Document Type : Research Paper

Authors

Abstract

     In range management, appropriate time for utilization is set based upon plant life stages. Accordingly, phenology of Stipa hohenackeriana was studied in three research sites of Roudshor, Hasaan Abad and Khojir. This study was performed during three growth stages in 3 years. Twenty species were selected and was regularly visited from mid-March 2005. Vegetative, flowering, seeding and winter dormancy were considered as phonological stages. Collected data were interpreted using climatic data (temperature and precipitation) and for each stage, growth degree days were calculated. Results showed that start and end of growth differed in different years and these changes were affected by climatic conditions especially temperature and soil moisture. St.ho had a longer growth period in cool and humid years compared to warm and dry years. But required cumulative temperatures were almost the same in different years. Results indicated that plant growth was affected by growth degree days (GDD) and cumulative rainfall during growth season. Also, the analysis of variance showed that differences in plant height at different sites and also in different years were statistically significant (P<0.05).
 

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