Evaluation of crude protein of dry rangeland species in two phenologocal stages and comparing with critical limit needing for native animal (case study: Kahnuj, Kerman province)

Determining the forage quality of plant species is among the factors necessary for proper range management. Therefore, the crude protein of 14 species was measured in two phenological stages in Kahnuj (Kerman province) using Kjeldahl methodology. The crude protein content of the study species was compared using ANOVA, and a paired t test was used to compare the crude protein content of each species between the two phenological stages. In addition, one-sample t-test was used to compare the average crude protein with critical level. According to the obtained results, the protein content of the study species showed significant differences at each phenological stage, so that in the vegetative stage, the highest and lowest crude protein was recorded for Astragalus triboloides (19.61%) and Ziziphus spina-christ (4.18%), respectively. In seed ripening stage, the highest and lowest crude protein content was recorded for Rhazia stricta (14.85%) and Stipa capensis (5.23%), respectively. The crude protein showed a downward trend for all species except two. The average content of crude protein measured at vegetative stage was higher as compared with the critical level. However, this difference was not significant for the second stage. Overall, preservation and development of species having high percentage of crude protein with low changes in protein during the growing season like Taverniera cuneifolia is recommended.