Hashem Keneshlo; Hosein Ameri
Volume 19, Issue 2 , September 2012, , Pages 344-354
Abstract
In order to find some phenological phenomena of Atriplex griffithii with climate properties such as as temperature and precipitation, this study was carried out in the north-east of Semnan province from 2001 to 2004.In this survey, 10 Atriplex griffithii were selected and marked. Phonological stages ...
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In order to find some phenological phenomena of Atriplex griffithii with climate properties such as as temperature and precipitation, this study was carried out in the north-east of Semnan province from 2001 to 2004.In this survey, 10 Atriplex griffithii were selected and marked. Phonological stages (germination, vegetative, flowering, seeding, and regrowth) were measured in 15-day periods while reproductive traits were measured in 7-10 day intervals. Analysis of climatic data and recorded phonological stages showed that the growth of Atriplex griffithii varied with the fluctuations of drought and temperature in different seasons and two distinctive stages (vegetative and seeding) were recognized for each year. The first growth stage started from late winter and continued to mid-August and the second growth stage started from second half of August and ended in second half of December. Flowering started from May and seeds matured in June. Phonological stages also differed among geographical directions due to differences in rainfall, temperature and evaporation rate as flowering and seeding stages in southern slopes occurred in May and June and in northern slopes were in October and November, respectively. Obtained results can help range managers to set a time calendar for livestock entry and exit and also grazing season.
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.