Journal of Range and Watershed Managment
Year:2015 | Volume:67 | Issue:4|Papers Count:13

The WEPP physically model is able to dynamically simulate runoff and soil erosion using physical concepts of erosion and hydraulic of overland flow science considering plant growth, residue decomposition, winter process. Determination of the capability of this model in runoff and erosion estimation in different range type with investigation the effects of management were the main objectives of this research. This research was conducted in the Kabode placed across the Gharasoo watershed by installing erosion plot with dimension of 10×3 meter and three replications in three range types at the slopes of 25, 35 and 45%. Climate data including rainfall and air temperature was recorded in the site and additional data including wind velocity and direction, solar radiation and dew point temperature was prepared from Kermanshah synoptic climate station. Event based erosion and runoff was simulated in each plot by the v2008.9 version of the model. Results from model assessment for prediction of runoff indicated that the maximum model accuracy was in 45% slope. Also, mode relative error in runoff in 25 and 35% slope was about 0.61 liter. Overall, model performance in runoff estimation was sought in all three slopes, so that Nash-Sutcliff index was 0.96 to 0.73. Minimum and maximum estimation error in erosion prediction was occurred in 35 and 45% slope, respectively. Model prediction results indicated under-estimation in all the slopes. Negative amounts of Nash-Sutcliff index indicated confirms the low efficiency model especially in conditions prevailing in two slopes of 25 and 35%.

Flood spreading has an effective role in the soil improvement and fertility, ground water storage, revival of vegetation and prevention of fluent sands movement. One of the main problem of flood spreading projects is the entrance of sediment to the spreading systems and sedimentation in it. Sediment reduces the efficiency of the flood spreading system and after awhile lose its efficiency. The main aim of this research is the investigation of infiltrate changes trend under effect of flood spreading in Tangestan flood spreading station (Bushehr province). In this research, soil surface infiltration in spreading and control area were measured with double rings method. For investigating of these changes the intervals between flood spreadng channels, the first, second and third rows were selected. Data were analyzed by Kruskal-Wallis test. Due to the significant level of this test, less than 0.01, can be expressed that between the infiltration of flood spreading rows and control area were significant difference.

Zygophyllum atriplicoides is one of the most important rangeland plants that often seen as associated species and rarely seen as the dominant species in ranglands rangelands which is very critical for soil  in starting and ending points of each transect. Measured soil properties (included gravel, texture, organic matter, lime, pH and electrical conductivity) and physiography (elevation and slope) is measured also. By importing the information layers in appropriate model and using necessary statistical analysis in ENFA model, the map of its potential habitat has been created. The results showed that 25200 hectares of study site is potential habitat of Zygophyllum atriplicoides which is 34 percent of study site. To evaluate the verity of this model, Boyce index has been used and model rectitude in this test was determined as 87.2 percent. The result of this model is shown that PH and Lime are the main effective factor to determine potential suitable of this plant species.

Investigation of drought event has a great importance in the natural resources management and planning water resources management. In this research, the effect of the climate change on drought characteristics in northwest of Iran was investigated using the HadCM3 model under A2 scenario. The statistical downscaling was executed using SDSM 4.2.9 and observed daily precipitation, observed predictors and large-scale predictors derived from the HadCM3 model. Afterwards the SPI was calculated for different time scales of 3, 12, 24 and 48 months in the observed period of 1977-2006 and three periods of 2007-2036, 2037-2066 and 2067-2096. Obtained results show that the mean annual precipitation at the stations of Ardebil, Khoy and Oroomieh was decreased in the future periods and it was also increased at the station of Tabriz in the future period. The Ardebil station with the depletion of 97 mm (32%) in the fourth period than the observed period has maximum rate of the depletion. The results also show that the drought occurrence with more intensity, duration and frequency can occur in the future periods. The comparison of the results between different stations shows that the Ardebil station has the most intensity of dry period in time scales of 3, 12 and 24 months based on the maximum cumulative intensity of dry periods among the stations. On the time scale of 48 months, the Oroomieh station with the cumulative intensity of -92.78, has the most intensity of dry period between the different stations.

To find the effect of Atriplex canescens on soil chemical properties, two adjacent areas, each with and area of 1 ha, were selected in Hossein Abad Hapeshloo Shahryar. In one area it was planted Atriplex canescens in 2003 while the later one without Atriplex canescens was considered as control area. To sample soil, random- systematic method was used along 3 transects with a length of 100 m. In planting site transects were established perpendicularly on furrows were while in control site they were established parallel. Along each transect, 3 profiles were dug in initiate, medium and end points of each transect under shrubs and samples were taken from two depths (0- 30 cm and > 30 cm). Then, soil characteristics including texture, pH, Ec, Lime (CaCo3), ESP, organic mater (OM) and elements of Na, K, Ca, Mg and N were measured in laboratory. The results of this study showed that pH and Mg were significantly reduced in planting site compared of control. In addition, Na, Mg, Lime and Ca were significantly increased in planting site in comparison to control.

Improved pasture establishment in plants, especially in arid and semi-arid is very important Application of biological fertilizers in pasture can be considered as a useful approach. that is one of the sources of the symbiotic fungus. The purpose of the present study was to investigate the possibility of enhancing seedling establishment and growth rate of Bromus kopetdaghensis under natural habitats by inoculation with mycorrhiza species, Seeds of alfalfa were sown under greenhouse for 20 days and inculcated with two species of Glomus intraradices and Glomus mosseae. After one month growth, the inoculated seedlings were transplanted into the natural as sub plots as split plot based on RCBD (Randomized complete block design) were evaluated with three replication. Inoculation percent with G.mosseae was 62.7% and with of G. intraradices 81.3% Symbiosis increased establishment of alfalfa at the early and late growth stages, with stronger effects G, intra than G .mosseae. Furthermore leaf and root dry matter, total dry matter and the ratio of above ground to underground plant parts was increased in association with G. intraradices, where as such effects were not associated with G. mosseae. In conclusions, it Glomus intraradices can be used as a biological fertilizer for establishment of alfalfa in semiarid rangeland of Bahar Kish rangeland, Quchan.

Endozoochory is one of the seed dispersal modes through animal’s digestive systems transmission and the increases rate germination and plant establishment. The aim of this study, investigated the relationship between seed characteristics and the passage through the digestive tract of livestock and domestic animals (cattle, sheep and goats) in the 7 species perennial grass 8 species perennial forbs and 3 species annuals forbs in semi-steppe rangelands of Chaharmahal and Bakhtiari. The first, morphological seeds characteristics including: seed weight, length, width and shape of the seeds measured, and Seeds were fed to the livestock (animal treatments) and the excreta collected to order records germination success of plant species in a greenhouse during a four months experiment. Using multiple regression models the relationship between seed characteristics and success germination was evaluated and compared for different animals. Simple linear regression showed that the percentage of germination after passing through the digestive tract of livestock and properties measured, there is no communication and seed size, weight, length and width of the seed does not affect the animal through the gastrointestinal tract. The logarithmic regression showed that for perennial grasses between seed length and germination, exists direct relationship in all animal treatments. The results of this study showed that, there is no Correlation between morphological characteristics of seeds and passing through the digestive tract of livestock.

Erosion is one of the important factors in soil degradation and decrease fertility and slope length is one of the most effective factors in land form and amount of erosion. The objective of this study was investigation of spatially variation of sediment concentration in slope length until to receive transport capacity. To obtain this goal a hill slope simulator system designed and manufactured. This system include 10 flumes, each has five meter length which after series them become fifty meters. This system can produce cumulative flow via fifty watering can tube which are install on flumes with one meter interval and each flume discharging is 100 cc. Other variables include two type of soil and slope in three level 15, 22.5, 30 percent. Three replications were used for each treatment and totally 18 experiment was done. In each experiment four samples were gathered from end of each flume and concentration was determined. Complete randomized design with factorial arrangement was used for data analyzing. Richard’s function was used for fitting a suitable curve on observed data. Result was shown that effect of soil type on sediment concentration was not significant while slope and slope length effects was significant. Otherwise sediment concentration in the two last flumes was located in same class which is shown that sediment concentration achieved to transport capacity in this slope length. Also results were shown that Richard’s function can simulate trend of concentration variety in slope length.

Desertification relates to the both the process and end state of drylands degradation. Salinization and alkalinization are two indicators of soil degradation in arid and semi-arid regions. The main objectives of this research is monitoring of soil salinity using high spectral and spatial resolution of remote sensing to assess desertification in the Marvast plain, Yazd province. Two images of Terra satellite, ASTER synchronous to 2003 and 2010 are used. After preprocessing and analyzing of the images, relationship between parameters of soil salinity (i.e. SAR and EC) and spectral reflections were determined and, both two satellite images were classified using maximum likelihood method. Then, the surface area of each class and the amount of its changes were calculated. Results showed that during the period of 7 years (2003-2010), area of non-saline lands has decreased while, the area of saline land has increased, which leads to the salinization of agricultural lands, reduction of its yield and also extent of desertification in this region. Accuracy of EC map classification for 2003 and 2010 images are 87.5% and, 82.5%, respectively. Kappa coefficients for both images are 0.83 and 0.76. Accuracy of SAR map classification for 2003 and 2010images are 87.5% and 87.5%, respectively. Kappa coefficients for these two images are 0.81 and 0.77, respectively. Generally, it can be conclude that using of remote sensing data, especially ASTER images has high efficiency for change detection analysis in soil salinity and natural resources management.

Aim Of this research is landslide hazard zoning in Syahdare watershed using logistic regression. Therefore, outset landslide points recognized using air photography and extensive field studies. Then distribution of landslide map was makes. Then each effective element on landslide occurred for example slope, aspect, elevation, litho logy, land use, distance of road, distance of drainage, distance of fault and precipitation map makes in GIS environment. These data were saved in raster and vector format in GIS soft ware and they used for analysis with logistic regression. Logistic analysis obtained by Arc GIS 9.2 soft ware and SPSS. Results showed the most important elements in Land slide occurred in this area are slope, elevation, precipitation, distance of drainage and distance of fault respectively. Most of the land slides have occurred in the classes of 10 to 15 degree slope, elevation of 2350-2500 meters, precipitation (473-523 mm) are located. 50% Landslide is located at a distance of 30 meters of the stream. In this region the most landslides are occurrence in the 300 meter to fault distance. While the from 500 meter distance to the fault reduced number and susceptibility to landslides. The evaluation of accuracy model and the results obtained with three methods for the presence of all variables, 98.2 percent, 0.692 and 0.519 respectively. So showed that logistic regression had high accuracy in making landslide susceptibility map in study area.

This research was done in order to submit a model for salinity map made with TM satellite data and salinity values in a Buienzahra. The necessary processings such as principal component analysis and producing of different indices was done on the main bands. The 38 soil samples using random sampling (with 10×10 km dimension) from different horizons were designed and performed on the study area. The position of each node was registered with global positioning system (GPS), and the surface electric conductivity of samples was measured using EC meter instrument in soil saturation extract. Correlation between spectral values (main bands, produced indices) with electrical conductivity values were investigated for 80% of the samples. The regression analysis of ECe showed that there is a significant correlation between ECe with spectral data in all of main bands and with BI, NDMI, SI1, SI2, SI3 indices in 99% levels. The accuracy assessment of estimations using validation 20% samples was done. Results showed the produced ECe model could predict the soil salinity with ME and RMSE of 0.08 and 2.53 dS/m respectively. At finally, Salinity map with different salinity classes ( 0-2, 2-4, 4-16, 16-32, 32< dS m-1) was produced.

Combating desertification which is a serious threat for the environment and human welfare requires understanding complex issues of this phenomenon using evaluation, awareness of severity of it’s processes and determination of it’s factors. So here, after recognizing the characteristics of the region showing existence desertification, we assess its current status with emphasis on climate, water, geology-geomorphology, soil and wind erosion as the most criteria of desertification. According to more consensus on regional model or flexible model to modify, Iranian Model for Desertification Potential Assessment (IMDPA), which is calibrated to use in arid area of Iran, was chosen. At first the rainfall seasonality indicator was added to the model as a special climate character. Then primary assessment of desertification was done. At last according to the result of primary assessment, the area environmental conditions and revealed issues during assessment the model was modified, final assessment and mapping of desertification were done. At last according to the result of primary assessment, the area environmental conditions and revealed issues during assessment the model was modified, final assessment and mapping of desertification were done. Based on the results desertification intensity in 33.94% and 66.06% of the area are severe and moderate respectively. Also the major factors affecting desertification across Damghan region are climate, salinization of water and soil resources, improper land use, over exploitation of underground water, over grazing and improper irrigation method.