Emitter Discharge Research Articles

Improvement of an ionic wind blower’s flow characteristic by auxiliary electrodes for thermal management of light-emitting diodes

Electronic device advancements in power, size reduction, and integration have resulted in increased heat flux and operating temperatures, negatively impacting the reliability of electronics. Ionic wind cooling is a new, environmentally friendly, and energy-efficient thermal management approach that effectively cools high heat flux local heat sources. However, enhancing ionic wind strength continuously can be challenging. In this study, an ionic wind blower consisting of an emitting electrode, a collecting electrode, and auxiliary electrodes is constructed. The experimental verification confirms the supplemental acceleration capacity of the auxiliary electrodes. When determining the optimal operating voltage applied to the auxiliary electrodes, the power consumption of the system and the intensity of the output ionic wind are taken into consideration. Theblower’s operational and structural factors, such as the emitter structure, discharge gap, and distance between the auxiliary electrodes and collectors, are optimized according to how they affect the device’s functional qualities. The improved blower’s heat dissipation ability is evaluated by cooling an LED chip. The results demonstrate that the system performs optimally with an emitter having seven needles, a discharge gap of 5 mm, and 9 mm between the auxiliary electrodes and the collector. The wind speed reaches 2.47 m/s, while the power consumption is only 1.6 W. Compared to the absence of auxiliary electrodes (47.7 W/(m2∙K)), the system’s mean convective heat transfer coefficient can reach 61.12 W/(m2∙K), resulting in a temperature reduction of the LED chip by up to 41.6 °C. With increasing voltage, the heat transfer enhancement ratio improves, enabling a blower with auxiliary electrodes to provide significant cooling while consuming less power.

Assessing Design of Drip Emitters by Evaluating Hydraulic and Manufacturing Performance of Online Drip Emitters

The efficiency of drip irrigation is closely influenced by the accuracy of its design, particularly the hydraulic and manufacturing performance of the emitters. This study investigates the hydraulic performance and flow variation of 8 litres per hour (lph) drip emitters. Discharge rates for 100 emitters were measured at a pressure of 1 kg/cm² to determine the manufacturer's coefficient of variation and the flow variation due to hydraulic factors. The relationship between pressure and discharge was modelled using power function regression, demonstrating a strong correlation between predicted and observed emitter discharge rates, with a root mean square error (RMSE) of 0.56 lph. A design chart was derived from this model, illustrating the relationship between input pressure at the head end and output pressure at the tail end of the system. The manufacturing coefficient of variation for the 100 emitters was found to be 0.0521, classifying the emitters as "good" according to manufacturing standards. The study provides important understandings for designers aiming to create efficient drip irrigation systems and effective water management strategies. By addressing both hydraulic and manufacturing variations, the study confirms that it is possible to achieve more uniform water distribution, enhance crop yield, and optimize resource utilization.

Evaluation of saline and magnetized water on emitter hydraulic performance and clogging in drip irrigation

The present investigation was carried out at the National Irrigation Laboratory of Agricultural Engineering Research Institute (AEnRI), Dokki, Giza, Egypt. This study was performed to investigate the hydraulic performance and clogging ratio of drip irrigation with magnetized water. Magnetized water was created by transferring water through a permanent magnet connected to a feed pipeline. Two main treatments of magnetized and non-magnetized water, as well as three sub-treatments of irrigation water salts, including fresh water (219 ppm) and the addition of 1000 and 2000 ppm to irrigation water with three replications were applied under different operating pressure (75, 100, 125 and 150 kPa). At the beginning of the experiment, results show that hydraulic parameters were almost the same for both the magnetized and the non-magnetized water and for all salinity levels. At the end of working time, the hydraulic parameters were improved for the magnetized water under salinity levels compared to the non-magnetized water. Average emitter discharge increased with roughly 2.7% and 5.6%, coefficient of variation (Cv) decreased by 0.6 and 0.91%, emission uniformity (Eu) increased about 1 and 1.1% and variation of average flow rate (qavr) decreased by 21.3 and 29.4% when 1000 and 2000 ppm were used, respectively. Magnetized water had slight effect on clogging at non-saline water at the end of experiment. At 1000 and 2000 ppm salinity levels, the clogging ratio decreased by 1.97 and 2.45% at different pressure, respectively. The results show that magnetized water treatment could effectively relieve and delay the occurrence time of clogging.

Spatial and Temporal Distribution of Soil Moisture in Maize Using Frequency Domain Reflectometry Sensor

Field experiment was conducted during kharif 2018, rabi 2018-19 and kharif 2019 at Department of Soil Water Engineering, Dr. NTR College of Agricultural Engineering, Bapatla, Andhra Pradesh to study the spatial and temporal distribution of soil moisture in maize using FDR sensor.The experiment was laid out in split plot design consisting of three irrigation levels (0.6 ETc (I1), 0.8 ETc (I2) and 1.0 ETc (I3)) and four nitrogen levels consisting of fertigation levels (80% RDN (N1), 100% RDN (N2), 120% RDN (N3) and Manual application (N4) on sandy clay loam soil. Water requirement of the maize crop was calculated on the daily basis by using CROPWAT 8.0. Frequency Domain Reflectometry (FDR) Sensor was used to measure soil moisture data by installing 34 access tubes up to a depth of 100 cm with an interval of 10 cm from the soil surface and measured soil water content during crop period. Soil moisture was evaluated for 2.0 lph emitter discharges at 3h after irrigation, 6h after irrigation, 24h after irrigation at emitter, 15 cm from emitter, 30 cm from emitter and 45 cm from emitter for soil moisture in the soil for arriving the best irrigation strategy. The soil water distribution under all drip irrigation treatments indicated that it was relatively high near the dripper and decreased as the distance from the dripper point increased.

Numerical simulation and structure optimization for hydraulic performance of perforated drip irrigation emitters

ABSTRACT The perforated drip irrigation emitter (PDIE) is a novel drip irrigation emitter incorporating multiple energy dissipation mechanisms, chiefly hedging, deflection, and friction. To characterize the influences of structural parameters and vortices on the hydraulic performance of PDIE, the discharge exponent, discharge rate, and emitter unit constant were analyzed via hydraulic performance experiments and numerical simulation. The key findings are: (1) Discharge exponents of PDIE ranged from 0.478 to 0.515; average high-pressure hydraulic performance exceeded low pressure by 4.882%. (2) The four key structural parameters impacted hydraulic performance from large to small as follows: the width of the perforation (a), the angle of the scalariform perforation plate (α), the distance of the two perforations (b), and the length of the channel cavity (c). Among them, the discharge exponent changes significantly with a and α. (3) Vortex-retaining PDIE exhibited a lower emitter discharge exponent versus vortex-removed versions. However, vortices increase discharge rate and reduce energy consumption of PDIE. After optimization, the emitter discharge exponent of the PDIE with the reserved vortex is 0.461, which is relatively improved by 3.556%. This study can provide a theoretical reference for the structural design of new drip irrigation emitters and functional analysis of vortices.

Performance Evaluation of a Drip Irrigation System inside the Automated Greenhouse in Huye Ecological Condition

This research, titled Performance Evaluation of a Drip Irrigation System inside the Automated Greenhouse in Huye ecological Condition, was carried out in the Research Center of Integrated Polytechnic Regional College (IPRC)-Huye Campus, which is located in the Ngoma Sector of Huye District of Rwanda, in 2023. The study has mentioned the specific objectives of determining the average emitter discharge of the irrigation system, evaluating Christiansen Coefficient Uniformity (CU), and evaluating the distribution uniformity (DU) of the system. The research design was a randomized complete block design with four replications. The experiment was conducted on 24 laterals and 288 drippers installed in the greenhouse. Each lateral had an equal distance of 36.5m and carried 94 total drippers. Data analysis of variance (ANOVA) and LSD for means were used as statistical tools in MINITAB software version 17. The confidence interval was 95%. The obtained results indicated an average discharge (q) of 3.98 L/h in the drip irrigation system, coefficient uniformity (CU) of 99.96%, and distribution uniformity (DU) of 57.72%. The research concludes that the performance of irrigation systems is excellent for water application. However, the way water is distributed in all systems is poor. In addition, the drip irrigation system may reach an adequate level of performance when it works in a shifty manner.

Исследование динамики влажности почвы при капельном поливе

Purpose: to study the dynamics of moisture in soils on the drainage layer during drip irrigation to save water resources and ensure uniform watering of crops using moisture contours. Materials and methods. The study is based on the theory of moisture transfer under the influence of drip irrigation on soil. Moisture contours were studied in laboratory conditions using a soil lysimeter, which was used to model the geological cross-section of the irrigated area, represented by alluvial meadow soils formed on pebbles. The pebble layer thickness was assumed to be up to 3 m. A regression analysis of moisture movement was carried out, and a mathematical model describing the nature of its movement on the drainage layer was obtained. The estimated volume of wet soil was defined on the basis of moisture contours as a result of calculating the volume of the formed lathe object using cartograms for each hour of irrigation. Results. Data on the moisture distribution in soil profile according to irrigation hours, presented on cartograms constructed using a personal computer, were obtained. The contours with the same humidity – isolines on which the humidity was displayed: 5; 10; 40 % are highlighted on the cartograms. It has been determined that water at an emitter discharge of 2.5 l/h reaches the drainage layer 4 hours after the beginning of irrigation. The graph for moisture distribution in soil volume by hour, reflecting the dynamics of water distribution supplied from an emitter with a constant discharge over 10 hours of irrigation has been constructed. Conclusion. The dynamics of moisture distribution during drip irrigation in soils located on a drainage bed was studied. Under experimental conditions, when crop irrigation lasts for more than 8 hours, an ineffective excess of irrigation rate and an increase in the design capacity of the drip irrigation system are observed.

Manipulation of Irrigation, Emitter Discharges, and Some Anti- Stress Substances in an Attempt to Elevate Le-Conte pear Trees Productivity

Manipulation of Irrigation, Emitter Discharges, and Some Anti- Stress Substances in an Attempt to Elevate Le-Conte pear Trees Productivity

Field Use of Drip Irrigation System and Its Impact on The Values Depended Evaluation Standards

A field study was conducted at the Agricultural Research Station, affiliated to the College of Agriculture, located in Al-Buetha area, Al-Ramadi District, - center of Anbar Province. During the autumn season in 2022, in a sandy clay loam soil. This study was conducted to investigate the effect of field use of drip irrigation system and its impact on the adopted evaluation criteria before and after planting. To determine the effect of the drip irrigation system duration of using on its field performance. Before planting, the irrigation system was evaluated in the field by conducting tests at three different operating pressures, namely 0.3,0.5 and 0.7 bar to determine the actual discharge of the emitters closed to their design discharge. The evaluation criteria in this study were emitters discharge rate, uniformity coefficient, emission uniformity, discharge variation ratios. The results indicated that the operating pressure of 0.5 bar was the best among the selected pressures, where gave the highest actual discharge of 7.87 L h-1 which closed to its design discharge i.e., 8 Lh-1. Additionally, the highest coefficient of uniformity was achieved, reaching 96.39%, along with the highest emission uniformity of 95.93%. The lowest variation in discharge between emitters was recorded at 9.58%. Consequently, this pressure (0.5 bar) was adopted for operating the drip irrigation system throughout the study period.

EFFECT OF CHEMICALS ON RECOVERY OF CLOGGED DRIP EMITTERS FOR MAXIMUM UTILIZATION OF TREATED EFFLUENT FOR IRRIGATION

The growth in agriculture production is possible with wastewater utilization using the advanced technology of Drip Irrigation System (DIS). Drip irrigation is negatively affected by emitter clogging which entails reduced emitter discharge and irrigation system efficiency. The role of acid and chlorine contact time in emitter recovery with treated effluent is crucial. A combination of phosphoric acid (30,20 and 10 minutes) and sodium hypochlorite contact times (30,25 and 20 minutes) was used to study the recovery of in-line labyrinth drippers clogged with Treated Effluent (TE). A 1.2 ml/L of phosphoric acid and 20 mg/l of sodium hypochlorite was injected singly using a venturi dosing system. Nine (9) laterals with clogged emitters were implemented for treatment and the recovery discharge rates were measured for 5 minutes and characterized. Physicochemical and biological water analyses were carried out to determine parameters triggering clogging and the effect on recovery. The results showed that the chemical treatments had a significant effect on clog removal and recovered the discharge rates by 99.89 % of the initial flow at acid and chlorine contact times of 30 minutes each. This also had a relatively major effect alleviating emitter clogging from a discharge ratio variation (Dra) value of 33.50% to 123.23%. The recovery Dra values in each contact time with the chemicals were deemed effective (Dra≥ 75%). This was an indication that clogging in this study was mainly due to the chemical precipitation of Fe, Ca2+ and pH of the wastewater. The acid dissolved the mineral precipitates and chlorine disintegrated the organic matter built-ups. ANOVA tests for the acid and the chlorine contact time indicated that there were no statistically significant differences at p<=0.05 on the effect of the average flow. This could be indicative of the sole effect of the phosphoric acid and sodium hypochlorite on the different clog type target. The chemical treatments recovery on CV, Uc and Dra could address the constraints in DIS and provide sustainable practice guidelines for the reduction of clogging, more beneficial because it can improve the system’s irrigation efficiency with the utilization of TE

Modeling of soil moisture movement and wetting behavior under point-source trickle irrigation

The design and selection of ideal emitter discharge rates can be aided by accurate information regarding the wetted soil pattern under surface drip irrigation. The current field investigation was conducted in an apple orchard in SKUAST- Kashmir, Jammu and Kashmir, a Union Territory of India, during 2017–2019. The objective of the experiment was to examine the movement of moisture over time and assess the extent of wetting in both horizontal and vertical directions under point source drip irrigation with discharge rates of 2, 4, and 8 L h−1. At 30, 60, and 120 min since the beginning of irrigation, a soil pit was dug across the length of the wetted area on the surface in order to measure the wetting pattern. For measuring the soil moisture movement and wetted soil width and depth, three replicas of soil samples were collected according to the treatment and the average value were considered. As a result, 54 different experiments were conducted, resulting in the digging of pits [3 emitter discharge rates × 3 application times × 3 replications × 2 (after application and 24 after application)]. This study utilized the Drip-Irriwater model to evaluate and validate the accuracy of predictions of wetting fronts and soil moisture dynamics in both orientations. Results showed that the modeled values were very close to the actual field values, with a mean absolute error of 0.018, a mean bias error of 0.0005, a mean absolute percentage error of 7.3, a root mean square error of 0.023, a Pearson coefficient of 0.951, a coefficient of correlation of 0.918, and a Nash–Sutcliffe model efficiency coefficient of 0.887. The wetted width just after irrigation was measured at 14.65, 16.65, and 20.62 cm; 16.20, 20.25, and 23.90 cm; and 20.00, 24.50, and 28.81 cm in 2, 4, and 8 L h−1, at 30, 60, and 120 min, respectively, while the wetted depth was observed 13.10, 16.20, and 20.44 cm; 15.10, 21.50, and 26.00 cm; 19.40, 25.00, and 31.00 cm, respectively. As the flow rate from the emitter increased, the amount of moisture dissemination grew (both immediately and 24 h after irrigation). The soil moisture contents were observed 0.4300, 0.3808, 0.2298, 0.1604, and 0.1600 cm3 cm−3 just after irrigation in 2 L h−1 while 0.4300, 0.3841, 0.2385, 0.1607, and 0.1600 cm3 cm−3 were in 4 L h−1 and 0.4300, 0.3852, 0.2417, 0.1608, and 0.1600 cm3 cm−3 were in 8 L h−1 at 5, 10, 15, 20, and 25 cm soil depth in 30 min of application time. Similar distinct increments were found in 60, and 120 min of irrigation. The findings suggest that this simple model, which only requires soil, irrigation, and simulation parameters, is a valuable and practical tool for irrigation design. It provides information on soil wetting patterns and soil moisture distribution under a single emitter, which is important for effectively planning and designing a drip irrigation system. Investigating soil wetting patterns and moisture redistribution in the soil profile under point source drip irrigation helps promote efficient planning and design of a drip irrigation system.

Performance Evaluation of Drip Irrigation System for Green Pepper (Capsicum annum, L.) Production in the Tamale Metropolis of Ghana

Performance evaluation is a diagnostic tool used to identify problem areas in an irrigation system and to indicate where improvements can be made in an existing irrigation system. Performance evaluation enables irrigation managers to redesign, improve upon the design and the irrigation strategies used. This study was carried out to assess the performance of a drip irrigation system installed and managed by Motor-King Company Limited in the Tamale Metropolis. The drip irrigation system consisted of two (2) reservoirs; 1500 litres and 1000 litres polytanks mounted at 1.2 m and 3.6 m high respectively. The drip irrigation system had a 32 mm main line and 16 mm lateral line with 2.7 l/h emitters spaced at 0.3 m. Three (3) laterals and nine (9) emitters were randomly selected in each plot. Emitter discharge was measured using catch cans. Five (5) performance indicators such as emitter flow variation, co-efficient of emitter flow variation, application efficiency, distribution uniformity and statistical uniformity were assessed. From the results, co-efficient of variation (7%) was rated good, emitter flow variation (18%) was rated acceptable, application efficiency was excellent (97.0%), low quarter distribution uniformity was good (87.2%), statistical uniformity was excellent (93.0%). These results imply that the drip irrigation performed satisfactorily and can still be used to produce vegetables with minimal losses.

Combining sub-surface fertigation with conservation agriculture in intensively irrigated rice under rice-wheat system can be an option for sustainably improving water and nitrogen use-efficiency

ContextThe rice-wheat cropping system in the Indo-Gangetic plains (IGP) of South Asia has been shown to have higher productivity. However, this benefit is offset by the unsustainable over-drafting of groundwater resources. Given the growing scarcity of water, it is imperative to investigate alternative crop establishment and irrigation methods that do not rely on the conventional puddled transplanting method (PTR). ObjectiveThis study aims to assess the impact of combining conservation agriculture-CA with sub-surface drip irrigation-SSD referred to as CA+, at different nitrogen (N) doses on physiological performance, crop yield, irrigation and nitrogen use-efficiency, as well as farm profitability of rice in the north-western IGP of India. MethodA two-year field experiment was conducted to assess the effects of medium-term CA and the combination of CA with SSD (CA+) at three levels of N (0%, 75%, and 100% of the recommended dose), in comparison to PTR using recommended dose of nitrogen-RDN (120 kg N ha-1). Indicators of crop growth (under CA, CA+), i.e., biomass, grain yield, water-use, water-use efficiency (WUE), nitrogen-use efficiency (NUE), and economic analysis of rice production were evaluated and compared with PTR. ResultThe results revealed that the PTR plots produced 15% and 11% higher grain yield than CA and CA+ systems, respectively, even at 100%RDN, due to a significantly higher number of fertile tillers. However, the application of 100%RDN and irrigation through SSD resulted in a significant increase in nitrogen uptake (4.5%) and remobilization (7.5%) into the grain compared to PTR. The CA+ plots demonstrated a reduction in irrigation water usage by 1.5 and 2 times compared to the CA and PTR systems, leading to a respective increase in WUE by 1.6% and 1.8%. PTR exhibited highest net returns, while the CA+ treatment– SSD-N100 achieved the highest benefit-cost ratio. ConclusionThe combination of CA with SSD at 100%RDN offers significant benefits, including notable water saving, improved WUE, NUE and crop yield. This integrated approach presents a promising solution to address the pressing issues of food security and sustainability arising from water scarcity and groundwater depletion in South Asia. Future implicationThere is a need to increase awareness among farmers about the benefits of CA coupled with SSD i.e., CA+ , for water-intensive rice-based systems. Additionally, further research should focus on identifying ideal rice cultivars suitable for CA+ systems and determining the optimal specifications for drip lines and emitter discharge rates for diverse water-scarce agro-ecological conditions.

Experimental study of the expansion of soil wetting fronts from a point source in heterogeneous sloping lands

This research intended to measure wetting front advancements (WFA) under various conditions using a physical model. Wetting front advance, along with its distribution in soils, is one of the important parameters in drip irrigation. It is influenced by many factors, including land slope, emitter discharge and soil texture. The effects of these factors were investigated by constructing a physical model with dimensions of 60 cm in width, 120 cm in height and 160 cm in length. The experiments were conducted using two heterogeneous soils, three land slopes (0, 10 and 20%), three emitter discharges (2, 4 and 8 L/h) and a constant volume of irrigation water (24 L). The results of the heterogeneous soils with three horizontal layers were also compared with those of three homogeneous soils (heavy, medium, and light textures). The results indicate that on sloping lands, the wetted area of the WFA downstream from the emitter was, on average, 20–62% greater than upstream from the emitter. With increases in land slope, the wetted depth under the emitter decreased by 3–18%. Also, when land slope changed from 0–10% and then again from 10–20%, the maximum radius of the wetting front increased, on average, by 32%, 44.8% and 77.5% for discharges of 2, 4 and 8 L/h, respectively.

Subsurface irrigation with ceramic emitters improves the yield of wolfberry in saline soils by maintaining a stable low-salt environment in root zone

The high salt concentration in soils depresses crop growth and saline soil reclamation. An appropriate irrigation method is essential to alleviate water shortage and promote wolfberry (Lycium barbarum L.) cultivation in saline soils. Subsurface irrigation with ceramic emitters (SICE) is a novel technique that maintains a stable soil water environment through adaptive outflow and holds a beneficial impact on saving water and increasing yield. However, the effect of SICE on salt leaching remains to be investigated. A field experiment was executed to investigate the salt leaching process in SICE and subsurface drip irrigation (SDI) in saline soils and their effect on wolfberry yield. HYDRUS-2D was calibrated and validated using experimental data to investigate the spatial-temporal variation of soil salinity. Subsequently, the salt leaching efficiency with different emitter discharges (0.10, 0.15, 0.24, and 0.33 L h−1) was assessed via HYDRUS-2D. Results indicated that SICE leached soil salt below the stress threshold after 50 days of irrigation, while SDI required 148 days. At the end of irrigation, SICE formed a low-salt zone that occupied 74.14% of the main root zone, while the zone with SDI was 60.69%. Generally, SICE provided a stable low-salt environment for wolfberry root system for 117.5 days (69.9% duration of growth period). SICE improved the wolfberry yield and root-zone soil desalination efficiency (DE) by 0.17 t ha−1 and 0.41% cm−1 than SDI, respectively. When emitter discharge increased to 0.24 L h−1, the root zone of wolfberry was protected from salt stress, but DE decreased gradually. SICE with an emitter discharge of 0.24 L h−1 was recommended for wolfberry in saline soils of Ningxia. The results reveal that SICE is an efficient salt leaching method for saline soil management and crop yield improvement.

Hydraulic Performance of a Solar-Powered Drip Irrigation System

The effect of emitter type and operating pressure on some hydraulic properties of a solar-powered drip irrigation system, under three types of dots, Turbo, Spiral, and GR, and three operating pressures100, 150 and 200 cm piezo meters were used. The results showed an increase in the values of the emitters discharge rate, emission consistency, and the decrease in the values of the variance ratio in the discharge and the coefficient of manufacturing variation by increasing the operating pressure for the Turbo, Spiral and GR emitters, respectively. The highest values of the droplet discharge rate were 4.98 and 5.56 L.hr-1 for GR and Spiral compared to 7.31L.hr-1 for Turbo type. The results showed that the operational pressures had a significant effect on increasing the rate of discharge and the consistency of the emission and decreasing the values of the rate of synthetic variation and the percentage of variation in the discharge, as the lowest coefficient of variation was 0.0260, 0.0393 and 0.0436 for the Turbo, Spiral and GR emitter, respectively. The use of different operating pressures led to an increase in the rate of discharge as well as the values of consistency of the flow and reduced the percentages of variation in expenses and the coefficient of manufacturing variation of the drippers. The average expenditure values were 3.732, 4.679 and 5.952 liters.hour-1 for operating pressures 100, 150 and 200 cm, respectively. The emission consistency values were also increased and were 91.11, 93.78 and 95.53%, and the coefficient of variation ratios were reduced by 32.13, 17.08 and 8.89% for the aforementioned operating pressures.

Influencing factors and characterization methods of the anti‐clogging ability of labyrinth channel emitters

AbstractTo quantitatively evaluate the anti‐clogging performance of labyrinth channel emitters, literary data were used to study the clogging of different emitters under different conditions. The results showed that the emitter clogging comprehensive evaluation index (Ia) can be used as an inherent property of labyrinth flow channel emitters, denoted as the anti‐clogging ability characterization index, which is affected by flow channel structure parameters and dimensions. The larger Ia is, the more likely it is for the emitter to be clogged and for clogging to be more serious. The emitter anti‐clogging ability is affected by the emitter discharge (Q), flow path length (L), width (W), depth (D), cross‐sectional area (A, which equals W × D), minimum sectional size (min(D, W)), etc. The Ia value with Q, W, D, A and min(D, W) increases first decreases and then increases, and with L increases first increases and then decreasing, and a critical threshold range exists. Ia can be estimated by Q, W, D, A and min(D, W) and can be used as an effective indicator to quickly estimate emitter anti‐clogging ability and emitter configuration in drip irrigation systems. In practical applications, an emitter with x < 0.47 (flow index) should be selected, and an emitter with Ia < 0.45 has a better hydraulic performance and anti‐clogging ability. To obtain a better anti‐clogging ability, Q, W, D, A and min(D, W) should be 1.33–2.13 L/h, 0.71–0.90 mm, 0.55–0.71 mm, 0.33–0.68 mm2 and 0.60–0.75 mm, respectively. When L is 26.47–58.31 mm, the emitter anti‐clogging ability is relatively low.

Effects of lateral depth and emitter discharge rate on pH and nitrogen distributions in the wetted‐soil volume using drip fertigation

AbstractAccelerated soil acidification from excessive nitrogen fertilizer use and unreasonable irrigation has seriously increased. The advantages of saving water and fertilizer make drip irrigation feasible for reducing soil acidification. However, it is still unknown how drip irrigation influences the distribution of pH in the soil. Experiments were conducted in 30° wedge‐shaped plexiglass containers to study the transformation of nitrogen and the distribution of pH in the soil profile under subsurface drip irrigation. The apparent cylindrical water application rate varied from 4.8 to 12 L, the emitter discharge rate varied from 1.8 to 5.5 L/h, and the lateral depth ranged from 0 to 20 cm. Ten days after irrigation ended, a lateral depth of 20 cm noticeably reduced soil pH at a depth of 10–40 cm, while the pH at a shallow lateral depth decreased in the topsoil; similarly, an emitter discharge rate of 1.8 L/h significantly decreased soil pH at a depth of 0–40 cm, while the pH with a greater emitter discharge rate was slightly decreased in the topsoil. Furthermore, an increase in the application rate resulted in an increase in the area of pH decrease in the soil at 10 days after irrigation ended. Additionally, the growing nitrogen application rate significantly increased the nitrogen content in the soil profile, and the potential risk of deep‐soil pH declined. To reduce NO3‐N leaching and avoid deep‐soil acidification, a dripline depth of 10 cm with a minor irrigation level and nitrogen application rate through an emitter discharge rate of 3.2 L/h may be suggested.

Water Discharge Control in BLDC Motor Driven Pumps to Increase Drip Irrigation Accuracy

Drip irrigation is the most energy and water-efficient irrigation. The multi-sector drip irrigation system can irrigate various types of plants which are divided into several sectors. Changes in the number of active sectors due to differences in irrigation duration resulted in unstable emitter discharges. This instability makes irrigation inaccurate and results in excess or shortage of water supply for crops. Water pump control is needed to match the amount of active emitter discharge. This study controls the discharge of water pumps in multi-sector drip irrigation so that the discharge is in accordance with the number of active emitters. The pump discharge control uses the proportional integral and derivative (PID) method. The type of centrifugal water pump used is driven by a Brushless DC (BLDC) motor with a six-step speed control method. The test results show that the pump can adjust the water discharge with a steady state error of 2.8%.

Development of a soil wetting pattern estimation model for drip irrigation

Abstract Accurately estimating the soil wetting pattern that closely reflects the measured value can improve the water use efficiency for drip irrigation. Ignoring the effect of the initial soil water content on the soil wetting pattern affects the accuracy of the estimated results to a certain extent. This research aimed to develop a soil wetting pattern estimation model for drip irrigation that included four easily measurable parameters (i.e., initial soil water content, saturated hydraulic conductivity, total volume of applied water, and emitter discharge rate) based on dimensional analysis theory. In this study, the wetting front advance data of 12 typical soil textures were obtained in Hydrus-2D/3D. The estimated values were then compared with measured or simulated wetting front advance values. For different experiments, the mean absolute error, root mean square error, and mean relative error varied from 2.77 to 4.69 cm, 6.20 to 10.61 cm, and 5.61% to 10.51%, respectively. Compared with the existing models, the proposed model was more consistent between the measured and simulated values. Therefore, the proposed model of this study is efficient and simple, which can help accurately estimate the soil wetting pattern of drip irrigation with a variety of soil textures.