Showing 4 results for Distribution Uniformity
H.a Alizadeh , F Abbasi , A Liaghat ,
Volume 14, Issue 51 (4-2010)
Abstract
The application of N fertilizers with surface irrigation stream (surface N fertigation( is a key approach for fertilizer management. The main objective of this study was to investigate furrow fertigation management effects on distribution uniformity and runoff losses of nitrate in field scale. A field corn experiment was carried out with a complete randomized block design having 12 experiments. The field experiments were carried out in free draining furrows having 165 m length and 0.006 m/m slope in Karaj. Required urea fertilizer was applied in four stages: before planting, in seven leaves stage, shooting stage and earring stage. The first stage was accomplished by traditional method and other stages were applied with irrigation water (fertigation). Fertigation timing was respectively 60, 35, and 20 min in the three fertigation stages. Results showed that distribution uniformity of water and fertilizer of low half (DULH) provided high values for all experiments. DULH ranged between 88.0 to 99.0% and 89.7 to 96.0%, respectively for water and fertilizer. Also, distribution uniformity of low quarter (DULQ) ranged between 86.0 to 98.2% and 85.7 to 91.5%, respectively for water and fertilizer. Nitrate losses through surface runoff ranged between 5.7 to 42.0%. Duncan test results for comparison between different experiments showed that there was significant difference (p=0.95) between fertilizer losses at the level of fertilizer injection time of 60 and 35 minutes, but there was no significant difference between levels of 35 and 20 minutes.
A. Faryabi , E. Maroufpoor , H.ghamarnia ,
Volume 14, Issue 54 (1-2011)
Abstract
Precision in design of sprinkler irrigation systems and their proper management are very important for both development and also improvement of those systems. Therefore, the main objective of this study was to evaluate the design and management of the solid-set sprinkler systems in Dehgolan plain located in Kurdistan province. For this purpose, 10 solid-set sprinkler systems were selected randomly and a few performance parameters such as: Christiansen’s uniformity coefficient (CU), distribution uniformity (DU), potential application efficiency of low-quarter (PELQ) and application efficiency of low-quarter (AELQ) were estimated. The results of investigation showed the mean values of 66, 50.6, 44.8 and 43. 8%, for the above mentioned parameters, respectively. Also, the results of investigation showed both low PELQ values and water distribution uniformity of those evaluated systems compared to the recommended values by Merriam and Keller (1978). Moreover, due to deficit irrigation, except for one evaluated system, in all other systems, AELQ values were equal to PELQ. The results of our investigation also showed that non-suitable design and implementation of the evaluated systems were among the most important reasons for low values of PELQ, because of non-suitable operating pressure. The most important reasons for low water distribution uniformity were the simultaneous use of many sprinklers and also performance of different sprinklers models in a system. Finally, the results of our investigation showed poor operation for the evaluated systems in many cases.
V. Rahmatabadi , M. Behzad, S. Borumandnasab , H. Sakhaei Rad,
Volume 19, Issue 73 (11-2015)
Abstract
In order to increase the distribution uniformity of sprinkler irrigation systems, some influential parameters such as wind speed, arrangement, space and type of sprinklers must be studied and controlled. In this study, a set of experiments were conducted based on ISO 7749/2(1990) standard to evaluate the ADF 250 and Nelson, F80APV sprinklers. To study the effects of wind velocity, operating pressure, various sprinkler layouts and spacing on water distribution uniformity, the experiments were conducted based on a single sprinkler method. Four operating pressures in the range of one recommended by the manufacturer for each sprinkler were applied and three sprinklers’ spaces on lateral pipelines (22, 26, and 30 m) were simulated for square and rectangular layouts to estimate the water distribution uniformity. Results showed that the distribution uniformity of Nelson sprinkler in existing wind velocities and operating pressures had smaller changes than ADF sprinkler. The 4.5 bar pressure for ADF sprinkler was better than other pressures, and operating pressures for Nelson sprinkler did not have any significant effect on distribution uniformity. With the decrease of sprinkler spacing to the wetting diameter in the simulated space, uniformity coefficient was increased. The recommended sprinkler spacing to the wetting diameter for these sprinklers ranged from 0.4 to 0.5 for square and rectangular layouts.
Amir Mahdi Bayat, Mohammad Shayannejad, Mahmood Akbari,
Volume 30, Issue 1 (3-2026)
Abstract
Mathematical models are a suitable tool for surface irrigation design. The EDOSIM model, as a surface irrigation simulation-optimization model, utilizes simulation with the volume balance model and meta-heuristic optimization. In this study, with the aim of improving the simulation of the advanced phase in the EDOSIM model, the Full Hydrodynamic model was replaced by the Volume Balance model for furrow irrigation design, leading to the development of the EDOSIM-HD model. The Saint-Venant equations were discretized using the implicit Preissmann’s finite difference scheme and transformed into a set of nonlinear equations in the form of a system of equations. The resulting system of equations was linearized using the Newton-Raphson method and solved using the Sparse matrix method. The results were compared with the SIRMOD software to validate the simulation. Using the particleswarm solver of the MATLAB software optimization toolbox, the inflow rate as a decision variable was used to optimize the hydraulic objective function consisting of efficiency, adequacy, and uniformity. The results in the experimental field showed that in the initial simulation with an inflow rate of 1.4 lps, important irrigation times, infiltration volume, performance indicators, profiles, and hydrographs showed a deep percolation loss of about 50 percent of water. Also, the results of the EDOSIM-HD model were closer to the Hydrodynamic model of the SIRMOD software than the EDOSIM model. By optimizing and increasing the optimal flow rate (1.8 lps) compared to the initial inflow rate, the advance, cut-off, depletion, and recession times were reduced, and the required infiltration time remained unchanged. The reduction in infiltration volume was also achieved by applying higher inflow rates in less time. All performance indicators also moved closer to their optimal state. Except for Tail Water Ration (TWR), which showed a slight increase of 11 percent (due to higher inflow rate), was negligible compared to the sharp 22% reduction in Depth Percolation Ratio (DPR), and 10% increase in Application Efficiency (Ea). Totally, according to the performance indicators obtained in the validation with the SIRMOD, the simulation of the EDOSIM-HD model was better than in the EDOSIM model in the advanced phase of furrow irrigation design
