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Journal of Desert Research ›› 2021, Vol. 41 ›› Issue (4): 109-120.DOI: 10.7522/j.issn.1000-694X.2021.00041

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Soil enzyme activity and carbon, nitrogen and phosphorus stoichiometric characteristics under different types of biocrusts and subsoil in Mu Us Sandland

Jin Fana(), Shiyao Lia, Hailong Yua(), Juying Huangb   

  1. a.Institute of Geographical Sciences and Planning /, Ningxia University,Yinchuan 750021,China
    b.Institute of Ecology and Environment, Ningxia University,Yinchuan 750021,China
  • Received:2021-01-16 Revised:2021-03-26 Online:2021-07-27 Published:2021-07-27
  • Contact: Hailong Yu

Abstract:

Biocrusts play an important role in soil nutrient accumulation and cycling. Soil enzyme activities could be used as significant biological indexes of extent of soil restoration and important biological indices in evaluating ecological restoration and health in desert region. In this study, by using the method of space-time interchange,biocrusts of different succession stages(algal crusts, mixed crusts, moss crusts, respectively)in Mu Us sandland, China, was investigated and chosen as study objects, biocrust and subsoil physicochemical properties and enzymatic activities were measured, and how biocrusts affect soil enzyme activities and stoichiometry characteristics were discussed. The results showed that the positive succession of biocrusts could increase the activities of urease, sucrase, alkaline phosphatase and catalase (P<0.05). Of the three biocrusts types, soil enzymatic activities under the cover of moss crusts, were the highest (P<0.05). There were remarkable differences in C, N, P contents and stoichiometric ratios among three types of biocrusts. The contents and stoichiometric ratios of C, N, P in the biocrustal layer were significantly higher than those of soils below biocrusts. Redundancy analysis result indicated that the effect of environmental factors on biocrust and subsoil enzymatic activity variation was ranked as follows: total nitrogen > available potassium > soil water content > total phosphorus> C/P > organic carbon > available nitrogen > pH > bulk density > available phosphorus, which meant total nitrogen (TN), total phosphorus (TP), available potassium (AK) were the dominant factors that influenced the enzymatic activities. And soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), C/P, N/P ratios were positively correlated with enzymatic activities of alkaline phosphatase and catalase; available potassium, total phosphorus and available phosphorus were positively correlated with enzyme activities of urease and sucrase. But the activities of all the four kinds of enzymes were negatively correlated with pH value, bulk density and porosity. The progressive succession of biocrusts could enhance the improvements of physical and chemical and activities of enzymes of biocrustal layer and soils below biocrusts, but the improvements of biocrustal layers were significantly higher than that of soils below biocrusts.

Key words: biocrusts, enzymatic activity, stoichiometry characteristics, progressive succession, Mu Us Sandland

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