Daruosh Ghorbanian; Mohammad Jafari
Volume 14, Issue 1 , January 2007, Pages 1-7
Abstract
In this study one site with good coverage of Salsola rigida species selected in desert region of Shahrood area. Four plots of 100 m2 were chosen in this site and two soil profiles were digged in each plot; one profile under Salsola rigida plants and another in the space between this species. Soil samples ...
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In this study one site with good coverage of Salsola rigida species selected in desert region of Shahrood area. Four plots of 100 m2 were chosen in this site and two soil profiles were digged in each plot; one profile under Salsola rigida plants and another in the space between this species. Soil samples were collected from three depth of 10-25 cm, 10-25 cm and>25cm. For asessing elements of biomass and their effects on the soil, plant sample were analysed in laboratory. Results indicated that organic matter percentage as well as N, K and HCO3 increased significantly. An increase of Ec, Caco3 and Na are the main detrimental factors for expanding Salsola rigida species.
Ebrahim Farahani; Khalil Falahi; Kosar Mirzakhani
Volume 14, Issue 1 , January 2007, Pages 8-18
Abstract
Rehabilitation of arid and semi-arid rangelands need particular species which are well-adapted to unsuitable regional and ecological condition and can produce enough forages for livestock, rich in nutrition andpalatability as well. Atriplex canescens, an exotic evergreen species which is resistant to ...
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Rehabilitation of arid and semi-arid rangelands need particular species which are well-adapted to unsuitable regional and ecological condition and can produce enough forages for livestock, rich in nutrition andpalatability as well. Atriplex canescens, an exotic evergreen species which is resistant to drought and chilling, has been planted in some rangelands of Iran for several years. Major objectives of this experiment was to determine the best seeding date for producing seedlings and proper young plants for transplanting. Complete Randomized Design with treatment of seeding dates and 3 replications were used in this study. Four characteristics including percentage survivals, plant height, root length and number of branches were measured and analysed statistically. Overall data indicated that mid-August is the best seeding date for desert condition of the study area.
Hosein Gharadaghi; Hosein Arzani; Hasan Ebrahimzadeh; Mohammad reza Ghnnadha; Naser Baghestani
Volume 14, Issue 1 , January 2007, Pages 19-32
Abstract
Rangelands are one of the important natural ecosystems in our country that were deteriorated during recent decades because of many causes especially earlier and intensive grazing. Grazing management need to determine beginning of grazing season and intensity in rangelands. It is very important to know ...
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Rangelands are one of the important natural ecosystems in our country that were deteriorated during recent decades because of many causes especially earlier and intensive grazing. Grazing management need to determine beginning of grazing season and intensity in rangelands. It is very important to know much about physiological and phenological status of rangeland species. Total nonstructural carbohydrates (TNC) and their changes during seasonal growth is one of the important physiological parameter in perennial plants. Also these reserves are primary source of energy in respiration, growth and survival of perennial plants during their quiescence and growth season and regrowth after grazing or cutting. In this research seasonal changes of TNC reserves in three perennial and desirable grass species(Bromus tomentellus, Festuca ovina, Dactylis glomerata) were studied in Polor summer rangelands(altitude, 2600m; annual precipitation, 535mm; with cold mountain climatic) at the north of Tehran province. Samples were collected in ten stages of plants phenology stages with three replications from above and underground matter (canopy and roots). Samples were oven dried at 70◦C during 48 houres. TNC concentration were measured by phenol-solpheric method (mg per gr dry matter). Data of all attributes were analyzed in the frame of rondomized compeletly block design by using Minitab software, and ANOVA one and two ways. Seasonal changes of TNC reserves in any of studied species and also their root and canopy were shown in annual curves. The results indicated that all species have distinct seasonal changes and they had the lowest TNC reserves at early spring and end of the seasonal growth and then increased. The results showed significant differences in TNC reserves between phenology Stages in root and canopy during seasonal growth (P= 0.05 & 0.01) and all species had higher amount of TNC reserves in root than canopy (P=0.01). The rate of TNC restoration was different between studied species. These differences were related to phenology and seasonal growth along. So in this area Dactylis glomerata is more sensitive to grazing and Bromus tomentellus conversely is more resistant to grazing. At the end we concluded that critical period for all species in relate of their TNC reserves is from starting growth in early spring till early May and at the end of seasonal growth, mid August. Beginning of grazing season from late may until early August is recommended for this area.
Abolghasem Dadrasi Sabzavari; Mojtaba Pakparvar
Volume 14, Issue 1 , January 2007, Pages 33-52
Abstract
Desertification is one of the most difficult issues which has been taken into consideration in the world. The main objective of this study is determination of lands affected by desertification using remote sensing and geographic information systems, in Sabzevar. To meet the objective, Satellite ...
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Desertification is one of the most difficult issues which has been taken into consideration in the world. The main objective of this study is determination of lands affected by desertification using remote sensing and geographic information systems, in Sabzevar. To meet the objective, Satellite imagery of Landsat TM- 29 April 1987 and 13 May 2001 were selected and used, after haze and geometric correction. Principal Components (PC) and False Color Composit (FCC) were calculated, finally FCC521: RGB was selected for background of classification because of the best correlation. The Satellite images were classified by the maximum likelihood algorithm on the basis of field data. A study was conducted to determine the iso line of change in groundwater salinity and depth, in the study area, by using subsurface water data ( quality and quantity). The results show that on non saline parts and in the area of gypsum, the changes are negligible. The area of land uses are more or less the same except in agriculture which the land has increased by 3632 ha and in urban area which developed 672 ha. Merging and processing the whole data shows that the agriculture lands increased from 1987 to 2001. More salinity and less depth of groundwater are the results of groundwater data analysis, specially in south east part of the region
Hamid Habibian; Abbasali Sanadgol
Volume 14, Issue 1 , January 2007, Pages 53-67
Abstract
Nowadays; planting of Atri;lex species are used, in range rehabilitation. Soil erosion control and wildlife programs. Optimum density, and periods of prunning of Atriplex lentiformis on quantity of forage production are important. The Atriplex lentiformis was planted in a split-split plot design with ...
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Nowadays; planting of Atri;lex species are used, in range rehabilitation. Soil erosion control and wildlife programs. Optimum density, and periods of prunning of Atriplex lentiformis on quantity of forage production are important. The Atriplex lentiformis was planted in a split-split plot design with 3 replications and 45 treatments in Dadin of Kazeroon in 1993 and investigated for 10 years. The main treatment was planting distance at levels. Sub-treatment was prunning period and the sub-sub-treatment was cutting height. Canopy coverage diameter, height, forage production, and percentage of survival of the plant were measured in different years throughout of the study. The nutritional value of the forage was measured in the last year. The data were analysized by EXCEL, SPSS, and SAS softwares. The results showed that the highest production attained from treatments of 2*2 m planting space, 40 cm height, and once per year cutting, and the least one, resulted of the treatment of 4*4m planting space, zero cm and once per three years cutting. Control and zero height cuttings showed a significant difference (P<0.05) with the other treatments in forage production. The 20, 40, and 60 cm cutting heights showed no significant difference (P>0.05). Zero and 20 cm cutting height showed a significant differece (P>0.05). Zero and 20 cm cutting height showed a significant difference with other treatments in percentage of survival (P<0.05).
Hosein Arzani; Mahdi Abedi; Ehsan Shahriyari; Mahdi Ghorbani
Volume 14, Issue 1 , January 2007, Pages 68-79
Abstract
Management activities like grazing intensity and land cultivation effects rangelands characteristic. For sustainable utilization of rangeland, information of changes is required. Soil surface indicators and functional attributes help to judging about management impact. So for investigation on these activities ...
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Management activities like grazing intensity and land cultivation effects rangelands characteristic. For sustainable utilization of rangeland, information of changes is required. Soil surface indicators and functional attributes help to judging about management impact. So for investigation on these activities effects in semi arid rangeland, one vegetation community was selected in Taleghan region. Five cases including: three grazing intensities (heavy, moderate and low), recently cultivated and relict areas that were cultivated in last two decades were assessed. Landscape function analysis (LFA) method was used to evaluate management effects on soil surface characteristics and rangeland functional attributes. In this method for determination of three functional attributes of stability, infiltration and nutrient cycle, 11 soil surface indicators were considered. They are soil surface cover (soil protection from erosion), perennial canopy/basal cover, litter (cover, origin, degree of decomposition), cryptogam cover, crust brokenness, type and severity of erosion, deposited material, soil surface roughness, soil surface resistance to distribution, slake test (soil stability test) and texture. Based on the results, land cultivation reduced functional attributes. By increasing grazing intensity, palatable species are eliminated and in heavy grazing area the dominated vegetation cover are annuals. Vegetation and soil surface layer degradation increased soil erosion, created gully and reduced functional attributes. In relict area because of re-establishing homogenous annuals, soil indicators and functional attribute were improved.
Ahmad Ahmadian; Abbasali Sanadgol
Volume 14, Issue 1 , January 2007, Pages 80-87
Abstract
Mountain areas are important sources of livestock forage production, water, energy, and biological diversity. Furthermore, they are sources of such key resources as minerals, forest products and agricultural products and of recreation. Mountain environments are susceptible to accelerated soil erosion, ...
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Mountain areas are important sources of livestock forage production, water, energy, and biological diversity. Furthermore, they are sources of such key resources as minerals, forest products and agricultural products and of recreation. Mountain environments are susceptible to accelerated soil erosion, landslide and rapid loss of habitat and genetic diversity. They are essential to the survival of the global ecosystem. In the West Azarbaijan province of Iran the existed livestock are about two times more than range capacity. Nowadays considering genetic erosion and plant cover retrogression, the study of balanced grazing as an approached strategy for proper management of natural resources is necessary and inevitable. For the study of livestock productions the weights of sheep under balance grazing and traditional grazing were compared with each other. In this study the vegetation type of Festuca ovina -Bromus tomentellus with fair condition, negative trend and grazing capacity of 0.7 animal units in three month was selected. This vegetation type with considering grazing capacity and range readiness was studied under balanced grazing from 1999 to 2003. The results indicated that the range condition promoted from fair condition to good condition, and the grazing capacity reached to 2.7 animal units per month. The average of plant cover and soil protection values reached from 24 and 54 percent to 33 and 64 percent respectively (significant difference at 5 % level of probability)
Jamshid Khatir Namani
Volume 14, Issue 1 , January 2007, Pages 88-96
Abstract
Study of vegetation changes of grazed and ungrazed rangelands is important in range management programs. In order to do this, Chut rangelands located between Dashly Boroon and Maravehtappeh of north Golestan province chosen as the study area. Chut rangeland is saline with slow drainage and 180 mm annual ...
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Study of vegetation changes of grazed and ungrazed rangelands is important in range management programs. In order to do this, Chut rangelands located between Dashly Boroon and Maravehtappeh of north Golestan province chosen as the study area. Chut rangeland is saline with slow drainage and 180 mm annual precipitation. Vegetation type of this rangeland is Poa bulbosa- annual grass and forbs. Two sites of grazed and ungrazed area were selected and factors such as soil erosion, canopy cover, plant composition and vigority of plants were measured and recorded for five years. Results showed that forage production and density of annual grasses and forbs increased inside the exclosure. There was no significant difference between vegetation cover percentage and outside the exclosure (grazed and ungrazed rangelands). Generally, the results indicated that vegetation changes in the study area are slow and gradual.
Hamidreza Moradi; Mansur Rajabi; Manuchehr Faraj zadeh
Volume 14, Issue 1 , January 2007, Pages 97-109
Abstract
Drought is the most complex and unknown natural disaster that affects human more than other natural disasters. Droughts occurred in Fars province in recent decades showed the importance of drought study in this region. In this research, standard precipitation index (SPI) was calculated based on monthly ...
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Drought is the most complex and unknown natural disaster that affects human more than other natural disasters. Droughts occurred in Fars province in recent decades showed the importance of drought study in this region. In this research, standard precipitation index (SPI) was calculated based on monthly rain of 26 stations in a period of 36 years (1963-1999). For investigation of spatial droughts changes in study area Kriging interpolate method were used. Then analyses were performed using linear regression model trend and Man-Kendal nonparametric test in studied stations. The results showed that the intensity of droughts in central parts of this province is more than other regions. The trends exist in all of studied stations except Chardangeh station.