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Acta Prataculturae Sinica ›› 2022, Vol. 31 ›› Issue (12): 31-40.DOI: 10.11686/cyxb2021467

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Effects of Ligularia virgaurea on plant and soil nutrient levels and soil microbial biomass characteristics in degraded alpine grassland

Yu-qin WANG1(), Mei-ling SONG1, Rui ZHOU1, Hong-sheng WANG1, Hua LIU2, Xiu-lian ZHU3, Yu-shou MA1()   

  1. 1.State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University of Animal Science and Veterinary Medicine,Xining 810016,China
    2.Qinghai Provincial Grassland Station,Xining 810008,China
    3.Haiyan County Grassland Station,Haibei 812200,China
  • Received:2021-12-13 Revised:2022-01-27 Online:2022-12-20 Published:2022-10-17
  • Contact: Yu-shou MA

Abstract:

Ligularia virgaurea is considered to be an important indicator species of vegetation degradation in alpine meadows. A study of grassland ecosystem vegetation, soil and microbial nutrient cycling would make a significant contribution to understanding its invasion mechanism. An area with L. virgaurea invasion was studied. Chemical agents were used to remove the competitive advantage of L. virgaurea, and the subsequent changes in the nutrient levels of vegetation functional groups, soil nutrients and soil microbial biomass were measured and analyzed. We found that the carbon (C) content of Cyperaceae in the study area was increased. The nitrogen contents of Poaceae and Fabaceae and the phosphorus (P) content of Fabaceae were significantly increased, while the P content of Cyperaceae was significantly decreased (P<0.05), and C content in L. virgaurea was significantly higher than that in other functional groups (P<0.05). Across functional groups, the C∶N was significantly higher in Cyperaceae than in Fabaceae and forbs (P<0.05), and C∶P of Cyperaceae was significantly higher than that of other functional groups (P<0.05). Stoichiometrically, there was a negative correlation between C content and N or P content, and a positive correlation between N content and P content. The total nitrogen content of soil increased significantly in the study area after chemical treatment of L. virgaurea, and the contents of available nitrogen, total potassium and available potassium and the C∶N decreased significantly, while N∶P increased significantly (P<0.05). L. virgaurea caused an increase in soil microbial biomass (and also microbial C, N, and P) and increased soil microbial activity. Microbial C∶N and C∶P ratios in the study area were also higher than those in the control area, and microbial N∶P was slightly lower than that in the control area, indicating that the demand for N in L. virgaurea is greater than the demand for P. The plant contents and stoichiometric ratios of plant C, N, and P were linked to soil and soil microbial biomass nutrient levels and stoichiometric ratios. Results of a redundancy analysis showed that soil levels of C, N, and P in the study area were highly correlated with those in microbial biomass, and the P content of plants was significantly related to that of soil and microbial biomass (P<0.05), and the nutrient requirements of each functional group of plants in the control area were evenly distributed, which shows that the nutrient distribution pattern in grassland was affected by L. virgaurea.

Key words: Ligularia virgaurea, hazard, physical and chemical properties, stoichiometry