water conservation strategy: Insights from field experiments and model simulation

Deficit irrigation has emerged as a viable approach to increase agricultural water productivity. The objectives of this study were to 1) develop water conservation strategies by investigating responses of green bean (Phaseolus vulgaris) and sweet corn (Zea mays var. saccharata) to four irrigation treatments and 2) evaluate the performance of the Decision Support System for Agrotechnology Transfer (DSSAT) model in simulating growth and yield responses of green bean and sweet corn under four irrigation treatments. A field experiment was conducted using 32 experimental plots, established under a linear move sprinkler irrigation system equipped with variable rate irrigation (VRI) technology, at the Tropical Research and Education Center (TREC), Homestead for two cropping seasons between November and March in 2020–2021 and 2021–2022. The experiment involved four irrigation treatments: full irrigation (FI) (T4), and three levels of deficit irrigation, 75% FI (T3), 50% FI (T2), and 25% FI (T1) with four replications arranged in a completely randomized block design (RCBD) for each crop. The average soil moisture content of the full irrigation treatments was maintained above the management allowable depletion (MAD). Field data collection included various parameters of the crops including plant phenology, plant height, canopy width, fresh and dry biomass, and yield. Results confirmed that all three deficit irrigation treatments did not significantly affect the yield and yield components of the two crops during both seasons compared to the T4. This finding revealed that the highest crop water productivity was achieved from T1, 38.3 and 41.4 kg m−3 for green bean and 54 and 53 kg m−3 for sweet corn during the 2020–2021 and 2021–2022 seasons and up to 75% irrigation water saving could be achieved without affecting plant growth and yield. The DSSAT model performed well in simulating yield and yield components for the two crops in response to the four irrigation treatments. Model evaluation results showed that the minimum mean absolute error (MAE) for green bean fresh pod yield simulation was 2.1 Mg ha−1 with an index of agreement (d-Stat) of 0.6, while for biomass, it was 0.24 Mg ha−1 with a d-Stat of 1. Similarly, for sweet corn, the model simulated fresh cob yield with a minimum MAE of 6.51 Mg ha−1 and d-Stat of 0.9 and biomass with MAE of 1.63 Mg ha−1 and d-Stat of 0.9. Overall, implementing deficit irrigation in green bean and sweet corn fields could result in considerable water savings while achieving acceptable crop yield. The DSSAT model could be also a useful tool to simulate green bean and sweet corn responses to different irrigation scenarios and aid water management decisions under South Florida conditions.

Chicory production under different hydroponic systems using magnetized water at different irrigation rates

Chicory production under different hydroponic systems using magnetized water at different irrigation rates

Information and Theoretical Foundations for Control of the State of Agrocenoses in Real Time

Objective: Presentation of a complete theory of management of the state of agrocenoses, including sowing crops and weeds. This theory makes it possible to obtain a given crop yield with the required reliability. Such management is formed on the basis of estimates of the parameters of the state of crops, soil environment and weeds, formed according to the data of Earth remote sensing in real time. Methods: The presented theory is based on new mathematical models of the parameters of the state of agricultural crops, soil environment, weeds, as well as models of the relationship of these parameters with remote sensing (RS) data. Control factors in agricultural technology are doses of mineral fertilizers, herbicides and irrigation rates. Therefore, the parameters of the state in the management system under consideration, in addition to the parameters of the biomass of agricultural crops and weeds, are the chemical parameters of the soil environment. All technological operations are carried out at the onset of certain phenological phases of the development of crop sowing. RS data are entered precisely at such moments of time when the parameters of the state of crops and weeds are estimated on their basis. The presented theory is based on classical control principles used in modern dynamic systems. The most important feature of the proposed approach to solving the problem of agrocenoses management is the development of the principle of spatial distribution of agricultural technology parameters. It consists in using models with spatial variables, which are complemented by models of spatial approximation of controls in the form of multidimensional power polynomials. The parameters of the approximation models are evaluated according to the optimal parameters of technological operations obtained on 15-20 test sites of the field. Results: In accordance with the proposed theory, mathematical models of agrocenoses, a real-time control algorithm using RS data and a specialized software package were developed, with the help of which the control system was tested on the example of spring wheat sowing. Conclusion: As a result of testing a specialized software package for the implementation of the proposed theory, the operability of the proposed theory of agrocenoses control in real time and the possibility of using it in practical systems for automated control of agricultural technologies were established.

Modeling of soil moisture and water fluxes in a maize field for the optimization of irrigation

Precision irrigation is becoming more and more important in agricultural crop production due to the limited water resources resulting from the negative effects of climate change. Modeling of irrigation can support decision makers in the maintenance of the quantitative and qualitative parameters of the cultivated crops, while improving the efficiency of water consumption. In the present paper, a 3D hydrodynamic model was created in the HYDRUS environment to support the modeling of the temporal changes and spatial variations in the water balance (WB) of a maize cultivated Hungarian study site, thereby providing inputs for irrigation scheduling and variable rate irrigation for stakeholders. Beside soil physical parameters, crop evapotranspiration (ETc) values were also considered as model inputs for the phenological crop development stages of the maize from the sowing to the harvesting. This period was between the 3rd of May and the 10th of September in 2020 and the 20th of May and 14th of September for the year 2021. The performance of the model for soil moisture conditions were validated by on-field soil moisture measurements. The overall performance (full vegetation period) of the model was good (r2 = 0.88 for 2020 and r2 = 0.91 for 2021), but slightly varied among different phenological stages. Based on the model, the water balance of the investigated area was determined without any irrigation, alongside the cumulative water fluxes (CWF) through the boundaries including the root water uptake (RWU) of the maize as well. The results revealed that the incoming precipitation was not sufficient to supplement the water content in the soil to the optimal soil moisture range, except when the precipitation level is high enough to balance it. It was concluded that the water balance was negative for the investigated time periods without any irrigation. The specific water deficit (WD) values were calculated considering the area of the study site, which is 1439 m3/ha for 2020 and 2068 m3/ha for 2021. From the obtained results, optimal irrigation schedules were presented to keep the soil moisture content in the optimal range (20.92–14.41 V/V%) in the modeled area for two different vegetation periods. It was found that due to the irrigation the crop water productivity (CWP) increased by 6% and 4% in 2020 and 2021. Overall, the model is able to cope with changing circumstances that could help to mitigate the negative effects of climate change with the reasonable use of limited water resources in the future.

Influence of Hydrothermal Parameters on Potato Irrigation Regime

Background: The article presents the results of studies that allow us to calculate and predict the water consumption of cultivated vegetable crops depending on the moisture availability of the growing season. Hydrothermal indicators of the territory during the entire growing season have a significant impact on the irrigation regime and water consumption of cultivated crops. Methods: In the present study, the assessment of natural moisture during the growing season was determined by the hydrothermal coefficient (GTC) according to the criterion of T.G. Selyaninov. The irrigation rate was calculated according to the modified formula of A.N. Kostyakov. Biological productivity was taken into account by the method of meter sites in three-fold repetition. Result: The value of the irrigation norm varies depending on the intensity of atmospheric droughts when growing potatoes in the conditions of the dry-steppe zone of the Lower Volga region. To maintain a given pre-irrigation threshold of soil moisture, it is necessary to take into account the hydrothermal indicators of the territory during the entire growing season. The use of modern resource-saving irrigation methods, such as drip irrigation, makes it possible to ensure an uninterrupted supply of moisture to plants and, as a result, to obtain high-quality crop yields. Thus, in order to obtain high and stable yields of potatoes grown on drip irrigation, depending on the heat and moisture availability of the growing season, it took from 2,250 to 3,040 m3/ha of irrigation water.

EFFECTS OF DEFICIT IRRIGATION ON BARLEY YIELD USING SEVERAL IRRIGATION SCENARIOS

Deficient irrigation is a very significant study, especially with the limited water. Therefore, the current research aims to study the deficit irrigation depending on several different scenarios, by adding different amounts of water and irrigation rates (10%, 30%, 50%, 70%, 90%) of the full irrigation with changing irrigation time and studying its effect on productivity. The results showed that there is a clear effect on the productivity of barley at the level of irrigation (10%-30%) of the full irrigation and for all irrigation dates when changing the date of the first irrigation only, while the results showed when changing the second irrigation only and the first and second irrigation at the level of irrigation (10% - 30% -50%) of the full irrigation, the productivity will decrease by 13.75 - 84.7 kg/ha. It was also noticed that changing the irrigation level for the first irrigation has a very small effect on productivity compared to changing the irrigation level for the second irrigation and for all irrigation dates, and the reason for this is the difference in the stages of yield growth. While the results showed that changing the irrigation level for the first and second irrigation together will have a greater effect on productivity than the rest of the other scenarios.

A planning strategy for sprinkler-based variable rate irrigation

Automated variable rate irrigation (VRI) is one of the frontiers for sustainable water use in agriculture. In this paper, we describe a planning procedure for self-propelled rain gun sprinklers, a type of equipment largely used in irrigation of open field crops thanks to its relatively low cost and easy deployment in multiple sites. The sprinkler is commanded by an information system which acquires data from remote sensors (satellite), processes vegetation indices and spatial maps describing the water need of the crop, and computes a VRI prescription map for a specific field, i.e. the water quantity to be supplied to each field sub-area. The VRI prescription map is used to compute the motion commands for a rain gun system pulled by a hose reel. The procedure is based on a sprinkler model, has been validated by simulation, and is fully automated. Experiments have shown the precision in water distribution achievable with software-controlled sprinklers and effective planning strategies.