نشریه تخریب و احیاء اراضی طبیعی
پیاپی 3 (بهار و تابستان 1400)

Rangeland ecosystems cover a large area of the world and are of special economic and environmental importance, so considering the expansion of the use of exclosure to improve rangelands and carbon sequestration, its effects on soil properties and value calculation the economics of precipitated carbon are important. This study was carried out by investigating the effect of exclosure on some soil properties and carbon sequestration in Dozalum dry rangelands of Golestan province. In this study, soil sampling was performed using systematic-random method and the establishment of three transects with a length of 100 meters, points were identified along each transect. Soil samples were taken at each point. Soil samples were taken at each point. A total of 30 samples of topsoil (from a depth of 0-15 cm) were taken in each area. Then in the laboratory, soil properties, bulk density, soil porosity, soil moisture, acidity, electrical conductivity, sodium, potassium, calcium, magnesium, lime, nitrogen, sodium uptake ratio, and soil carbon were measured. An independent t-test was used to compare the control and exclusion zones for homogeneous data and Mann-Whitney nonparametric test was used for the carbon variable. The data obtained from the experimental results were analyzed using SPSS software. To evaluate the performance of carbon sequestration, carbon tax policy and carbon emission costs were used as the shadow value of carbon. The results of the analysis of changes in soil parameters at the two sites show that rangeland confinement for 15 years in the study areas had little effect on soil properties and only the ratio of sodium uptake was statistically significant. The results also showed that the rangeland confinement operation in comparison with the control area had no significant effect on the amount of deposited carbon and the confined area has an economic value of 255909.5 Tomans in terms of carbon sequestration function.

Fire is one of the most important ecological factors that can change the function of natural ecosystems. Plant growth depends on the soil, and fire can cause various changes in it. In order to investigate the effect of fire on soil and vegetation, two sites were selected including control and firefighting, each of them with an area of 37 ha, in Varcheshmeh Tusmal Rangeland of Kiasar in Mazandaran province. And in each site was done sampling of vegetation and soil by random – systematic sampling. In each site, 10 drilling and sampling profiles were performed from a depth of 0-15 and 0-30 cm. 30 square plots (1m2) were used to collect vegetation data. Plant characteristics including life form, biodiversity and soil characteristics including moisture, texture, electrical conductivity, acidity carbon, organic matter, lime, nitrogen, phosphorus, potassium were determined. The results of life forms in control and burnt rangelands showed that due to the fire of perennial species, the burned areas decreased by 33.15% compared to control. While it did not have a significant effect on annual and biennial species. The results of the effect of fire on the diversity of the whole species showed that the characteristics of the number of species, Simpson, Shannon, Margalf and Mannhinik richness were decreased 66.66, 45.6, 57.92, 67.74 and 129.49% respectively. While fire had no significant effect on the uniformity index. The results of soil experiments showed that the percentage of sand and silt, soil absorbable potassium, adsorbent phosphorus, soil nitrogen, lime, carbon, organic matter, soil acidity and electrical conductivity in burned treatment increased significantly. However, the percentage of clay and the percentage of soil moisture in the burned areas compared to the control showed a decreasing trend.

Drought is one of the environmental events and an integral part of climate change in any region and has significant effects. Due to the benefits of monitoring the combined climatic, hydrological, and agricultural conditions, vegetation indices (NDVI), land surface temperature index (LST), and standardized precipitation index (SPI) were used for analyzing drought intensity in Sistan and Balochestan province. To obtain NDVI and LST indices, MODIS satellite images were used in the months of growth seasons (September to October) from 2000 to 2019. Three stations of Iranshahr, Zahedan, and Zabol were selected to calculate the SPI index due to their long-term statistics (2000-2019), low statistical deficiencies, and appropriate distribution. A geographic Information System (GIS) was used to zoning the drought intensity. In this regard, after examining the types of interpolation models, the IDW method was used to prepare raster maps. Then, the obtained maps were classified from high to low SPI using the opinion of geography experts, and the drought zoning map was prepared. This study showed that the NDVI and LST indices experienced the highest intensity from 2008 to 2011 and the lowest intensity from 2003 to 2008, respectively. According to the SPI index, the trend of drought changes in the whole region in 2000-2006 and 2009-2014 is in the class close to moderate and high drought, respectively. The results indicate that the study area is sensitive to medium and short-term droughts. Most of the droughts occurring in this region are mild and moderate droughts, and drought is more likely to happen in the central and northern areas of the province.

Today, land degradation and declining of soil and vegetation quality around industrial areas have become a challenge. The purpose of this field research is to evaluate the environmental effects of Ilam Cement Factory on the surrounding areas. In this regard, a systematic sampling network established around the cement factory, then 20 soil samples were taken in different directions and using atomic absorption apparatus, the concentrations of manganese, molybdenum, zinc, cobalt, copper, lead, cadmium, nickel and chromium Soil samples were measured. Then the methods of Geoaccumulation Index, Contamination Factor, and Pollution Load Index were used to determine the distribution of the studied metals. On the other hand, using ETM satellite images for the periods of 1984, 2007 and 2014, the trend of land use change in the region was examined. Then, using Mann-Kendall test, the precipitation trend in the mentioned periods was investigated and the effect of climate change and its role in vegetation changes were investigated. The results showed that the cement factory in the form of both direct land degradation and land quality degradation in the long term due to the accumulation of heavy elements can lead to land use change, land degradation and air pollution in the region. Therefore, the purpose of this study is to evaluate the effects of industry on the surrounding environment.

Soil hydrophobicity is an effective characteristic on plants growth, surface and subsurface hydrology and soil erosion. The application of soil conditioners can be have the various effects on hydrophobicity phenomenon. Therefore, the present study was conducted with study aim of effect of zeolite, compost and combination of these two conditioners on changing soil hydrophobicity and different time periods. For study of changing soil hydrophobicity used from two types of organic conditioner (compost) and mineral conditioner (zeolite) in laboratory conditions. The experiments performed at before and after application of rainfall simulator and the applied values for compost and zeolite were with rates of 7.1 and 5.8 g, respectively. Also in the present study, the phenomenon study of hydrophobicity was conducted using time periods of 24 hour, two, four, eight, 16 and 32 weeks. The results showed that the zeolite as an organic conditioner had the maximum effect before and after application of rainfall simulator on hydrophobicity changes with changes percentage -93.7, 18.9, 71.72, 57.24, -3.10 and 78.28% (before rain simulator) and -22.7, 56.8, 60.9, 54.5 , -54.9 and 78.1percent (after rain simulator). Also, the separation effect of conservation treatment, time and rainfall simulator had positive an effect on changing hydrophobicity was significant at level of 99 percent.  Also, the results showed that the hydrophobicity rates decreased after simulator application toward before simulator application.

Shadegan International Wetland is one of the most important environmental assets of the country due to its very high biodiversity and diverse functions. Awareness of wetland changes is one of the basic needs in the proper management and exploitation of this valuable ecosystem. In this regard, remote sensing methods are a useful tool to study and detect changes in wetlands. Therefore, in this study, with the aim of investigating the trend and revealing the changes in Shadegan wetland, Landsat TM, ETM + and OLI satellite images of 1988-1998-2007 and 2017 were used. Three stages of preprocessing, processing and post-processing were performed on the images, Supervised vector classification (SVM) was used and the images were classified into three classes of water, vegetation and without cover or soil. Classification accuracy for images was calculated using two indicators, overall accuracy and kappa. In order to reveal these classes, changes in 9 classes were analyzed. To show the changes, the graph revealing the changes of uses in three time periods was used. The results showed that in the period 1988 to 1998, water area increased by 1.5% in 1998 and vegetation increased by 5% and soil or uncovered area decreased by approximately 7%. Between 1998 and 2007, water area increased by 4% and vegetation decreased by 20%, and soil or uncovered area increased by approximately 15%. In 2017, there was a 7% decrease in water, a 36% decrease in vegetation, and a 30% increase in soil or uncovered area. This study demonstrates the need for immediate attention to the conservation of wetland residual resources for sustainable use for the next generation.

Natural and human factors have caused the level of groundwater aquifers to decline in recent decades, so the management of groundwater resources is very important. In groundwater resources management, rainfall storage in the basin and its infiltration into the aquifer and consequently the relationship between precipitation and runoff can be considered a very important factor in hydrological studies. In this study, the height of runoff in Baghan basin (Jam and Riz) was calculated using the method of the US Soil Protection Organization (curve number method). The main factor in this method is the appropriate estimation of the curve number, which is based on land use and hydrological groups of soil in the study area. After selecting the best statistical distribution of daily rainfall using the Hyfran hydrological model and also determining the curve number, finally the runoff height was calculated by calculating the surface retention. The results of this study show that due to the mountainous and low permeability, the area is prone to severe floods, so it is necessary to identify areas for artificial feeding and flood storage projects as well as reduce flood damage. The results of this study showed the efficiency of GIS in estimating runoff height, as well as increasing runoff height by increasing the return period and reducing the probability of occurrence.

The severe and widespread droughts in Ardakan, especially in recent years, have added to the livelihoods of farmers and villagers and have caused irreparable damage to the economy of the city. The present study was conducted to investigate the drought vulnerability or zoning in order to implement and implement comprehensive drought management in Ardakan. In this study, the effective factors that affect the drought vulnerability of the study area were transformed into information layers and then the relevant classifications were made. Then, the layers created in terms of importance in agricultural drought vulnerability were prepared using the Analytical Hierarchy Process (GIS) and weighted maps (GIS) maps of each layer of information in the Model (AHP) Was. Finally, the aforementioned environmental maps (GIS) are integrated and finally, the areas of the study area are classified into five classes of agricultural drought vulnerability (very severe, severe, moderate, low, very low) as the final damage map. Agricultural drought susceptibility of Ardakan city was classified. The results showed that the garden lands with an area of ​​1485.63 hectares were located in high drought class and less area in other drought classes. Most of the agricultural land with an area of ​​4558.59 ha was also in high drought class. Also, in terms of topography status, less than 1% of the lands and agricultural lands occupy the highest area of ​​29.62 square kilometers in the most vulnerable class. Also the area located on slopes of 1 to 2 and 2 to 5% in the next rank (13.68 and 2.17 sq km) are in high drought class. The results showed that the most agricultural drought vulnerability was related to central part of Ardakan and parts of Kharanagh. Ardakan, Ahmadabad and Torkabad village in the central part of the country are in the class of agricultural vulnerability. The village of Chah Afzal is also in a very vulnerable agricultural class. The villages of Aghda are divided into low and very low clusters. The results also indicate the importance of the topography of the region, especially the slope parameter in the impact of drought.

Land use patterns, agricultural activities, and decreased vegetation have accelerated land degradation processes. Therefore, implementing land and vegetation-based management measures and utilizing land resources according to suitability/capability is essential to achieve integrated watershed resources management in critical watersheds. Hence, the present study was planned to evaluate the changes of erosion and sediment yield to evaluate management scenarios based on land capability in the high priority sub-watersheds of Glazchai watershed Oshnavieh, West Azerbaijan province, Iran. Therefore, the land capability of priority sub-watersheds was first extracted according to the FAO method. The soil erosion, sediment yield variability, and the maximum discharge were estimated using the IntErO model. The results showed that six percent of the study area in studied sub-watersheds did not follow the land capability rules. The forest land use had a 2.21% net increase. Also, the good rangeland area had a net change of 1.2% compared to the current conditions. In this regard, the allocation of land capability in these areas will reduce the erosion amount, sediment yield, and the maximum discharge of the watershed by 7.1 and 1.33%, respectively. At the watershed scale, the amount of specific sediment yield is also reduced by 12.6 m3y-1km-2. The present study results can provide a suitable management approach for planners and policymakers to make a sound decision regarding the land use-oriented measures in high-priority areas at the watershed scale.

Due to the significant expansion of surface structures and geology sensitive to linear erosion factors and severe human intervention, moaterosion is one of the important factors in the loss of surface soils in the basin. Due to the importance of the issue of gully erosion in the basin, 35 samples of gully were selected in field work and some of their dimensions such as length, width, depth of the average slope of the gully were morphometric. Then, the correlation relationships of the parameters were determined through linear regression and their effects were analyzed. In order to determine the susceptibility of the basin to linear erosion, especially gully. Also soil moisture fluctuation (Ws) and hydrothermal coefficient (ET) indices as well as pH and electrical conductivity (Ec) of the basin soils were determined after sampling. Values ​​of hydrothermal coefficient of 2.524, (pH) and electrical conductivity of the samples between 6.3 and 8.2, respectively, indicate the susceptibility of soils to linear erosion. In total, the average rain erosion of the basin in terms of tons per hectare per year according to the results of the above formulas was 201.05 ton. Hec.y and the total annual soil erosion in the basin was estimated at 41121525 tons and 291 tons per hectare. The results show high rate of soil erosion and development of gully in the basin. Ultimately some approaches for decreasing and controlling of soil and gully erosion are suggested.

Mapping soil salinity changes on a large scale is very costly and time consuming. One of the most cost-effective ways to map soil salinity is to use satellite imagery. Investigation of spectral characteristics of soils with saline surfaces and determining the extent of areas affected by this phenomenon, by using new images with relatively high spatial and spectral resolution can be used in preparing soil salinity maps. In recent years, many indicators have been developed to detect and extract the characteristics of saline surfaces from satellite images, most of which have been studied based on the spectral reflection of these surfaces in different bands of satellite images or intermediate ratios. The purpose of this study is to estimate the salinity changes from 2001 to 2016 in Miandoab region located in West Azerbaijan province. For this purpose, 42 samples with appropriate distribution were taken from the area. The samples were then transferred to the laboratory to measure soil salinity parameters. To evaluate soil salinity, in addition to sampling of topsoil, the NDSI, IBI, NDVI, SI7 and NIR, RED, SWIR2 bands of Landsat 7 for 2001 and Landsat 8 for 2016 were used. The regression equation for determining soil salinity for 2001 showed that soil salinity has a positive and significant correlation with NDSI index at the level of 5%, While for 2016, the highest significant correlation at the 5% level was with the RED and NIR bands of the Landsat 8 image. In 2001, the highest and lowest lands in the region were non-saline lands (39%) and very saline lands (12%), respectively; While in 2016, the highest and lowest lands in the region are relatively saline lands (35%) and non-saline lands (18%). The results of the present study showed that the salinity of the region can be easily calculated using Remote sensing indices. Due to its proximity to Lake Urmia, the study area faces soil salinity problems, so the identification and classification of saline areas is necessary for land management.

One of the most important issues that put a lot of pressure on the quality of the world’s environment is the phenomenon of desertification and land degradation. Irrigation with effluent can have the greatest impact on the physical and chemical properties of the soil. Heavy metals are the most important environmental pollutants that are found in large quantities in domestic and industrial waste water. These metals are important because of their physiological effects on soil, plants and living organisms even at very low concentrations. Therefore, in this study, the effect of organic adsorbents and nanomaterial’s on reducing concentrations Heavy metals in soil and wheat plants irrigated with industrial wastewater were investigated. In this regard, using polyethylene pipes, pots used in this study were prepared. Also, special filters were made of sawdust (micro-sawdust, nano-sawdust of ornamental tree at 0.1%, nano-sawdust at 0.25%, nano-sawdust at 0.5% level). The wastewater used in this study is passed through these filters. Then, to investigate the effect of filters on the amount of zinc collected in the plant, a number of wheat seeds were planted in each pot. At the end of the experiment, soil and plant samples were prepared for each pot and the concentration of zinc metal was measured by atomic absorption (GBC). Statistical analysis of results and data analysis was performed by completely randomized design (CRD) and comparison of means using Duncan test using SPSS software version 22. The results showed that the treatment of nano sawdust at the level of 0.5%, had the greatest effect and micro-sawdust had the least effect on reducing the accumulation of zinc metal in soil and plant.