Abstract
Caragana tibetica Kom. is a key constructive species in desert steppe and desert transition zones. Long-term enclosure has led to population decline and even mortality of C. tibetica, while populations outside enclosures grow well. However, the biological mechanisms underlying the continued growth of C. tibetica under grazing remain unclear. Therefore, this study aimed to clarify the effects of stubble management on the photosynthetic physiology and antioxidant characteristics of C. tibetica, and to determine the optimal stubble intensity. Plants were subjected to five stubble gradients (0%, 25%, 50%, 75%, 100%). The results showed that stubble treatments caused significant changes in both photosynthetic and antioxidant traits. Interestingly, the correlations between photosynthetic and antioxidant characteristics varied with the growth season: they were positively correlated in the early growth season, but negatively correlated in the middle and late stages. Using a generalized algorithmic model, we found that stubble intensities ranging from 0.5% to 38.7% enhanced the stress resistance of C. tibetica, with 21.6% being the optimal intensity. This study demonstrates that moderate stubble management promotes the stress resistance of C. tibetica, providing important theoretical and scientific support for vegetation restoration and ecological construction in desert steppes.