Journal of Spatial Analysis

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Identification of the factors influencing the hazards and the difference in the volume of sediment accumulated in the villages of Nimroz
 
Abstract
Seasonal lakes or playas are considered as a major source of wind sediments and dust storms due to locating in post-topographic areas in dry and desert areas with strong winds system and also the presence of fine-grained and separated particles. Sediments and wind deposits in Sistan have caused the lives of thousands of people in these areas and especially the students to be at risk. The volume of wind sediments in this county has been multiplied in the last ten years; therefore the purpose of this research is to identify the effective factors on the volume difference of accumulated wind sediments in the schools of the villages of Nimroz County. The research method in this study is quite field and as direct observation, besides library resources has also been used. After the initial investigations, it was found that the geographical location, type of soil and topography have little effect on the volume difference of accumulated sediments in the studied schools. The findings of the study show that the three factors in Bash Delbar area, Hamoon Lake and lack of agriculture and the lack of vegetation in Deh Isa area are the most important factors in increasing or decreasing the volume of wind sediments.
 
Keywords: wind deposits, primary schools, Human Beast, the lake plain, the city of Nimroz
 

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The study and Comparison of desertification process on the basis of climate Criterion (Case Study: Abbas and Dehloran Plains, Ilam)
Soraya Yaghoobi, Kamran Karimi, Marzban Faramarzi
Abstract:
Nowdays desertification is a disaster in many countries , especially in developing countries. This problem includes natural factors and improper human activities. According to the expansion of desertification, providing the appropriate management methods will be reduced desertification intensity and its expansions. In this way, knowledge of processes of desertification and factors causing and  the intensifier it and also awareness of intensity and Weakness the processes and factors that are important and necessary   that should review and evaluate. Recognition criteria and indicators for provide a model to show the process of desertification and for determine one of the  best reason effective factors for prevent the spread of desertification factors is necessary. To knowledge and Trend of desertification and separation of  vulnerable  areas versus degradation factors .we should indentifi and evaluat  criteria and indicators affecte  at desertification. Therefore in this study of  the Iranian model IMDPA to assess trends and Comparison of desertification in recent years has used.
The studied area of  Dehloran plain is located in southeast of Ilam province (47^◦ 02′ 16″ to 47^◦ 25′ 07″ E and 32^◦ 48′ 33″ to 32^◦ 18′ 48″N) with an area of 54252  hectares, With precipitation  average 251.6 mm and Abbas plain is located in south of Ilam province(47^◦ 37′ 55″ to 47^◦  50′ 57″ E and  32^◦ 17′ 77″ to 32^◦ 29′ 25″N) with an area of 34104 hectares With precipitation  average 227.1mm. In this study, in dehloran plain of six stations in this Inside and outside the area also in Abbas plain of five  stations outside the area  used to measure the amount of rainfall in different seasons of year. In this study, to assessment  and Comparison of desertification in two study area of the Iranian model IMDPA used. In this study, of climate criteria, were used. which according to the IMDPA model for this criteria, indexes are considered for evaluation e.t.c: Climate criteria: (1) the amount of annual rainfall 2-drought indexe(SPI) 3. continuing drought In IMDPA model  All measurements  do in this work  units. To this end, first, working unit maps (geomorphologic facies) were created using slope, geology, and land use maps. a map was generated for each index according to assigned weights, such that the qualitative map of the desired criteria were obtained using the geometric mean of indicators.
The results earn  of  evaluation  of desertification  showed that  in the period  2005-2009  weight average of climate criteria is same with 1.50 all of the region are in the classe Middle sub class 1 and class low sub class3 . in the period  2010-2014  Also  weight average of climate criteria is same with 1.88 in classe Middle sub classes 2 and 3.  Also weight average of climate criteria in Abbas plain In the first period is same with 1.92  in the classe Middle sub classe2. Also In the second period with weight average is same 2.3 in classe Middle sub classes 2 and 3. The results showed that SPI index, as the most effective indexes, in plain Abbas In the first and second periods with the weighted average 3.04and 3.2 in the intense class under class 2 and 3. in front in Dehloran plain SPI index in the first and second periods with weighted average of 1.93 and 2.25 in the moderate classe and sub-classes 1, 2 and 3 and intense sub-classe 1.
In this study, to assess and Comparison of desertification Dehloran and Abbas Plains to provide regional model has done. . In this way  of  a criteria, also important and effective indexes belonging to this criteria of desertification used in dehloran and Abbas plains . The obtained results of the analysis criteria and Indexes indicated that in dehloran and Abbas plains in the first period ( 2005-2009) And second period (2010-2014)  between  indexes  the amount of annual rainfall, standard precipitation index (SPI) and drought duration Evaluated on the areas respectively standard precipitation index (SPI),  rainfall and drought duration index the most important factors in exacerbating desertification. Can be concluded that the intensity of desertification in Abbas plain compared to dehloran plain terms of climate is In more adverse conditions. In general, it can be concluded that desertification would intensify in future decades.
Keywords: Desertification, IMDPA, Climate, Abbas Plain, DehloranPlain
 

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1- Introduction
Desert dust is formed under the influence of the special weather and environmental conditions of desert areas, enter the atmosphere. Localized hurricanes caused by ground air instability and sweeping dry deserts clear silt and sand particles enter the atmosphere from the surface. Ecologically as well as physically desert dust Effects such as pulmonary heart disease, disruption of plant physiological circulation, and erosion of growing structures include heavy metals deposited on soil surfaces, water surfaces, and canopies Plant surfaces that cause chemical changes and physiological damage to environmental ecosystems. Difficult Metal generally refers to a group of metal elements with a specific gravity of 6g/cm3 or more. Atomic weight greater than 50 g. Heavy metals important from an environmental point of view Cadmium, arsenic, cobalt, vanadium, zinc, mercury, iron, manganese, nickel, lead, chromium, copper, that do not decompose naturally. In addition, the long life of heavy metals is also considered. In the studies that have investigated the effect of dust on citrus fruits, it has been very few and even garden plants have been done on a case-by-case and limited basis. Citrus and especially oranges are one of the important and economic garden products in Iran, which are cultivated in tropical areas with mild and cold winters. Khuzestan plain, especially Dezful, is one of the poles of citrus and orange cultivation. But in Khuzestan, it is under the influence of many environmental stresses, which can be mentioned as drought stress and air pollution in the region. The rising trend of the phenomenon of desert dust in recent years has been shown as a danger and its effect on the environmental health and economy of the region is very severe, and the most damage has been reported to the agricultural sector. Although the damage caused by micro-pollens to the agricultural sector is expressed as an economic figure, the effect on plants, especially citrus fruits, remains unknown. Although researchers have studied the effect of fine dust on sugarcane, grapes, legumes, nectarines and peaches in Iran, India and Pakistan, the effect of fine dust on vegetative traits and orange fruit has not been investigated in Khuzestan. Considering that the first step in controlling the effect of air pollution on plants and horticultural crops is to know how it affects the plant, on this basis, the main goal of the current research is to reveal and evaluate the effect of micro-pollens. Desert is on vegetative and reproductive characteristics of Thomson orange in Dezful.


2- Methodology
In order to evaluate the effect of desert pollen on the quantitative and qualitative yield of orange fruit, Thomson variety, a field experiment in the form of randomized complete block design with four treatments and three replications was carried out in Dezful in 2018-2019. The treatments included 1) road dust and desert fine dust, 2) desert fine dust, 3) washing after the occurrence of fine dust and 4) control away from fine dust. The chemical and functional characteristics of the trees were measured after applying the treatments, which included chlorophylls a and b, relative water content of the leaves, number of fruits, diameter and weight of the fruit, soluble solids of the fruit and the final yield of the tree.

3- Results
The results showed that chlorophyll a decreased by 21% and 11%, respectively, in the road dust and desert fine dust treatments compared to the control. Chlorophyll b also decreased to the same amount compared to the control. The diameter of the fruit also decreased by 20% in the desert dust treatment compared to the control. The number of fruits per tree also decreased by 22 and 20% in the treatments of pollen and fine desert dust compared to the control. In the product yield of each tree, in the treatments of road dust combined with desert fine dust and the second treatment, which was only desert fine dust, it decreased by 22 and 17 percent, respectively, compared to the control. Tukey's mean comparison showed that the difference of all quantitative and qualitative characteristics between the treatments was significant and Desert dust has a negative and decreasing effect on the yield of Thomson orange trees; However, washing the trees after the occurrence of micro-pollen removed the effects of micro-pollen on the performance of trees and it even increased compared to the control; So, washing increased the yield of oranges by 40, 35, and 12 percent compared to the first and second treatments of road dust and fine dust, as well as the control.

4- Discussion & Conclusions
Plant growth cycle and biochemical interactions of plants show different reactions under the influence of environmental stresses. The results of previous studies indicated that fine dust and dust storms have been identified as an environmental stress for plants that have a negative effect on grapes, medicinal plants, sugarcane, nectarines, peaches and legumes. The effect of fine dust on the plant can be investigated in several characteristics and periods of plant phenology. In the first stage, the deposition of desert fine dust on the leaves of the plant causes shading and reducing the light received by the leaf pigments. Fruit formation is the most important phenological period of the plant, and the occurrence of environmental stress can affect the yield and products of the plant. The present research showed that the number of fruits in orange trees showed sensitivity to desert pollen and the settling of soil particles on orange flowers reduced the amount of fruit formation and finally the number of healthy and ripe fruits in the trees treated with road dust and Desert fine dust decreased compared to the control. Finally, the yield of control orange trees decreased by 17% and 22%, respectively, compared to desert dust and road dust treatment with desert dust. The yield of cotton plants in China decreased by about 28% compared to Desert dust. It can be concluded that although desert dust and road dust reduce the yield of Thomson orange fruit, washing it compensates for the damage and will be economical from the economic point of view.

Key words: Citrus, Photosynthetic pigments, Fruit yield, Dust, Dezful