Soil microbial community structure and function responses to successive planting of Eucalyptus

Abstract

Many studies have shown soil degradation after the conversion of native forests to exotic Eucalyptus plantations. However, few studies have investigated the long-term impacts of short-rotation forestry practices on soil microorganisms. The impacts of Eucalyptus successive rotations on soil microbial communities were evaluated by comparing phospholipid fatty acid (PLFA) abundances, compositions, and enzyme activities of native Pinus massoniana plantations and adjacent 1st, 2nd, 3rd, 4th generation Eucalyptus plantations. The conversion from P. massoniana to Eucalyptus plantations significantly decreased soil microbial community size and enzyme activities, and increased microbial physiological stress. However, the PLFA abundances formed "∪" shaped quadratic functions with Eucalyptus plantation age. Alternatively, physiological stress biomarkers, the ratios of monounsaturated to saturated fatty acid and Gram+ to Gram-bacteria, formed "∩" shaped quadratic functions, and the ratio of cy17:0 to 16:1ω7c decreased with plantation age. The activities of phenol oxidase, peroxidase, and acid phosphatase increased with Eucalyptus plantation age, while the cellobiohydrolase activity formed "∪" shaped quadratic functions. Soil N:P, alkaline hydrolytic nitrogen, soil organic carbon, and understory cover largely explained the variation in PLFA profiles while soil N:P, alkaline hydrolytic nitrogen, and understory cover explained most of the variability in enzyme activity. In conclusion, soil microbial structure and function under Eucalyptus plantations were strongly impacted by plantation age. Most of the changes could be explained by altered soil resource availability and understory cover associated with successive planting of Eucalyptus. Our results highlight the importance of plantation age for assessing the impacts of plantation conversion as well as the importance of reducing disturbance for plantation management.

Effects of the successive planting of Eucalyptus urophylla on soil bacterial and fungal community structure, diversity, microbial biomass, and enzyme activity

“…Many factors in the forest ecosystem can affect microbial communities (Janssens et al, ). Significant shifts in the microbial communities in response to the successive planting of Eucalyptus have also been found in previous work (Chen et al, ; Wu et al, ). Nevertheless, the methods used in these studies do not accurately determine which bacteria have undergone significant changes.…”

“…These values may be correlated with the high organic matter content in the stand. We found that the high acid phosphatase levels observed in high phosphorus soils may be due to phosphatase activating the phosphorus, which is vital for improving soil phosphorus availability in this area (Chen et al, ).…”

Changes in nitrogen budget and potential risk to the environment over 20years (1990–2010) in the agroecosystems of the Haihe Basin, China

“…Groundwater pollution has become much heavier over the past few decades and more than 60% of rivers have become polluted in the Haihe Basin . There is a clear qualitative relationship between N surplus and nitrate concentrations in the groundwater in a given crop-growing area, meaning that massive N accumulations in fields are likely to increase the risk of groundwater nitrate contamination (Zhao et al, 2009b;Hou et al, 2012;Chen et al, 2013).…”

Influence of phosphorus application and water deficit on the soil microbiota of N2‐fixing and non‐N‐fixing tree

“…, Chen et al. ). In this study, we found a species‐specific partitioning of microbial communities in response to drought treatments and phosphorus addition (Appendix : Table S2; Figs.…”

“…, Chen et al. ). However, little is known about the response of soil microbiota, including protozoa, microbes, and associated enzyme activities, to the specific identity of aboveground tree species (nitrogen and non‐nitrogen‐fixing) or even the absence of vegetation, particularly in the presence or absence of other ecosystem‐limiting factors (drought and P addition).…”