Hajar Taheri; Mehdi Ghobadinia; Hasan Tabatabaei; Habib Beygi; Hossein Kazemian
Abstract
Water shortage in agriculture leads to use of marginal water resources such as wastewater. Use of Zeolite as a soil improvement material is necessary for application of wastewater for irrigation. In this research, the effect of application method, amount, and size of the zeolite on the changes of the ...
Read More
Water shortage in agriculture leads to use of marginal water resources such as wastewater. Use of Zeolite as a soil improvement material is necessary for application of wastewater for irrigation. In this research, the effect of application method, amount, and size of the zeolite on the changes of the electrical conductivity, pH, BOD5, sodium, and total calcium and magnesium of wastewater was studied while passing soil columns. To do this, two application methods (mixed and layered), two particle size range of zeolite (between 125 and 63 microns and smaller than 63 microns), two zeolite rates (2% and 4%), and four irrigations (first, fourth, ninth, and thirteenth) were studied in PVC columns of 10.5 cm inner diameter and 60 cm height. The experiments consisted of 9 treatments and 3 replications. The soil samples were irrigated 13 times with wastewater in a weekly interval. In irrigation cycles numbers one, four, nine, and thirteen, the mentioned factors were measured in the input and output of wastewater samples. Results showed that calcium and magnesium absorption rate increased by average of 75.7% and 142% in mixed and layered treatments, respectively, in comparison to the control. Removal efficiency for BOD5 was increased by average of 43.1% and 87% in mixed and layered treatments, respectively, in comparison to the control. Application of zeolite also increased sodium, pH, and electrical conductivity of soil columns.
Sonia Zebardast; Hasan Tabatabi; Behzad Ghorbani
Abstract
Furrow irrigation is one of the common surface irrigation methods whose hydraulic behavior is under the influence of the inflow hydrograph. Accurate prediction of the advance phase is very important for design, management, and evaluation of this kind of surface irrigation system. In this study, the advance ...
Read More
Furrow irrigation is one of the common surface irrigation methods whose hydraulic behavior is under the influence of the inflow hydrograph. Accurate prediction of the advance phase is very important for design, management, and evaluation of this kind of surface irrigation system. In this study, the advance phase was simulated for six different hydrograph conditions of continuous and cutback inflows to furrow by using surface irrigation mathematical models. Field experiments were performed in Aboureihan campus, located in the southeast of Tehran province. The field data collected included inflow and outflow hydrographs, advance and recession data, cross sectional area and geometry of furrow, field slope, and infiltrated water depth along the furrows. The results showed that the least value of root mean square error(RMSE) (with an average of 6.32) and the highest value of the model efficiency factor (average 0.95) were related to the cutback hydrograph whose flow was reduced to 0.75 of the initial inflow after 60% of the cutoff time. The highest value of the RMSE (with an average of 12.30) and the least value of the model efficiency factor (with an average of 0.83) belonged to the continuous hydrograph whose discharge was reduced to 0.25 of the total discharge and irrigation continued for the entire time of irrigation. The results also showed that in cutback inflows section, the hydrodynamic, zero-inertia, and kinematic wave models were not applicable for reduction of flow in any lengths or any times. The selection of mathematical model for simulation of the advance of flow in the furrow depends on the amount of inflow and cut off time.