Patterns of soil microorganisms and enzymatic activities of various forest types in coastal sandy land

Abstract

Microorganisms and enzymes are essential soil components that catalyze various biochemical processes (decomposition and nutrient turnover) and can be used to assess soil quality and health. To understand how various plantations can boost the soil ecological condition in coastal areas, we investigated the seasonal dynamics of six soil enzyme activities and microorganisms in different vegetation types, as well as their responses to shifts in soil physicochemical properties in the southeast coasts of China. Four types of shelter forests (Bambusa oldhamii, Pinus elliottii, Eucalyptus robusta, and Casuarina equisetifolia) from the southeast coasts of China were randomly selected to investigate changes in seasonal patterns of soil enzyme activities (protease, urease, acid phosphatase, cellulase, peroxidase, and polyphenol oxidase), soil microorganism quantities (bacteria, fungi, actinomycetes, and total microorganisms), and correlated with soil physicochemical properties (soil pH, soil moisture, soil temperature, soil carbon, and nitrogen contents). We noticed that the activities of protease and peroxidase in four shelter forests varied seasonally, with significantly higher activities in June in relation to other seasons. However, different shelter forests showed significant seasonal differences in urease, acid phosphatase, cellulase, and polyphenol oxidase activities. The soil bacteria, fungi, and total microorganism quantities in four shelter forests increased significantly (P < 0.05) in September except for soil actinomycetes. Overall, in B. oldhamii forests, the soil urease, acid phosphatase, and polyphenol oxidase activities and microorganisms (soil bacterial, fungi, and total microorganisms) were the highest relative to C. equisetifolia forests, following E. robusta and P. elliottii forests. Whereas, compared to other forest types, the C. equisetifolia forest had significantly (P < 0.05) greater quantities of actinomycetes at each season. Correlation analysis and principal component analysis (PCA) of 80.7% cumulative variance contribution rate indicated that soil enzymatic activities were strongly associated with soil microorganism quantities and soil physicochemical properties in C. equisetifolia and B. oldhamii forests. Our findings indicate that higher soil enzymatic activities and abundant soil microorganisms both in C. equisetifolia and B. oldhamii forests can help to accelerate soil nutrient absorption and utilization, by improving their adaptability to coastal sandy soils.

Keywords

• Coastal shelter forests
• Enzymatic activities
• Microorganism quantities
• Seasonal variation