The comparison of advance and erosion of meandering furrow irrigation with standard furrow irrigation under varying furrow inflow rates

Meandering furrow irrigation (Gholam-gardeshi irrigation) is a modified form of furrow irrigation, which has being used in Iran, but to date, there is no study about the erosion of this method of irrigation. To measure the erosion of meandering furrow irrigation and to compare the results with standard furrow irrigation, two experimental fields with different soil textures and furrow inflow rates were used. The experiment utilized a randomized factorial design with three replications for each treatment. In both methods, the developed second order polynomial equation for the erosion, and advance equation were able to predict the field data with coefficients of determination of more than 0.94. The results showed that the velocity of advance, tail water runoff and erosion are significantly lower for meandering furrow irrigation as compared to standard furrow irrigation. As the furrow inflow rates increased, erosion and runoff in both irrigation methods increased significantly.     

Comparison of sprinkler,trickle and furrow irrigation efficiencies for onion production

In the Mesilla Valley of southern New Mexico, furrow irrigation is the primary source of water for growing onions. As the demand for water increases, there will be increasing competition for this limited resource. Water management will become an essential practice used by farmers. Irrigation efficiency (IE) is an important factor into improving water management but so is economic return. Therefore, our objectives were to determine the irrigation efficiency, irrigation water use efficiency (IWUE) and water use efficiency (WUE), under sprinkler, furrow, and drip irrigated onions for different yield potential levels and to determine the IE associated with the amount of water application for a sprinkler and drip irrigation systems that had the highest economic return.Maximum IE (100%) and economic return were obtained with a sprinkler system at New Mexico State University’s Agriculture Science Center at Farmington, NM. This IE compared with the 54–80% obtained with the sprinkler irrigation used by the farmers. The IEs obtained for onion fields irrigated with subsurface drip irrigation methods ranged from 45 to 77%. The 45% represents the nonstressed treatments, in which an extra amount of irrigation above the evapotranspiration (Et) requirement was applied to keep the base of the onion plates wet. The irrigation water that was not used for Et went to deep drainage water. The return on the investment cost to install a drip system operated at a IE of 45 was 29%. Operating the drip system at a IE of 79% resulted in a yield similar to surface irrigated onions and consequently, it was not economical to install a drip system. The IEs at the furrow-irrigated onion fields ranged from 79 to 82%. However, the IEs at the furrow-irrigated onion fields were high because farmers have limited water resources. Consequently, they used the concept of deficit irrigation to irrigate their onion crops, resulting in lower yields. The maximum IWUE (0.084 t ha⁻¹ mm⁻¹ of water applied) was obtained using the sprinkler system, in which water applied to the field was limited to the amount needed to replace the onions’ Et requirements. The maximum IWUE values for onions using the subsurface drip was 0.059 and 0.046 t ha⁻¹ mm⁻¹ of water applied for furrow-irrigated onions. The lower IWUE values obtained under subsurface drip and furrow irrigation systems compared with sprinkler irrigation was due to excessive irrigation under subsurface drip and higher evaporation rates from fields using furrow irrigation. The maximum WUE for onions was 0.009 t ha⁻¹ mm⁻¹ of Et. In addition, WUE values are reduced by allowing the onions to suffer from water stress.     

Sediment transport in furrow irrigation

Irrigation-induced erosion in furrow irrigation causes loss of fertile soil and water quality degradation. Hence, quantification of irrigation-induced erosion is essential for efficient management of furrow irrigation. In this study, sediment transport was studied under bare and cropped field conditions for a furrow plot consisting of three parabolic shaped furrows of 40 m long and 0.5% slope. The inflow rates of 0.2, 0.3, 0.4 and 0.5 L s⁻¹; and 0.3, 0.4, 0.5, 0.6 and 0.7 L s⁻¹ were used for bare and cropped field conditions, respectively. The furrow cross section measured at every 5 m distance from the head end (before and after the irrigation event) was used to study the erosion pattern (erosion/deposition) along the furrow. The runoff collected at regular intervals of 10 min was used to study the sediment load. The total sediment export for an irrigation event was estimated using furrow cross-section data (FCD) and the sediment rate data (SRD), and compared with the total sediments collected at the tail end. For both bare and cropped conditions, soil erosion took place at the head and tail ends (free drain system), while the deposition occurred at the middle. The sediment transport increased initially and slightly decreased with time. A power relationship was obtained between the total sediment export and the inflow rate for bare furrow condition, whereas a linear relationship between these parameters was obtained for cropped field condition. The relative percentage errors suggested that both SRD and FCD methods can be used to estimate total sediment export from the field. The analysis (PSD) of the total sediments revealed that the geometric mean diameter of the sediment particle was 0.18 and 0.20 mm for bare and cropped field conditions, respectively.     

Design and management nomograph for furrow irrigation

There exist capabilities for analyzing the behavior of surface flow and the ultimate distribution of infiltrated water in furrow irrigation. The corresponding synthesis, i.e., the selection of appropriate combinations of inflow rates, cutoff times and length of furrow — design and management, currently not so well established, is treated herein. A design-management nomograph is proposed for free draining graded furrows. This is a plot of efficiency, time of cutoff and uniformity coefficient contours each given on a length-flow rate space adjacent to one another, for a furrow with given infiltration characteristics, flow geometry, slope, roughness and required depth of application. The nomograph can be used to determine the combinations of length, time of cutoff and flow rate that would yield in optimum combination of efficiency and uniformity.     

Effect of tillage and furrow irrigation timing on efficiency of preplant irrigation

Summary A field study to determine the efficiency of preplant irrigating with furrow irrigation and the effects of tillage and fall or spring application of preplant irrigation on this efficiency was conducted during 1983, 1984, and 1985 at the Texas Agricultural Experiment Station, North Plains Research Field at Etter, Texas on a Sherm, silty clay loam soil. Sorghum residue from the previous crop was shredded, gravimetric soil samples were taken, and five tillage treatments were imposed in the fall. The tillage treatments consisted of various combinations of disking, chiselling, moldboard plowing, and disk bedding. A preplant irrigation was applied in the fall to half of each tillage plot and in the spring to the other half of each plot. Soil samples were taken from each plot one month after the spring preplant irrigation. Sorghum (Sorghum bicolor L. cv. NC 178) was planted and irrigated similarly on all plots during the growing season. On the average, 237 mm of water were required to irrigate the tillage treatments during fall preplant irrigation and 466 mm were required during spring preplant irrigation. The additional water requirement in the spring was associated with increased water uptake by non-wheel-track furrows. Treatments with chiselling required larger water application during spring preplant irrigation. All treatments had similar soil water contents at planting time. Neither timing of preplant irrigation nor type of tillage had any effect on sorghum grain yield. Therefore, fall preplant irrigation was considerably more efficient than spring preplant irrigation. Averaged over the three years do study and five tillage treatments storage efficiency was 26% for fall application and 17% for springtime.Contribution of the Texas Agricultural Experiment Station, Paper No. 21724     

Potato water use and yield under furrow irrigation

Field experiments were conducted to study the effects of plant-furrow treatments and levels of irrigation on potato (Solanum tuberosum L.) water use, yield, and water-use efficiency. The experiments were carried out under deficit irrigation conditions in a sandy loam soil of eastern India in the winter seasons of 1991/92, 1992/93, and 1993/94. Two plant-furrow treatments and two levels of irrigation were considered. The two plant-furrow treatments were F₁ - furrows with single row of planting in each ridge with 45 cm distance between adjacent ridges, and F₂ - furrows with double rows of planting spaced 30 cm apart in each ridge with 60 cm distance between adjacent ridges. The two levels of irrigation (LOI) were I₁ - 0.9 IW/CPE and I₂ - 1.2 IW/CPE, where IW is irrigation water of 5 cm and CPE is cumulative pan evaporation. Treatment F₂ produced highest tuber yield in all years with average value of 10,610 kg ha ^-1 and 12,780 kg ha ^-1 at LOI of I₁ and I₂, respectively. On average, six irrigations with a total of 25 cm, and seven irrigations with a total of 30 cm were required for both treatments F₁ and F₂ at LOI of I₁ and I₂, respectively. Treatment F₂ resulted in a significantly higher number of branches and tubers per plant, foliage coverage and water-use efficiency for both irrigation levels than treatment F₁. Average daily crop evapotranspiration was found to range from 1.1 to 3.4 mm and from 1.2 to 3.9 mm for treatment F₁ and from 1.1 to 3.6 mm and from 1.2 to 4.0 mm for treatment F₂ at LOI of I₁ and I₂, respectively.     

Forecasting and optimizing furrow irrigation management decision variables

Furrow irrigation can be better managed if the management decision variables (irrigation time and amount; inflow rate and cutoff) can be determined ahead of time. In this study, these decision variables were forecast and optimized using 1 day ahead grass reference crop evapotranspiration (ET₀) forecasts, based on the ARMA (1,1) time-series model, with a seasonal furrow irrigation model for both homogeneous and heterogeneous infiltration conditions. Heterogeneity in infiltration characteristics was restricted to variations along the furrow length as opposed to variations between furrows. The results obtained were compared with their counterparts using the observed ET₀ for the same period during the 1992 cropping season. Seasonal performance (application efficiency, inflow, runoff and deep percolation volumes) and economic return to water (yield benefits minus seasonal water related and labor costs) were affected by infiltration conditions, while irrigation requirement and bean yield were unchanged. In a given infiltration case, seasonal performance, irrigation schedules, bean yield and economic return to water were comparable (lower than 4% difference) for the two ET₀ conditions. For each ET₀ condition, individual irrigation events resulted in different irrigation designs (inflow rate and cutoff time) except inflow rates with heterogeneous infiltration. Differences in inflow volume were less than 2% and 5%, respectively, for homogeneous infiltration and heterogeneous infiltration. For the conditions studied, furrow irrigation management decision variables can be forecast and optimized to better manage the irrigation system, because irrigation performance was the same for both (forecast and observed) ET₀ cases. Received: 9 October 1999     

Optimal furrow irrigation scheduling under heterogeneous conditions

In California, better farm water management practices are needed to meet the increasing water demands by competing water users (industrial, urban, wildlife, etc.), increasing environmental awareness and cost of water. Management can be improved through better irrigation scheduling and irrigation system designs. In this study, optimal furrow irrigation schedules, designs and irrigation adequacy were determined for heterogeneous soil conditions. The seasonal performance between optimal and full irrigation was compared. For the bean crop studied, the maximum return to water was achieved with the irrigation adequacies of 63, 59, 54, 49 and 50%, respectively, for irrigation intervals of 10, 12, 14, 18, and 21 days. An irrigation interval of 10 days with 63% adequacy gave the global maximum return to water. However, the Natural Resource Conservation Service recommended irrigation adequacy for homogeneous soil condition is 87·5%. For any given irrigation interval, optimal irrigation required less (48–63%) water than full irrigation. This also reduced both the deep percolation and runoff losses and caused a 31–43% increase in the application efficiency. Furthermore, loss in revenue due to yield reduction was less than the savings in irrigation cost, which resulted in higher (32–54%) net return to water under the optimal irrigation compared with full irrigation. These results indicate that the optimal irrigation strategy has potential not only for water conservation, but also for reducing non-point source pollution.     

Simulation of furrow irrigation practices (SOFIP): a field-scale modelling of water management and crop yield for furrow irrigation

Because of the spatial and temporal variabilities of the advance infiltration process, furrow irrigation investigations should not be limited to a single furrow irrigation event when using a modelling approach. The paper deals with the development and application of simulation of furrow irrigation practices (SOFIP), a model used to analyse furrow irrigation practices that take into account spatial and temporal variabilities of the advance infiltration process. SOFIP can be used to compare alternative furrow irrigation management strategies and find options that mitigate local deep-percolation risks while ensuring a crop yield level that is acceptable to the farmer. The model is comprised of three distinct modelling elements. The first element is RAIEOPT, a hydraulic model that predicts the advance infiltration process. Infiltration prediction in RAIEOPT depends on a soil moisture deficit parameter. PILOTE, a crop model, which is designed to simulate soil water balance and predict yield values, updates the soil moisture parameter. This parameter is an input of a parameter generator (PG), the third model component, which in turn provides RAIEOPT with the data required to simulate irrigation at the scale of an N-furrow set. The study of sources of variability and their impact on irrigation advance, based on field observations, allowed us to build a robust PG. Model applications show that irrigation practices must account for inter-furrow advance variability when optimising furrow irrigation systems. The impact of advance variability on deep percolation and crop yield losses depends on both climatic conditions and irrigation practices.     

Zero-inertia model for surge flow furrow irrigation

Summary A surge flow furrow irrigation model was developed based on the zero-inertia concept originally developed by Strelkoff and Kastapodes, (1977) for border irrigation and later modified for continuous furrow irrigation by Elliot et al. (1982). The model simulates all phases of continuous and surge flow irrigation including simultaneous advance and recession and can also be applied to basin and border irrigation with various field slopes. The surge model was verified for a wide range of actual field conditions and management alternatives. A sensitivity analysis was performed for the size of time step and the physical input parameters.     

Best management of pesticide — furrow irrigation systems

Summary Effects of furrow irrigation designs, water management practices (irrigation scheduling, etc.), soil types and pesticide parameters on pesticide leaching were simulated. A hydraulic kinematic-wave irrigation model was used to estimate water infiltration for alternative furrow lengths and inflow rates. A one-dimensional simulation model then simulated the movement of pesticides through soils following furrow irrigation. Potential ground-water contamination by pesticides can be reduced by an integrated use of the best management practices (BMPs) such as careful selection and use of pesticides, efficient furrow irrigation designs and improved water management techniques (irrigation scheduling, etc.). Procedures for designing an appropriate furrow irrigation system for a particular site and pesticide, and selecting pesticides for a particular site, crop and furrow irrigation system are illustrated. These procedures are being used to develop decision support computer models for developing different BMPs for pesticide-agricultural management decisions.     

Soil water variability under subsurface drip and furrow irrigation

Non-uniformities in soil hydraulic properties and infiltration rates are considered to be major reasons for the inefficiencies of some surface irrigation systems. These non-uniformities may cause non-uniformities in soil water contents and could potentially affect plant growth. To investigate whether the non-uniformities in soil water contents can be overcome by well-managed irrigation systems, fields with clay loam soils and planted to cotton were irrigated with a continuous-flow, a surge flow, and a subsurface drip system. Measurements of water contents in each field were taken throughout the growing season at several depths. The water contents measured within the top 0–0.9 m in the three irrigations systems were evaluated in terms of their spatial and temporal variabilities. The analyses indicated that on this soil, use of the surge flow system did not lead to increased spatial uniformities of soil water contents compared with the continuous-flow system. Use of the subsurface drip system resulted in very non-uniform soil water contents above the depth of the emitters. Variability in water contents below the emitter depth was comparable to the surface irrigation systems. Received: 26 March 1996     

Modeling and error analysis of kinematic-wave equations of furrow irrigation

A moving control volume approach was used to model the advance phase of a furrow irrigation system whereas a fixed control volume was used to model the nearly stationary phase and the runoff rate. The resulting finite-difference equations of the kinematic-wave model were linearized and explicit algebraic expressions were obtained for computation of advance and runoff rate. The solutions for the advance increment and the runoff rate were compared with the nonlinear scheme, the zero-inertia model, and a set of field data. A close agreement was found between the models and the field data. Assuming a constant infiltration rate, a differential equation was derived to estimate the error between the kinematic-wave model and the zero-inertia model in predicting the flow cross-sectional area along the field length. The differential equation and two dimensionless terms were used to define the limits for use of the kinematic-wave model in furrow irrigation.     

Empirical functions for dependent furrow irrigation variables.

A complete set of dependent furrow irrigation variables has been identified, for which empirical functions, of general applicability, have been developed. A one-dimensional sensitivity analysis technique coupled with dimensional analysis was employed to reduce the number of independent irrigation variables to a manageable size. Simulation experiments were carried out to generate the data used in developing the pertinent functional relationships. Regression analysis was used to ascertain the specific form of the equations. The predictive quality of the functions has been assessed by comparing their output with those of a zero-inertia model, and was found to be satisfactory. Received: 22 May 1996     

精准畦灌过程实时反馈控制技术

为了研究一种以关口时间为控制参数的地面灌溉实时反馈控制方法,构建了以灌溉信息实时采集与传输设备为支撑条件、以计算机处理系统为核心基础、以灌溉水流控制设备为应用条件的精准畦灌过程实时反馈控制系统.灌溉信息实时采集与传输设备自行研发的田间水流水位检测装置和无线信息接收管理装置,解决了灌溉信息容易漏测、接收距离短以及野外供电等难题;计算机处理系统根据实时采集的灌溉信息借助灌溉模型估算土壤特性参数值,预测灌溉过程,并根据选取的灌溉控制目标生成优化控制方案;最后由灌溉水流控制设备进行田间闸阀开闭.系统在北京、河北、新疆等地的试验基地进行了应用,结果表明:精准畦灌过程实时反馈控制系统对于加强畦灌过程可控性,提高畦灌田间灌溉效率,促进灌溉农业由经验型的粗放式管理向计算机控制的集约型管理转变具有十分重要的理论意义和现实意义.     

A real-time optimisation system for automation of furrow irrigation

An automated real-time optimisation system for furrow irrigation was developed and tested in this study. The system estimates the soil infiltration characteristics in real time and utilises the data to control the same irrigation event to give optimum performance for the current soil conditions. The main components of the system are as follows: the sensing of flow rate and a single advance time to a point approximately midway down the field, a system for scaling the soil infiltration characteristic and a hydraulic simulation program based on the full hydrodynamic model. A modem is attached to a microcomputer enabling it to receive signals from the flow meter and advance sensor via a radio telemetry system. Sample data from a furrow-irrigated commercial cotton property are used to demonstrate how the system works. The results demonstrate that improvements in on-farm water use efficiency and labour savings are potentially achievable through the use of the system.     

Assessment and simulation of water and nitrogen transfer under furrow irrigation

The objective of this study is to simulate water and nitrogen transfers under two furrow irrigation technologies (every furrow irrigation (EFI) and alternative furrow irrigation (AFI)) on Chromic Luvisol in Sofia region, Bulgaria. A bi-dimensional water and solutes transport modeling approach, HYDRUS-2D model [Simunek, J., Sejna, M., Van Genuchten, M.T., 1999. The HYDRUS-1D and HYDRUS-2D codes for estimating unsaturated soil hydraulic and solutes transport parameters. Agron Abstr. 357] is adopted in order to consider the technology of irrigation and fertilization. The model is calibrated in six steps using detailed data observed in two cropped lysimeters. The data consist of water and nitrogen (N) profiles below ridge and furrow bed, precipitation, drainage and water/N uptake by plant. Hydrological components of the soil are derived from laboratory: water retention data (step (i)) and adjusted to field conditions when EFI is approximated by one-dimensional (step (ii)). Then a two-dimensional water flow is adopted in model simulations for parameter calibration and verification, under EFI (step (iii)) and under AFI technology (step (iv)). This model calibration and validation is then used to calibrate the solute transport parameters, that is the aim of step (v) and step (vi). EFI and particularly AFI technologies points out the necessary 2D model using for the N transfer simulation under specific fertilizer applications. Thus, this calibrated model allows predicting the impact of furrow irrigation practices and distribution uniformity on drainage and nitrogen leaching under the studied conditions.     

Factors affecting uniformity and optimal water management with furrow irrigation

Summary A kinematic wave mathematical model which simulates the hydraulics of continuous flow furrow irrigation was linked with a crop yield model and used in combination with an economic model to analyze the effects of inflow rate, water infiltration characteristics and furrow length on uniformity of infiltrated water, runoff, gross profits and optimal number of 12 hour irrigations for corn (Zea mays) assuming other management practices to be constant. Higher uniformity of infiltrated water but more runoff and, in some cases, more deep percolation resulted from increased flow rates. Increases in uniformity of infiltrated water leads to greater profits, which are however offset by the associated increases in runoff and deep percolation. The study shows economically optimal water management for furrow irrigation can be obtained with proper balance between changes in the input variables and runoff and to some extent deep percolation.Contribution of the Department of Soil and Environmental Sciences, University of California, Riverside 92521. This study was supported by California State Water Resources Control Board Contract # 2-043-300-0     

A furrow irrigation model to improve irrigation practices in the Gharb valley of Morocco

In developing countries, modernization of surface irrigation is the most common solution to water management problems in irrigated areas because it is well adapted to the socio-economical context. This solution was adopted in the Gharb area near Kenitra in Morocco where an experimental site was set up to obtain irrigation and drainage references. Meaningful improvements in irrigation efficiency and better crop yields have yet to result from the modernization effort. Different sources of heterogeneity affecting the infiltration process can hinder the improvement of irrigation efficiency even in a modernized furrow irrigation context. The respective impact of deterministic and stochastic heterogeneity sources on the advance-infiltration process is analyzed. Then, a model based on the spatial and temporal variability of infiltration is developed to simulate the impact of irrigation practices on water saving during an irrigation season. This work will later contribute to the elaboration of a modelling approach simulating fertilization and irrigation practices.     

Infiltration parameters from optimisation on furrow irrigation advance data

Knowledge of the soil infiltration parameters is necessary for efficient furrow irrigation. A method is proposed for the determination of the parameters in the Kostiakov-Lewis infiltration equation from measurements of the furrow irrigation advance and inflow. The method employs a volume balance model using optimisation to minimise the error between the predicted and measured advance and differs from existing approaches in that only advance data and inflow rates are required. The average cross sectional area of the furrow and the final infiltration rate are treated as fitted parameters and need not be measured. A simple but effective optimisation algorithm is developed which allows for the solution of the four parameters without user input. The speed and simplicity of the optimisation may lead to application in real-time control of furrow irrigation. Received: 16 August 1995