Abstract Effective grassland restoration practices can promote degraded meadows recovery. However, little has been documented regarding the effect of water addition on the restoration of degraded meadows in the Qinghai–Tibetan Plateau (QTP) . A field experiment with five water addition levels was established to identify the interactions between soil bio-physicochemical properties and plant of the degraded alpine meadows in the Sanjiangyuan region, QTP. Soil enzyme activity (α-glucosidase, αG; β-1,4-glucosidase, βG; β-D-cellubiosidase, βDC; β-xylosidase, βX; β-1,4-N-acetylgucosaminidase, NAG; leucine aminopeptidase, LAP; phosphorus, P), microbial biomass C (MBC) and N (MBN), MBC: MBN, physicochemical properties (soil moisture content, SMC; bulk density, SBD; pH; total organic C, TOC; total N, TN; soil C: N; ammoniacal N, NH4+-N; nitrate N, NO3−-N; nitrite N, NO2−-N), and plant diversity and productivity were analyzed throughout the growing season. The results indicated that soil SMC, available N (NH 4 + -N and NO 3 − -N), TOC, the activities of αG, βDC, βX, NAG, MBC and MBN significantly increased with water addition levels, whereas the activity of LAP and P, and MBC: MBN decreased (p 4 + -N, and NO 3 − -N, were significantly related to plant diversity and productivity. The changes in soil enzyme activity (especially βDC, βG, LAP) under water addition might the key drivers affecting soil nutrients such as TOC, NO 3 − -N and NH 4 + -N, which subsequently increased plant coverage and productivity. Our findings suggested that the obviously increase in enzymes activity and nutrients might be beneficial for the vegetation recovery of degraded alpine meadow on the QTP under water addition.

中文翻译：

---

青藏高原加水通过调节土壤酶活性和养分促进退化高寒草甸植被恢复

摘要 有效的草地恢复实践可以促进退化草地的恢复。然而，关于加水对青藏高原（QTP）退化草地恢复的影响的文献很少。通过田间试验，确定了青藏高原三江源地区退化高寒草甸土壤生物理化性质与植物之间的相互作用，建立了五个加水水平的田间试验。土壤酶活性（α-葡萄糖苷酶，αG；β-1,4-葡萄糖苷酶，βG；β-D-纤维二糖苷酶，βDC；β-木糖苷酶，βX；β-1,4-N-乙酰氨基葡萄糖苷酶，NAG；亮氨酸氨基肽酶，LAP ；磷，P)，微生物生物量 C (MBC) 和 N (MBN)，MBC：MBN，理化特性（土壤水分含量，SMC；容重，SBD；pH；总有机 C，TOC；总 N，TN；土壤C：N；氨态 N，NH4+-N；硝酸盐 N，NO3--N；亚硝酸盐 N、NO2--N)、植物多样性和生产力在整个生长季节进行分析。结果表明，土壤SMC、速效氮（NH 4 + -N和NO 3 - -N）、TOC、αG、βDC、βX、NAG、MBC和MBN的活性随着水分添加量的增加而显着增加，而LAP、P、MBC：MBN降低（p 4 + -N、NO 3 - -N，与植物多样性和生产力显着相关。土壤酶活性（尤其是βDC、βG、LAP）在加水条件下的变化可能影响土壤养分的关键驱动因素，如 TOC、NO 3 - -N 和 NH 4 + -N，进而增加植物覆盖率和生产力。我们的研究结果表明，酶活性和养分的明显增加可能有利于植被恢复在加水条件下，QTP 上退化的高寒草甸。