Stump height after regenerative cutting of sea-buckthorn (Hippophae rhamnoides) affects fine root architecture and rhizosphere soil stoichiometric properties

This study aimed to clarify the effects of stumping on the fine root architecture of decaying Hippophae rhamnoides plantation in feldspathic sandstone areas, and to determine the optimal stump height that is contributive to the recovery and growth of H. rhamnoides. The fine root architecture, and the econometric properties of soil organic carbon (C), total nitrogen (N) and total phosphorus (P) in fine roots and rhizosphere roots as well as the underlying correlations were analyzed after different stump height treatments (0 cm, 10 cm, 15 cm, 20 cm, no stumping). The above treatments all significantly affected fine root architecture, which grew into fishtail branches in all treatments. Especially, at the stump height of 15 cm, the topological index (0.75), total branching rate (1.91), specific root length (69.69), and average diameter (0.62) of fine roots were all better than after other treatments. Stumping did not significantly affect C content of fine roots, P and C: N ratio of rhizosphere soils, but very significantly affected other nutrient contents and the stoichiometric ratios of both fine roots and rhizosphere soils. These results indicate the stump height of 15 cm better promote the growth of H. rhamnoides. Principal component analysis shows the N, P, C:N of fine roots, and the C, C:P of rhizosphere soils maximally affect the fine root architecture. Our findings are critical for vegetation recovery and soil erosion prevention and control in feldspathic sandstone areas.