Kazem Dashtekian; Mojtabah Pakparvar; Jalal Abdollahi
Volume 15, Issue 2 , January 2008, Pages 139-157
Abstract
Managing and monitoring of salinity is one of the most important affair in agriculture, specially in arid and semi arid area. For this purpose we have to use new technology like remote sensing and GIS. Most of scientist use maximum likelihood algorithm for mapping soil salinity, but in this method field ...
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Managing and monitoring of salinity is one of the most important affair in agriculture, specially in arid and semi arid area. For this purpose we have to use new technology like remote sensing and GIS. Most of scientist use maximum likelihood algorithm for mapping soil salinity, but in this method field sampling is necessary. In this study several methods were used for producing soil salinity map. These methods are Brightness Index (BI), Normalized Difference Salinity Index (NDSI), Salinity Index (SI), Yazd Salinity Index (YSI), maximum likelihood and average of regression with some Bands. By analyzing and comparing methods with real soil salinity map, suitable method for this region were: 1. Average of regression with standardized band 1,2 and 3. 2. salinity index method.
Bahram Mohammadi golrang; Gholam ali Gazanchian; Ramzani Ramzani moghadam; Hasan Falahati; Hamid Rouhani; Mojgan Mashayekhi
Volume 15, Issue 2 , January 2008, Pages 158-178
Abstract
Knowledge of forage production is one of the most important factors in range management program. Direct measurement of forage production is rather expensive and time consuming. The major objective of this study was to fit a model and to estimate the annual forage production of 19 shrub and forbs species. ...
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Knowledge of forage production is one of the most important factors in range management program. Direct measurement of forage production is rather expensive and time consuming. The major objective of this study was to fit a model and to estimate the annual forage production of 19 shrub and forbs species. In Kashmar flood spreading area of Khorasan province. Annual forage production of 30 plants of each species were measured and compared with measurements of plant height and crown diameter at flowering stages and multiplication of the values of these two factors. Results showed that plant height times crown diameter in all species except Poa bulbosa and Polygonum arenastrum are a good estimation of forage yield and dry matter production. In general there was a positively significant linear relationship between forage production and crown diameter or plant height * crown diameter for all species under study (P< 0.05) . An exponential model for forage production of Scoriala orientalis, Artemisia siberi and poteropyrum olivieri were detected. These results suggest that a linear or exponential model based on annual growth (height and crown diameter) is a good estimation of forage production if adequate sampling and suitable time is considered.
Kian Nadjafi–Tireh–Shabankareh; Adel Jalili; Nemat.. Khorasani; Ziba Jam zad; Uones Asri
Volume 15, Issue 2 , January 2008, Pages 179-199
Abstract
The Genu Protected Area encompasses Kuh–e–Genu, a single and isolated mountain rising above the Persian Gulf Coastal plain. The Genu Protected Area is located in Hormozgan province, 30 km north west of BandarAbbas between latitudes (27°18′50″-27°29′16″ ...
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The Genu Protected Area encompasses Kuh–e–Genu, a single and isolated mountain rising above the Persian Gulf Coastal plain. The Genu Protected Area is located in Hormozgan province, 30 km north west of BandarAbbas between latitudes (27°18′50″-27°29′16″ N) and longitudes (55° 57′30″-56°18′4″E), at about 70 to 2347m above sea level. It covers an area of about43000 hectares. The main aim of this research is to identify relationship between plant associations and environmental factors. In this investigation the relationship between environmental factors and establishment and expansion of plant associations was carried out. The each plant association, 38 ecological factors including different soil characteristics such as soil texture, lime, saturation moisture, gypsum, acidity, electrical conductivity, soluble ions (Na+, K+, N, P, Mg2+, Ca2+, CL-, CO32-, HCO3- , SO42-) in two depth, elevation and slope of habitat were determined too. Multivariate method (Principal component analysis) was used to analyze the collected data. A matrix of vegetation and environmental factors was prepared and the ordination was done by the PCA using PC-ORD software. The results show that the measured environmental variables affected the plant association distribution pattern. The most important factors that have influenced plant associations separation are as follows: electrical conductivity, elevation, moisture saturation, organic matter, lime, K+, Na+, SO42-, Ca2+, CL-, Mg2+ and slope of habitat, respectively. The multivariate analysis expression, the effects of the complicated environmental variables on the plants in a simpler way and introduce the most important factors. As a general, each plant association depends on habitat conditions, ecological needs and tolerance shows a significant relation with environmental factors especially some soil properties.
Mohammad reza Najib zadeh; Adel Sepehri; Gholam ali Heshmati; Ali akbar Rasooli
Volume 15, Issue 2 , January 2008, Pages 200-214
Abstract
Land degredation is a common phenomenon of arid rangelands. Improper utilization of rangelands out of their potential capability is the main cause of land destruction. To avoid damageing environmental resources, it is necessary to use lands based on their natural potentials. To have both sustainable ...
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Land degredation is a common phenomenon of arid rangelands. Improper utilization of rangelands out of their potential capability is the main cause of land destruction. To avoid damageing environmental resources, it is necessary to use lands based on their natural potentials. To have both sustainable development and optimum utilization, we need to evaluate potential productivity of rangelands baesd on simple models that easly relate measurable environmental parameters to potential herbage productivity of rangelands. In this study our aim is to evaluate ERAMS model to evaluate land capability of Yekkeh Chenar Maraveh tappeh rangelands using GIS. This model includes 4 parameters including: slope, salinity, soil depth and rainfall. To get the final land capability map of the area, digital layers(maps) of those parameters were prepared and intered in the model using overlay functunality of GIS. Cross tabulation was used to asses the degree of agreement between the actual and potential land capability maps produced by ERAMS model. Kappa Index of Agreement value shows an overall agrement of 41% between the actual and potential land capability maps. That means ERAMS model was able to define the potential land capability of the area with 41% accuracy. Result also shows that the highest attained agreement belong to the category of high density vegetation. This model can predict the potential productivity of rangelands with high productivity rate better than those of low productivity as was the case for the study area.. This model is thus recommended to be used for vast and densly vegetatated areas.
Mohammad Jankju-Borzelabad; Mahdeyeh Tavakkoli
Volume 15, Issue 2 , January 2008, Pages 215-226
Abstract
Due to the increasing attentions on multiple uses from rangelands, methods of improving seed germination rates were investigated on 10 arid rangeland species, which have ornamental and/or pharmacological values. 9 dormancy breaking treatments were applied, in a completely randomized design. Seeds ...
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Due to the increasing attentions on multiple uses from rangelands, methods of improving seed germination rates were investigated on 10 arid rangeland species, which have ornamental and/or pharmacological values. 9 dormancy breaking treatments were applied, in a completely randomized design. Seeds were then located in an incubator and daily germination rates were recorded. Between treatments, gibberlic acid caused the greatest influence, on germination of 5 out of 10 species. Low temperature, potassium nitrate, high temperature, sulphuric acid, and water imbibitions also increased germination rates of 3, 3, 3, 2, and 1 species respectively. Lowest effect was found for polyethylene glycol and wet sand treatments. The applied treatments led to high increases in germination rates of Stachys inflata, Pteropyrum aucheri, Capparis spinosa and Fortynia bungei. However, the results for Atraphaxis spinosa, Calligonum polygonoides, Calligonum bungei, Isatis cappadocica, Glaicium oxylobum, and Iris songarica may not be applicable for field workers, because of low (0-5 %) germination rate of these species, while they are valuable for researchers. Further interesting results of this experiment was a logical relationship between treatment that caused the highest increase in germination rate, and phenology stages, habitat conditions of some species.
Abol ghasem Dadrasi; Mohammad khosroshahi
Volume 15, Issue 2 , January 2008, Pages 227-241
Abstract
One of the major consequences of desertification is development of destructive floods in spite of ground water level falling in the lower parts of basins, which will lead to water quality/ quantity decline, landslide and blending of saline and fresh water tables. Each of these symptoms individually or ...
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One of the major consequences of desertification is development of destructive floods in spite of ground water level falling in the lower parts of basins, which will lead to water quality/ quantity decline, landslide and blending of saline and fresh water tables. Each of these symptoms individually or in combination with the others clearly notifies the development of desertification. Identification of suitable areas for flood control will assist the natural aquifer recharge in the basin’s upstream and will reduce the development saline and gypsiferrous waters in the ground water of basin’s downstream and surrounding area, which in turn will cause secondary salinization in the lower parts of basins. Off course computer models are the most suitable methods for determination of the best sites in this regard, and because of variety of available models in the first step we should determine the best model. In this research compiling of effective factors using establishment of information layers and then regionalization in conceptual models which were applicable in GIS media like as Boolean logic model, overlap index model and Fuzzy logic model was used. The main research technique is analytical comparison of results using these models. These models were done in GIS media by scoring to the variables affecting flooding and aquifer recharge based on their effectiveness. We compared models due to natural conditions of the region to determine the best model for quantitative analysis of flooding in 6 towns of Khorasan-e-Razavi province, with emphasis on determination of flood control capability of these regions to combat desertification. Results showed that Fuzzy model with summation operator gives the best adaptivity compared to the other models to determine the floodable and capable for flood control areas.
Hamid reza Mir davoodi; Hojat.. Zahedi poor; Hamid reza Moradi; Gholam reza Godarzi
Volume 15, Issue 2 , January 2008, Pages 242-255
Abstract
Improper management and unsuitable exploitation of land are the two most important problems of land resources utilization in the country. Unsuitable pattern of landuse together with sever landuse changes causes different environmental crisis including: environmental pollution and deterioration, expanding ...
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Improper management and unsuitable exploitation of land are the two most important problems of land resources utilization in the country. Unsuitable pattern of landuse together with sever landuse changes causes different environmental crisis including: environmental pollution and deterioration, expanding desertification, soil erosion, natural resources depletion, reduction of biological diversity and reduction the potential of land capability. These problems significantly influence the production resources of recent and future generation and prevent sustainable development of the country. In this research, ecological land capability of Markazi Province that is the most important part of the procedure of landuse planning were determined with preparing ecological resources maps such as topography with scale of 1/25000, geology, soil, climate and related parameters, vegetation cover, faults, water resources and etc. Slop, aspect and height class maps also were established based on Digital elevation model of the area and integrated together to form landform map of the Province. Environmental units with base 1, 2 and 3 also were established with overlaying land form, soil and vegetation maps. Ecological land capability of agricultural and rangeland were put in 7 classes. The results show that from total 2921364.6h area of Markazi Province, 15000 ecological units could be determined of which 121689.5h or %4.16 were in class of 1, 191634.77 h or %6 in class of 2, 615791.5 h or %21.07 in class of 3, 569834.8 h or %19 in class of 4, 1170699.6h or %40 in class of 5, 188381.18 h or %6.44 in class of 6 and 63333.2 h or %2.16 in class of 7 of agriculture and rangeland ecological capabilities.
Gholam reza Ghaderi; Ali Gazanchian; Mahmood Yousefi
Volume 15, Issue 2 , January 2008, Pages 256-268
Abstract
Intercropping is considered for increasing and stability of yield in per unit. In general, mix cropping legumes and grasses species has been applied to enhancement of nutrient value and supply energy and protein on grasses and legumes respectively. A field experiment, was conducted to compare forage ...
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Intercropping is considered for increasing and stability of yield in per unit. In general, mix cropping legumes and grasses species has been applied to enhancement of nutrient value and supply energy and protein on grasses and legumes respectively. A field experiment, was conducted to compare forage production of mixed alfalfa (Medicago sativa v. cody) and wheatgrass (Agropyron desertorum) species with proportion of 33, 50 and 66 percent and pure cropping in the north Khorassan (Sisab station) from 1994 to2001 with two levels 15 and 20 kg/ha of seeding rate. The seeds were sown into furrows with 40 cm wide for row intercropping and broadcasting for mixed cropping treatments. The treatments were arranged in split plot and randomized complete block design with four replications. Forages harvested at flowering and heading stage of alfalfa and wheatgrass, respectively. Dry matter weight considered for comparison of yield production of the treatments. The average forage yields of alfalfa and wheatgrass were 1.8 and 1.2 ton/ha respectively in pure stands. Alfalfa standes gradually dominated the wheatgrass in mixed and row intercropping. The highest yield was obtained in the mixed cropping of 66% alfalfa and 33% wheatgrass. There were no differences between seeding rate treatments. However, the results suggest that the best combination species for improving production is 66% alfalfa and 33% wheatgrass. This ratio could be used for renovation of pastures in the poor and dry areas in north Khorassan province.
Noor ... Abdi; Hasan Madah arefi; Ghava din Zahedi amiri
Volume 15, Issue 2 , January 2008, Pages 269-282
Abstract
Atmospheric carbon dioxide concentrations have substantially increased in recent decades. Land management practices, however, offer opportunities to mitigate the rise in atmospheric CO2 concentration through sequestration of this additional carbon via storage in plant biomass and soil organic matter ...
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Atmospheric carbon dioxide concentrations have substantially increased in recent decades. Land management practices, however, offer opportunities to mitigate the rise in atmospheric CO2 concentration through sequestration of this additional carbon via storage in plant biomass and soil organic matter in a process termed terrestrial C sequestration. Rangelands ecosystems have a large potential to sequester C because they occupy about half of the world's land area. In Iran, the Astragalus rangelands with about 17 million hectare area have 10% of the country land area and have the important role in carbon sequestration. In order to investigation the role and potential of Astragalus rangelands in carbon sequestration, a study was carried out at a key area of Astragalus verus-Bromus tomentellus vegetation type in Malmir rangeland site, Shazand township of Markazi province and the content of aboveground and underground biomass carbon, litter carbon and soil organic carbon was determined. The results showed that the total carbon sequestration per hectare was 32.95 ton and 87.43 % of total carbon sequestration was soil organic carbon. The results of biomass carbon distribution showed that the carbon content in aerial biomass was higher than underground biomass. Correlation and stepwise regression analysis revealed that the content of carbon sequestration was positively related to Astragalus height and volume, aerial and underground biomass, total biomass, litter amount and soil organic carbon (SOC) content. It was concluded that the Astragalus rangelands have a large potential to sequester carbon and the soil is most important sink for organic carbon storage in this rangelands
Sadegh Esfandiary; Ali morad Hasanli; Hooshmand Safari; Mohsen Farshad far
Volume 15, Issue 2 , January 2008, Pages 283-294
Abstract
In this research, the effect of deficit irrigation on some characteristics of five species of medics: physiological properties, yields, plant quality, and resistance to drought in the Islamabad region were investigated. Five different irrigation amounts (0, 25, 50, 75 and 100%) and five species of medics ...
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In this research, the effect of deficit irrigation on some characteristics of five species of medics: physiological properties, yields, plant quality, and resistance to drought in the Islamabad region were investigated. Five different irrigation amounts (0, 25, 50, 75 and 100%) and five species of medics with three replications in a split plot design experiment were considered. The irrigation requirements using Penman-Montith with CROPWAT software on the basis of climatic data of study region with irrigation efficiency of 90% was estimated. The variance analysis indicated that a significant variation at 1% level for the effect of medic species on all indices was observed. The results of stress intensity index indicated that minima species had the greatest sensitivity to stress. radiata and turbinata species showed the greatest resistance to drought. Although the rigidula species had the greatest yield in all levels of irrigation it were sensitive to drought. Based on drought tolerance index, rigidula species showed the lowest resistance to drought and had the largest water productivity. Based on the calculated indices rigidula species is recommended for irrigation and turbinata species for rainfed. The orbicularis, and radiata species showed the lower production in rainfed condition.