Microbial Biomass, N Mineralization and Nitrification, Enzyme Activities, and Microbial Community Diversity in Tea Orchard Soils

Abstract

Understanding the chronological changes in soil microbial and biochemical properties of tea orchard ecosystems after wasteland has been reclaimed is important from ecological, environmental, and management perspectives. In this study, we determined microbial biomass, net N mineralization, and nitrification, enzyme (invertase, urease, proteinase, and acid phosphatase) activities, microbial community diversity assessed by denaturing gradient gel electrophoresis (DGGE) of 16S rDNA polymerase chain reaction (PCR) products, and related ecological factors in three tea orchard systems (8-, 50-, and 90-year-old tea orchards), adjacent wasteland and 90-year-old forest. Soil microbial biomass C (C mic ) and activity, i.e., soil basal respiration (R mic ), microbial biomass C as a percent of soil organic C (C mic /C org ), N mineralization, invertase, urease, proteinase, and acid phosphatase, significantly increased after wasteland was reclaimed; however, with the succeeding development of tea orchard ecosystems, a decreasing trend from the 50-to 90-year-old tea orchard became apparent. Soil net nitrification showed an increasing trend from the 8-to 50-year-old tea orchard and then a decreasing trend from the 50-to 90-year-old tea orchard, and was significantly higher in the tea orchards compared to the wasteland and forest. Urea application significantly stimulated soil net nitrification, indicating nitrogen fertilizer application may be an important factor leading to high-nitrification rates in tea orchard soils. The Shannon's diversity index (H) and richness (S) based on DGGE profiles of 16S rRNA genes were obviously lower in all three tea orchards than those in the wasteland; nevertheless, they were significantly higher in all three tea orchards than those in the forest. As for the three tea orchard soils, comparatively higher community diversity was found in the 50-year-old tea orchard.

Ammonia-oxidizing archaea have more important role than ammonia-oxidizing bacteria in ammonia oxidation of strongly acidic soils

“…HZ soil was collected from a 50-year-old tea orchard characterized by a subtropical wet monsoon climate with mean annual rainfall of 1500 mm, which received a high-rate nitrogen fertilizer input, averaging about 450 kg N Ha À1 per year (Xue et al, 2006). YH, QJ, QY and TY soils are also located in a subtropical monsoon climate, with a mean annual temperature of 16.2 1C, 14.5 1C, 18.1 1C, and 16.5 1C, respectively, and mean annual rainfall of 1550 mm, 1030 mm, 1288 mm, and 1437 mm, respectively.…”

Links between Ammonia Oxidizer Community Structure, Abundance, and Nitrification Potential in Acidic Soils

“…High levels of nitrogen fertilizer are applied, altering N cycling and microbial community structure (45,54). Soils under tea plantations are often acidic, with pH values ranging from 3.5 to 5.5, but, despite the potential sensitivity of AOB to low pH, nitrification rates and nitrate concentrations are high (9,35,51,53). Soil type and vegetation have potentially additional effects on microbial community composition (27), and it is therefore pertinent to compare tea soils with other vegetated systems on the same soil type.…”

Long-term application of organic manure changes abundance and composition of ammonia-oxidizing archaea in an acidic red soil

“…Digital images of the gels were further analyzed with Quantity One ® 1-D Analysis Software (Bio-Rad Laboratories, Hercules, CA, USA). Removing the background intensity from each lane, the software performs a density profile through lanes, detects individual bands and matches bands occupying the same position in different lanes (Xue et al 2006). The genetic diversities were analyzed by Richness (S), Shannon diversity (H) and Evenness (E H ) indices (Xue et al 2006).…”