نشریه پژوهش های آبخیزداری
پیاپی 102 (بهار 1393)

The Species has a particular time period for growing readiness and grazing at a particular time must also stop. Moreover, rangeland soil is ready only in certain times to sever livestock. Without understanding these characteristics, determining the grazing season and livestock management and grazing is not possible. With this study, the revising of grazing rangeland management programs in similar areas with similar vegetation will be possible. So in order to determine the timing of entry and exit of livestock to and from rangeland this study was carried out in a semi-steppe rangeland in Alamut of Ghazvin province, 100 km North eastern of Ghazvin five years from 2006 to 2010. In this study, first selected floristic list of range species and selected 2 valuable and important species. The two studied wheat species was Dactylis glomerata (class I) and Agropyron intermedium (class II). So information of phenology plant noted in 2 stages: growth stage in every 15 days and reproductive stage in every 7 days. The results showed that A. intermedium starts its vegetative stage at beginning of (April), their flowering time is the half of Khordad (June) and its seeding phases start at beginning of Tir (July). In the last week of May, we do the seeding phase. Reproductive stage of D. glomerata began from second half of Ordibehesht (April), in Khordad (May) entered at the flowering stage and from mid of Khordad (May) start its seeding phase. The results showed that the time of the start and end of the species growth varied in the different years in this species affected by rainfall and temperature.

There are very factors that effect on plant species distribution and vegetation cover in dry lands. Geomorphology effect on vegetation is one of the most prominent factors on plant survival and establishment in arid lands. In this study we surveyed relationship between vegetation cover percentage and geomorphology units. We measured weathering degree and amount of vegetation cover percentage, type and life forms in different geomorphology units, slope degrees and aspects on different lithology. Our results show that there are significant differences between vegetation cover percentage in different geomorphology units, aspects and slopes. Also tree species only there are on limestone lithology geomorphology units. It is clearly that different lithology and geomorphology units have different properties in regard to soil formation, therefore there are different plant communities in these units. It was concluded that the first prominent factor is lithology and second prominent factor is geomorphology unit on plant cover percentage in this study area.

Desertification process as a great problem effects most of the countries in the world especially developing countries. This process has high rate in arid and semi-arid countries as Iran. Alamarvdasht area due to the existence of decimation of water and soil resources, desertification is increasing. IMDPA model was selected to study the most effective criterion and indicator in the Alamarvdasht region. In this case study criteria including: water, vegetation cover and soil were studied and some indicators for each criterion were considered based on local condition. Then final map of desertification intensity of region was prepared by composing the layers and using of their geometrical average. According to the three selected criteria, the map of desertification shows the medium and high levels of desertification. The water criterion with average value of 2.78 and vegetation criterion with value of 2.77 were settled in high class while the soil criterion with value of 2.07 were considered as medium class of desertification.

γ- ray specterometry of fallout radionuclides especially in case of soil redistribution was taken into acount by greate number of researchers around th world. These specterometry was done in lab or in-situe. Due to 137Cs importance in soil redistribution studies, its specterometry was conducted in reference area and three Sub-catchments of Kachik basin of Golestan province. For this, 132 soil samples collected from reference area and Agh emam Sub-catchment and their specterometry were done in lab. Mean of 137Cs activity for these areas were 14.30± 0.74 and 4.29± 0.25 Bqkg-1, respectively. For Testifier and Sample Sub-catchments, portable HPGe was used. Mean of 137Cs activity for these Sub-catchments were 7.04 ±4.74 and 6.72± 4.53 Bqkg-1 in turn. To compare in-situe and lab measurement, 120 samples for every measurement taken into account. Delta Activity for lab measurement was significantly lower than that in-situe measurement. While compared these two methods for 120 situations by portable HPGe and 120 samples measured in lab, results confirmed suitabielity of portable HPGe. Using portable HPGe, cost and time of getting results can be reduced by 2.08 and 6.25 times, respectively.

Identification prone areas to landslide occurrence and mass movement is one of the first steps in natural resource management and planning and development. Identification and mapping of landslide risk potential zones to reduce  landslide damages is necessary. [k1] In this study, landslide hazard zonation have been evaluated with statistical density level method techniques using remote sensing and GIS in the basin Ala-RoodZard Baghmalek of Khuzestan province. For this purpose, initially landslide distribution map was prepared by aerial photographs, existing geological maps and field investigations, in these basins. Then affecting factors landslide include Lithology, elevation, slope, slope direction, the maximum 24-hour rainfall, earthquake acceleration and informative layers was prepared. Finally effective factors weighted, then with GIS and using method of density levels statistical index, landslide hazard zonation maps were classified in five different zones, stable, largely stable, stable moderate, unstable moderate and unstable. The results showed that 61.67 percent of the existing landslide have occurred in two zone of unstable moderate and unstable. Accuracy of area density statistical zonation method levels in the study area is 63%, which shows it possesses great accuracy.

In this study the efficiency of statistical regression models and, also, the relationships between rainfall characteristics with runoff and sediment yield were investigated in the plot scale. For this purpose, data from runoff and sediment yield of 12 storms during October 2010 to October 2011 were used in the plot scale, which, installed in representative basin of Khamsan located at south of Kurdistan province. Hence, after each storm-runoff event, amounts of runoff and sediment were collected and measured after transporting to the laboratory. The storms data were also acquired from meteorological station located in the basin. Results showed that, sediment yield of plots have the most correlation with runoff volume, maximum intensities of storm in 60, 55, 65, 25 and 20 minute with correlation coefficient of (0.887, 0.821, 0.818, 0.814, 0.813 and 0.810). in the other hand, the runoff production of plot has the most correlation with rainfall height and 3th & 4th quartile of rainfall in significant level of 99 percent. It has been also revealed that Logarithmic model with the highest determination coefficient (0.825), efficiency coefficient (0.84) and the least value of relative error (11.57) and Root mean square (0.058) is the best model for predicting plot’s runoff production. It is Followed by power and inverse models with values of efficiency coefficient (0.8 & 0.794), determination coefficient (0.769 & 0.768) and relative error of verification (4.73 & 3.84). Results, therefore, demonstrated that multi-variation models is better to explain sediment yields of storm followed by S curve, cubic, quadratic, exponential, power and linear models.  

Amygdalus lycioides as exclusive and important species of wild almond, cover large areas of Iran including Ilam province. In this research, by aim of determine the effect of ecological factors on distribution and physiological properties of the species, first the range of almonds habitats was plotted on 1:50000 maps in Ilam province. Then, ecological factors, habitat characteristics and physical characteristics such as: qualitative and quantitative characteristics, in each ecological units, and were taken and recorded. It was used of stratification method (stratified random) for sampling. In each of the ecological units, depending on their area, at least three random plots of size 300 × 200 m in a north - south direction was implemented. All of region characteristics in terms of climate, topography, soils, geology, vegetation and associated characteristics of the species, such as height, crown diameter, etc. were recorded. In orther to evaluation of ecological effects on morphological characteristics, it is used randomly perfect method and compares means by Donkan's method and use of SPSS and SAS softwares. The results show that, the species is spread in 27 spots, with altitude ranging from 600 to 1900 meters above sea level and in four climates of the province. In semi-arid temperate climate and altitude range of 900 to 1100 meters, is reached to high canopy cover and density and the maximum its basic dimensions. It has not been observed significant differences between altitude and climate classes in this regards.  

Seed deterioration is a natural event that affected by improper storage or maintenance in the unsuitable conditions for long periods in places such as a gene bank. Seed deterioration is identified with symptoms such decrease in speed of germination and increase in non-living seeds. This study was conducted to study impact of hormone priming, vitamin priming and matrix priming on the repairing ability in Atripelex lentiformis deterioration seeds. Concentrations of vitamin solutions were included 50, 100 or 150 mg of pyridoxine per liter. For hormonal treatments concentrations were 16.6, 33.3 and 50 mg per liter ABA and for salicylic acid, concentrations were 200, 400 and 600 mg per liter. Matrix priming also was used as -0.8 -1.0 and -1.2 bar of PEG concentrations. For seed deterioration, the aging test was done at 41°C and relative humidity close to saturation for 48 hours. Then the seeds were treated with solutions. The petri dishes was arranged using completely randomized design. Data were collected and analyzed by Mstatc software. The results showed that all the vitamin and hormone treatments had a positive effect on seed viability repair but the effect of PEG was not significant. It was concluded that concentrations of 50 mg pyridoxine per liter and 600 mg L salicylic acid with average values of 84% and 87.3%, respectively, had the highest germination% than that control treatment with 66% germination.

Since plant species palatability is different in various phenological stages and also at different times of day, information of plant species palatability is essential for available forage production estimation in each pasture habitat. For this purpose, palatability of four shrub species including Artemisia sieberi, Salsola kernery, Aelienia subaphylla and Eurosia ceratoides were determined and compared at different times of day and in various phenological stages using direct observation via timing technique by stopwatch in Nodushan-Yazd rangelands. Firstly 3 heads of goats were selected in desired herd, then livestock were followed using timing technique with stopwatch, 3 times a day (morning (8:30), noon (12:30) and afternoon (4:30)) and each time for 30 minutes in each phenological stage (vegetative, flowering and seedling) and afterward the amount of time that each livestock spent eating each plant species was noted. Thus, variance analysis and mean comparison of data were performed. Results showed that there are significant differences between palatability of different species, at different times of day and also in various phenological stages (P<0.01). Species interaction in time and stage was also significant (P<0.05). E. ceratoides had the lowest Palatability in the seeding stage in the noon, and A. sieberi had the most Palatability in the flowering stage in the morning.

This study was conducted to compare the allelopathic potential of aqueous extracts of prosopis juliflora (Mesguite), Acacia nilotica (Scented[pod Acacia) and Ziziphus spina (Jujube) chiristiin concentrations of 0, 30, 50 and 100 gr/lit, also mixture of leaf and sand with ratio of 1:15, 1:10 and 1:5 (leaf:sand) on germination and seedling growth of Avena fatua. Two completely randomized designs (CRD) with 4 replications were used for both germinator and glasshouse experiments. Results showed that applying aqueous extract of prosopis juliflora and Acacia nilotica reduced germination percentage, radicle and plumule length of Avena fatua, in all three concentrations. Ziziphus spina chiristi had no effect on germination percentage, but it reduced significantly radicle and plumule length in comparison with control. All three leaf and sand mixture treatments had reducing effect on germination percentage and radicle growth. Decreasing the leaf:sand ratio caused increase in germination percentage and seedling growth. Ziziphus spina chiristi leaf didn’t show any effect on plumule growth. It was concluded that the most effective aqueous extract and leaf:sand mixture belonged to prosopis juliflora.

Unfortunately the groundwater balance in all plains of Chaharmahal va Bakhtiari province is negative. The area of this province is only 1% of Iran Country, whereas it has 10% of water resources in this country. So, flood spreading will be helpful both in increasing the water table and flood control. Hence this research carried out to determine the most suitable areas for flood spreading in Kiar, Mizdej, Sefiddasht and Borujen plains. Slope, infiltration rate, alluvial thickness, alluvial quality and land use factors were explored as affective parameters in flood spreading. These parameters were explored, classified, weighted and overlaid using GIS system. Boolean logic, overlay Index and Fuzzy clustering methods were used to overlay these layers and the study areas were divided into two suitable and unsuitable classes for flood spreading. Results showed that based on overlay Index, Boolean logic and Fuzzy clustering 10.85%, 10% and 14.4 % of study area was suitable for flood spreading, respectively.  Infiltration rate was recognized as most limiting parameter among explored parameters that it due clay texture of soil in most parts of province. Alluvial thickness was recognized as another limiting factor for water spreading in Chaharmahal va Bakhtiari province.  

Performance of hydrological models will depend on how they are calibrated. In these models, the value ​​of some parameters can be estimated with direct observations and measures. But some others are not directly observable and their estimations can be carried out by indirect techniques of model fitting in historical data. The main aim of this study is to investigate about the performance of soil moisture accounting model (HMS SMA) in annual, semiannual, seasonal and monthly time scales to estimate the effect of soil moisture on causing of runoff. In this research, after of Zolachay watershed Modeling with Extension HEC-GeoHMS and finally by estimating accounting model parameters of soil moisture, the rainfall- runoff simulation in other scales has been done. By analysis of measures and enhancement of HMS SMA Model parameters, we can claim that monthly time scale in calibration model can work more accurate than seasonal, semiannual, and annual time scales. Regarding the estimation of peak flow, it can also be said that time - seasonal scale is the best one to meet the above- mentioned goal.

Landslide is one of the types of natural hazards that are causing great damage. With the development of human society and social-economic activity damage was related to more landslides. One of the areas prone to natural factors in the occurrence of Vaz watershed a from the north country. Therefore weights of evidence models, logistic regression and Analytic Hierarchy Process to landslide hazard assessment of this area and determine its performance in GIS environment was used. To perform theFirst, landslide points were recognized by using aerial photographs, extensive field studies and subsequently the distribution of landslide map was made. AHP method to prioritize factors in landslide occurrence was used. Review the action feature lithology and distance of road, the most important factors in the occurrence of landslide showed. In the next stage of the model landslide hazard assessment with the four risk categories low, medium high and very high was prepared that Combining with t hazard maps was determined that 20.82 percent of high hazard areas and 45.14 percent in the class field is very high hazard that these statistics show the watershed and from the occurrence of landslide is located in a dangerous situation. Assessment model showed weight of evidence model the amount of 1.22 weight among the highest efficiency model is capable of zoning.

Information of forage quality index are of paramount importance in animal and rangeland management. To that end quality of important common forage spices in Ghareh Bagh semi steppe rangelands, was determined. In the present study, 6 species were sampled at three different phenological stages (vegetative, flowering and seeding) in 2009. All species were belonged to most important plant type of study site. Forage quality index namely; crude protein (CP), acid detergent fiber (ADF), dry matter digestible (DMD) and metabolisable energy (ME) were determined to meet animal requirements in maintenance condition. Analysis of variance was used to compare the index among species and different growth stages. Specific differences were evaluated by Duncan’s test. The results showed that maximum value of crude protein (10.20%) belonged to Teucrium polium and maximum value of dry matter digestibility (55.01%) and metabolisable energy (7.35 Mj/Kg/DM) were belonged to Helichrysum plicatus. The minimum value of crude protein (7.07%), dry matter digestiblility (46.13%) and metabolisable energy (5.84 Mj/Kg/DM) recorded for Festuca ovina. Average crude protein values for different phenological stages were 13.22, 8.13 and 5.03% with higher value for vegetative and flowering stages and with values lower than critical amount (7%) to meet animal maintenance requirements in seeding stages. Average dry matter digestibility values for different phenological stages were 58.07, 49.55 and 43.08 with higher value for vegetative stage and with values lower than critical amount (50%) to meet animal maintenance requirements in flowering and seeding stages. Metabolisable energy in vegetative, flowering and seeding stages were 7.87, 6.42 and 5.32 Mj/KgDM espectively with lower than critical level (8 Mj) to meet a animal unit maintenance requirement. This suggests that desirable quality of pasture forage at different times grazing is not same and determination of daily animal units requirement based on forage quality is needed. It is clear that forage quality is changed with variation of weather, but due to the expense of determination forage quality is very high, can use the results of this research for estimate of animal requirement in different years.

Climate scientists have concluded that the earth surface temperature has increased severely in recent years and it has been foreseen that this trend will continue in 21st century and along with changes in hydrologic cycle of watersheds will also continue. Climate change in the studied area (Tajan) is an important subject, because this region is an important source of water supply in Sari City (center of Mazandaran Province) for different uses. For this purpose the non-parametric Mann–Kendall test is used to detect the trend of major hydroclimatic variables and Kendall’s τ test is applied to detect correlation between temperature and precipitation with runoff in the Tajan River Basin. The results showed that three mean annual precipitation, evaporation and runoff experienced a decreasing trend with the amount of 249mm, 182mm and 75mm respectively, while annual air temperature demonstrated an increasing trend by 0.42 ˚C. Decreasing trend of precipitation and evaporation is significant in %1 probability level, and decreasing trend of runoff and increasing trend of temperature is not significant. The test of correlation between temperature and precipitation with runoff showed that correlation of precipitation and runoff with respect to correlation of temperature and runoff is higher, and one can say that precipitation variations has more effect on runoff variations. Also, in this study, in relation to effect of land use changes on runoff, the annual and seasonal water balance during the time duration has been investigated and it was shown that in addition to undeniable effect of climate change, the land use changes also can increase and decrease runoff in different seasons into two different shape.