Distribution Uniformity Coefficient Research Articles

Uniformidade de distribuição do microaspersor Hadar 7110 operando sob variabilidade de pressão de serviço e espaçamento em condições de campo

The hydraulic characteristics of an emitter are fundamental in the agronomic design of an irrigation system. However, emitters such as the HADAR 7110 micro sprinkler from the manufacturer NaanDanJain require more technical information to be available due to their relevant use in agricultural and landscaping environments. This study aims to evaluate the hydraulic characteristics of this emitter operating in field conditions, in order to assist technicians and farmers in decision making in projects and management of irrigated agriculture. An experimental, field and quantitative research was carried out where the HADAR 7110 micro sprinkler was subjected to service pressure variability of 0.5, 1.0, 1.5, 2.0 and 2.5 Bar and spacings of 3x3, 3x4, 3x5, 4x4, 4x6 and 6x6 m. The test was carried out to comply with ABNT's NBR 15084 standard. The standard collector mesh method was adopted for uniformity testing, distributed at a spacing of 1.5x1.5 m, for each test the system was activated for an interval of 45 minutes, after this period, the system was turned off and it was verification of the volume collected by the collectors using a graduated cylinder began. The CUC (Christiansen Uniformity Coefficient) and CUD (Distribution Uniformity Coefficient) coefficients were used to evaluate the issuer's performance. The best CUC and CUD were obtained when using the 3x3 m spacing at pressures of 2.5, 2.0, 1.5 and 1.0 bar, therefore, it is noted that the pressure recommended by the manufacturer can be adopted in the field, as long as a spacing of 3x3 m be used.

Statistical process control in pulsed drip irrigation systems

Pulse drip application is a management option to prevent clogging and improve water-use efficiency. The measurement of distribution uniformity is opportune for pulse irrigation projects to ensure efficiency since the shorter the pulse time, the more negative influence the transition periods have. The objective of the present work was to monitor the quality of a drip irrigation system with different emitter models and different pulse times. The experiment was conducted under laboratory bench conditions, and 25 tests were performed for each pulse application (2, 3, 6 and 12 minutes) and emitter model (non-compensated and auto-compensated). Uniformity was determined using Christiansen's uniformity coefficient (CUC) and distribution uniformity coefficient (DUC) and monitored by Shewhart control charts and exponentially weighted moving average (EWMA). The decrease in pulse time caused a decrease in flow rate and uniformity only in drip irrigation systems with non auto-compensated emitters. However, this decrease is subtle, to the point that uniformity presented an excellent performance for all pulses tested. The use of the Shewhart and EWMA control charts were effective in monitoring the uniformity of the pulsed drip irrigation system. The Shewhart control chart was more robust in identifying isolated non-compensated uniformities, while the EWMA control chart was more sensitive in identifying unstable propensity. In the treatments with the non-compensated emitter, the statistical process control was able to identify that shorter pulse times resulted in greater application instability. As for the auto-compensated emitters, the statistical process control highlighted the concern with application uniformity after maintenance interference.
 Keywords: anti-drain emitter, high-frequency irrigation, irrigation interval, statistical quality control.

Fixed Spraying Systems Application in Citrus Orchards: Nozzle Type and Nozzle Position Effects on Droplet Deposition and Pest Control

Pesticide application is an essential means of controlling plant diseases and pests in citrus orchards. In recent years, fixed spraying systems have gradually been used as alternatives to traditional sprayers and manual sprayers in some hilly citrus orchards. In this paper, influences of fixed system spraying parameters, such as droplet size and spraying height, on spraying quality were elucidated and analyzed. The performances of two nozzle types, pressure-swirl nozzles and fixed spray plate sprinklers, were assessed and compared by effective droplet coverage ratio (DCR), droplet distribution uniformity coefficient of variation (CV), and droplet penetration ratio (DPR). The results showed that appropriately increasing droplet size and spraying height could improve the DCR and distribution uniformity of pressure-swirl nozzles. The DCR and distribution uniformity of fixed spray plate sprinklers had a positive correlation with droplet size, while spraying height had no significant effect on these variables. Additionally, with the increase in droplet size, DPR initially increased and then gradually decreased. The optimized results showed that the optimal parameters for pressure-swirl nozzles were a droplet size of 240 μm and spraying height of 100 cm, while for fixed spray plate sprinklers, the results were a droplet size of 240 μm and spraying height of 50 cm. Comparison results showed that the spraying quality of fixed spray plate sprinklers was better overall, with values of DCR, CV, and DPR being 37.15%, 24.20%, and 71.67%, respectively, while the corresponding values for pressure-swirl nozzles were 39.65%, 35.41%, and 56.02%. Based on the above results and the occurrence rule of citrus pests and disease, the optimal spraying parameters of fixed spraying systems were selected to control the Asian citrus psyllid Diaphorina citri. Furthermore, the effect of fixed spraying systems on controlling Diaphorina citri reached the maximum at 3 days after spraying, which was 97.83%, and the effect declined at 14 days after spraying, which was 85.47%. This study provides valuable scientific references for guiding the application of fixed spraying systems in hilly citrus orchards.

Effects of particle shape, physical properties and particle size distribution on the small-strain stiffness of granular materials: A DEM study

The effects of particle shape (angularity α and sphericity S), physical properties (shear modulus Gp and Poisson’s ratio νp) and particle size distribution (uniformity coefficient Cu) on the small-strain stiffness Gmax were investigated via the discrete element method (DEM) in this study. The Gmax values were obtained by DEM simulations of drained triaxial tests. Microscopic analysis indicates that Gmax uniquely depends on two microscale variants, i.e., the mechanical coordination number CNm and contact stiffness between particles. The particle shape effect was only related to CNm. The contact stiffness can be represented by the values of Gp and Cu. Accordingly, an empirical expression composed of CNm, Gp and Cu that can predict the Gmax of granular materials with different particle properties (e.g., particle size distribution, particle shape, and fabric effect) was proposed. The accuracy of the expression has been verified by comparing the data with previous studies.

Effect of wind speed on distribution uniformity and uniformity coefficient of sprinkler irrigation system in Western Haryana

An experiment was conducted to study the effect of wind speed (0-4 km/h, 4-8 km/h and 8-12 km/h) with lateral spacing (6 m × 9 m) on distribution uniformity of sprinkler irrigation system at the field of the village Luhana located in Western Haryana, India, during 2019-20. The basic principle used in this experiment was using the catch-cans to estimate applied water depth over the field under varying wind conditions. The distribution uniformity of the sprinkler irrigation system was determined using a low-pressure portable rotating sprinkler system. The results shows that for spacing 6 m × 9 m was used, the average distribution uniformity was highest (75.42%) at a range of wind speed 0-4 km/h followed by at ranges of wind speed 4-8 km/h and 8-12 km/h, the average distribution uniformity was 75% and 74.16% respectively and similarly the average uniformity coefficient was highest (86.33%) at a range of wind speed 0-4 km/h followed by at ranges of wind speed 4-8 km/h and 8-12 km/h, the average distribution uniformity was 84.04% and 82.05% respectively. At wind speed range 0-4 km/h, variation of uniform water distribution was less prominent. But it was observed that a range of wind speed 8-12 km/h, significant deviation from the uniformity distribution of water was observed.

Evaluating soil water movement and soil water content uniformity under sprinkler irrigation with different soil texture and irrigation uniformity using numerical simulation

Water movement and its distribution uniformity in the soil are essential for the design of sprinkler irrigation systems. They are both crucial factors influencing nutrient migration and the productivity of crops. In this study, a new numerical simulation method was proposed to investigate the soil water movement in sprinkler irrigation under nonuniform infiltration boundary conditions using COMSOL software. Besides, two soil tank experiments were conducted to test the reliability of the simulation model. Finally, the model was applied to evaluate the effects of sprinkler irrigation uniformity, soil texture, and initial soil water content on soil wetting patterns and soil water content uniformity. The results showed that the COMSOL-2D predictions of the vertical wetting fronts were in good agreement with the experimental data. The soil texture and initial soil water content influenced the soil wetting pattern and the risks of surface runoff and deep percolation in sprinkler irrigation systems. When the water application rate was 11.35 mm h−1 with an irrigation duration of 10 h, it was easy to cause surface runoff in silty clay loam while deep percolation in loamy sand. Additionally, when the initial soil water content is high, it should be better to avoid irrigation or cut down the irrigation duration to prevent percolation. The water within the soil was more uniformly distributed than that applied through a sprinkler irrigation system. The uniformity coefficient of soil water content distribution (CUs) increased from 87.75 % to 95.56 %, as the uniformity coefficient of sprinkler irrigation (CU) increased from 40.74 % to 82.41 %. Although a higher initial soil water content brought a higher soil CUs value, it also led to a higher risk of percolation. The experimental and simulation results indicated that the COMSOL-2D model could be used to accurately simulate soil water movement in sprinkler irrigation and determine the suitable operation mode of low-pressure sprinklers.

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.

Effects of Bio-Organic Fertilizer on Soil Infiltration, Water Distribution, and Leaching Loss under Muddy Water Irrigation Conditions

This study analyzes the soil water infiltration characteristics under muddy water irrigation and bio-organic fertilizer conditions in the current context of muddy water irrigation rarely being used in agricultural production and in combination with the problems of water resource shortages and low soil fertility in arid and semi-arid regions. An indoor one-dimensional soil column infiltration device was used for studying the effects of four muddy water sediment concentration levels (ρ0: 0; ρ1: 4%; ρ2: 8%; ρ3: 12%) and four bio-organic fertilizer levels (FO0: 0; FO1: 2250 kg·hm−2; FO2: 4500 kg·hm−2; sFO3: 6750 kg·hm−2) on soil water infiltration, evaporation characteristics, and leaching loss. The results demonstrated that a higher muddy water sediment concentration and fertilization level resulted in a smaller wetting front distance and cumulative infiltration amount within the same time, but the infiltration reduction rate (η) gradually increased. The three infiltration models (Kostiakov, Philip, and Horton) were fitted, and it was discovered that all three had good fitting results (R2 > 0.8), with the Kostiakov model displaying the best fit and the Horton model exhibiting the worst fit. The cumulative evaporation amount and evaporation time in muddy water irrigation and fertilization conditions was consistent with the Black and Rose evaporation models (R2 > 0.9), the Black model was proved to be higher than the Rose model. In comparison to ρ0, muddy water irrigation increased conductivity and total dissolved solids (TDS) in the leaching solution, but it reduced cumulative evaporation, soil moisture content, the uniformity coefficient of soil water distribution, and leaching solution volume. Compared with FO0, the application of bio-organic fertilizer increased soil water content and reduced soil water evaporation while also reducing the leaching solution volume, conductivity, and TDS in the leaching solution. The results of this research can provide scientific reference for the efficient utilization of muddy water irrigation and the rational application of bio-organic fertilizer.

Experimental and parametric analysis of exhaust heat exchanger used in thermoelectric generator

A thermoelectric generator system consists of an exhaust heat exchanger, a thermoelectric module, and water heat exchanger. Perfect heat exchangers recover as much heat energy as possible from engine exhaust with an acceptable pressure drop. The capacity and efficiency of the heat exchanger depend on its shape, type, and material of the heat exchanger. The main objective of this research was to perform a parametric analysis of the test section of the exhaust heat exchanger by using simulation tools. The simulation results were validated with the experimental results to ensure the performance of the simulation model. The performance of the test section was measured in relation to geometry, pressure drop, temperature distribution, fluid velocity, and temperature uniformity coefficient. The test section of 60 mm × 60 mm × 180 mm (F-type) shows a higher surface temperature with an allowable pressure drop than the other types of test section without inserts. The inserts played a vital role in enhancing the surface temperature distribution and uniformity coefficient. The cone type (G-type), cone-cylinder type (H-type), and cone-cylinder-cone type (I-type) inserts were used to improve the performance of the F-type test section. The G-type and H-type test sections of the exhaust heat exchanger have a high surface temperature, high-temperature uniformity, and allowable pressure drop.

Application for evaluation of the uniformity of systems of pressurized irrigation

The evaluation and monitoring of the performance of irrigation systems are crucial in maintaining water efficiency and conservation of water and energy resources. Therefore, the objective of this study was to develop and validate an application for the coefficient of uniformity coordinators of pressurized irrigation systems. So, the UniIrrig® application was developed, using the integrated development environment Android Studio10 version 4.0.1, in JAVA language, with applicability in devices with the Android operating system. For quantitative verification, the same input values in the UniIrrig® application were also inserted in Microsoft® Excel 2010, in all uniformity conductors used in the application. For the qualitative analysis, together with the experience of the user, 68 students of the Agronomy course at the Federal University of Ceará (UFC) participated in tests in order to evaluate the perception of usability, design, usefulness, and general satisfaction of the tool. To validate the application in the field, a uniformity test was carried out on a center pivot in the municipality of Cascavel, Ceará state, with the aid of collectors (Kit Fabrimar) to deliver the applied depth and the consequent result of the distribution uniformity coefficient (DUC), of Hart (HDC) and weighted mean depth analysis. These values were compared to the results obtained in Microsoft® Excel 2010. The dynamic analysis of the data evolved in “r”= 1, thus providing perfect adaptation between the results obtained by the application and by Microsoft® Excel, finding an error equal to zero. In the qualitative assessment, 84.1% consider the application a good tool for coefficient determination. It is concluded that the UniIrrig® application, designed for the Android operating system, can be used to quantify the assessed irrigation uniformity coefficients.

Adapting climate resilient center pivot irrigation system through monitoring and operating under microclimate change: The case of Wonji-Shoa Sugar Estate, Ethiopia

Microclimate and physiological changes are consequences of the evaporation of water lost during and after irrigation and these losses depend on the application rates and irrigation duration under the center pivot irrigation system. This study analyzed the uniformity of water distribution and estimated water losses for the center pivot irrigation system, using a double row of catch can in the morning, midday and late afternoon. For this purposes multiple linear regression models were developed using the Software package for social science (SPSS) to estimate the water loss under center pivot irrigation system by determining the factors that predominately affect the applied water at Wonj-Shoa, Sugar Estate Ethiopia. The results showed that the center pivot irrigation system exhibited low distribution uniformity in the study area. The average values of coefficient of uniformity (CU) and distribution uniformity (DU), during the morning, midday and late afternoon were, 77% and 63%, 66% and 60%, 80% and 65%, respectively. At all the test times, the distribution uniformity was within the poor performance range. Water loss from the pivot ranged from 1.03% to 7.74%. The study concludes that; air temperature, relative humidity and travel speed of the last tower are the main factors that predominately negatively affect the applied water; hence, all stakeholders, government and managers of the center pivot should operate when the climate demand is low to increase the yield per applied water. This study has significant implications for improving climate resilience using precision irrigation.

Study on the irrigation uniformity of impact sprinkler under low pressure with and without aeration

The distribution of water deteriorates when the operating pressure of an impact sprinkler (IS) decreases to some level. The aeration jet method is utilized to form an aeration impact sprinkler (AIS), aiming to improve the uniformity of water distribution under low pressure. Based on the structures of a 20PY2 impact sprinkler, an IS and AIS with the same sprinkler discharge were studied under operating pressures range between 150 and 250 kPa. A square test zone was formed by the four sprinklers, and the combined irrigation experiment was conducted under windless conditions. The results showed that the water loss ranged from 3% to 9.5% in all 18 test schemes. The coefficient of uniformity (CU) and distribution uniformity (DU) were used to quantify the degree of uniformity. The AIS had an approximately 3%–7% greater CU than the IS, which resulted in the CU reaching the specified value in the IS standard when the sprinkler functioned under low operating pressure. A linear relationship was found between the CU and DUlq. The uniformity of water distribution clearly changed with the operating pressure (150 kPa, 200 kPa, and 250 kPa) but decreased slightly with the increase in combination spacing (1 R, 1.1 R, and 1.2 R). In addition, the results of field experiment were compared with those of the simulation developed from a single sprinkler indoor experiment based on the water distribution radial curve. The simulated coefficient of uniformity was highly consistent with the experimental data and had an error of <7%. A sprinkler water jet with the aeration method was proven to be a feasible solution to reduce the operating pressure.

Assessment of Various Uniformity Aspects under Surface Drip Irrigation System in Tomato

Background: Water in any form is the prime constitute of plant growth and development. Right amount of water applied at right time and in right quantity to any crop will helpful to get maximum yield potential of that crop. This is possible with surface drip irrigation method. Uniform application of water through emitters is the necessary aspect to avail benefits like higher water use efficiency of surface drip irrigation. Uniformity of surface drip irrigation system can be measured by various uniformity aspects viz., coefficient of variation (CV), distribution uniformity (DU), statistical uniformity (SU) and coefficient of uniformity (CU). Factors like land levelling, maintenance of drip lines, pressure management etc. plays a vital role in conserving the uniformity of outflow of emitters.
 Methodology: In this trial, all these uniformity aspects were measured using catch cane method at initial stage of drip irrigation system installation and on the basis of these dataset several improvements were made for better uniformity of emitter outflow at later planting stage.
 Results: Coefficient of uniformity (CU) of surface drip irrigation system was recorded 96.89% at initial stage and later on it was improved to 97.02% during the first experimental year whereas in second year it was noted 95.58% at initial stage and was improved to 96.80% at later stage.

Design and experiment of cone disk centrifugal shellfish seeding device

This paper designed a centrifugal shellfish seeding device with a conical disc structure to improve the seeding efficiency and uniformity of the centrifugal shellfish seeding device. The dynamic model of the shellfish seedling moving on the conical disk is established, and the main parameters affecting the shellfish seedling’s movement characteristics are determined as the cone angle of the impeller, the speed of the impeller, and the offset angle of the blade. Using the EDEM software and the shellfish seedlings blanking rate as the influencing factors, a single factor simulation test was performed. The research found that the variation trend of shellfish seedlings distribution in a single statistical area gradually decreased along the horizontal direction of both sides, with the origin being the center of the seedling sowing device. Test orthogonal rotation simulations using the variation coefficient of seedlings distribution uniformity and the effective job width as evaluation indicators. Use Design Expert software to optimize the structure of the seedling sowing device based on the test results, and determine the optimal structure with the maximum width and the minimum variation coefficient as constraints: the impeller cone angle is 7.72°, and the blade offset angle is -0.9°. Use the above-mentioned seeding device for simulation and actual seeding testing. The simulation results show that when the impeller speed is 750r/min and the blanking rate is 0.65kg/s, the variation coefficient of seedlings distribution uniformity and the effective job width are 12.84% and 24.98m, respectively, while the actual test results are 13.77% and 23.25m, respectively. The object of the seeding performance test was commonly used size shellfish seedlings of the Philippines clam. The results showed that the impeller speed, blanking rate, quadratic term of shellfish seedling size, quadratic term of blanking rate, and interactive term of impeller speed and blanking rate had significant effects on the variation coefficient of the distribution uniformity of shellfish seedlings (P<0.01). Shellfish seedling size, impeller speed, and interactive term of impeller speed and blanking rate all had a significant impact on job width (P<0.01). The results of this study provide a reference for the mechanized design of shellfish seeding.

Demonstration of Center Pivot Uniformity Evaluation and Retrofit to Improve Water Use Efficiency

Agricultural irrigation is a primary user for freshwater withdrawal. Irrigation plays an important role in crop production, as it provides the benefit of reducing the effects of prolonged dryness and erratic precipitation. Center pivot irrigation system is the most common irrigation system in agriculture. As the center pivot irrigation system ages, the system could develop a leaking joint, clogged sprinklers, and physical damage. This can cause areas of non-uniformity that can lead to under- or over-irrigated in some areas of the land, resulting in excess energy use and cost, wasting resources, and environmental impacts. Thus, it is important to evaluate the performance of a center pivot irrigation system regularly to maximize return on investments and minimize wasting resources. This study focuses on evaluating the impacts and benefits of improved center pivot irrigation distribution uniformity by performing distribution uniformity evaluations pre- and post-retrofit. This study also focused on demonstrating an unmanned aerial vehicle (UAV) to assess the performance of the center pivot irrigation system in two irrigated farmlands. The Coefficient of Uniformity (CU), Distribution Uniformity (DU), and Scheduling Coefficient (SC) were calculated based on the catch can test data. The values were utilized to evaluate water and energy savings from the improved coefficients. The team has found that replacing sprinkler packages increased the CU from 78 to 89 and the DU from 77 to 82, and reduced the SC from 1.3 to 1.2 in Field A. In Field B, replacing sprinkler packages increased the CU from 73 to 91 and the DU from 62 to 84 and reduced the SC from 1.6 to 1.2. The estimated water savings in Field A due to the reduced scheduling coefficient was approximately 151,000 liters/hectare/year, with consideration of the corn and soybean rotation field in Michigan. The estimated water savings in Field B was 608,000 liters/hectare/year. The data from this demonstration study showed the value of distribution uniformity evaluation and retrofit of irrigation systems. This information will encourage farmers and agricultural industries to consider performing more distribution uniformity evaluations, ultimately improving irrigation water use efficiency and supporting sustainable water management in agriculture.

Investigation of the inlet layout effect on the solid waste removal in an octagonal aquaculture tank

The optimization of the inlet layout in aquaculture systems is essential to ensure minimal solid waste discharge into the environment and improve fish production efficiency. In the present study, laboratory experiments were carried out to investigate the effects of the jetting position d/a (where d is the distance from the pipe axis to the tank side and a is the side length of the tank wall) and the jetting angle θ (the acute angle between the jetting direction and the nearest tank wall) on the solid waste removal efficiency in single-inlet and dual-inlet octagonal Recirculating Aquaculture System (RAS) tanks. To this end, three jetting positions (d/a) of 1/50, 1/8, and 1/4 and ten jetting angles (θ) of 0° to 80° were considered in the experiments. The Particle Image Velocimetry (PIV) technique was applied to measure the flow characteristics in the tank and analyze the solid waste removal under different working conditions. Residual mass of the solid waste, time of complete removal of solid waste, average velocity (vavg), and uniformity coefficient of velocity distribution (DU50) were analyzed to evaluate the solid waste removal efficiency. The obtained results indicate that adjustments of the inlet layout significantly affect the solid waste removal efficiency. It was found that a single-inlet tank with a d/a of 1/8 and θ in the range 10° to 40° has a good solid wastes removal performance, and the optimal efficiency occurs at a jetting angle of 30°. Moreover, the optimal solid waste removal efficiency in a dual-inlet tank can be achieved with a d/a ratio of 1/8 and a θ of 20°. The performed analyses reveal that from the aspect of solid waste removal efficiency, a tank with a d/a ratio of 1/8 outperforms a tank with a d/a ratio of 1/4 or 1/50. The results of this article offer novel insights in the layout of octagonal RAS tanks and provide a guideline to improve self-cleaning features of aquaculture tanks.

Effect of Border Width and Micro-Sprinkling Hose Irrigation on Soil Moisture Distribution and Irrigation Quality for Wheat Crops

Micro-sprinkling irrigation is a small-flow irrigation technology that uses the grouped outlets on the micro-sprinkling hoses to spray the pressure water evenly in the field. Plants’ barriers during the middle to late growth period of winter wheat significantly reduce the irrigation quality of the micro-spray system. It is still unclear whether soil border width in wheat fields can alleviate the negative effect. In this study, a popularly-used variety (c.v. ZM 369) was adopted to test the mitigation effect of soil borders on irrigation quality, as well as soil moisture distribution, in wheat fields. Two irrigation quotas (i.e., 75 mm and 45 mm per time) and three border widths (i.e., 2.3 m, 3.3 m, and 5.3 m) were arranged in a randomized block design in the experimental years of 2020–2022. Soil moisture distribution and irrigation quality during the middle to late growth period of winter wheat (i.e., jointing to heading stage and grain filling stage) were investigated, as well as the effects on grain yield and water use efficiency (WUE). The results showed that irrigation water distribution in the direction perpendicular to micro-spray tapes generally decreased with the distance from tapes increasing. The maximum difference between the irrigation amount and water collected under the canopy was 134 mm. The uniformity coefficient of soil moisture distribution was increased by 25.8% with a 5.3 m border width compared to a 2.3 m width. Although an irrigation quota of 75 mm was beneficial for ensuring better irrigation uniformity and more stable grain yield, grain yield and WUE were produced with an irrigation quota of 45 mm. In conclusion, it is appropriate to increase border width and adopt a small quota for the micro-spray system in the North China Plain for wheat crops.

The Design and Technical Performance of Two Aeroponic Systems in Ghana

Climate change and its associated variabilities is having major impacts on agricultural production across the globe. Sustainable production options that reduce the vulnerability of the food system to climate change impacts are being advocated for, with a lot of ongoing research in that direction. Aeroponics production, a soilless production system has been identified as a sustainable system that can produce food with less input (land per unit area, water, nutrient and energy). It also makes for an environmentally friendly production system. In areas of extreme soil degradation and limited land area and water, aeroponics have shown great advantages over geoponics and sustained production, thus improving on food security. The central and northern parts of Ghana where yams are predominantly grown, is challenged with access to fertile lands, rainfall variabilities and other associated threat such as pest and disease outbreaks and seasonal bush fires. The production of seed yam, which form about 25% of the production cost for yam cultivation is hampered by all these challenges. To abate these challenges and improve on the adaptation measures taken by farmers around the region, two aeroponic systems were developed in this research, to be used for the production of seed yams propagated from vine cuttings. Two designs were made: one power independent (the gravity-fed open loop system) and the other power dependent (pressurised close loop system). In the systems design, the following aspects were taken into consideration: selection of head control and emitter; design of laterals and pipe sizes (inlet and outlet pipes); and the selection of growth chamber and feed tank. Apart from the selection of the growth chamber and the design of laterals and outlet pipe, different design considerations were also taken into account for the gravity fed system. This included the selection of drip lines and emitter flow rate. Technical evaluation of the aeroponics systems were done to ascertain its effectiveness as a fertigation system based on the performance indicators for a sprinkler and drip irrigation system. Results from the technical evaluation gave a mister discharge for the power dependent system ranging from 59.00-60.5 kPa. The emitter flow rate, the equivalent evaluation parameter for the power independent system also ranges from 0.10-0.12 L/h. There was a linear correlation between the mister operating pressure, mister discharge and swath diameter for the power-dependent system. For a Christensen’s Coefficient of Uniformity (CU) and Distribution Uniformity (DU) values of 97.52% and 96.16% respectively, the power dependent system can be said to be very efficient in its operations. The same could be said for the power independent system having a CU and DU of 94.49% and 90.80% respectively. These two developed systems have shown their capability to be adopted for u se in seed yam production to reduce some of the associated challenges, especially, access to land, water, seasonal bush fires and pest and disease outbreaks.

EFFICIENCY AND UNIFORMITY OF AN SUBSURFACE DRIP IRRIGATION SYSTEM IN SUGARCANE CROP

Agricultural productivity in irrigated areas depends on several factors, including the design and maintenance of irrigation systems. Excessive or insufficient applications of water affect plant growth and development, hence agricultural productivity. For this reason, the evaluation of the irrigation system is essential to avoid water loss during application. This study aimed to evaluate the efficiency and uniformity of a subsurface drip irrigation system in sugarcane crops in an area of the company Usina Coruripe, Alagoas, Brazil. For data collection, the flow rates were obtained in four points along the lateral line, in the first dripper, in the drippers located at 1/3 and 2/3 of the lateral line length, and in the last dripper of each operational unit of the irrigation project. In each row, four emitters were evaluated, totalizing 16 emitters, using a chronometer, collectors, and a measuring cylinder for data collection. In these emitters, the volume of water was collected for 3 minutes, with three repetitions. Christiansen's uniformity coefficient, distribution uniformity coefficient, statistical uniformity coefficient, Hart's uniformity coefficient, and application efficiency were estimated. The irrigation system was considered excellent for distribution uniformity. The application efficiency was classified as acceptable, with an average value of 88.9%. However, despite the application efficiency being classified as acceptable, periodic evaluations of the system are recommended.

Effect of Catch Cans Size and Can Spacing on Calculation of Uniformity Water Distribution for Grid Sprinkler Systems

The research included studying the effect of each of the size of catch cans and the spacing between them on the calculation of water distribution uniformity coefficient and with different spacing between sprinklers and for several sprinklers heads, The research included conducting 10 tests, each test of a different sprinkler head, which included finding three patterns for water distribution along a ray, each representing a radius of a circle of wetness at its center, using different sizes of catch cans, where for each ray there is a different diameter of catch cans. And 480 patterns were found to distribute the field sprinkler irrigation water to cover the sizes and spacing of the catch cans and the spacing between the sprinklers and the different sprinkler heads. The research showed that when the water distribution pattern is symmetric around the sprinkler and there is no wind; there is no effect of the diameter of the catch cans on each of the water distribution pattern along the ray, which represents the radius of the wetness circle, its center is the sprinkler, the uniformity coefficient UC and the distribution uniformity coefficient DU. And both the distribution uniformity coefficient UC and the distribution uniformity coefficient DU increases with the increase of the spacing between the catch cans. Two equations were also devised to express the uniformity coefficient UC and the distribution uniformity coefficient DU at the spacing of catch cans (1 m * 1 m) as a function of each of them at greater spacing between catch cans..