To evaluate the effect of olive mill wastewater (OMW) application on soil hydraulic and transport properties, two treatment sites, which had been irrigated with OMW for 5 and 15 years, and one control site being irrigated with freshwater were compared. The transport and leaching experiment results showed that a portion of the total soil water was available for transport processes while the remaining of the soil water was considered immobile and not readily accessible for solutes. The separation in water fractions of different mobilities was surprisingly consistent among OMW treatments. The bromide recovery rate decreased with the application of OMW showing that tracer molecules became trapped within immobile water phases. The application of OMW increased significantly the soil water-holding capacity, whereas the soil hydraulic conductivity in the near saturation range decreased significantly with long-term OMW application. The soil irrigated with OMW had significantly higher organic matter content, lower bulk density and relatively higher total porosity, but lower macroporosity than that of control sites. We concluded that the soil was increasingly coated with complex organic molecules originating from OMW, as a result, solute exchange between inter-and intrasoil aggregate water was hindered. Although OMW could cause soil and water pollution, its use in agriculture is promoted because of high nutrients and organic matter contents.
An alternative strategy for saving limited water resources is using treated wastewater (TWW) originating from wastewater treatment plants. However, using TWW can influence soil properties owing to its characteristics compared to conventional water resources. Therefore, assessing the effect of TWW on soil properties and soil water infiltration is crucial to maintain sustainable use of TWW and to increase the water use efficiency of the precious irrigation water. Moreover, several studies were carried out to assess the performance of infiltration models. However, few studies evaluate infiltration models under the use of treated wastewater. Therefore, this study aims to assess the effect of TWW irrigation on soil properties after 2 and 5 years and to evaluate five classical infiltration models with field data collected from soil irrigated by treated wastewater for their capability in predicting soil water infiltration. This study revealed that using TWW for irrigation affects significantly on soil properties after 2 and 5 years. The soil irrigated with TWW had significantly higher electrical conductivity, organic matter, sodium adsorption ratio, cation exchange capacity, and lower soil bulk density compared to control. The basic infiltration rate and cumulative infiltration decreased significantly compared to control (60.84, 14.04, and 8.42 mm hr−1 and 140 mm, 72 mm, and 62 mm for control, 2, and 5 years’ treatments, respectively). The performance of the infiltration models proposed by Philip, Horton, Kostiakov, Modified Kostiakov, and the Natural Resources Conservation Service was evaluated with consideration of mean error, root mean square error, model efficiency, and Willmott’s index. Horton model had the lowest mean error (0.0008) and Philip model had the lowest root mean square error (0.1700) while Natural Resources Conservation Service had the highest values (0.0433 and 0.5898) for both mean error and root mean square error, respectively. Moreover, Philip model had the highest values of model efficiency and Willmott’s index, 0.9994 and 0.9998, respectively, whereas Horton model had the lowest values for the same indices, 0.9869 and 0.9967, respectively. Philip model followed by Modified Kostiakov model were the most efficient models in predicting cumulative infiltration, while Natural Resources Conservation Service model was the least predictable model.
This study evaluated the process of in-site sorting of the generated solid waste (SW) in some educational institutions in Ma'an city, Jordan. The study included eight schools and one University. The students and employees of seven schools, as well as the students and employees of the University, had received the awareness campaigns concerning the importance and benefits of in-site sorting of SW. As a control, one school student and employee who had not received awareness campaigns were involved. The institutions were provided with four bins at each collection site (glass and plastic, paper and cardboard, metals, and bread). The content of bins in each institution was collected and sorted manually to evaluate the efficiency of the conducted awareness campaigns on onsite sorting behavior. The mass ratios of many SW components in their designated bins in the reference school (control) were higher than the average ratios in the assigned bins for the same component in all schools. As for the University, the results of the manual sorting showed that all bins included a mix of SW in different ratios; moreover, the proportions of glass and plastic, and metals were lower than the proportions of other components. On the basis of the above mentioned results, it can be concluded that the awareness campaigns did not achieve the stated goals; subsequently, the in-site sorting failed in the schools and the University. Thus, different awareness campaigns should be assessed to identify the best approach positively affect the SW sorting and disposal habits of people.
Knowledge of upper and lower limits of soil water content (ULSWC, LLSWC) is indispensable to calculate the water depth that should be applied by irrigation , and to determine water availability, which is a crucial factor in assessing the suitability of a land area to produce a given crop. However, direct measuring of these limits is time consuming and expensive. Several attempts have been made to establish a relation between readily available soil properties, like particle-size distribution, organic matter, and bulk density and ULSWC, LLSWC. These relationships are referred to as pedotransfer functions (PTFs). Therefore, the objective of this study was to evaluate some PTFs with respect to their accuracy in predicting the two limits of soil water content for some Jordanian agricultural soils. Fourteen widely used PTFs were selected for evaluation. Eight of the selected PTFs predict soil water content at certain matric potential, whereas the others predict water retention function parameters. In order to quantify the prediction accuracy, the mean error (ME), the root mean square error (RMSE), unbiased root mean square error (URMSE), and the Pearson correlation (r) were used. The PTFs showed good to poor prediction accuracy with RMSE ranging from 0.00149 to 0.03789 m 3 m -3 , ME values ranging from -0.01560 to -0.26785 m 3 m -3 and with URMSE ranging from 0.00017 to 0.00331 m 3 m -3 . The validation indices showed that British soil survey (topsoil and subsoil), and Rawls-Brakensiek were found as the best method to calculate the limits of soil water content for the evaluated Jordanian soil data set. Rosetta exhibited an intermediate value in estimation of soil moisture limits of the evaluated soil set. The implementation of soil bulk density as an extra input value did not improve the accuracy of the estimated soil water content limits. This may be due to the fact that more input data are required in our soil set.
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