نشریه مرتع و آبخیزداری
سال شصت و سوم شماره 1 (بهار 1389)

Using of different systems of soil plough after changing unconsciously and non-scientific of land use, other soil physical and chemical characteristics affected. This fact, especially in marginal lands and mountainous regions is more visible. This research compared with the purpose of studying land use changing on some soil physical and chemical characters like very tiny sand percent, pH, Ec, clay percent, sand percent, silt percent, soil moisture, calcium carbonate in Gachsaran and Aaghajari formation. So that in aghajari formation 7 points and with 3 replicates and in gachsaran formation 6 points and with replicates in three land uses range, residential and agricultural land uses sampling of soil was done. Sampling of the depth 0-20 cm soil was done. After tests implement are concerned, the results were investigated. According to the results, range land in two Aghajari and Gachsaran formations in terms of clay percent, sand, EC, pH, moisture and Calcium Carbonate a meaningful difference have, and in other cases was not seen any disagreement. between agriculture land use in two Aghajari and Gachsaran formations in terms of very tiny sand percent, sand, clay, moisture and calcium carbonate meaningful difference have, and in other cases was not seen any disagreement. In residential land use in two Gachsaran and Aghajari formations only in clay percent and EC, there are a meaningful difference, and in other cases was not seen any disagreement. In each formation also land uses had effective role in soil physical and chemical characteristics.

By determining relative importance and contributions of erosion types to sediment yield, erosion susceptible areas in a watershed will be identified, and sediment control and soil conservation projects can be focused on that areas. Because of many problems associated with traditional procedures for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as valuable and effective approach to assemble such information. In this method, a suitable composite (set) of diagnostic properties and a multivariate mixing model are employed to estimate the relative contribution of sediment sources to sediments transported to basin outlet. In this study, using suitable composites of geochemical elements, radionuclides, organic Carbon, Nitrogen and Phosphorous, capable of discriminating two groups of erosions (namely, sheet and rill erosions, and gully, channel and river bank erosions) of the study basin, and a multivariate mixing model were used to determine contributions of that erosion types to sediment yield. The suitable composite fingerprints (elements) were obtained using discriminant analysis. The study basin is Ghara aghaj basin, located in Makoo township, West Azarbaijan province. The suitable composite fingerprints having capability to distinguish the above mentioned erosion types include, 137Cs, OC and Nb. Mean contributions from the two main erosion types, namely sheet and rill erosions, and gully, channel and river bank erosions were estimated as 34.6% and 65.4% respectively. Low mean absolute errors (less than 12%) showed high degree of correspondence between measured and predicted properties. High model efficiencies (greater than 0.99) confirmed the goodness of fit of the mixing models. Also it is argued that fingerprinting estimates for sediment sources are consistent with field observations.

The objective of this research was to evaluate the effect of different concentration of salicylic acid on enhancement germination characteristics of Sanguisorba minor L. under salt and drought stress. The experimental design was factorial arranged in a completely randomized block design with four replications. Treatment were combination of 5 levels of salt and drought stress, separately (0, -0.3, -0.6, -0.9 and -1.2 Mpa) and 4 concentration of salicylic acid (0 as a control, 100, 200 and 300 mg/lit). The results revealed that all germination characteristics decreased by increasing strength of salt and drought stress but treated seeds showed lower decrease. Application of salicylic acid increased germination percentage and rate and also decreased mean germination time significantly, but had no effect on root, shoot and seedling length. Since 200 and 300 mg/lit concentrations of Salicylic acid had more effect than the 100 mg/lit on germination attributes, on the other hand no significant difference was observed between 200 and 300 mg/lit concentrations. Considering the economic issues and also considering this fact that higher concentrations of salicylic acid may lead to accelerated stress in plant, 200 mg/lit salicylic acid concentration was suggested in S. minor in order to improve germination and seedling establishment under salt and drought stress.

Gully erosion has an important role in Fars province due to sediment production and enormous damages to land, roads and infrastructures. In this research, 15 gullies were selected to measure their morphometric characteristics. The length, depth, top and bottom width and volume of gully erosion were then measured. Influential factors on the sediment production and gully development were analyzed and determined by using stepwise method in SPSS software. The results indicate that sediment production due to gully development is related to three variables including drainage area, silt and the sand percent of the watershed above the gully heads. These results imply that surface runoff is acting as dominant hydrologic process on gully development. Investigation on the topographic threshold reveals that drainage area exponent (b) is negative and these results are in the same line with the results of some recent relevant studies. The results also indicate the watershed characteristics and geological formation impact on the gully sediment production. Gully development could be reduced by decreasing the area of bare land as the main source of surface runoff by vegetation planting and terracing. Constructing of small earth dams at the end of gullies collect surface runoff and provides better situations for vegetation establishment around gullies.

The aim of this research is the assessment of the relation between rainfall and large scale synoptically patterns at Khorasan Razavi province. In this study, using adaptive neuro fuzzy inference system, the rainfall estimation has been done from April to June in the Area under study. Spring rainfall data including the information of 38 synoptic, Climatologic and rain gauge stations from 1970 to 2007 has been selected from Iranian Meteorological Organization and Ministry of Energy. In this paper, we are analyzed 38 years of rainfall data at Khorasan Razavi province located in northeastern part of Iran at latitude-longitude pairs (34°-38°N, 56°- 62°E). The Adaptive Neuro-Fuzzy Inference system based on synoptically patterns with 38 years of rainfall data was trained. For performance evaluation, network predicted outputs were compared with the actual rainfall data. In this Study, at the first step, the relationship Between synoptically pattern variations including Sea Level Pressure (SLP), Sea Surface Temperature (SST), Sea Surface Pressure Difference (?SLP), Sea Surface Temperature Difference (?SST), air temperature at 700 hpa, thickness between 500 and 1000 hpa level, relative humidity at 300 hpa and precipitable water were investigated. As the second step, the model was calibrated from 1970 to 1997. Finally, rainfall prediction is performed from 1998 to 2007. The model that used in this research has an input layer, one hidden layer and an output layer. The number of neuron for input layer, hidden layer and output layer was 13-28-1, respectively. The results of simulation reveal that adaptive neuro fuzzy inference systems are promising and efficient.

Nowadays, population growth and on the other hand resources limitations astonish authorities. Population changes cause variation in economic activities and land use changes. As a whole, overusing, improper land use and human disturbances over natural resources make environmental imbalances worse. In recent decades, we have seen land use changes in Taleghan basin. Land use changes were produced by many factors, e.g. in abandoned lands, some parts of the region have been converted to residential areas and constructions. Since one century before, because of vicinity to population centers like Tehran and upland condition, this region has been a suitable place for recreation of travelers. Also one of the most important factors has been changed in population which has occurred in Taleghan. So that the statistical information shows substantial decrease in villages population in Taleghan. Similar to the, other regions in Iran, landuse changes especially in rangelands, is an important subject in Taleghan too. This paper tries to illustrate the relationship between population and land use changes in the given region of study and to detect the land use changes in a 15-year period. For determining the landuse, we used geographic information system and statistical methods, remote sensing also landSat images for 1987 and 2001 together. Population size were gained and analyzed for computing the population growth rate. According to what we concluded, in abandoned lands in given region of study the growth rate was positive and in other word, it increased and for other land uses this rate was negative together with negative increasing in all villages, therefore the population decreased. The villages of this region according to their magnitude of reduction in population growth and abandoned lands are: Gateh deh, Narian, Noviz oliya, Dizan, Jovestan, garab, Orazan, Nesa Bala, Mehran, Khachireh, Drapy. Thus, great number of settlers during these years migrated and the population decreased and following this trend, great area of rangelands (37.88%) which has already converted to rain-fed lands, has emerged in the form of abandoned lands in this region. In Gateh deh village, the area of rangelands had the maximum reduction and on the contrary, abandoned lands had the maximum amount of growth. Finally, it could be inferred that, there is a logical relationship between population growth and the area of abandoned lands.

Globally, soil erosion is one of the most important environmental problems which is threaten soil and water resources. Soil properties are main parameters to affect runoff and soil erosion processes. So, this study was conducted to investigate the effects of some soil properties on runoff and soil erosion in the forest lands located in vicinity of Sari city. Rainfall simulator was set in 15 random points in 2 sites to create experimental rainfall. Runoff and sediment yield resulted from each experiment was measured based on field and laboratory investigations. Soil samples from 0-20 cm depth close to the simulation points were collected and analyzed. The results showed that soil initial moisture, percentage of soil organic matter (% SOM), bulk density and sand percent are most effective factors in runoff generation, respectively. Also, the results illustrated that percentage of soil organic matter, soil initial moisture and silt percent affect on soil erosion, respectively. The results of multiple linear models showed that runoff and soil erosion can be predicted based on percentage of soil organic matter, soil initial moisture and percentage of clay with coefficient of determination of 0.638 and 0.752, respectively.

The establishment of rational balance between number of users and productivity capacity of rangelands and suitable number of the folk in the ranch units is one of the necessities of the sustainable management of rangelands. Also growth and efficiency of the productive factor would lead to the economical benefit maximum. This study was done in order to evaluate the optimal ranch size basis on the social and economical relative sustainability in the rangelands of Urmiya. The statistical information were derived from 203 questionnaire collected from 34 rangeland ranch units in the study area at the year of 2007-2008. Then the costs, incomes and grazing capacity were evaluated in each unit. The suitable number of folk and optimal ranch size were determined based on some criteria such as Total Efficiency Index. Productivity factors and annual costs of family were analyzed using Eviews economic software. The results showed that ranch size per a rancher is not optimal and each productivity unit has used from the rangeland less than optimal limit. At present, utilizable rangeland average per a user is 71 ha. Also the suitable minimum size of folk and rangeland per a family including 5 members is 550 and 350 ha, respectively. So it is able to supply the annual costs of family. Also economically suitable folk number and optimal ranch size were determined 667 and 297 ha, respectively. Therefore we can totally conclude that the folk size of 300 to 350 is a suitable size, either with respect to efficiency of production factors livelihood or preparing of the livelihood per a family unit, which completely depends on the ranching in the region.

The purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. The study area is located in west of Tehran province and southeast of Hashtgerd, next to Najm-abad village. After field studies, the index vegetation types were selected and randomized-systematic sampling method was used for soil and vegetation cover sampling in each key area. The area of each plot was determined according to type of plant species and their distribution using minimum area method. Some vegetation cover parameters such as canopy cover percentage, density and frequency of plant species were measured in the area. Then soil sampling were done from 2 horizons including 0-10 cm and 10-30 cm in each plot and soil attributes such as texture, pH, organic carbon percentage and gypsum were measured in the laboratory. Afterwards, statistical methods like multivariate regression, analysis of variance and RDA technique were used for analyzing soil and vegetation cover data. The results showed no specific difference between soil and vegetation data except for gypsum. In other word the effective factor on vegetation cover variation was soil gypsum.