ECOPERSIA
Volume:3 Issue: 4, Autumn 2015

There are many reports of serious problems of dust storm events in the western parts of Iran. Based on many researches, Iraq is one of the main sources of dust storms in western parts of Iran. The Radial Basis Function Network (RBFN) model has been used to assess wind erosion hazard in Iraq as a main source area of dust storms over several western cities of Iran. The percentage of vegetation is the only changeable factor of RBFN model. The wind erosion hazard map in two time periods (2003 and 2012) verified the vegetation changes over time. The results showed that the vegetation percentage index in all land use types of 2003 was higher than those of 2013. In addition to drought as a natural parameter, overgrazing, dam construction on Tigris and Euphrates Rivers (in Turkey) and high amount of water for crop production are human and policy factors causing loss of vegetation cover in source area and wind erosion exacerbation.

Soil alkalinity and salinity are serious problems in arid and semi-arid regions, and therefore monitoring of soil pH and electrical conductivity (EC) is necessary in any region. The present study aimed to properly interpolate soil pH and EC as soil quality indices in a semi-arid mountainous area with annual precipitation of 342.4 mm. The study area is the Karimabad rangelands in Hamadan Province, western Iran. A total of 266 composite soil samples were collected from 0-25 cm soil depth in a systematic random design. Soil samples were processed for pH and EC analysis and then further used for interpolating based on the optimal interpolation method for the study area. The overall soil pH and EC ranged from 7.3-7.9 and 0.33-2.13 dS m-1, respectively, presenting the slightly alkalinity and salinity problem in the region. The results showed the accuracy of spatial prediction of interpolation methods, particularly inverse distance weighting and radius basis function. However, based on root mean square error, the radius basis function was the most appropriate interpolation method to predict spatial distribution of soil pH and EC of topsoil in the study area. While salinity and alkalinity were low, still monitoring these soil indices is highly recommended to prevent the salinization and alkalization in the study area.

The control of biological, hydrological and geochemical cycles of soil is the key part of the earth system. The objective of this research was to evaluate changes in soil chemical properties due to deforestation occurred in the Gazafolya Village, Merek Watershed, Kermanshah Province, Iran. Toward this attempt, 35 soil samples were collected from top soil layer using auger in early June, 2013. Soil analysis including pH, carbonate content, electrical conductivity (EC) and exchangeable sodium (Na), soil organic carbon (SOC) and cation exchange capacity (CEC) were made. The results showed that there were no significant differences between soil pH, carbonate content, EC and Na in the forest and rainfed areas while there was significant difference (P> 0.005) between SOC in the forest (2.10%) and rainfed (1.35%) areas. The semi-variance analysis also revealed that the spatial dependence class of SOC in the forest was strong, while it was mainly moderate in the rainfed areas due to improper plowing practices in the rainfed area there was moderate. In addition, the results showed the soil CEC in the forest and rainfed areas were 33.3 and 25.1 cmolckg-1, respectively, indicating significant higher level in the forest area. Semi-variance analysis also revealed a strong spatial variation for CEC in the forest. Finally, there were no significant differences for EC and Na with moderate spatial variation in both areas. It was concluded that SOC and CEC significantly reduced by severe deforestation phenomenon of Zagros Forest.

There is different methods for simulating river flow. Some of thesemethods such as the process based hydrological models need multiple input data and high expertise about the hydrologic process. But some of the methods such as the regression based and artificial inteligens modelsare applicable even in data scarce conditions. This capability can improve efficiency of the hydrologic modeling in ungauged watersheds in developing countries. This study attempted to investigate the capability of the Adaptive Neuro-Fuzzy Inference System (ANFIS) for simulating the monthly river flow in three hydrometric stations of Pole-Almas¡ Nir¡ and Lai; which have different rate of river flow. The simulations are conducted using three input data including the precipitation¡ temperature¡ and the average monthly hydrograph (AMH). The study area islocated in the Gharasu Watershed¡ Ardabil Province¡ Iran. For this aim¡ six groupsof input data (M1¡ M2¡ … M6) were defined based on different combinations of the above-mentioned input data. Theconducted simulations in Pole-Almas and Nir stations have presented an acceptable results; but in Lai station it was very poor. This different behavoirs was referred to the lower volume of flow and consequently irregularity and variability of flow in Lai station¡ which cause the decrease of accuracy in the simulation. The AMH parameter had an important role in increasing the accuracy of the simulations in Pole-Almas and Nir stations. The findings of this study showed that ANFIS is an efficient tool for river flow simulation; but in application of ANFIS¡ the selection and utilization of relevant and efficient input data will have a determinativerole in achieving to a successful modeling.

The appearance of sowbugs (Hemilepistus shirazi Schuttz) in the sedimentation basins of the artificial recharge of groundwater (ARG) systems in the Gareh Bygone Plain (GBP) in southern Iran is considered an ecological breakthrough in desertification control. This study was performed at the Kowsar Floodwater Spreading and Aquifer Management Research, Training and Extension Station in GBP, 200 km from the south east of Shiraz, Iran, on the alluvial fan of Bisheh Zard River. Invasion of sowbug to sedimentation of basin due to water increasing persuade us to study about this crustacean. To determine aggregate size distribution, the soil samples were dried, and then the soil was sieved through a set of sieves (8, 4.75, 2.8, 2.0, 1.0, 0.8., 0.3 and

The purpose of the present research was to study the properties of natural habitats and growth status of the genus Tamarix in Miankangi, Sistan Province, South-eastern Iran. Selective sampling was used to examine the natural stands structure. Then, the one ha-rectangular sample plots were stablished in the stands and surrounding bare lands as control plots. Quantitative variables of stands viz. collar diameter, total height, canopy surface and density in the plots were recorded. In each plot, the soil sampling was carried out from 0-30 and 31-60 cm depths, and some physicochemical parameters of the soil including soil texture, pH, EC, SP, OC, total N, available P, K, Na, Ca and Mg were measured. Data were analyzed using one-way ANOVA. The Duncan''s test was used to compare the means. The soil texture of the region was loamy-silty and clay-sandy-loamy. The soil of Tamarix habitats was saline and alkaline. The results showed that the growth variables were different among the habitats. In addition, the soil clay and silt, pH, potassium and sodium absorption ratio (SAR) were significantly different among the habitats and the control. Correlation between vegetation and soil properties also showed that the diameter of Tamarix trees had positively correlated with the soil SP at also the first depth and with the clay viriable at the second depth.

Pot experiment was carried out to investigate the effects of ethylenediaminetetraacetic acid (EDTA) on some morphological characteristics of Thlaspi caerulescens L., and also on the accumulation of lead (Pb) and zinc (Zn) in roots and shoots of T. caerulescens L.. Experiments were then set up in three treated pots with doses of 3, 6 and 9 mmol kg-1 of EDTA and control pots (C: uncontaminated soil and W: contaminated soil). The results indicated the significant effect of EDTA on morphological characteristics and accumulation of heavy metals in the plant (P