JWSS - Journal of Water and Soil Science

This study investigates the impact of agricultural activities on the soils of southern Mehriz by analyzing their geochemical composition and comparing the physicochemical properties of pistachio orchard soils (agricultural soils) with those of undisturbed natural soils. The results indicate that agricultural practices have led to an increase in Total Organic Carbon (TOC), averaging 1.5%, and a reduction in soil acidity. Additionally, phosphorus concentrations have risen in agricultural soils. These soils also exhibit enrichment in elements such as cadmium (Cd), antimony (Sb), chromium (Cr), nickel (Ni), lead (Pb), scandium (Sc), and rare earth elements (REE) compared to natural soils, with a more homogenized REE distribution pattern. Although the concentrations of these trace elements remain within national environmental standards and below critical thresholds, the study highlights a significant increase in the bioavailability of heavy metals due to agricultural activity. This finding underscores a potential environmental risk if such changes are not properly managed in the future.

Rice is one of the most important crops and the primary food source for more than half of the world's population. The present study was conducted to compare the direct-seeded rice (DSR) of three rice varieties (Jozdan, Firuzan, and Sazandegi) using surface (DI) and subsurface (SDI) drip irrigation systems. The experiment was performed as a split–split plot arranged in a randomized complete block design with three replications in two years (2019 and 2020) in the research farm of Isfahan University of Technology in Najaf-Abad. According to the results of the variance analysis, the most suitable cultivar for DSR in the region (among the tested cultivars) is Sazandegi with a grain yield of 3400 kg/h-1. The results of this experiment showed that the amount of water consumed in DI was 20% less than in SDI. Also, DSR reduced water consumption by 40% compared to transplanted rice (TPR) in the region. However, the grain yield also decreased by about 45%.

The effect of climate change on agricultural productivity and efficiency is a major concern and challenge for the agricultural industry. Different hydrometeorological variables, such as extreme temperature, precipitation, and their variations, affect the growth and yield of agricultural products. Saffron is one of the most important agricultural products in Iran. Iran produces the largest amount of Saffron globally, and Hamadan Province is one of the major saffron-producing regions in Iran. This study uses different Artificial Intelligence methods not only for clustering and sensitivity analysis of the hydroclimatological variables but also for evaluating the impacts of climate change on Saffron yield in Hamadan Province. Results indicated that the Random Forest algorithm performs the best for sensitivity analysis among all algorithms. Extreme climate change indices, particularly those related to the monthly maximum and minimum temperatures, have the highest negative impact on saffron yield compared to other hydroclimatological indices. Furthermore, the minimum temperature has a more significant negative impact on saffron yield compared to the maximum temperature. Additionally, the counties of Malayer, Nahavand, and Asadabad, located in the south and west of Hamadan Province, exhibited the highest accuracy in sensitivity analysis. The findings suggest that monthly extreme temperatures can be used to assess the risk of saffron production, increase agricultural productivity, and improve decision-making for the cultivation of this product.
 

Soil contamination by metals is a major problem in terrestrial ecosystems, particularly in and around industrial areas, and can pose a threat to human health in various ways. Therefore, in the present study, the bioaccumulation of heavy metals in the earthworm (Eisenia fetida) in soil around the Abik Cement Factory in Alborz Province was evaluated. Sixty soil samples were collected at depths of 0-20 cm at distances of 500, 1000, and 2000, in the directions of north, south, east, and west. Earthworm samples were also randomly collected from these distances and directions. The wet digestion method was employed to determine heavy metal concentrations in soil and earthworms, and Zn, Cu, Pb, Cr, and Ni were measured using an atomic absorption spectrometer. One- way ANOVA and Kruskal- Wallis statistical methods were used to examine the effects of distance and direction. The bioaccumulation factor (BAF) was used to evaluate the ability of earthworms as a biological indicator. According to the results, the average concentrations of heavy metals in the soil around the lands of the Abik Cement Factory for Cr, Pb, Cu, Zn, and Ni were 22. 20, 10. 19, 6. 34, 7. 63, and 135. 75 (mg/kg), respectively. The average concentrations of heavy metals in earthworms in this region for Cr, Pb, Cu, Zn, and Ni were 51.57. 57, 9. 66, 5. 18, 5. 45, and 106. 17 (mg/kg), respectively. The results indicated that the distance effect was significant only for Ni (p< 0. 05), and the direction effect was significant for all heavy metals except Zn (p> 0. 05). A decreasing trend in the concentrations of Cu, Zn, and Pb was observed with increasing distance from the cement factory, indicating the impact of the Abik Cement Factory on heavy metal pollution in the agricultural soil of the surrounding lands. The highest bioaccumulation factor (BAF) was calculated for zinc and was greater than 1, indicating bioaccumulation of Zn in earthworms. It can be concluded that earthworms can be used as a suitable biological indicator species for monitoring soil contamination with heavy metals, especially for Zn.

Conventional methods for desalination of water and wastewater are usually not economically viable for providing the water required for agricultural production due to high energy consumption and equipment costs. This study aimed to evaluate the efficiency of magnetic nanobiochar produced from sugarcane bagasse to remove sodium ions from agricultural wastewater under the influence of a magnetic field. Non-nanoactive, nanoactive, and magnetic nanoactive adsorbents were produced using a pyrolysis process in an electric furnace at 600 °C, chemical activation with potassium hydroxide, and magnetization with a combination of hexahydrate ferric chloride and heptahydrate ferric sulfate. The results showed that the highest removal rates of chloride ions (44.6%) and sodium ions (58.3%) were obtained in the magnetically activated nano-biochar under the influence of a magnetic field of 0.5 Tesla, for an activator-to-biochar ratio of 3, a microwave power of 400 W, and an activation time of 10 minutes. Surface analyses including FT-IR spectroscopy and scanning electron microscopy (SEM) confirmed that the hydroxyl, carboxyl, and carbonyl functional groups on the surface of the adsorbent play a key role in the adsorption of sodium and chloride ions. It was also observed that the application of a magnetic field improved the orientation of the ions towards the adsorbent and weakened the hydrogen bonds in water, which led to an increase in the efficiency of the adsorption process. This study shows that magnetic nano-biochar, under a magnetic field, could be an economical and sustainable solution for reducing the salinity of agricultural wastewater.