To achieve sustainability and land degradation neutrality in rangeland ecosystems, understanding the growth stages of key plants to develop land management and conservation plans is vital. This study was conducted to determine the nutritional value of Gundelia tournefortii and its changes during different growth stages as one of the most dominant rangeland plants in Khorasan Razavi province, NE of Iran. The plants were randomly sampled in three stages of growth (vegetative, flowering and seeding) in the Senowbar rangeland and eventually moved to the laboratory for chemical analysis. Results showed that crude fiber and acid-detergent fiber and neutral-detergent fiber increased and dry matter, crude protein, ether extract decreased. Ash, Ca, P, K and Na decreased during plant matured; furthermore, these changes were statistically significant (Duncan’s test, 99% and 95%). Dry matter intake, digestible dry matter and relative feed value decreased during growth, which was statistically significant (p < 0.01). The metabolizable energy of Gundelia tournefortii during growth periods reached values of 11.77, 11.58 and 10.46 Mj/Kg, respectively. Also, organic matter digestibility showed a similar decreasing trend. It is concluded that the best time to harvest Gundelia tournefortii from rangelands and to feed is the vegetative period dated from March to April, so harvesting during this period does not prevent seeding.

为了在牧场生态系统中实现可持续性和土地退化的中立性，了解关键植物的生长阶段以制定土地管理和保护计划至关重要。进行这项研究以确定Gundelia tournefortii的营养价值及其在不同生长阶段的变化，是伊朗东北部霍拉桑·拉扎维省最主要的牧场植物之一。在Senowbar牧场的三个生长阶段（营养，开花和播种）中随机取样这些植物，并最终转移到实验室进行化学分析。结果表明，粗纤维，酸洗涤纤维和中性洗涤纤维增加，干物质，粗蛋白，醚提取物减少。植株成熟过程中灰分，钙，磷，钾和钠含量下降；此外，这些变化具有统计学意义（Duncan检验，分别为99％和95％）。生长期间干物质摄入量，可消化干物质和相对饲料价值下降，具有统计学意义（p  <0.01）。香根草的代谢能在生长期间，分别达到11.77、11.58和10.46 Mj / Kg的值。同样，有机物的消化率也显示出类似的下降趋势。结论是，从牧场收获和繁殖的最佳时间是3月至4月的营养期，因此在此期间的收获不会阻止播种。