Proper grazing management by consideration of Bromus tomentellus phenological stages

The recognition of different phenological stages of valuable rangeland species is highly important for grazing planning. It also assists managers to adjust the grazing period in accordance with the time of phenological stages of the species with high palatability and nutritive value and also detect the appropriate time for seed collection. Phenological stage of Bromus tomentellus were studied at 12 different vegetative regions within different sites during 2007-2010. The site characteristics of each location were recorded and 10 B. tomentellus plants were selected to study the phonological changes. The growth, flowering, seed maturity, and drying stages of the species were recordedevery other week and once a week in growing and reproductive stages, respectively. Ombrothermic curves of the studied areas were drawn using the meteorological data of the nearest synoptic station and were used to compare with different phenological stage of B. tomentellus. According to the results, in some years (2008, 2009 and 2010), especially in dry and warm weather condition in 2008, phenological stages of the species started and finished 1 to 3 weeks earlier than the wet years. In a relatively wet year (2007) the growth period and fall regrowth of the species was longer than normal years. The results indicated that vegetative growth in good rainfall condition differed from late March to early April and consequently flowering, seed maturity and drying stages were delayed with increasing altitude. Also, the species in sites with similar altitude had the same phonological periods. These results can be used by range mangers to adjust the grazing program and identify the appropriate time of seed collections for restoration projects.