Low Quarter Distribution Uniformity Research Articles

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.

Evaluating Uniformity of Center Pivot Irrigation Systems in Western Oklahoma

Highlights63% of the 24 center pivots tested in western Oklahoma had acceptable uniformity.On average, 7% of pumped water was lost before reaching the soil surface.Irrigation nonuniformity can have major, yet variable effects on water fluxes.Abstract. Nonuniform application of water through center pivots can lead to under- or over-irrigation at parts of the field, which can lead to water stress and yield reductions or loss of limited water resources and leaching of applied chemicals, respectively. In this study, irrigation uniformity tests were performed to determine the application uniformity and conveyance efficiency of 24 center pivots in western Oklahoma. The average coefficient of uniformity and low quarter distribution uniformity of the tested systems were 78% and 69%, respectively. These values indicate an overall borderline acceptable application uniformity. The average water conveyance efficiency was 93%, indicating that 7% of pumped water was lost before reaching the soil surface. Measured ratios of collected water in each collector to the average collected water for corresponding center pivots were used to simulate the effects of observed nonuniformity on water fluxes for a 10-year period. Under-irrigation (e.g., caused by clogged nozzles) led to considerable reduction in crop transpiration at the simulation location in the Panhandle, while the decreasing effects were more notable for deep percolation for the location in west-central Oklahoma. Over-irrigation (e.g., caused by leaks or missing nozzles) resulted in substantially larger deep percolations at both locations. Keywords: Catch-can, Conveyance efficiency, Water fluxes.

Precision surface irrigation with conjunctive water use

The Indus Basin Irrigation System is characterized as a gravity surface irrigation system, with minimal on-line or off-line storage and limited distribution control. An important characteristic is the limited water availability. On field irrigation within the Indus Basin Irrigation System is almost entirely using surface irrigation and only very few farms adopting pressurized irrigation systems. The objective of the warabandi management system that characterizes the Indus Basin Irrigation System is to distribute the limited available water as equitably as possible. This research evaluates surface irrigation under furrow and border strip irrigation using canal water and groundwater conjunctively. This paper presents results from a numerical model and field observations, to examine the precision surface irrigation paradigm within the water supply constraints imposed by the warabandi system of the Indus Basin Irrigation System. We conclude that laser grading within the IBIS is achievable at a modest cost and effort. Our findings suggest that the improved laser-graded profile persists for at least three crop seasons. Furrow irrigation can attain a high performance using either available canal or groundwater with low quarter distribution uniformity and low quarter application efficiency as performance indicators. Border irrigation can also attain a high performance provided irrigation is changed to fortnightly. Model predictions of advance curve and low quarter distribution uniformity are compared to field observations and in-situ measurement.

Temporal and spatial distribution of soil water and nitrate content affected by surface irrigation and fertilizer rate in silage corn fields

Among surface irrigation systems, long border and furrow are more adaptive to mechanized farming but may cause a non-uniform distribution of water and nutrients. In this study, field experiments were carried out in a flat silage corn field in Hebei, China to investigate the uniformity along the length of border or furrow to understand the spatial and temporal distribution characteristics of soil water, electrical conductivity, and nitrate. This will guide irrigation and fertigation management recommendations, land consolidation, and high standard farmland construction. Border and furrow irrigation were tested using fertilizer rates of 750, 600, 450 and 300 kg/ha. Low quarter distribution uniformity (DUlq) and storage efficiency (E) were quantified to determine the distribution of soil water and soil nitrate content. The results indicate heterogeneity along the length of the border or furrow is weak for soil water content and is moderate for nitrate content, based on the uniformity coefficient (CV). The average low quarter distribution uniformity of soil water (DUlqW) was 96.34, there was a significant effect of irrigation type on DUlqW, and the DUlqW for border irrigation was 0.8% larger than that for furrow irrigation. The average low quarter distribution uniformity of nitrate content DUlqN was 79.04, and there was no significant influence of irrigation type and fertilizer rate on DUlqN. Spatial and temporal distribution analysis showed that the variation of soil water in the 0–60 cm soil layer was larger than that in 60–100 cm soil layer, and the electrical conductivity (EC) and nitrate content gradually decreased with increasing soil depth. There was a decreasing trend in soil EC and nitrate content with decreasing fertilizer rates. The storage efficiency of water (EW) for border irrigation was 56.63, and significantly lower than that for furrow irrigation over the whole growth duration. The nitrate storage efficiency (EN) was 65.47, and there was no significant effect of irrigation type or fertilizer rate on EN. Even with longer borders or furrows of 90 m, the uniformity of water and nitrate along the length of the border or furrow is weak or medium, which can create non-uniform conditions for crop growth. Furrow irrigation may store slightly more water in the top 60 cm of soil compared to border irrigation. Fertilizer rate had no significant effect on the uniformity and distribution of soil water or nitrate.

Evaluation of hydraulic performance: a case study of etana small scale irrigation scheme: wolaita zone, Ethiopia

The conventional furrow irrigation system is inherently inefficient in wolaita zone, while the suboptimal management and operation (inflow discharge and cutoff time) are considered as one of the main reasons for satisfactory hydraulic performance. Addressing these issues, the furrow irrigation system which is only practiced in the study area was evaluated on three fields under routine farmer management in wolaita zone. The study consisted of field experiments and simulation modeling. Irrigation performance including application efficiency, Potential Application Efficiency, Adequacy and distribution uniformity, runoff ratio and deep percolation ratio of two irrigation events were evaluated using surface irrigation evaluation and simulation Model WinSRFR 4.1.3. The study revealed satisfactory irrigation efficiencies, with higher distribution uniformity and water losses. Therefore, hydraulic performance of the study area had a value of application efficiency (55% to 73%), low quarter adequacy (0.96 to 1.28) and low quarter distribution uniformity (0.89 to 0.96), runoff ratio (7% to 38%) and deep percolation ratio (1% to 25%) on farms. In addition, irrigation over irrigation status practiced was found in study area with the average low quarter adequacy of 1.14. The existing irrigation application efficiencies of irrigated fields at ETANA SSIS are poor having a mean value of AE and LQDU are 62% and 0.93.

Border irrigation performance with distance-based cut-off

Border irrigation is widely practised for winter wheat production on the North China Plain. Winter wheat is mainly irrigated with groundwater as a supplement to insufficient precipitation to maintain high agricultural production. As a result of the increased demands for water, groundwater levels have declined. Therefore, improvements to border irrigation performance and water use efficiency are urgently needed. The objective of this study was to determine the optimal distance at which to cut off inflow under different inflow rate conditions in closed-ended border systems. The experimental treatments included three inflow rates (high, moderate, and low, with average rates of 6.91 l s−1 m−1, 4.95 l s−1 m−1, and 2.81 l s−1 m−1, respectively) and three cut-off ratios (CRs) arranged in three replications at the CAS Ecological Agricultural Experiment Station in Nanpi, Hebei Province, China. The surface irrigation hydraulic simulation model WinSRFR was used to examine the sensitivity of the existing design to a range of bottom slopes, surface roughness values, and inflow rates to demonstrate the robustness of the solutions in terms of their application efficiency and low-quarter distribution uniformity. The results present the optimum CR values for different inflow rate conditions to maximize irrigation performance. The results indicate that irrigation performance above the optimum CR values for high, moderate, and low inflow rates is not very sensitive to bottom slope, and no substantial changes in performance were noted when Manning’s roughness coefficient was between 0.04 and 0.09. A set of inflow rate ranges that corresponds to the recommended CRs that could achieve high irrigation performance is presented.

The potential of precision surface irrigation in the Indus Basin Irrigation System

In this research we explore the potential of precision surface irrigation to improve irrigation performance under the warabandi system prevalent in the Indus Basin Irrigation System. Data on field dimensions, field slopes along with characteristic soil infiltration properties and outlet discharge were collected through a survey of a sample tertiary unit of Maira Branch Canal, Khyber Pakhtunkhwa Province, Pakistan. The performance of all fields in the tertiary unit was analysed and reported in aggregate, with detailed results of one field presented for illustration. The objective is to determine the optimum field layout, defined as the number of border strips, for the observed field characteristics to maximize performance. The results indicate that performance improvement is relatively easily achievable through changes in field layout within current irrigation services. Estimated application efficiency is sensitive to the selected depth of application, and it is important that a practical depth of application is selected. We recommend a depth of application of 50 mm and show how this is achievable and leads to a low quarter distribution uniformity of 0.750 and an application efficiency of 80 %. We also explore the feasibility of a 10-day warabandi rather than the 7-day warabandi and show that there is no significant change in the performance under a 10-day warabandi.

Sprinkler irrigation uniformity: Impact on the crop yield and water use efficiency

In this work, an assessment of the effect of distribution uniformity over water use efficiency is shown. The experimental study took place in Sebha region, southern Libya, characterized by arid climate and interested a barley field. The results of water irrigation in the sprinkler irrigation system with respect to the operating pressure (P) and raiser height of sprinkler (H) are reported with respect to distribution uniformity and water use efficiency. The main objective of irrigation is to apply the optimum amount of water to the crop root zone that is needed for its growth and maturation, and it is, hence, important for to check the uniformity of irrigation systems in order to adjust the operating parameters involved. To assess uniformity, the coefficient of uniformity (CU), the low quarter distribution uniformity (DU), and the coefficient of variation (CV) were considered, while the grain yield (GY), the crop height (CH) and the water use efficiency (WUE) weremeasured in order to find the best solution in terms of operating conditions. The highest values reached by the uniformity parameters with varying the operating conditions defined the best operating practices under which the irrigation system works efficiently: the results demonstrated that the maximum values for CU and DU, 91.37% and 0.85, respectively, were obtained at the highest P and H, and under the same conditions, also grain yield, plants height and WUE recorded the highest values: 5.50 t·ha−1, 63.49 cm and 0.75 kg·m−3, respectively. The results emerged in this work can be useful for similar arid regions like Sebha region, in order to solve the problems related to water scarcity and water use efficiency.

Harvesting water in a center pivot irrigation system: Evaluation of distribution uniformity with varying operating parameters

The main objective of irrigation is to apply the optimum amount of water to the crop root zone that is needed for its growth. Also, when irrigation systems are used to apply fertilizers and pesticides, the irrigation process becomes even more critical in terms of uniformity. Consequently, it is important for center pivot owners and operators to periodically check the uniformity of their systems in order to adjust all the operating parameters involved. To assess the real distribution uniformity of irrigated water, a study was conducted in southern Libya; this paper reports the results of water irrigation in a center pivot system with respect to the effects that the operating pressure (P), the spacing between sprinklers (S), and the height of sprinkler above the ground surface (H) show on the distribution uniformity. Several factors define the uniformity of water distribution; in this work the coefficient of uniformity CU, the low quarter distribution uniformity DU lq , and the coefficient of variation CV are considered. The highest values reached by the uniformity parameters with varying the operating conditions define the best operating practices under which the whole system works efficiently. The final results are given in terms of operating conditions able to save total costs in the studied area and in places characterized by similar geo-hydrological conditions.

Infiltration Evaluation Strategy for Border Irrigation Management

Water infiltration into soil plays a vital role in the performance of surface irrigation. Real-time information on infiltration characteristics is necessary to use surface irrigation models to manage irrigation systems. The present field study deals with the evaluation of the Kostiakov infiltration parameters using water front advance information at three different locations (50, 75, and 100% of the field length) along the alfalfa irrigated borders. Two irrigations were conducted on four border checks. The parameters of the Kostiakov infiltration model were determined using the one-point and two-point methods for these locations. The infiltration parameters for each border were used in a surface irrigation model to evaluate their impact on irrigation performance measures. The mean irrigation performance measures, such as inflow volume, application efficiency, tailwater ratio, deep percolation ratio, and low quarter distribution uniformity, were significantly different for one-point and two-point methods. However, the mean performance measures were not significantly different for infiltration functions evaluated at three different locations using the two-point method. Furthermore, performance of individual irrigation events was in close agreement for all three locations. Thus, infiltration parameters can be estimated using the water front advance information up to 75% of the field length (to reduce the impact of soil spatial variability) and can be used to predict irrigation performance measures reasonably well. A cutoff strategy that ensures the advancement of the wetting front to the downstream end of the field was devised on the basis of the infiltration parameters evaluated at 75% of the field length. This cutoff strategy resulted in savings of applied water (18%) and reduction in both tailwater and deep percolation losses, which gave higher application efficiency. The methodology presented in this article has the potential for use in real-time management of border irrigation systems.

Operational Analysis of Water Application of a Sprinkler Irrigation System Installed in a Golf Course: Case Study

Popup sprinkler irrigation systems are usually installed in golf courses, orchards, and lawns. Evaluation of these systems is considered essential to identifying any necessary improvements. To this end some performance indicators have evolved for comparison of the existing performance with established design criteria of the system. The irrigation uniformity and application efficiency of any irrigation system are important factors which are strongly affected by pressure and wind speed. In this study, the water application uniformity, system efficiency, water application rates, jet losses, and soil infiltration characteristics were considered as the basic performance indicators. The low quarter distribution uniformity of the system varied from 43 to 57% and the application efficiency was found to be only 34–47%. The Christiansen uniformity coefficient varied from 61.7 to 68.9% for different operating pressures. More losses were found for day time irrigation than for night time irrigation. Surface runoff was...

Uniformity of Water Application under Drip Irrigation in Litchi Plantation and Impact of pH on Its Growth in Partially Reclaimed Alkali Soil

A field experiment was conducted to study the effect of varying water application and soil pH on the growth parameters during the establishment of litchi (Litchi chinensis Sonn.) plantation in a partially reclaimed alkali environment. The plant growth parameters such as plant height and girth at collar were studied. Hydraulic performance of drip system was monitored by observing the individual and plant wise emitter discharge. The Christiansen's Coefficient of Uniformity (CCU), Wilcox-Swailes Coefficient of Uniformity (WSCU), Statistical Coefficient of Uniformity (SCU), Low Quarter Distribution Uniformity (SDU1q), and Coefficient for Emitter Flow Variation (CEFV) for the rate of water application were determined. The average value of CCU remained close to 0.63 and 0.75, respectively, on emitters' and plant basis when 4 drippers were employed per plant. Different levels of soil pH as experienced by the litchi plants were grouped into seven soil pH groups viz. less than 7.75, 7.75-8.00, 8.008.25, 8.25-8.50, 8.50-8.75, 8.75-9.00 and more than 9.00. In each of the above pH groups, different emitter discharges were observed. The plant wise discharges received in each pH group were further sub-divided and grouped in less than 10, 10-15, 15-20,20-25,25-30 and above 30 litter per hour (1h-1). The plant growth parameters were significantly different at different soil pH levels. The plant mortality was high and plant height and girth at collar reduced when the soil pH exceeded 8.5. A positive linear trend was observed in growth parameters and the application of discharge at or below a pH level of 8.5, after which the trend was reverse.

Uniformity testing of variable-rate center pivot irrigation control systems

As water supplies become limited, agricultural water use needs to become more efficient to maintain current productivity levels. The efficiency of center pivot and linear move irrigation systems can be increased by matching the amount and rate of water application to specific soil conditions that vary in the field. Such site-specific application can be achieved by variable-rate control systems. Although such systems are being developed, their effects on center pivot and linear move uniformity have not been documented. The uniformity along the length of a center pivot and a linear move irrigation system was measured at two system movement speeds and three variable-rate settings. One variable-rate system is commercially available using pneumatically actuated solenoid valves to turn groups of sprinklers ON and OFF at fractions of a minute corresponding to the cycle rate, for example a 50% cycle rate is 30 s ON and 30 s OFF. The other variable-rate system used commonly available electric solenoid valves to accomplish the same task. Overall, the coefficient of uniformity and low quarter distribution uniformity averaged 93% and 0.90, respectively for the center pivot irrigation system; 84% and 0.74 for the linear move system. The results were not significantly (P > 0.05) affected by wind speed, cycling rate, or system movement speed. The type of nozzle did influence the uniformity because of the distinctly different application characteristics of rotator, fixed plate, and wobbling low pressure sprinklers. Thus, the variable-rate technologies tested under the conditions presented in this paper had at least as good uniformity as the center pivot and linear move systems when functioning in non-variable-rate mode.

Performance and Water Conservation Potential of Multi-Stream, Multi-Trajectory Rotating Sprinklers for Landscape Irrigation

Multi-stream, multi-trajectory rotating (MSMTR) sprinklers represent an alternative to fixed spray heads for the irrigation of small landscape areas. Preliminary investigations have suggested that MSMTR sprinklers can apply water with higher distribution uniformities than fixed sprays, offering the potential for water conservation. This article presents the results of field audits comparing the performance of fixed spray and MSMTR sprinklers in landscape irrigation. Individual zones were audited before and after a conversion from fixed spray to MSMTR sprinklers. Average low quarter distribution uniformity (DULQ) improved by 0.26, from 0.44 to 0.70, after the conversions. Average low half run time multiplier (RTMLH) decreased by 0.39. New performance measures, directly related to water conservation, were developed and applied to the field audit data. Water conservation diagrams were used to illustrate performance improvements and the potential for water conservation due to improved performance. Estimated water conservation potential due to the conversion from fixed spray to MSMTR sprinklers depends on pre-conversion uniformity and choice of run time multiplier (RTM). The average water conservation potential estimated for the fixed spray to MSMTR conversion ranged from 22% to 40% of the pre-conversion application depending on pre-conversion choice of RTM. A good single-point estimate for water conservation potential due to fixed spray to MSMTR conversion is 31%. MSMTR sprinklers have lower precipitation rates than fixed spray heads, and may be expected to need longer run times to meet a given required amount. The higher uniformity of the MSMTR sprinkler partially mitigates this. Sample calculations assuming no runoff from the higher precipitation rate fixed sprays indicate the net MSMTR systems may need to run 1.7 to 2.3 times as long as fixed sprays used to run to deliver the same net application.

Analysis of Residential Irrigation Distribution Uniformity

Irrigation has become commonplace for residential homeowners desiring high quality landscapes in Florida. The goal of this project was to document irrigation system uniformity in Central Florida and to quantify distribution uniformity of residential sprinkler equipment under controlled conditions. The catch-can testing procedure used was a modified version of both the American Society of Agricultural Engineers standard and Florida Mobile Irrigation Laboratory (MIL) procedures. The modified version included a larger sample size to ensure complete sample collection over the entire irrigated area. The standard MIL procedure may overestimate the uniformity for residential systems. From the tests on residential irrigation systems, the average low quarter distribution uniformity (DUlq) value was calculated as 0.45. Rotary sprinklers resulted in significantly higher DUlq compared to fixed pattern spray heads with 0.49 compared to 0.41, respectively. From uniformity tests performed on rotor and spray heads under ideal conditions, rotor heads had more uniform distributions than the spray heads of 0.55 compared to 0.49, respectively. Spray heads had better uniformity when fixed quarter circle nozzles were used as opposed to adjustable nozzles. Both residential irrigation system and controlled tests resulted in (DUlq) at the low end of industry guidelines. Residential irrigation system uniformity can be improved by minimizing the occurrence of low pressure in the irrigation system and by ensuring proper spacing is used in design and installation.

BORDER STRIP FERTIGATION: EFFECT OF INJECTION STRATEGIES ON THE DISTRIBUTION OF BROMIDE

Fertigation using surface irrigation is a cost-effective and simple method of applying fertilizer across the field. The primary objective of this study was to compare different strategies for timing injection of bromide and its fate when injected into the irrigation water, as a surrogate for nitrate, during the irrigation of narrow sloping border strips. A fertigation experiment was conducted on sloping borders strips in the Coachella Valley Water District, California, on a Coachella fine sand, (sandy, mixed hyperthermic Typic Torrifluvents) and the crop was date palms (Phoenix dactylifera L.). Four treatments were used: bromide injection during the first half, the last half, and the middle half of the irrigation and during the entire irrigation (100%). The average low quarter distribution uniformity (DUlq) for water application was 0.73. For bromide, DUlq values ranged from 0.21 for the last half injection strategies to 0.64 for the 100% treatment. Use of one-dimensional models (EVALUE and SRFR) predicted satisfactory water but not bromide distributions. This is mainly because the models do not account for the flow through the furrows adjacent to the border dikes. The results of this study support the general finding that unless the soil is extremely sandy, injection during the entire irrigation produced the best distribution uniformity of added bromide. In this study, injection during the first half of the irrigation was not statistically different from injection during 100% of the irrigation.

STATISTICAL APPROACH TO INCORPORATING THE INFLUENCE OF LAND-GRADING PRECISION ON LEVEL-BASIN PERFORMANCE

Monte-Carlo simulation was used to determine the suitability of statistical equations for estimating theinfluence of soil surface elevations on the low-quarter distribution uniformity, DUlq, of level-basin irrigation systems. Itwas shown that these equations give reasonable estimates of DUlq, provided that the advance curve is known. The Monte-Carlo simulations also provided an estimate of the variation in DUlq for different fields with the same standard deviationof elevations. The statistical equations demonstrate that irrigation uniformity is influenced by the ratio of soil surfaceelevation standard deviation to average depth infiltrated. For conditions that would be typical of laser-leveled basinswithin the U.S., the influence of elevation variations on DUlq is small. However, for poorly leveled fields, as frequentlyoccur in Egypt, these elevation variations can significantly reduce DUlq, thus limiting potential efficiencies. In somecases, these simple equations can be used to adjust level-basin designs to account for the variation in surface elevationswithout the need for extensive simulation studies.

Cotton Yield Variability Under Level Basin Irrigation

Field experiments were conducted in central Arizona on a sandy loam soil to evaluate the effects of irrigation uniformity on the lint yield of cotton grown with level basin irrigation. Treatments of High, Medium, and Low irrigation received seasonal water application depths of 900, 700, and 500 mm, respectively, after crop establishment. The level basin system was operated to provide a high irrigation uniformity in 1987 and a low irrigation uniformity in 1988. The measured depth of water replaced by irrigation was characterized by the low-quarter distribution uniformity which varied from 80-85% in 1987, compared to 69-82% in 1988. Under the higher irrigation uniformity in 1987, correlation between the measured yield and total depth of water replaced was not significant within either the High or Medium irrigation treatments. Under the low irrigation uniformity of 1988, yield variability within the field was more extensive, and the yield was significantly correlated with total depth of water replaced within all irrigation treatments. When expressed relative to the mean lint yield of the local farm area, yields of the High, Medium, and Low irrigation were about 6, 2, and 7% greater under high than low irrigation uniformity, respectively.