Study of the Suitable Time of Entry and Exit(Range Readiness) of Livestock in key ranges of 5 bioclimatic rangelands of Iran (Saleh Abad Rangelands - Ilam Province)

Range species consist of different plant species, each with different vegetative and reproductive stages. Thus, each species has a particular time period for growing readiness and grazing at a particular time must also stop. Moreover, rangeland soil is ready only in certain times to sever livestock. Without understanding these characteristics, determining the grazing season and livestock management and grazing is not possible. With this study, the revising of grazing rangeland management programs in similar areas with similar vegetation will be possible. So in order to determine the timing of entry and exit of livestock to and from rangeland this study was carried out in a semi-steppe rangeland in Saleh Abad of Ilam, 35 km soute West of Ilam for five years from 2006 to 2010. Data such as the stages of plant phenology, total height of five range species and soil moisture conditions were recorded since the beginning of growing season to plant drying for of 24 weeks and 4 years to determine the appropriate time for livestock exit from rangeland utilization percentage evaluation method was employed to compare their level of exploitation with the main range species. The results showed that there were significant differences among five species of rangeland in terms of phenology stages in the years studied. Plant growth in wet years starts two or three weeks earlier, and in dry years the same period also begins later in terms of vegetative and reproductive activity of different plants. Longitudinal growth of annual plants, finished in March and reproductive growth stage begins, the maximum vegetative growth of perennial plants is the first of April. Suitable time to enter the trap with soil and plant phonology in mid-March, but common stock based on the Exploitation permit and norm, 90 days before the pasture is ready. These factors increase the density of grassland soils, reducing water infiltration into the soil, vegetation and increased soil erosion and grazing have been premature, and it works perfectly in the region is evident. Livestock exclusion of pasture in the dry year (1387) was appropriate, but in other years, the trap were quickly removed. Thus rate of utilizations lower than the rate Allowable limit of exploitation is permitted. In other words, the time of entry and exit of livestock to pasture is early. Based on the results, changes in the current calendar grazing are recommended. Based on the results of suitable time of entry and exit(range readiness) of livestock in mid-March and mid June is recommended.