Emitter Flow Research Articles

Evaluation of Drip Lateral Spacing on Yield and Economic Return of Onion (allium cepa l.) at Awash Melkassa, Ethiopia

Water availability is becoming a critical issue in Ethiopia in semi-arid climate mainly in Rift Valley areas. Field experiment was carried out during the dry cropping season of 2019/2020 to evaluate the performance of drip lateral spacing on onion yield and its net return with two adjustments of drip lateral spacing at full irrigation application viz., lateral placed in every row and between two rows. The performance of drip lateral spacing system was evaluated on the basis of parameters like emitter flow rate (q), emission uniformity (EU), emitter flow rate (qvar), coefficient of variation (CV), uniformity coefficient (CU). The mean values of upper, middle, and lower lateral spacing showed non- significant (P ≥ 0.05) difference in emission uniformity of drip lateral spacing. An average emitter uniformity parameter value was 93.66%, 96.28%, 12.05 %, 1.68 % for emission uniformity, uniformity coefficient, emitter flow variation and coefficient of variation respectively. The designed drip lateral spacing was operated excellently as all values of emitter uniformity parameter were in the recommended range in each case. The average basic infiltration rate was found to be 18 mm/hr. From the result, onion yield and yield parameters was affected by the effects of drip lateral spacing. Maximum onion bulb yield of 41.44t ha-1 and 25.83t ha-1 were obtained from lateral spacing in every row and between two rows respectively. Total bulb yield was reduced by 37.65% when drip lateral between two rows was used. But the cost of drip lateral between two onion plant rows was 26.14% less than drip lateral in every onion plant rows. Therefore, onion could be irrigated by drip lateral spacing in every row to get better onion bulb yield.

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.

Application of Numerical Newton-Raphson Method in Calculation of Emitter Water Discharge of Drip Irrigation System in “Mutis Cemerlang” Coffee Plantation

Based on the slope class, the shape of the area and the elevation of dry land in Nusa Tenggara, agricultural land in Noepesu Village is suitable for planting coffee plants with an agroforestry scheme. To overcome the problem of limited water, drip irrigation system technology can be applied. The use of drip irrigation as an agricultural technology in Noepesu village has been carried out by many farmer groups. Still, the installation process does not consider the pipe specifications (pipe length and pipe diameter) and the condition of agricultural land. This causes the service life of drip irrigation to be not long. If this continues, of course, it will increase system installation costs. To optimize service life, a hydraulics analysis method is needed for drip irrigation pipe network systems that take into account pipe specifications and agricultural land conditions.The hydraulics analysis of the drip irrigation network system determines the emitter’s water flow rate. The emitter flow rate forms a nonlinear equation known as the closed pipe equation. In the process of solving these equations, numerical methods can be used, specifically the Newton-Raphson method. This study focuses on applying the Newton-Raphson method to calculate the amount of water discharge from each emitter of the drip irrigation network system on the farmland of the Mutis Cemerlang Farmer Group in Noepesu Village. The drip irrigation system is designed with 250 nodes, 275 pipes, 26 loops, and 86 outlets divided into two sides, with the left side containing 84 outlets with one emitter and the right side containing 102 outlets with two emitters. The amount of water discharge for each emitter is 0,0008 ml/second≤Q≤2,6 ml/second for the left side and 0,001 ml/second≤Q≤1,1 ml/second for the right side, as determined by simulation calculations utilizing the Newton-Raphson method and Matlab software. The simulation results show that the amount of water discharge at each emitter is ideal in the first iteration because it has a discharge correction value (∆Q)≈0.

Analysis of internal flow characteristics and determination of the core structural parameters of a stellate labyrinth channel irrigation emitter

The hydraulic and anti-clogging performance of irrigation emitters are mainly governed by the internal flow characteristics in the flow channel. Computational fluid dynamics (CFD) and experiments were used to analyse internal flow characteristics and determine the key structural parameters of a stellate labyrinth channel irrigation emitter. Through experimental verification, the realisable k-ε model provided the best results for simulating the flow field. Five structural parameters of stellate labyrinth channel emitter were selected to study the influence on the flow characteristics inside the flow channel comprehensively. The velocity fields and profiles are presented along the stellate labyrinth channel. Turbulence properties and turbulent kinetic energy of flow inside the stellate labyrinth channel are analysed and discussed. The vortex zones consume energy and promote the deposition of particles. The swirling motion zone in stellate labyrinth channel emitter flow channel must be described to analyse flow characteristics. The advanced Q-criterion method was applied to identify and characterise the vortex zones in the stellate labyrinth flow channel. Through analysis results of the influence of different structural parameters on velocity fields, turbulence properties, and swirl characteristics, it was shown that a, r, h, and θ are main structural parameters that affect the flow characteristics in stellate labyrinth channel irrigation emitter. The results of this study provide references for the design theory of the new types of flow channel emitter.

System Performance Evaluation for Tea Plants Replacing Sprinkler with Drip Irrigation using Water Uniformities in Dooars, India

Tea gardens are facing water scarcity; moreover, their irrigation utilises overhead sprinklers, which lack uniformities and controlled irrigation methods. Evaluating the performance of drip irrigation is an important research area for better water resources management. To address these issues different drip irrigation methods have been experimented with having different combinations of drippers. Two plots are online drip systems while the other two are inline systems operated at the same pressure on water application uniformity while other conditions remain similar. Earlier studies witnessed experimentation of drip irrigation with only the same emitter flow. While in this research, the uniformity coefficient, emission uniformity and performance index are calculated. It is found that due to various dripper discharges and systems the water application significantly changes. Extreme values of discharge variation of the emitters were observed during field operations under the same pressure and length of laterals. From the evaluation of the uniformities and investment cost, the performance of an inline system with a 4 lph dripper at 60 cm with 1-m lateral spacing is found to be the best model for tea irrigation under the specified conditions. Later stage and further research efforts should be aimed at the findings of the efficiencies and yield response of tea under the four drip systems.

Геометрия контуров капельного увлажнения почв

Purpose: to determine dependencies and develop a methodology for calculating the geometric dimensions and constructing the outline of local moisture contours formed in the soil space during drip irrigation. Materials and methods. The factual basis of the development was the data of full-scale (field) measurements of the contours of the drip-moistened soil space and their office processing. The studies were carried out on experimental sites with different soil cover, represented by steppe, dry steppe and steppe-desert soil types: chernozems (ordinary and southern) and chestnut soils with a wide range of granulometric texture, water-physical properties and with different levels of pre-irrigation moisture, when ir-rigated with emitters productivity from 1,0 to 6,0 l/h. Results and discussion. During the study, the following things were considered as determining the process of contour formation and the contour geometry: soil conditions characterized by the physical clay content, the min-imum water capacity, bulk density and the level of pre-irrigation moisture; technological pa-rameters determined by the level of post-irrigation moisture, the given depth of soil moisture, the flow rate of drip micro-water outlets and the volume of water supply. Empirical depend-ences that allow determination of the linear dimensions, the wetted area dimensions and the volumes of moisture contours are obtained according to the given values: the physical clay content in soil within 18.0–77.0 % of the dry soil mass (DSM), the lowest moisture capacity in the range 16.5–32 % DSM, wetting depth from 0.5 to 1.2 m, additional irrigation moisture from 60 to 80 % of the level of the minimum water capacity, emitter flow from 1.0 to 6.0 l/h. Conclusion. A system of empirical dependencies has been obtained, and methods for predict-ing the external shape, linear, areal and volumetric dimensions of local moisture contours formed in the soil space during drip irrigation have been developed.

О ВЛИЯНИИ ИНТЕНСИВНОСТИ ВОДОПОДАЧИ НА ГЕОМЕТРИЮ ЛОКАЛЬНЫХ ЗОН ВЛАЖНОСТИ ПОЧВЫ ПРИ КАПЕЛЬНОМ ПОЛИВЕ

Purpose: to determine the impact of emitter flow rate on the geometric parameters of local moisture contours formed in soil space under drip irrigation. Materials and methods. The empirical basis for the development was the data of experimental field studies of moistened soil local contours when irrigation water was supplied to the land surface from the above-ground emitter. Field studies were carried out on three experimental sites, the soils of which are characterized by the content of silt-and-clay of 15.0; 52.0 and 76.0 % of the dry soil mass and the lowest moisture capacity of 14.0; 26.0 and 31.0 % of the dry soil mass, respectively. Irrigation was carried out from above-ground emitters with a flow rate of 1.0 to 6.0 l/h. When setting up the experiments and processing the experimental material, the methods and technologies of the field experiment were used. Results. As a result of field studies, the geometric and moisture parameters of 12 local moisture contours which were formed on three experimental sites with different soil conditions during drip irrigation with varying water supply intensity were recorded. In the process of cameral treatment of created profiles of soil moisture contours, the values of the ratio of the contour diameter and its depth were established for all combinations of soil and technological irrigation conditions provided for by experience. As a result of the analysis of the data obtained, the impact of water supply intensity and soil conditions on the geometry of local contours of soil moisture was determined, and a dependence describing this relationship was proposed. Conclusions. Experimental data on the parameters of moisture contours formed in soil under drip irrigation with different water supply flow rates were obtained. A relationship that makes it possible to assess the impact of water supply intensity on moisture contours geometry and to predict the values of contour diameters for a given depth, depending on soil conditions of the site and the flow rates of drip water outlets.

Structural optimization and hydraulic performance analysis of bionic pit flow channels based on a genetic algorithm

Orthogonal experiments have mostly been used in the structural optimization of drip irrigation emitter flow channels. To further improve the efficiency of the optimal design, this study used a genetic algorithm to optimize the structure of the bionic pit flow channel. Based on the structural similarity and performance optimization of the torus-margo bordered pit structure, the constitutive equation of the flow channel unit was constructed. The selection, crossover and mutation operators were set by the genetic algorithm, and the objective function value was calculated. The design variables and known variables that met the requirements were put into the computational domain model, and the pit flow channel structure was simulated and optimized. The results showed that there were large low-velocity regions at the junctions and corners of the pit flow channel units at a working pressure of 50 kPa, and no complete low-velocity vortices were observed, indicating that the flow channels had good anti-clogging performance. The distribution of flow velocity on the same cross-section was quite different, which made the flow layers collide and mix, which intensified the loss of energy, indicating that it had a good energy dissipation effect. The multivariate linear regression analysis showed that the four variables of tooth stagger value (j), flow channel angle (θ), tooth spacing (l) and inner and outer boundary spacing (h) had a decreasing degree of influence on the flow index (x). The flow index (x) was negatively correlated with the tooth stagger value (j), flow channel angle (θ) and tooth spacing (l), and positively correlated with the inner and outer boundary spacing (h). The test results of physical samples showed that the average error between the simulation results and the real values was 3.4%, indicating that the accuracy was high, which can provide a basis for the structural optimization design of related pit drip irrigation emitters.

Anti-Clogging Performance Optimization for Shunt-Hedging Drip Irrigation Emitters Based on Water–Sand Motion Characteristics

To improve the irrigation quality and anti-clogging performance of the emitter, it is necessary to design and optimize its flow channel structure. The shunt-hedging drip irrigation emitter (SHDIE) flow channel is a new type of flow channel. Using computational fluid dynamics, by setting different conditions (such as particle size and injection position), the motion trajectory of sand particles and flow field distribution characteristics of the shunt-hedging flow channel were simulated. According to the simulation results, a new anti-clogging structural optimization scheme was proposed, and physical experiments verified its feasibility. The results showed that the flow index of the original flow channel (SHDIE1) and optimized flow channel (SHDIE2) were 0.479 and 0.486, respectively, which mainly relied on the shunting and hedging of water flow to energy dissipation. For sand particles with diameters of 0.05, 0.10, and 0.15 mm, the average values of the velocity amplitude ratio, η, were 0.9998, 0.9994, and 0.9991, respectively; the average values of the velocity phase difference, β, were −0.143°, −0.320°, and −0.409°, respectively. A larger sand particle diameter led to worse followability and a higher risk of blocking the channel. When the sand particles collided with the sensitive region of the flow channel, their movement direction would suddenly change, entering the vortex area. After colliding with the sensitive region of edge A, the maximum probability of sand particles entering the vortex area was increased to 87.5%, and then they stayed in the vortex area under the effect of the sensitive regions of edges B and C. After the sensitive regions were removed, the motion trajectories of sand particles became regular and smooth. The optimized flow channel’s (SHDIE2) anti-clogging performance was greatly improved by 60%, with a 1.46% loss of hydraulic performance. This study can provide theoretical support for designing the high anti-clogging emitter.

Coupling Regulation of Root-Zone Soil Water and Fertilizer for Summer Maize with Drip Irrigation

Water scarcity is the most significant constraint for grain production in the North China Plain (NCP). Water-saving irrigation technology is a valuable tool for addressing the NCP’s water scarcity. Drip irrigation is considered as one of the most water-saving irrigation technologies. However, drip irrigation is not now commonly used in NCP field grain crops (particularly maize). Fertilizers are accurately administered to summer-maize root soil by recycling the drip-irrigation system of winter wheat. To increase the water and fertilizer-use efficiency of summer-maize fields, the coupling body of root-zone soil water and fertilizer for summer maize was thoroughly adjusted using a combination of emitter flow rate, irrigation quota, and fertilizer frequency. In this experiment, a split plot design with randomized blocks was employed. The primary plot was emitter flow rate (0.8 and 2.7 L/h), the subplot was irrigation water quota (120 and 150 m3/hm2, 1 hm2 = 10,000 m2), and the final plot was fertigation frequency (7, 14, and 28 days). The grain yield, water-use efficiency and fertilizer-use efficiency of summer maize were measured in this study. The results showed that grain yield and water-use efficiency (WUE) of the small-flow drip-irrigation treatment (emitter flow rate < 1 L/h) were significantly higher than the large-flow treatment (emitter flow rate > 1 L/h); the rates of grain yield increase were 8.2% and 13.3% and WUE were 3.5% and 8.0%, respectively. A higher irrigation quota can increase the yield of summer maize. The maximum yield and WUE were observed at the fertigation frequency of 7 days under small-flow drip-irrigation conditions. All comparisons and analyses showed that small-flow drip irrigation combined with high fertigation frequency could obtain higher yield and WUE in the NCP. This study proposes a new way to improve water and fertilizer utilization efficiency to achieve the goal of “increasing grain yield by fertilizing” and “adjusting the quality by fertilizing”, from the perspective of winter wheat–summer maize no-tillage annual rotation planting.

Performance assessment of the TORO Company Neptune PC AS dripline

In order to design an efficient microirrigation system, a monitoring approach allowing quantifying the main variables affecting the level of uniformity should be pursued. In the present work, we assess the performances of a commercial dripline, the product “Neptune PC AS”, furnished by TORO Company, employing an ad hoc built experimental benchmark, in doing so defining the dripline acceptable working conditions. Neptune PC AS has been tested at different operating pressure heads (range 1.5 - 3.5 bar) and its performances have been evaluated employing a series of metrics (the emitter technological variation coefficient, the emitter uniformity and the application efficiency). The obtained results show that Neptune PC AS is characterized by a strong pressure-compensating effect on the emitters and by very good / excellent performances for all the investigated operating pressure heads. Moreover, Neptune PC AS is characterized by limited differences between the maximum and the minimum of the emitter flow rate, in case of operating pressure heads equal to 1.5 bar and 2.0 bar, while such differences tend to increase for higher operating pressures.

Aerated drip irrigation increased the emitter clogging risk of the Yellow River water drip irrigation

AbstractThe influence of aeration on the emitter clogging of Yellow River water drip irrigation was evaluated, and reasonable measures to slow down the emitter clogging were investigated. A short‐cycle intermittent irrigation test and sediment settlement test were performed under the conditions of aeration and no aeration. The results showed that aeration accelerated the settlement of sediment at the inlet of the flow channel, increased the clogging rate of the flow channel inlet and exacerbated the clogging of the emitter. With the decrease of sediment particle size, aeration increased sediment deposition and emitter clogging. With the increase fencing inlet area, the effect of aeration on sediment settlement and emitter clogging decreased. Under aeration conditions, the upward position of the emitter outlet significantly reduced the mass of emitter blockage and increased the emitter flow compared with the downward positioning of the outlet. Thus, the recommendation is to select an emitter with a large area of fencing inlet, and the outlet of the emitter should be positioned upwards in order to improve the anticlogging performance of the emitter for Yellow River water aerated drip irrigation.

Backpressure effects on emitters flow rate in subsurface drip irrigation

Subsurface drip irrigation success depends on surpassing the backpressure obstacle, a phenomenon which occurs when the water application intensity exceeds the infiltration rate of soil, which reduces the emitter flow rate. Thus, this study aimed to determine the flow rate variation, in relation to surface flow, of four drip emitters when buried at two depths in a loam soil (Yolo Loam soil), and the backpressure generated by the soil on subsurface condition. The cavity radius developed around the emitters outlet was also obtained. The experiment was conducted in a completely randomized design, in a strip-plot scheme, with three treatments: installation depth of driplines (two levels: 0.10 and 0.20 m); dripline type (four levels: D5000, JardiLine, TalDrip and and Hydro PCND) and irrigation time (three levels: 0.5, 1.0 and 3.0 h). The results showed that the flow rate variation between the surface and subsurface application on Yolo Loam soil, with inlet pressure of 145 kPa, was greater the higher was the emitter flow rate. For pressure-compensating emitters, even under backpressure influence, this was not enough to cancel the pressure-compensating device operation, of the emitters. The emitters installation depth, as well the irrigation time, did not affect the backpressure and, consequently, the flow rate variation.

Performance Evaluation of Drip Irrigation System in Grapes Field

A commercial drip irrigation system was evaluated at farmer’s field under grapes to study the various parameters viz emission uniformity, emitter flow variations and statistical uniformity during the year 2019. The soil characteristics of the experiment field at different profile depths was analyzed and sandy loam soil is available at 0 to 15 cm depth and sandy clay loam is available from 15 cm to 60 cm depths, Irrigation was given daily based on potential evaporation. The soil moisture status during the crop growth period at various depths under the emitter was studied. The soil moisture in the field was maintained in a range of 21 to 23% under drip irrigation in the 60 cm depth irrespective of the duration. During the rainy season when no irrigation was given, the soil moisture fluctuated depending upon the intensity of rainfall. The system performance was good as indicated by high uniformity coefficient (93%) which indicates that the field is irrigated in a highly uniform manner. The yield was estimated as 27500 kg/ha and water use efficiency was found to be 566 kg.ha/cm The study revealed that superiority of drip irrigated soil regime and moisture content in the soil in 60 cm depth was more or less maintained constantly during the irrigation period.

A Comprehensive Model for Hydraulic Analysis and Wetting Patterns Simulation under Subsurface Drip Laterals

In the absence of suitable specialized models to simulate the soil wetting patterns in subsurface drip irrigation systems considering the hydraulic conditions along the laterals, a new model was developed and named a “comprehensive model” in this study. This model couples the subsurface drip irrigation lateral characteristics with the soil hydraulic properties and utilizes the Hydrus-3D software as a complementary section of the model to simulate the wetting front beneath the lateral. To evaluate the model, three 16 mm drip-line pipes of 62 m length with 20, 40, and 50 cm spacing emitters and 2 to 5 L/h discharge were buried at 0.2 m depth in a soil box containing clay loamy soil. Then, the experiments were conducted at 50, 100, and 150 kPa pressures, and the wetting pattern geometry associated with each lateral was measured at 1, 2, 3, and 24 h and compared with the model simulations. Moreover, the values of the root mean square error (RMSE), mean absolute error (MAE), and the refined index of agreement of the wetting depth beneath the lateral ranged from 0.013 to 0.03 m, 0.002 to 0.004 m, and 0.886 to 0.927 m, respectively. In addition, the mentioned indexes values at the first and the last cross-sections of the laterals varied between 0.001 and 0.004 m, 0.011 and 0.035 m, 0.814 and 0.942 m, respectively. These results proved that the differences between measured and predicted dimensions of the wetting pattern are not significant and comprehensive model provides good estimations of the emitter flow rates, as well as realistic wetting patterns.

Elimination of Clogging of a Biogas Slurry Drip Irrigation System Using the Optimal Acid and Chlorine Addition Mode

As an emerging contaminant, the clogging substances of emitters in biogas slurry drip irrigation systems affect the efficient return and utilization of biogas slurry to the field to a great extent. This can be prevented using acid and chlorination as engineering measures. Through a hydraulic performance test and sampling detection and analysis, under the same acid addition conditions (pH = 5.5–6.0), three chlorine addition concentrations (0, 1–3, and 4–9 mg/L) and four chlorine addition cycles (6, 10, 14, and 20 days) were tested, aimed to clarify the influence of acid and chlorine addition parameters (chlorine adding cycle, chlorine adding concentration, etc.) on the anti-clogging performance of emitters in biogas slurry drip irrigation system. The results showed that compared with no acid and chlorination treatment (CK), only acid and a reasonable combination of acid and chlorination can significantly reduce the probability of serious and complete clogging of biogas slurry drip irrigation emitters, and they can stabilize the relative average flow of emitters by more than 75%. The measures of adding acid and chlorine change the distribution characteristics of clogging substances at the front and rear of the drip irrigation belt. Furthermore, they promote the migration of clogging substances to the rear of the drip irrigation belt, facilitating the clogging of emitters located thereat. The measures of acid addition and sequential addition of acid and chlorine significantly inhibit the growth of an extracellular polymer in the emitter, and the effect of inhibiting the increase in extracellular polymer concentrations is relatively poor when the acid addition period is excessively long or short. There exists a negative correlation between the extracellular polymer content in the emitter and the change in the emitter flow. Based on the obtained results, to ensure excellent anti-clogging performance of biogas slurry drip irrigation systems, for acid-only treatment measures, the acid dosing cycle is recommended to be 10 days. When acid and chlorination measures are implemented sequentially, the acid chlorination cycle is recommended to be 14 and 10 days when the chlorine concentration is 1–3 and 4–9 mg/L, respectively. This study has important scientific significance and practical value for the establishment of long-term operation management and protection technologies of large-scale biogas slurry drip irrigation systems.

A Prediction Model of Labyrinth Emitter Service Duration (ESD) under Low-Quality (Sand-Laden Water) Irrigation

The reasonable evaluation of emitter service duration and appropriate emitter selection have become an important way to improve the efficiency of drip irrigation systems, and also provide a basis for the wide application of drip irrigation technology in agricultural and landscape irrigation. During field irrigation, both irrigation uniformity (CU) and relative average flow (Dra) play crucial roles in crop growth, so it is not appropriate to evaluate emitters based on one of these factors alone. In this study, a new comprehensive index for measuring the operating life of emitters—the emitter service duration (ESD) was established for selecting emitter products in the field. The indoor drip irrigation experiment was carried out under nine kinds of sand-laden water, and the emitters’ service duration, based on irrigation uniformity and emitter flow, was tested. By analyzing the individual effects and the comprehensive effects of them, the comprehensive measurement index of the ESD was established and the Pearson bivariate correlation analysis was used to explore the influencing factors. The results showed that the lower the quality of the irrigation water, the smaller the value of the ESD, which meant that the emitters were more likely to be blocked. Different irrigation water sources had different effects on the ESD, which were mainly caused by the characteristic size. Two dimensionless characteristic parameters (W/D and A1/2/L) are significantly correlated with ESD. Based on W/D and A1/2/L, the ESD prediction model was obtained and the accuracy could reach 86%. It could provide an accurate method for selecting emitters under different water source conditions, which is beneficial for the safe, efficient, and long-term operation of a drip irrigation systems using a low-quality water source.

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.

Design and Development of Smart Irrigation System for Watering Rooftop Garden

Rooftop gardening is one of the famous agricultural technology in urban areas of many countries including Bangladesh. Crop water requirement is very high in rooftop due to high temperature and high evapotranspiration. Irrigation as well as water management is the major limitation for this practice. Considering the necessity of rooftop gardening in urban areas and irrigation issue, it is essential to develop a low cost efficient irrigation method that helps to improve production techniques for rooftop garden. From this study, we developed a smart irrigation system for watering rooftop gardening where mainly used programmable digital timer, solenoid valve and electric pump operated drip system. In this irrigation system, programmable digital timer sends a signal to the solenoid valve and electric pump that leads to open or close the whole irrigation system and crop was watered the selected interval and frequency wise. From the results, average discharge (Qavg), distribution efficiency (Ed), application efficiency (Ea), coefficient of variation for emitter flow (cv) and statistical uniformity coefficient (SUC) were achieved good performance and was found meeting American Society of Agricultural Engineers (ASAE) standards. The designed smart irrigation system was operated excellently as the values of emission uniformity.

Analytical model for predicting activation pressure and flow rate of pressure-compensating inline drip emitters and its use in low-pressure emitter design

Drip irrigation has the potential to help farmers increase crop production with lower on-farm water consumption than flood or sprinkler irrigation; yet, its high costs keep it out of reach for many smallholder farmers, who make up about 20% of the world’s population. Pressure-compensating (PC) drip emitters enable uniform water delivery to all crops in a field by regulating the emitter flow rate, but typically require high pumping pressures, contributing to high capital and operating costs for the pump and power system. Redesigning PC emitters for lower pressure operation could enable more energy-efficient and affordable drip systems. However, the current lack of published design theory for PC emitters hinders the development of emitters with desired hydraulic performance. To address this gap, we present an analytical, parametric model for the hydraulic behavior (i.e., the flow rate versus pressure curve) of inline PC emitters before the flow-regulating regime. We combine this model with a validated prototyping method to demonstrate its utility in the design of PC emitters with target activation pressures and flow rates, and demonstrate a sample design that achieves 38% lower activation pressure than commercial emitters with similar flow rates. The proposed model sheds light on the parametric relationships between PC emitter geometry and performance. It may inform R&D efforts in the irrigation industry and lead to improved emitter designs with low operating pressures, helping reduce drip system costs and increase access to drip irrigation among smallholder farmers.