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.
Taghi Mirhaji; Abbas ali Sanadgol
Volume 13, Issue 3 , February 2006, , Pages 212-221
Abstract
The phenological stages of five species Festuca ovina, Koeleria macrantha, Koeleria phleoides, Melica cupani and Melica jacquemntii were studied for three years(2003-2005) in Homand-e-abesard rangeland research station, in 70 km east of Tehran. Annual life cycle of plants were divided into two ...
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The phenological stages of five species Festuca ovina, Koeleria macrantha, Koeleria phleoides, Melica cupani and Melica jacquemntii were studied for three years(2003-2005) in Homand-e-abesard rangeland research station, in 70 km east of Tehran. Annual life cycle of plants were divided into two large periods, more active and less active phases. data were recorded in the first phase every 7 days and in the second phase every 15 days. The Growth degree-days(GDD) were calculated for each phenological stages. 20 stands of each species were studied. The phenological stages include: growth initiation(gi), vegetative growth(vg), heading out(ho), full flowering(ff), seed ripening(sr), seed maturity(sm), temporary dormancy(td) and regrowth. The result showed that the five species started their growth from early March and dried in late July. There was dormancy for late August to early October and a regrowth stage from late November to late December. The Growth degree days were calculated for each phenological stage of 5 species in the different years. The result showed no GDD variation for the same phenological stages between years.