Taghi Mir haji; Abbas ali Sanadgol; Mohammad hasan Ghasemi; Soheila Nori
Volume 17, Issue 3 , October 2010, , Pages 362-376
Abstract
Phenology of four range species including Elymus transhircanus, Elytrigia libanotica Stipa bromoides and Stipa capillata were studied in Homand Absard Research Station, 70 km far from east Tehran, for five years (2003-2007). 20 plants were selected for each species and four important phenological stages ...
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Phenology of four range species including Elymus transhircanus, Elytrigia libanotica Stipa bromoides and Stipa capillata were studied in Homand Absard Research Station, 70 km far from east Tehran, for five years (2003-2007). 20 plants were selected for each species and four important phenological stages including early and vegetative growth, flowering, seed milk stage, seed maturity and autumn regrowth were recorded. Data recording was done once each week and once 15 days in growing and inactive seasons respectively. Phenological data were recorded during five years and interpreted using climatic data (temperature and precipitation) to calculate Growth Degree Days in each stage. The purpose of this study was to identify and introduce important phenological stages with a view to livestock grazing and farm management based upon phenology and Growth Degree Days. The results showed that onset and end of growth varied in different years and these changes occurred based upon temperature. Phenological period of all studied species in cool years was longer than that of warm years. But required Growth Degree Days for all mentioned species were almost similar. For example, Elytrigia libanotica required 833.3, 830.8, 834, 832 and 846.3 GDD for vegetative stage in 2003, 2004, 2005, 2006 and 2007 respectively. For flowering stage, 1342.1, 1342.8, 1355, 1344.8 and 1346.3 GDD were calculated from 2003 to 2007. In other words, Elytrigia libanotica species needs the mentioned GDD so that it can start seed milk stage. Start of growth varied in different years according to plant type and climatic condition and it was usually from mid to early March. Active growth continued to early July and then stopped. All studied species had an autumn regrowth in wet season.
Naser Ansari; Mohammad Fayaz; Mohammad hassan Gasemi
Volume 16, Issue 3 , December 2009, , Pages 293-304
Abstract
Rangelands degradation is the most important problem of Iran natural resources, especially in these decade .In this research for determination of the quality and quantity of rangelands degradation,9 provinces distributed within 3 main zones of Henry Pabbot’s climatic zones map of Iran territory, ...
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Rangelands degradation is the most important problem of Iran natural resources, especially in these decade .In this research for determination of the quality and quantity of rangelands degradation,9 provinces distributed within 3 main zones of Henry Pabbot’s climatic zones map of Iran territory, were selected. In these provinces, sample areas in each climatic zone were bounded on topographic maps. In the sample areas, converted rangelands to other usages, from 1955 to 1995(40 years) and then, lost and converted rangelands clarified. Considerable decline in forage production of the rangelands were also well described by comparing dry matter yield in an enclosure and the fenced area. Results showed that 9.1% of the rangelands areas, during 40 years between 1955-1995 periods, had been disappeared. Rangelands degradation in semi-desert zone with degradation index of 28.4% is lowest and in high-mountain zone with degradation index of 60.5% is the highest one. Degradation intensity in high-mountain zone is as twice as semi-desert zones. Average of degradation index for all the country zones, is 49.4% that revealed, about half of the production potential of the rangelands has been lost.
Naser Ansariri; Jafar Seyed Akhlaghi Shal; Mohammad hasan Ghasemi
Volume 15, Issue 4 , January 2009, , Pages 508-524
Abstract
The most important problem of natural resources of Iran in recent decades is natural resources degradation. This research was based on documental research method, field research method and desk research method, by using 3 questionnaires for villages, tribe settlements and stockholders. ...
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The most important problem of natural resources of Iran in recent decades is natural resources degradation. This research was based on documental research method, field research method and desk research method, by using 3 questionnaires for villages, tribe settlements and stockholders. Altogether, 131 sample areas in 3 main climatic zones of 11 provinces and sub zones were selected. In these sample areas, 487 village questionnaires, 1847 family questionnaires and 504 expert questionnaires were completed. Results indicated that degradation intensity from semi-desert zone toward semi-steppe, steppe ,dry forests and high mountainous sub zones of Iran-touranian zone have increased. In addition, 19 socio-economic factors are the most important and effective factors of natural resources degradation of Iran. These factors were ordered in three groups including animal and animal husbandry group, cutting and harvesting group and land use changing group. Stockholder ideas showed that animal and animal husbandry group were 47.2%, cutting and harvesting group were 16.9% and land use changing group were 35.9% effective in natural resources degradation. In contrary, expert opinions were 43.3% animal and animal husbandry group, 24.3%cutting and harvesting group, 32.4% land use changing group. Mean of these two ideas indicated that the first effective group in natural resources degradation with 45.9% is the animal and animal husbandry group, cutting and harvesting group with %33.5 is the second and land use changing group with 20.6% is the third. So, the most important factor in natural resources degradation of Iran is animal and animal husbandry group, including, increasing in livestock and herder numbers, premature grazing, over grazing and problems between stockholders.