Ali Farmahini Farahani; Mohammad Darvish
Volume 19, Issue 4 , March 2013, , Pages 547-556
Abstract
Desertification is a global problem and most of arid and semi-arid countries of the world including Iran face this phenomenon. Desertification causes many limitations in terms of agriculture, food supply, livestock farming, industry development and so forth. This phenomenon is a process that has gradually ...
Read More
Desertification is a global problem and most of arid and semi-arid countries of the world including Iran face this phenomenon. Desertification causes many limitations in terms of agriculture, food supply, livestock farming, industry development and so forth. This phenomenon is a process that has gradually developed and intensified and the costs of modifications increase exponentially. Therefore, identification and assessment of factors effective in desertification, and determining the regions affected by this disaster are necessary for each region. FAO and UNEP method is considered as one of the best methods to evaluate desertification in which several processes are investigated. Vegetation degradation, water erosion, wind erosion, decline in the quality and quantity of water resources and soil salinization as well as livestock and population pressure on the environment are considered as the main processes in this study. This study was carried out in a twenty-year period with considering the oldest data, aerial photographs and satellite images. To evaluate each process, several indicators were considered and selected indicators were evaluated by field and library work. Four classes of low, moderate, severe and very severe were also selected for separation of desertification intensity. Each process was studied from three aspects i.e. current situation, velocity and the potential of desertification. Desertification maps were generated in GIS and then integrated to produce final map of desertification. According to the results, 125853 ha (%23), 251504 ha (%45), and 158819 ha (%29) were classified in classes of low, moderate, severe and very severe, respectively. Severe desertification mainly was observed in mountainous areas with slopes over 60 percent, and in saline and sodic marginal lands of Kavire-e-Meighan basin. Vegetation degradation and water erosion were identified as the main factors of desertification in this basin and livestock grazing was the main cause of worsening desertification. Obtained results provide a basis for better recognition and proper combating desertification in this area.
Gholamreza Goudarzi; Ali Farmahini Farahani; Hamidreza Mirdavoudi
Volume 19, Issue 3 , December 2012, , Pages 395-405
Abstract
Determination of allowable use of the key species of rangelands is necessary to calculate the rangeland capacity. Actual rangeland capacity could be determined through having the exact values of this factor for rangeland species and the destruction of vegetation, soil and water loss on rangelands can ...
Read More
Determination of allowable use of the key species of rangelands is necessary to calculate the rangeland capacity. Actual rangeland capacity could be determined through having the exact values of this factor for rangeland species and the destruction of vegetation, soil and water loss on rangelands can be avoided. In this research, Artemisia aucheri, Bromus tomentellus, Kochia prostrata, Asperula glomerata and Buffonia koelzii were investigated as the key species of Arak Enjedan rangelands. A key area of one hectare was selected in Arak Enjedan rangelands and was fenced in the first year of the study. Then, 40 individuals were selected from each species and harvesting intensities of 25, 50, 75% and control treatment were implemented. Harvesting was done by a clipper monthly during grazing season for 4 years. The influence of harvesting was investigated in the second to fifth years through the study of changes in phenological characteristics, forage and seed production, vitality, and mortality and other characteristics of plant species. Results showed that increasing the harvesting intensity caused problems and decline of vital abilities of all species especially, As. glomerata and Br. tomentellus that are more palatable species. According to the results, an allowable use of 25% is recommended for Br. tomentellus and As. Glomerata while for Ar. aucheri, Ko. prostrata and Bu. Koelzii an allowable use of 50% was obtained with the least negative effects on plant characteristics. Results of the analysis of variance for forage production data were significant for all of the studied species in %1 level of probability.
Mostafah Zare; Mohammad Fayyaz; Gholamreza Goudarzi; Ali Farmahini farahani
Volume 19, Issue 1 , June 2012, , Pages 178-190
Abstract
The preference value is defined as selection of available species by livestock in the free grazing. This study was conducted in semi steppe rangelands of Anjedan located 35 Km far from east Arak. These rangelands are of important centers for keeping livestock which is under heavy grazing with a poor ...
Read More
The preference value is defined as selection of available species by livestock in the free grazing. This study was conducted in semi steppe rangelands of Anjedan located 35 Km far from east Arak. These rangelands are of important centers for keeping livestock which is under heavy grazing with a poor condition. The soil of the study area is loamy with high stone and gravel. This study was performed to determine the preference value of important species for sheep to support palatable species in range management plans. Direct observation (timing) method was used to calculate the time spent on livestock grazing and presence during grazing season for 3 years. Afterward, data were analyzed by SAS software in a complete random block design and Duncan test was used for mean comparisons. The results showed the preference value in different season grazing months significantly differed (p<0.01). Generally, annual grasses and forbsshowed maximum preference value. Plant litters, Bromus tomentelus, Artemisia aucheri, Buffonia koelzii respectively ranked next in terms of preference value.