Volume 13, Issue 4 (3-2023)                   2023, 13(4): 71-87 | Back to browse issues page


XML Persian Abstract Print


Department of Environment Sciences, Faculty of Natural Resources, University of Kurdistan, Sanandaj, Iran.
Abstract:   (451 Views)
Abstract
Direct use of raw urban sewage for agricultural irrigation may result in many harmful consequences. Therefore, wastewater treated through different technologies is preferred for reuse, especially in the water-limited areas. The purpose of this study was to compare the use of treated municipal sewage effluent compared to well water on the nitrate and phosphate concentrations in agricultural soil under barley cultivation. For this purpose, a plot of farmland with an area of ​​2000 square meters was divided into two equal parts of 1000 square meters, and for one growing season, one part was irrigated with well water and the other part was irrigated with treated waste water, while the quality of these two water sources was also determined in the laboratory. A total of 28 soil samples were also collected from each of the two plots (totally soil 56 samples) from the layer 0-20 cm and analyzed in the laboratory. Inverse Distance Weighting interpolation method was also used to investigate the spatial distribution of the soil properties. The results showed that the average concentrations of soil phosphate, potassium and sodium measured in the treated wastewater were much higher than of well water and the use of treated urban wastewater significantly increased ammonium, phosphate and nitrate concentrations, and total nitrogen of the soil. In addition, the use of treated municipal wastewater for irrigation could improve the yield of barley (Hordeum vulgare) compared to wastewater treatment. It is noteworthy that proper management in the use of treated wastewater and the selection of plants are important which can minimize the harmful effects of using treated wastewater on soil characteristics and crop yield.

Background and Objective: Wastewater obtained from water consumption in human daily life consists of 99.9% water and 0.1% mixture of suspended mineral, organic and gases (3). Therefore, the use of wastewater and sewage in the cultivation of crops can reduce the need to use chemical fertilizers (1). Considering the importance of food chain health in the development of sustainable agriculture, the aim of this study was to evaluate the changes of nitrogen and phosphorous concentrations in the soil irrigated with treated wastewater compared to well water in a farmland under barley cultivation.

Methods: Soil sampling was conducted in a farmland located in the north of Boukan city and 175 meters away from the treatment plant in an area of 40×50 square meters (2000 square meters) under barley cultivation irrigated with well water. The farmland was divided into two equal parts each 25×40 square meters during one growing season, one part irrigated with well water and the other part with treated wastewater from Bookan city wastewater treatment plant. Soil samples were obtained from the layer 0-20 cm before crop cultivation and also at the end of the growing season according to grid networks of 5×5 square meters with a distance of five meters from the peripheral border of each of the two lands (totally 56 soil samples including 28 controls and 28 treatments). The quality of irrigation waters was measured based on the standard methods (2). The results of soil physical and chemical properties, irrigation waters and crop yields were processed using SPSS v. 22 statistical software. Pearson's correlation, Duncan's post hoc and unpaired t tests were used to investigate the relationships between the initial soil physical and chemical properties, the effect of irrigation water sources on the soil properties, and barley yield. In order to investigate the spatial distribution of final soil properties, distribution maps were prepared using the Inverse Distance Weighting interpolation method by ArcGIS software v. 10.6.

Results: The average soil pH was greater than 7, and the means of electrical conductivity (EC) and calcium carbonate equivalent were 567.64 µS/cm and 4.75%. The soil texture was silt loam with low organic carbon (1.27%). Based on the findings, the average concentrations ​​of phosphate, nitrate, potassium and sodium measured in the well water treated soil were 0.36, 22.10, 2.56, and 0.47 mg/L and for the wastewater treated soil were 5.41, 10.73, 377.66 and 0.74 mg/L, respectively. The ammonium and nitrate concentrations in the wastewater treated soil compared to the well water treated one showed a decreasing trend (from 13.53 to 7.67 mg/kg and from 44.79 to 35.50 mg/kg, respectively). In comparison with the initial soil samples, the phosphate concentration and total nitrogen content significantly increased from 15.87 to 26.49 mg/kg and from 0.18 to 0.21 %, respectively, due to the wastewater application. The use of treated wastewater significantly increased the average number of spikes and the weight of the barley yield. The number of spikes and their dry weight per plant increased from 195 and 189 g in the well water treatment to 253 and 230 g in the treated wastewater, respectively. The height of the spike was significantly affected by the water sources used for irrigation as it increased from 3.7 cm in the well water treatment to 4.2 cm for the treated wastewater.

Conclusions: Since soil physical and chemical properies are very important for characterizing soil quality, it is very vital to accurately understand the influence of irrigation water quality on soil properties. Based on the results of this study, the average concentrations ​​of phosphate, potassium and sodium measured in the wastewater treated soil were much higher than in the well water treated one. Additionally, the use of treated wastewater significantly increased the soil phosphate and nitrogen concentrations. Also, it appeared that the use of treated municipal wastewater for irrigation could improve barley yield compared to use of well water. It is also necessary to mention that proper management in the use of unconventional waters and the selection of plants to minimize the harmful effects of treated wastewater on the soil properties and crop yield are very important.

References:
1- Al-Jaboobi, MTijane, M., EL-Ariqi, S., El Housni, A., Zouahri, A., Bouksaim, M., 2014. Assessment of the impact of wastewater use on soil properties. Journal Material Environment Science 5(3): 747-752.
2- Binaymotlagh, p., 2010. Guidelines and methods for measuring physicochemical factors and toxic inorganic chemical substances in drinking water, Ministry of Health. Medicine and Medical Education.
3- Musyoki, M.S., 2015. A study on the disposal of hazardous chemicals, domestic waste and waste water in Kenya. University of Nairobi Title.

 
Full-Text [PDF 2056 kb]   (285 Downloads)    
Type of Study: Research | Subject: Availability of soil water and nutrients for plant
Received: 2022/08/30 | Accepted: 2023/02/22 | Published: 2023/02/26

Rights and permissions
Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.