Desert
Year:2004 | Volume:9 | Issue:2|Papers Count:14

In this present essay, exploitation study of underground water in Minab Deltan has been taken into consideration in physical, geotechnic and geophysics studies format. Under study area is drainage basis of Minab Dam with an area of 800 square meters. Type of aquifers are selected in accordance with their type of electrical resistance and determination for quality and quantity of underground water tables in Minab.It should be mentioned that, penetration velocity of water is high in entrance area of Minab river to delta due to physical features and grading position of sediment inside water and then with regard to fine aggregate of sediment in lower area of delta, such a rate little by little decrease and fixed in a gravity force.As a result" with regard to this point that water flow in soil is due to change in soil and structure of land texture, then should bear in mind that method of use from utilization of underground water throughout delta is not equal from view point of quantity and quality in such a way that the best water with regard to measurement of EC (Electric conductivity) and TDS (total disolvs solids) is in river inlet to Minab delta and the most hardness is relating to end area of delta.We faced with some limitation regarding utilization of underground water in accordance with performed geophysics and geotechnics studies performed in northeast area.In southwest of the City of Minab, west direction of Minab city to Hormoz -Strait coast and southwest of the said mentioned delta, we have fine aggregate alluvium basis in such a way that, we faced with limit in possibilities of providing underground waters table.The top quality of Minab Delta underground waters is in distance between Minab bridge to Gourzang village due to having coarse aggregate and highest underground quality have considerable importance for taking into consideration.

It is estimated that 15 % of the total land of word in various are saline and soudic, and about 34 % of asia continent land are influences to the sa1inization. Iran because of spatial geographical position and also climate condition that is arid and semi arid, from salinization development viewpoint are the fifth level in the Asia. In this study we investigated a case study in the Gonbad Alagol plain, this plain located in 54´ 20° until 55´ 10° longitude,and in 37´until 37´ 40° latitude, average slop is 1/6 % and average high is 18 m, average annual precipitation is 314 mm, average annual temperature is 17.5c average evapotranspiration is 1659mm and the areas ofthis plain is about 1856.4 km2.For investigation of water degradation we studied surface and groundwater and for investigation of soils, we took some samples from different depth (0-50, 50-100, 100-150 cm) in the land unit. At the end, with use of geology, topography maps, arial photo and also water and soils information, we studied and investigated water and soil salinization in this plain.The results showed that natural and anthropogenic causes are effective in the soil and water salinization. In the natural causes category, the salinization indicators were: Caspian lake sediments in the past time, different geology formations, topography, low depth watertable, evaporation highly, low rain, and also influences of wind in the move of salin.And in the anthropogenic causes category, the salinization indicators were: Various irrigation system, undesirable drainage, built of road, and also entrance of industrial and domestic sewage in the lands. And also the results showed that in the 28 years period, about 2.4 % of soil in the plain changed from low salin (Ec:4-8ds/m), to the medium salin (Ec:8-15 ds/m), and 23.5 % of the soil changed from low saline to the high saline (Ec> 15 ds/m).And also the results from 9 years period for groundwater studied showed that amount of Ec in the 72.7 % of pizometers wells has been increasing, and in the 27.3 % of this pizometers has been decreasing, and also in the 68.75 % of the total pizometer the water level has been decreasing and in the 31.25 % of the pizometer has been rising.

The purpose of this study was to examine the relationships between vegetation types and certain environmental variables including elevation, slope and aspect in Tandooreh National Park, north of Khorasan province. Topographic map of the study area with the scale of 1:50000 were digitized. Digital Elevation Model (DEM) was constructed and slope and aspect images were derived from DEM. The available vegetation map was also digitized, rasterized and co-registered to other images. Some points were sampled in each vegetation types and their values were extracted from the slope, aspect and elevation images. Vegetation and different layers were overlaid and cross- classified to examine the impact of physical variables on discrimination of different vegetation types. The result showed that topographic factors viz. attitude, slope and aspect are important factors to determine the vegetation types of an area. The result of Discriminant Function Analysis has confirmed that the attitude is the most important physical factor to distinguish the plant communities.

Since of vegetation cover degradation, Kerman city has been faced to sand storm for 50 years. Sand storm have caused some problems such as agricultural land degradation, immigration of rural people, air pollution and respiratory. In 1966 combat desertification projects to decrease the mentioned effects were established these projects consist of seeding, molch windbreak, exclosure and sapling by Haloxylon persicom & Haloxylon aphylum in 48300 ha of Kerman-baghcing watershed. Results show that the most important effects of socio-economic and ecological as well as environmental consequences consist of conversation of Kerman city and some villages against wandering dunes. For example in 1966, som pants and streets like Motahari, Shahab, Malek and Behzad were occupied by shifting sand,also, Saadat-abad and Akbar-abad village were buried by sand dunes. Decreasing of economical damages and car accident as well as dusty air, which cause to respiratory disease, increasing farmland, wood of trwws in reclaimed areas and enhancing the grazing capacity are the most affective influences of combat to desertification projects. Total current value project expenditures is 88502023/4 Thousand Rials (TR), while the total current value of benefit from enhancing formatting is 9353001/59 TR,; therefore, total current value of net income of projects is 4928978/19 TR. Assessment of projects shows that in spite of mentioned benefits there are some failures and fainting points in these projects. For example: the implemented projects were not base on a complicated design, in the order words projects sponsors and experts decided to implement projects, without any former planning, in any place that they though it is in critical situation. Lack of planning caused that some projects could not be able to gain their aims. In the other hand since of pests, no reproduction, high density of vegetation, drought and heavy grazing as well as lack of control after implementation. Most of these areas will be degraded and refer to first situation.

Application of GIS and Geo-statistical methods has provided a great facility and a high accuracy for climatic mapping. These methods generally take into account all values of climatic parameters used for classifications. This paper proposes to divide each climatical parameter into two components:1- rational or algebric component which is calculated by correlation methods: 2- stochastic or error component:and to apply the geo-statistical methods in GIS media for the second component, only.This study is based on mean monthly precipitation and temperature over 30 year-period, for 73 meteorological stations spread over Azarbaijan Province at the North West of Iran. The basic formula in Selianinov classification is the hydro-thermique coefficient k=10.P/S, where P is the annual precipitation (mm) and S is the sum of heat units with 10 degrees Celsius threshold (degree-days). The following steps were undertaken for climatological zonning of the region:- Generating daily temperature from monthly values by developing a model which estimates annual heat units, S, for each station. - Performing linear regression analysis to obtain regression equations: (P=a1+ b1.Z+e1 = Pc+e1 and S=a2+b2.Z+e2 =Sc+e2) :where Z is altitude (m) and el and e2 are the errors of estimates. These equations are significant at 1% - Constructing a digital elevation model (DEM) in UTM projection system with a grid size of 500 x 500 meters in IDRISI environment. - Compiling six layers of maps for Pc, e1 Sc, e2 and consequently for P= Pc+ el and S= Sc+ e2 based an grid points. - Creating a climatologicallayer of k=10.P/S, using the above mentioned P and Slayers in IDRISI media, which gives the climatological zonning map of the region.The paper depicts the advantage of compiling error maps e1 and e2 instead of direct mapping of P and S, which reduces the interpolations errors considerably. The greater the correlation coefficient, the less the interpolation errors. The climatic map shows that the climate of Azarbaijan ranges from semi-arid to highland cold-humid. The areas of each climatic region are given as well.

According to rapidly change in urban life and accelerating load on urban infrastructureand service, also rural settlement because of decrease of population and migration havefaced to fundamental changes in their spatial-local system. The nature of geography science as a interdisciplinary science and also the study of relation between human being and environment and the study of rural and urban settlement distribution, lead to application techniques and regional planning models for spatial-local arrangement. This paper supposed to study the present conditions of 204 rural settlement of Calale county Situated in Golestan province and also to review the population indicators by use of linear planning, population center of gravity, Pearson correlation coefficient techniques the purpose of this research is to search new route for network power supply and also service center rural and migratory settlement (growth pivot) by application GIS.

This experiment was conducted in 2000 to study the effects of four irrigation intervals on the seed yield and physiological indexces of three sunflower cultivars. The experiment was performed on the experiment farm of Oil Seed Department, Seed and Plant Improvement Research Institute in Karaj. Cultivars were: Record, Golshid, and Hysun33. The irrigation intervals included; every seven, eleven, fifteen and nineteen days. The results indicated that with increasing irrigation interval the physiological indexes decreased. Physiological indexes including CGR, RGR, NAR in different cultivars had no differences. But LAI had a higher value in Hysun33 than other cultivars. Harvest index for this cultivar under water stress was higher affected less than other two cultivars. This cultivar produced a better yield even with use of less water. This might be -due to highest translocation during productive stage and grain filling. Cultivation (sowing) of this cultivar could give better yield by using less amount of water. It was concluded that these cultivars can be recommended to farmer.

The allelopathic effect of Sorghum halepense L. Chenopodium album L. Glycyrrhiza glabra L. Convolvulus arvensis L. and Polygonum aviculare L. on germination and seedling growth of chickpea was evaluated on a compeletly randomized design with four replicates in laboratorial studies. In these experiments, shoots, soil of root zone (rhizosphere) and extracted water from rhizosphere of weeds were used. Results indicated that, shoots, soil of root zone and extracted water from rizospher of Sorghum halepense, Chenopodium album and convolvulus arvensis significantly decreased germination and seedling growth of chickpea as compared to control. While, Glycyrrhiza glabra and Polygonum aviculare did not affect these traits. In most cases, Sorghum halepense had more inhibitory effect on the traits under study. Plumule growth was influenced more severely than radical growth.

The studied area is situated at southeastern part of Shahrood between 55 15´ to 57 15´ E and 33 15´ to 36 17´ N. Khartooran sand dunes with area about 165689 hectares is situated at southern part of Kale Shour basin. According to field observation, there are three types of dunes from dune dynamic point of view, active, semi active and established dunes, and vegetation pattern´ wary in each type. From general of view, vegetation cover includes some shrub species such´ as Calignum spp., Smirnovia turkestanica and some stable grasses such as Stipagrostis pennata, which are some indicator plants on sand dunes of studied area mixed with some shrubs or annual and perennial grasses. All the mentioned plants (dominant and scarce) play the important role in plant combination in this region. According some reports, there are some other plant species such as Zygophyllum spp. Artemisia spp. and Ferula assa foetida which are the typical Natural cover of sand dunes, also there are some species such as Tamarix spp. and Halocnemum strobilaceum which are the specific indicator plants for saline regions. According field evaluation, it was distinguished that due to over grazing before flowering periods of plant, it has led to destruction in indigenous plant species, also according to the obtained results, it was determined that the percent of clay and silt in dunes which have vegetation cover is more than bare dunes and it demonstrates the role of plants in changing the mixture of soil.

A large part of Golestan Province is covered with loess sediments. Although there are many evidence that these sediments are eolian, there still are many discussions about their source, mode of formation and prevailing wind direction. The changing" trend of grain size and quartz abundance in lateral direction determines not only prevailing wind flow direction, but also their source: grain size and quartz abundance decrease in wind flow direction. In this research, it was confirmed that these sediments are eolian and lateral variations of grains size and mineralogical composition, especially quartz were used to determine prevailing winds direction. Afterwards loess distribution map in the Province of Golestan was prepared by satellite data (ETM) and with help of Ilwis software. Loesses and weathered losses were sampled from the depth of 4 meters, to eliminate the effect of weathering. The samples were studied by Laser granulometry and XRD. According to the results, average grain size and amount of quartz considerably decrease from north-east to south-west: Grain size changes from 6.66φ to 4.97φ and quartz mineral abundance from56.2% to 45.5%. Therefore, according to the obtained results, prevailing winds direction during formation of these sediments was from north-east to south-west and south.

Understanding about plants which have resistance against salinity is necessary for aridland and semi aridland ecosystem management. We have many salt lands in Iran and planting whit halophyte plants which have forage value is an important method for vegetation reestablishment.In this research two species (Artemisia fragrans and Artemisia spicigera) have been studied. Both of these species are resistant against salinity and have forge value. Seeds of these species have collected from Khajeh village that is located on Tabriz- Ahar road. Seed germination were investigated in 5 treatment (EC=0, 4, 8, 16 and 20 ds/m) with 3 replication in germinator at 25 EMBED Equation.3 Results showed Ar. spicigera resistant is more than Ar. fragrans and germination rate decrease by increasing of salinity rate. Germination rate, root and stem length, reciprocal effect of species and concentration have significant difference.

In order to study remobilization and related traits under water stress conditions, this experiment was carried out in split plot design using RCB, in Torogh Agric. Res. Station during two consecutive cropping seasons (2001/2003). Water limitations were considered as main plots, and triticale genotypes (Juanillo 92 and 4 other triticale promising line) as sup plots. Water limitation included 6 levels: L1. optimum conditions, L2, L3, L4 water limitation in vegetative pre anthesis, reproductive pre anthesis and post anthesis stages respectively. Ls and L6 received rainfall during cropping seasons with only one supplementary irrigation at anthesis and grain filling period respectively. Results revealed that water stress in early stage of growth (L2) increased spike partitioning coefficient because of reduction in total dry weight at anthesis. Water stress in this stage (L2) had not significant effect on remobilization (increasing %4). Double ridge to anthesis water stress (L3) reduced spike dry weight at anthesis and spike partitioning coefficient, but had not significant effect on grin filling period in comparison with optimum condition. The highest remobilization (%63) belonged to L4 (post anthesis water stress). Significantly negative correlation was observed between yield and remobilization (r=-0.46), which revealed yield reduction and increasing remobilization in water deficit conditions in comparison to optimum condition. Grain yield can improve by increasing sink capacity which increase remobilization under terminal drought stress.

Surface layer in south of khorasan province has been studied to forecast minimum temperature and issue early warning for prevention of crop frosting in the area. At first effective parameters in surface layer temperature variation where studied, then necessary meteorological data from weather stations (Birjand, Ghaen and Gonabad) in the statistical period were analyzed and by using theoretical models of Brunt and Groen minimum temperature for clear and calm night forecast the result was that Groen model was more exact than the Brunt model. But Groen model in high humid condition is not acceptable.

The study was carried out to survey the effects of Atriplex canescens on vegetation characteristics in Aghzi Gang region of Zarand-Saveh. Considering the research objective, samples were taken from 8 areas in which were planted with A. canescens and 8 no planted (control) areas. Sampling was done upon randomized-systematic method using the nested plot. To commence the sampling, first point was selected randomly as first plot. In next step, two plots were established during the first plot with a distance of 200m. To measure the vegetation, 3*4m plot were used in spring for annual forbs and 6*8m plot for shrub vegetation. 15*15m plot was used to estimate Atriplex vegetation in autumn. Density of Artemisia sieberi around the Atriplex shrubs was measured too. Vegetation characteristics were compared in planted and control areas two compare means analysis. Results show that the Atriplex planting after 8 years, led to variation in composition and diversity of vegetation. This status is due to positive (microclimate and soil fertility) and negative (competition, alelophaty) effects of Atriplex and enclosure factor.