Journal of Irrigation and Drainage Engineering

Abstract

Irrigation is important for the growth of world agriculture, as it enables greater security in agricultural production. The use of center-pivot for irrigation is very common in Brazil. However, there are some information gaps, mainly related to spatial variability in the water application in variable topography. Thus, the present study aimed to apply the geostatistical approach to characterize and evaluate the magnitude of the pressure head (PH) spatial variability in center-pivot lateral lines operating in plots with variable topography. For this analysis, six different points were installed along the lateral line and measured with PH transducers in 18 lateral line angular positions in the study area. Universal kriging (UK) was used to estimate PH across the whole field. The semivariogram was adjusted by the hole effect theoretical model, indicating a strong spatial dependence on PH. A decision support system tool was developed to assist in the analysis of the PH spatial distribution along the center-pivot lateral line using a geostatistical approach (kriging). The proposed tool can be useful for managers of irrigable areas and to identify zones with high energy use (wasted PH) along lateral lines of center-pivot systems. The estimation of PH distribution using geostatistical and UK techniques was satisfactory, allowing the creation of a thematic map. Precision irrigation and monitoring using a thematic map of PH distribution from kriging can help monitor the operating conditions of a center-pivot, as well as improve the decision-making regarding proper management of the whole irrigation system.

Practical Applications

Center-pivot irrigation systems are very common in agricultural production areas around the world. Due to the large area irrigated by center-pivots, it is very important to study the reduction in water and energy use in these equipment. Thus, an important point to be studied is the PH distribution along the center-pivot lateral line in areas with undulating topography, where there is a significant PH variation. In this study, we present an analysis of the PH distribution along the lateral line using a geostatistical approach (kriging) to obtain PH values in the entire irrigated area. For this, PH data collected at six different points along the lateral line were used in a decision support system tool, developed to estimate PH in the entire irrigated area using the geostatistical approach. This estimate was satisfactory, allowing the creation of a thematic map. The proposed tool proved to be useful for easily identifying zones with high energy use (wasted PH). In this way, the use of precision irrigation and the analysis of the equipment through thematic mapping can help irrigators in monitoring the operating conditions of a center-pivot.

Emitters are widely used in drip irrigation technology. The clogging problem caused by emitters shortens the service life and affects the popularization of drip irrigation technology. Using fluctuating water pressure irrigation and flushing drip line can prevent the emitter from clogging. In order to explore the clogging characteristics and the mechanism of water and sediment movement of emitters under fluctuated pressure flushing, the authors selected the patch-type pressure compensation emitter as the research object and chose two flushing water modes (fluctuated pressure, constant pressure) and three flushing frequencies (4, 8, and 12 days) for anticlogging performance testing in this paper. The change of clogging characteristics ($D_{ra}$, $C_u$) under different flushing treatments was studied, and the content of silted sediment in the drip line was also analyzed. The gradation comparison and particle size analysis of the discharged sediment and clogged sediment from the emitter were carried out by using the laser particle size analyzer. The results show that (1) using fluctuated water pressure under high-frequency flushing treatment can significantly improve the service life of emitters. Under the coupling effect of the two, the service life of the emitter increases by 105.96%. (2) Different flushing treatments significantly impact the specific surface area blockage content ($p<0.05$), with M2 decreasing by a maximum of 55.54%. (3) Fluctuated water pressure flushing treatment acts on the sediment in the stagnant area of the flow channel, enabling it to return to the mainstream zone quickly and discharge from the body. Moreover, it promotes the discharge of sand particles and sensitive sediment (30–38 μm, 75–100 μm) and significantly reduces blocked sediment’s upper limit particle size. The research results provide an experimental basis for fluctuated pressure flushing treatment of emitters.

To explore the characterization of the transport and deposition of sludge particles in the mesh filter of water-saving irrigation systems, taking the inlet flow, particle concentration, and calculation time as experimental factors, a filtration test was carried out by computational fluid dynamics-discrete element method model (CFD-DEM) coupling and physical testing. Through the test results, deposition distribution, average particle size, and geometric standard deviation of the filter cake are analyzed. The cake pressure drop model of the filter cake’s average particle size and the filter cake’s geometric standard deviation are established. The results showed that the deposition of filter particles is triangular during the filtration process, and the axial deposition particles of the filter screen gradually increase. The proportion of small particles (smaller than 0.6 mm) in the cake layer formed by particles is the largest, greater than 70%; the main deposition area of particles is the lower filter screen (90%), and the particles deposited on the upper filter screen are all small particles. The increase in flow significantly affects the distribution of different sediment particles in the inlet and middle sections of the filter cake layer; the average particle size and geometric standard deviation of the filter cake increase with the increase of flow. An analysis of pressure drop was also conducted. The pressure drop of the filter cake decreases with the increase in geometric standard deviation and average particle size. Compared with the test pressure drop, the calculated pressure drop is consistent. The obtained results have important theoretical and practical significance for establishing a screen filter screen and cake pressure drop model, as well as optimizing filter media filtration efficiency and cleaning efficiency, and the relative error does not exceed 10%.

A series of laboratory experiments were carried out to study the hydrodynamics of flow through and over permeable grade-control structures with different dimensions and degrees of permeability. The local erosion downstream of the grade-control structures was measured at different flow regimes, and the effects of geometry and permeability of the grade-control structures were evaluated. Three flow regimes were observed in free-flow conditions, named as the through-flow regime, combined fully through-flow and overflow regime, and the transition between the two regimes. Semiempirical equations were proposed based on the theory of orifices and weirs to estimate the stage-discharge relationships over and through the permeable grade-control structures. The maximum scour depth at the downstream was predicted by implementing dimensional analysis and multivariable regression technique for both partial through flow (i.e., transition regime) and the combination through-flow and overflow regime. A series of numerical simulations was also performed to model the hydraulics of flow through and over grade-control structures. The numerical model was validated with the experimental results, and detailed information such as instantaneous and time-averaged velocity profile, bed shear stress, and turbulent kinetic energy were extracted from the validated numerical model. The numerical results clearly showed that the effect of crest length on jet deflection and formation vortex region at the downstream of structure was significant. The numerical outcomes indicated the existence of three zones in the surface jet above the grade-control structure, named the entrance zone, the upper roller zone, and the upper–lower rollers interaction zone. Numerical results confirmed a direct correlation between the structure’s length and the geometry of local scour hole and indicated that by increasing the crest length by three times, the maximum scour depth decreased by approximately 25%.

A four-year research experiment was conducted on sandy loam soil at the University of California Kearney Agricultural Research and Extension Center in Parlier, California, to investigate the effect of midsummer deficit irrigation on alfalfa yield, irrigation water productivity (IWP), and crop water productivity (CWP). The experiment was a randomized block design with two treatments: full and deficit irrigations with three replications. Applied irrigation water was measured using flow meters and soil matric potentials were monitored using watermark soil moisture sensors. Actual evapotranspiration ($E{T}_a$) values were estimated from Tule Technologies stations. The deficit irrigation treatments resulted in 454, 706, 625, and 815 mm of irrigation water savings as compared to the full irrigation treatments in 2019, 2020, 2021, and 2022, respectively. These values represent 30.3%, 40.9%, 37.0%, and 49.1% of the applied water savings. Alfalfa yield in the deficit treatments was reduced by 3.94, 2.04, 1.25, and $0.40\mathrm{Mg}{\mathrm{ha}}^{-1}$; the equivalent of 18.1%, 11.1%, 7.1%, and 3.0% of the yield for the full irrigation treatment for the four years: with an average reduction of 10.7%. IWP was higher when deficit irrigation was implemented and resulted in 17.09, 16.11, 15.40, and $15.54\mathrm{kg}{\mathrm{ha}}^{-1}{\mathrm{mm}}^{-1}$, in 2019, 2020, 2021, and 2022, respectively. The production function using applied irrigation water (IW, mm) was: $\mathrm{Y}(\mathrm{yield}\mathrm{in}\mathrm{Mg}{\mathrm{ha}}^{-1})=0.50\times {(\mathrm{IW})}^2-\mathrm{1,633.75}\times (\mathrm{IW})+\mathrm{1,338,472}$ and $\mathrm{Y}=-0.1137\times {(\mathrm{IW})}^2+233.55\times (\mathrm{IW})-\mathrm{103,036}$ for the full and deficit irrigation treatments, respectively. CWP was 18.6, 16.4, 14.9, and $12.3\mathrm{kg}{\mathrm{ha}}^{-1}{\mathrm{mm}}^{-1}$ for fully irrigated treatments, and 15.2, 14.9, 14.3, and $12.6\mathrm{kg}{\mathrm{ha}}^{-1}{\mathrm{mm}}^{-1}$ for the deficit irrigation treatments, for 2019, 2020, 2021, and 2022, respectively. Results from this work provide growers with viable deficit irrigation practices that could be implemented during drought periods.

Automatic check structures can be important for water distribution in irrigation networks. In this research, a control algorithm was developed for a variable height whirling (VHW) weir, as a regulating structure equipped with a control mechanism. A local feedback controller was established for adjusting the flow depth upstream of the weir within a marginal target range. The control performance of the VHW weir was investigated using two methods: (1) K nearest neighbor (KNN); and (2) artificial neural network (ANN). The required data for methods were compiled in a long trapezoidal canal using different water depth targets. The inputs consisted of the discharge at the canal entrance, the variation of the discharge in three sequential periods, the water level deviation from the target value, and the offtake discharge. The model output was the set point of the instantaneous weir angle value, which represents the crest weir height, for maintaining the water depth within the target range. Different statistical indicators were employed to investigate the control performance. The results indicated that the ANN models, which were applied to cases with and without offtake in operation, provided 0.95 and 0.93 correlation coefficients, respectively. Also, the proposed neural model performed slightly better than the KNN algorithm, which yielded marginally higher error in output predictions.

Abstract

Irrigation water with high sodicity risk can lead to soil dispersion, poor drainage, and groundwater contamination. The sodium adsorption ratio ($SAR$) of soil water is influenced by water loss through evaporation. Evaporation concentrates sodium (Na) and magnesium (Mg), and its impact on soluble calcium (Ca) and alkalinity is more intricate. This study presented a refined sodicity hazard assessment that quantifies the influence of evaporative water loss and calcite precipitation on drainage water. Specifically, the initial equivalent concentration of alkalinity and Ca predominantly determines the potential sodicity risk of drainage water. The alternative approach projects two pathways for potential drainage water $SAR$, which include limiting the sodium adsorption ratio ($LSAR$) to represent the upper limit boundary and evaporated-based sodium adsorption ratio ($ESAR$) to represent the lower limit boundary. When irrigation water alkalinity exceeds the soluble Ca concentration, soluble Ca in the drainage water is limited as calcite precipitates and the drainage water is dominated by Na and Mg. The $SAR$ approaches an upper limit ($LSAR$) determined by the initial relative concentration of Na and Mg. Conversely, if irrigation water alkalinity is less than the soluble Ca concentration, minimal calcite precipitation occurs, and drainage water is dominated by Na, Mg, and Ca. Then, the $SAR$ approaches a lower limit ($ESAR$) determined by the initial Ca, Mg, and Na concentrations. To validate the accuracy of this new sodicity risk assessment method, this paper analyzed data extracted from previously published lysimeter studies. Water composition boundaries for each source water were plotted, and these boundaries were compared to the recorded drainage water composition in the lysimeter studies. As salinity increased through evaporation, the drainage water followed a distinct salinization path but remained within the $LSAR$ and $ESAR$ boundaries. This information is essential for irrigation managers to quickly assess water sodicity levels and make timely management decisions.

Practical Applications

The application of irrigation water with high sodicity risk can lead to soil dispersion. Therefore, an accurate and straightforward approach to assess the sodicity level of the source water is crucial for irrigation management. The practical implementation of the proposed approach for evaluating the sodium (Na) hazard of an irrigation water source begins with source water analysis, considering soluble Na, calcium (Ca), magnesium (Mg), alkalinity, and electrical conductivity ($EC$). The irrigation water source is then categorized based on its Ca to alkalinity ratio: an alkalinity-rich water source is where the ratio of ${\text{Alk}}_{dw}^{-}/{\mathrm{Ca}}_{dw}^{2+}\ge 1$, and an alkalinity-poor water source is where ${\mathrm{Alk}}_{dw}^{-}/{\mathrm{Ca}}_{dw}^{2+}<1$. As soil water salinity or $EC$ increases through evaporation, the alkalinity-rich water is likely to approach the upper boundary, which is the limiting sodium adsorption ratio $(LSAR)=\sqrt{F_c}·{\mathrm{Na}}^{+}/\sqrt{{\mathrm{Mg}}^{2+}/2}$, and $F_c=E{C}_{dw}/E{C}_{iw}=1/LF$, where $E{C}_{dw}$ represents the $EC$ of irrigation water, $E{C}_{iw}$ represents the $EC$ of drainage water, and the leaching fraction ($LF$) represents the leaching fraction. On the other hand, alkalinity-poor water is likely to remain close to the lower boundary, which is the evaporation-adjusted sodium adsorption ratio $(ESAR)=\sqrt{F_c}\times {\mathrm{Na}}^{+}/\sqrt{({\mathrm{Mg}}^{2+}+{\mathrm{Ca}}^{2+})/2}$. This information can help managers determine the suitability of a water source or make sodicity management decisions if poor quality irrigation water is used.

Abstract

Water scarcity is a global issue that presents significant challenges to sustainable development. Recent Food and Agriculture Organization (FAO) evaluations revealed a concerning trend: more than half of agricultural water is wasted. The widespread use of manual irrigation systems, combined with diminishing water resources, necessitates efficient and effective irrigation methods. This study aims to address this issue by introducing a novel irrigation control system based on an Arduino mechanism. The goal of this research is to design and test an efficient and sustainable irrigation system that maximizes water usage, minimizes waste, and reduces electricity consumption. The study used an Arduino-controlled irrigation system equipped with soil moisture sensors. These sensors were strategically placed to monitor soil moisture levels and trigger irrigation when necessary. The system’s performance was evaluated using a series of experimental trials on small and medium-sized farm plots. The system required approximately 20% less water than traditional manual irrigation methods. Furthermore, there was a significant reduction in electricity consumption for water pumps, with an average 20% savings per year. The ease of integration into existing farm setups and the reduction in manual labor are also significant benefits. This system assists to conserve vital water resources and promotes sustainable agricultural development by optimizing water use and reducing electricity consumption.

Practical Applications

This study demonstrates a low-cost automated irrigation system for small and medium-sized farms that uses an Arduino control system. The system uses soil moisture sensors to ensure that plants receive optimal water exactly when they need it, thereby improving water efficiency and plant health. The use of a control system provides flexible programming options, making it simple to expand and integrate new control features. The system’s adaptability enables the simple integration of automation into existing farm setups, and the number of soil moisture sensors can be increased to cover larger farm areas. This intelligent irrigation solution not only conserves water resources but also reduces the amount of electricity required to power water pumps, resulting in lower operating costs and maintenance needs. Therefore, implementing the proposed automated control system can significantly reduce water usage, maintenance efforts, and electricity consumption, providing farmers with a long-term and efficient irrigation solution.

Abstract

A vertical tube surface drip irrigation system was designed to address the damage caused by soil drought and high surface temperature to sand-fixing seedlings in a plant sand-fixation area. Numerical simulation and experimental verification were used to study soil water movement with vertical tube infiltration and surface drip irrigation for four aeolian sandy soils with different hydraulic conductivity ($K_s$), drip discharge ($Q$), vertical tube diameter ($D$), and vertical tube buried depth ($B$). The results show that a power function relationship exists between the soil-stable infiltration rate ($i_f$) and $K_s$, $D$, and $B$ given the condition of vertical tube water accumulated infiltration, and its coefficient is 0.17. The power function indices of $K_s$, $D$, and $B$ are 0.87, 1.89, and $-0.37$, respectively. The $i_f$ can be used to determine the maximum drip discharge ($Q_{\max }$) of the dripper in the vertical tube to ensure that the sand-fixing plants are not submerged during drip irrigation through the vertical tube ($Q_{\max }=i_f$). The wetting front transport distance in the three directions increased with increasing $K_s$ and $Q$ but decreased with increasing $D$ and $B$. After determining the time required for water to reach the bottom of the vertical tube, an estimation model of soil wetting body transport for vertical tube surface drip irrigation, including $K_s$, $Q$, $D$, and $B$, was constructed. Compared with the experimental data, the root mean square error (RMSE) is between 0.17 and 0.42 cm, and the Nash–Sutcliffe efficiency (NSE) is at least 0.88. Therefore, the model is appropriate and can provide valuable practical tools for the design of vertical tube surface drip irrigation in different plant sand fixation areas.

Practical Applications

A surface drip irrigation system and pipe protection technology were combined to form a vertical tube surface drip irrigation system to address the damage caused by soil drought and high surface temperature to sand-fixing seedlings. However, this irrigation technology has the problem that it is difficult to quantify the matching of drip discharge and pipe parameters (vertical tube diameter and burial depth), wetted soil volume, and plant roots due to the single soil sample used in the laboratory experiments. This paper considers the influence of soil differences in diverse plant sand-fixing areas and establishes a stable infiltration rate model to determine the maximum drip discharge. Additionally, a soil wetted volume prediction model was developed by combining HYDRUS-2D simulations and experimental verification. The model is simple and has high prediction accuracy, which is convenient for designers to determine the appropriate vertical tube parameters for different plant sand-fixation areas.

In this paper, the feasibility of managed aquifer recharge (MAR) for southwestern Kansas was investigated. Multiple sources of water for MAR were investigated, including rainfall-runoff from fields, use of low-flow or ephemeral rivers and streams, and use of a large regional river. Use of the Arkansas River was found to be the most viable source of water. Construction of infiltration basins in existing sand mines was found to be the best MAR alternative in this region. The requirement for the reclamation of sand mines set out by the State of Kansas fits the requirements of infiltration basins, and there exists a local ditch system that can convey Arkansas River flows to the basins with little need of new construction. The salinity of the Arkansas River is of concern. The negative impact of this could be reduced by selecting salt-tolerant crops. This investigation is relevant throughout the State of Kansas, leading to the possibility that another region would have more suitable conditions.

Abstract

Real water saving is a important concept in water resources management, which can express previous failures in reducing agricultural water consumption, despite increasing irrigation efficiency. In the present research, while calculating the water requirement for the cultivation of the cropping pattern document in Khuzestan province of Iran and harvesting the intended yield, the crop substitution and changing the planting date method (in four scenarios) has been considered as a sustainable solution to reduce the actual agricultural water consumption. Scenarios 1 to 4, respectively, included replacing part of the cultivated area of sugarcane, fodder corn, and rice with sugar beet, fodder sorghum, and sesame, in 3 consecutive years, and changing the planting date of watermelon and tomato from summer to winter in 1 year. For this purpose, the actual evapotranspiration was determined using FAO-56 Penman–Monteith equations and the expected crop yield at the county scale. Then, using the history of cultivation of different crops in each county and the subwatershed map of the Khuzestan province, the actual evapotranspiration, net irrigation requirement, and water withdrawal from rivers in each subwatershed of Khuzestan province were determined. Results showed that implementation of scenarios 1, 2, 3, and 4 can reduce 551, 25, 194, and $79{\mathrm{hm}}^3$ of actual water consumption and decreases 2,160, 104, 775, and $303{\mathrm{hm}}^3$ of water withdrawal, respectively. If all the scenarios are implemented together, it can be expected that the reduction in actual agricultural water consumption and its water withdrawal will be equivalent to 5% and 20% of the rivers discharge in Khuzestan province, with a probability of 80%. By considering the real water saving, economic, and social criteria, it can be concluded that replacing sugarcane with sugar beet is the first priority of implementation, whereas changing rice with sesame is the last priority of implementation.

Practical Applications

Water reduction consumption is one the most challenging issues in agricultural water management. We know that agriculture consumes mostly fresh water to produce all kinds of agricultural products. The water is converted from liquid to vapor and removed from the target catchment area by atmospheric currents. Therefore, one of the most useful ways to reduce actual water consumption in agriculture is to improve the cropping pattern. Modifying the cropping pattern can challenge the indigenous knowledge of farmers and affect their habits as well as reduce the income of local communities in some cases. Therefore, it is important to pay attention to the profit of the replaced crop and the level of familiarity of the farmer with how to cultivate it in determining the cropping pattern. This research examines the modification of the cropping pattern in Khuzestan province of Iran, which includes replacement of sugarcane, fodder corn, and rice with sugar beet, sorghum, and sesame, respectively, to reduce agricultural water consumption. For this purpose, the reduction of water consumption, reduction of farmer’s income, and social tendencies have been seen in the defined scenarios.

Horton’s infiltration capacity is often used to separate rainfall excess from a rainfall hyetograph in watershed modeling. Nevertheless, this infiltration capacity is an implicit function of cumulative infiltration in soil, which is inconvenient in practical applications. This study found an explicit expression of infiltration capacity that is the sum of a steady-state term and a transitional term. The steady-state term is the critical infiltration rate or minimum infiltration capacity, and the transitional term is represented by a Lambert W function that tends to zero as time (or cumulative infiltration in soil) tends to infinity. The proposed method can be easily used, together with a unit hydrograph model, for direct runoff in watershed modeling.