Mohammad Khosroshahi; Zahra Saeedifar; Khosro Shahbazi; Samira Zandifar; Sakineh Lotfinasabasl; Azadeh Gohardoust; Fatemeh Dargahian; Maryam Naeemi; Tahereh Ensafi Moghadam; Leila Kashi Zenouzi; Zohreh Ebrahimi Khosefi; Morteza Khodagholi
Volume 30, Issue 4 , February 2024, , Pages 521-541
Abstract
Background and objectivesWind erosion and dust phenomenon are considered as one of the important processes of land degradation and a serious challenge in Iran. This phenomenon occurs due to the interaction between weather and terrestrial processes. The purpose of this research is to investigate and analyze ...
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Background and objectivesWind erosion and dust phenomenon are considered as one of the important processes of land degradation and a serious challenge in Iran. This phenomenon occurs due to the interaction between weather and terrestrial processes. The purpose of this research is to investigate and analyze the trend of temporal and spatial changes in the number of dusty days in Iran and to investigate the role of climate in its spread. MethodologyIn this research, after receiving hourly and daily statistics of dust events (through 148 synoptic and climatology stations) and parameters of precipitation, evaporation, temperature as key climatic elements (from 171 stations) in 22 provinces located in arid and semi-arid regions of Iran, The spread of dust was investigated and the correlation between climate and dust was determined. After calculating the number of dust days in Iran, the information was called in the GIS environment and a map of the spatial changes of the parameter of the number of dust days in the three decades of 1987-1996, 1997-2006, 2007-2016 was prepared. In the following, the spatial analysis of this parameter and its expansion over three decades were investigated. Next, the climate parameter that had the highest correlation with the number of dusty days was selected and after preparing a map of its spatial changes in the GIS software environment, the spatial compatibility of the desired parameter with the expansion of the number of dusty days was investigated. In the next step, after performing the homogeneity test on the dust occurrences, the partial square regression model was used to determine the contribution of the three mentioned climatic elements as independent variables and the number of dust days as a dependent variable. ResultsThe results showed that the number of dusty days and the area of its occurrence have increased in Iran, so that in the last decade under study (2007-2016) compared to the previous two decades, the dustiest event occurred in Iran. This increase has been more intense especially in the western and southwestern regions of the country, which were also affected by extra-local dust events. These dust events have spread to the central regions of the country with greater frequency. The homogeneity test in many provinces showed a common change point (year 2007-2008) in the number of dusty days, which could be related to the beginning of severe droughts and climate changes from this year in Iran. The study of climatic parameters (temperature, precipitation and evaporation) on changes in the number of dust days in Iran showed that during recent years, temperature had the highest significant correlation level (0.58) with the occurrence of dust. The temperature gradient map in the last decade (2007-2016) compared to the previous decade (1997-2006) also showed the increasing trend of temperature, especially in the western and southwestern regions as well as the southeastern regions of Iran. Modeling the effect of climatic parameters of temperature, precipitation and evaporation on the parameter of the number of dusty days showed that the contribution of the studied climatic parameters to the occurrence of dusty days is about 33% and other effects can be related to things such as human factors or soil characteristics, type of vegetation, solar radiation, etc. ConclusionIn general, the results of examining the trend of changes in the number of dust days and climatic indicators for nearly 3 decades indicate a significant increase in the number of dust days in most parts of Iran and the conditions for this increase have been provided and if the trend of changing these indicators in the coming years is according to the current trend, the risk of environmental problems in the country can be expected to increase.
Maryam Teimouri; Leila Kashi Zenouzi; Tahereh Alizadeh
Volume 30, Issue 4 , February 2024, , Pages 557-570
Abstract
Background and objectiveSoil is considered one of the most valuable natural resources and the existence of life on the surface of the earth depends on the existence of soil in addition to water and air. Soil stability is an important factor in the health of the soil system and it is a prerequisite to ...
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Background and objectiveSoil is considered one of the most valuable natural resources and the existence of life on the surface of the earth depends on the existence of soil in addition to water and air. Soil stability is an important factor in the health of the soil system and it is a prerequisite to perform processes such as the cycle of elements in the soil. Soil erosion is a serious problem and threat in different regions of the world, and therefore protecting and preventing soil erosion as a non-renewable natural resource is of high priority. To prevent soil erosion, there are various physical, mechanical, and chemical methods. Due to their high cost and harmful effects on the environment, today much attention is paid to biological methods that are friendly to the environment. This study aimed to investigate the potential of urease producing bacteria on biological stabilization and prevention of soil erosion. MethodologySoil samples were collected from the Bazoft area in Chaharmahal va Bakhtiari provinces and transported to the laboratory. The enrichment and selective method was used to screen urease producing bacteria in the urea agar base culture medium. The activity of the urease was investigated by the electrical conductivity method and three strains with the highest urease activity were selected and used in further steps. The selected strains were identified by molecular methods, colony PCR by using 14f and 1492r universal primers, and sequencing. The compressive and shear strength was estimated in inoculated soils after 14 days. The wind erosion threshold velocity was measured in the wind tunnel. The soil loss was estimated at different wind speeds (17.3, 22.09, and 27/20 m/s) in the inoculated soils. ResultsThe urease-producing bacteria were identified by changing the color of the culture medium from yellow to pink. The results showed that the soils of this area have a high potential for urease producing bacteria. Three species were selected based on their urease activity and identified as Bacillus thuringiensis (RIFR-U3), Bacillus sp. (RIFR-U7), and Exiguobacterium sp. (RIFR-U10). The compressive and shear strength increased in soil inoculated with the selected bacteria compared to the control. The highest compressive (1.56± 0.241 kg/cm2) and shear strength (2.066±0.18 kg/cm2) were detected in the soils inoculated with Bacillus sp. (RIFR-U7) and Exiguobacterium sp. (RIFR-U10) strains, respectively. The wind erosion threshold velocity was 12.19 m/s. The soil loss was less in the inoculated soils with bacteria compared to control and Bacillus sp. (RIFR-U7) had the highest efficiency in preventing soil loss. Conclusion The increased compressive and shear strength showed that these selected strains are moderate to good stabilizers for increasing compressive strength and very good for increasing shear strength. The wind tunnel results showed that Bacillus sp. (RIFR-U7) inoculated soil was more resistant to wind erosion compared to the other two strains and controls. In conclusion, it seems that different strains or a combination of them can be used based on what characteristic of the soil is to be improved or the purpose of resistance against which erosion
Farzad Heidari moorchekhortei; Mohammad Khosroshahi; Razieh Saboohi; Morteza Khodagholi; Leila Kashi Zenouzi
Volume 30, Issue 2 , September 2023, , Pages 196-213
Abstract
Background and objectivesResearch has been done on different materials to control and reduce wind erosion. Among them, we can mention the performance of agar gum biopolymer in reducing dust production at different concentrations of 0.5, 1.0, and 1.5%. Its results showed that the addition of biopolymer ...
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Background and objectivesResearch has been done on different materials to control and reduce wind erosion. Among them, we can mention the performance of agar gum biopolymer in reducing dust production at different concentrations of 0.5, 1.0, and 1.5%. Its results showed that the addition of biopolymer improves the water-holding capacity, increases the surface and compressive strength of the soil, and decreases dust production. In another study, agar gum biopolymer significantly improved soil mechanical properties. This study investigates the effect of polymer nuclei (M19) on controlling sand dunes. This research investigates the effect of nucleos (M19) mulch on reducing wind erosion and controlling sand dunes and dust. MethodologyThis research was carried out in Segazi Plain, a study and implementation priority due to its proximity to urban areas, military facilities, transportation, as well as industries and workshops located there, from the aspect of preventing wind erosion and desertification. After choosing the field, two plots of 500 square meters with the same conditions (an active hill with an area around it with natural and hand-planted vegetation) were selected. To determine the effect of soil cover, the area of each plot was determined by wooden stakes. In addition, the surrounding sand dunes were staked to measure their displacement. A pump sprayer mulched the measuring plot with nucleos (M19) mulch. Following the soil moisture changes, information including seedling survival and growth rate, soil cover's ability to control sand dune displacement, and compressive stress was examined during different months. Finally, the effectiveness of soil cover was compared with the control treatment using the T-test. Results The results of examining the changes in humidity and the effect of soil cover on it showed that the highest humidity in the area was after rain. No clear difference was observed between the drying process of the control plot and the mulched plot. It was also found that this mulch positively affects seedling growth rates. During the research period, the control sand dunes moved about 0.75 to 2.5 meters depending on the season and wind direction. In contrast, the mulched sand dunes remained stable. On the other hand, with time, the mulched field's surface became flaky, and signs of wear and tear were observed.ConclusionThe first point about using this polymer as a soil cover is its two phases during transportation and storage until mulching. In such a way, the two layers can be clearly distinguished. As a result, mixing is necessary for the uniformity of the polymer during the preparation of the final emulsion. This can be considered as one of the negative characteristics of the used polymer. This mulch positively affected soil moisture changes and increased soil moisture retention. On the other hand, the comparison of the growth of the seedlings in the mulched field and control also shows its effect on the growth of the seedlings. This soil cover's only positive and critical feature is its high flexibility after mulching in such a way that it is possible to drive on it with caution. Finally, after a year, cracks were first detected in the research field. Gradually, the number and depth of cracks increased, which caused the mulched field surface to become flaky. Following this complication, instability and signs of wear and tear were observed in the mulched area. However, no movement or change in location was observed in the mulched hill. It should be noted that with time, more destruction occurs on the surface of the mulched area. Following more flaking, the mulched surface may be destroyed, and hill erosion may begin. Considering these cases, mulching in this and similar areas is not recommended.
Shahram Banedjschafie; Mohammad Khosroshahi; Leila Kashi Zenouzi; Aliashraf Jafari
Volume 28, Issue 1 , April 2021, , Pages 106-117
Abstract
To replace oil mulches, this study examined the effect of degradable non-oil mulch under the brand name Nucleus (MA-19). This research assumed that the application of the mentioned mulch in biological stabilization projects has no adverse effects on seed germination and seedling growth. ...
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To replace oil mulches, this study examined the effect of degradable non-oil mulch under the brand name Nucleus (MA-19). This research assumed that the application of the mentioned mulch in biological stabilization projects has no adverse effects on seed germination and seedling growth. The effect of mulch was studied on the establishment of Haloxylon persicum and Nitraria schoberii in a pot experiment in weather conditions of Research Institute of Forests and Rangeland in Tehran, Iran in 2017-2019. Before the experiment, the seed germination test was made to ensure seeds which having standard germination. After determining the germination percentage of seeds (85-90%), seeds were planted in the greenhouse. Then, the soil surface of the pots was sprayed with mulch for comparison with the control. On the other hand, in potting experiments, which were in the form of planting seedlings, after placing the seedlings in the pot, the soil surface was sprayed with the mentioned mulch. The irrigation of the pots was uniform and equal to the field capacity of the soil and based on the soil moisture curve, which was done only once a month, depending on the weather conditions and temperature. Statistical test and comparison of means according to t-test results showed that mulch treatment did not have any negative effects on germination, viability, height, and diameter of seedlings, and in this regard, used mulch behaves as a control treatment (without mulch).
shahram schafiee; mohammad khosroshahi; Hassan Rouhipour; ali ashraf jafari; farhad khaksarian; leila kashi zenouzi
Volume 24, Issue 1 , May 2017, , Pages 224-237
Abstract
Due to the limited water resources and low rainfall, finding proper solutions to reduce the water consumption for vegetation production in natural areas has received attention more than ever before. For this purpose, this research was aimed to investigate the effects of superabsorbent polymer and Plantbac ...
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Due to the limited water resources and low rainfall, finding proper solutions to reduce the water consumption for vegetation production in natural areas has received attention more than ever before. For this purpose, this research was aimed to investigate the effects of superabsorbent polymer and Plantbac panels on the efficient use of water on Saxaul (Haloxylon persicum) growth. The study was conducted in the Agricultural and Natural Resources Research Station in Semnan province, Iran. Irrigation in this study was performed according to the soil water suction, reaching to pressures of 1.0, 5.0, and 15.0 bars. The water consumption in each of the aforementioned suctions was to reach the field capacity of the same soil. In addition to the above treatments, rainfed treatment was also considered. Before planting the seedlings, the superabsorbent polymer was mixed with the soil of seedling pits at a weight ratio of 0.6%. The Plantbac panels were placed in the bottom of the pits at dimensions of 60×60×50 cm. Therefore, treatments consisted of superabsorbent polymer and Plantbac panels. The experiment was conducted as a split plot design based on randomized complete block, in which soil water suctions levels were considered as main plot and superabsorbent polymers as sub-plot. The results of the combined effect of both water suctions and superabsorbent polymer showed that the water consumption at these suctions was reduced by prolonging the irrigation intervals to reach higher suctions (more negative). At a soil water suction of 5.0 bars, the water consumption for each seedling was 157 liter, showing 33% decline as compared to the soil containing polymer at the same suction. However, at a suction of 15.0 bars, water consumption in the Plantback declined to 34%. Our results clearly showed that the Plantbac panels could significantly increase the Saxaul growth in different irrigation levels more than that recorded for the control and polymer treatments.
Mohsen Yousefi; leila kashi zenouzi
Volume 22, Issue 2 , August 2015, , Pages 240-250
Abstract
The aim of this study was to determine some factors affecting dust storms phenomenon using different methods. In order to determine the best-input combination, variable reduction techniques such as factor analysis (maximum likelihood, principal component analysis), Gama test, and multivariate forward ...
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The aim of this study was to determine some factors affecting dust storms phenomenon using different methods. In order to determine the best-input combination, variable reduction techniques such as factor analysis (maximum likelihood, principal component analysis), Gama test, and multivariate forward regression analysis were used. Each of these methods presented different combinations used by feedforward neural network model, with Levenberg–Marquardt algorithm and multivariate forward regression with R²=0.87 and RMSE=0.04 was selected as the best suitable combination of neural network model. In addition, monthly and seasonal data were applied by neural network using the best-input combination, and the simulation of dust storm phenomenon was done in summer and spring during the months of April, May, June, July, August and September with a higher correlation coefficient and lower mean square error, due to the good distribution of the dust storm data. The results showed that based on these methods used in this study, dominant wind speed, horizontal visibility, continuity and average of wind speed were the most important factors affecting dust storm phenomenon in Yazd province.