The machair, a low-input agricultural system in the extreme north-west of Scotland, is a rare example of an extant system that has never been intensively cultivated. The bacterial community structure represents an opportunity to test variation connected with temporal, soil compartment and land use factors. To achieve this objective a two-year, three season sampling regime over the three major land uses present: cropped, fallow and grasslands was performed. Bacterial communities of rhizosphere and bulk soil compartments were assessed using terminal restriction fragment length polymorphism (T-RFLP). Machair bacterial community structure was primarily determined by soil compartment and temporal factors, with differences both between and within years highly significant. Although land use was not the main determinant of bacterial community, clear differences were detected. Cropped and fallow sites contained a similar bacterial community while grassland sites were different. Correlation with soil physico-chemical factors indicated that machair bacterial community structure may be driven to some degree by soil moisture content.This study highlights the need to take seasonal and annual variation into account when assessing bacterial communities in an agricultural setting.
Bibliographical noteFunding Information:
We would like to acknowledge Scottish Natural Heritage Uist and the crofters of the Uists for their assistance and cooperation, Jim McNicol (Biomathematics and Statistics Scotland Research Institution) for statistical support, and Robin Pakeman for helpful suggestions in internal review. S.N.V. acknowledges funding from the James Hutton Institute/University of Aberdeen for a postgraduate studentship. The James Hutton Institute is in part financially supported by the Scottish Government Rural and Environment Science and Analytical Services Division.
- Bacterial community structure
- Land use
- Low-input agriculture
- Soil moisture content
- Temporal variation