Award details

Process controls and mechanisms influencing soil organic matter quality and function: interaction with soil microbiology, transformations and outputs

Reference	BBS/E/G/00003110
Principal Investigator / Supervisor	Professor Stephen Jarvis
Co-Investigators / Co-Supervisors
Institution	Inst of Grassland and Environmental Res
Department	Inst of Grassland and Environmental Res Department
Funding type	Research
Value (£)	766,574
Status	Completed
Type	Institute Project
Start date	01/04/1999
End date	31/03/2003
Duration	48 months

Abstract

Sustainable soil function is mainly determined by soil organic matter (SOM) turnover and soil microbial biomass (SMB) activities. The interactions that occur between SOM and SMB and their controlling factors have pivotal influences on soil quality, nutrient (N, P and C) cycling and losses and gaseous (CO2, CH4, N2O, NOx, NH3) production and transfer into the wider environment. The overall quantity and quality of the materials involved will be determined by interactions between pasture management and inputs, inherent soil properties and climatic/environmental factors. Newly developing approaches, including those based on natural abundance stable isotope distributions, open up exciting opportunities to quantify the dynamics of changes in influential organic pools, their controls and linkage with SMB activities, location and composition. A mechanistic understanding of these is an essential prerequisite to defining optimal managerial actions to promote sustainable soils with respect to production, pollution and biodiversity. To this end, this project will test the hypothesis that A gradient of effects linked to the intensity of grassland management modifies both the physico- chemical nature of SOM and its transformations, as well as SMB community structure, function and location, with impact on overall soil function, nutrient transformation rates and cycling, and fluxes of mobile, environmentally active agents into waters or the atmosphere. The work will centre on the range of controlled management systems available within IGER (-including organically-based systems) and will therefore make maximum use of a wide tranche of background information on the net outcome of the processes involved. A combination of field and controlled laboratory experimentation will be employed to target, in the first instance, the dynamics of key SOM constituents ranging in size from molecular through to macro materials, with the aim of defining controls over rates and mechanisms of change with the following objectives: Definition of grassland SOM turnover and C and other nutrient fluxes to provide improved understanding the functional role of key SOM constituents using novel stable isotopic (particularly natural abundance) and other methods. Determination of effects of root, shoots, exudates and residues and their interactions with management and other (viz. climate change) perturbations. This will utilise microlysimetry systems to isolate exudates and other mobile materials and to determine effects and interaction with rhizosphere and other soil processes. Examination of long and short term effects of perturbations on soil mesofauna (in this instance using soil nematodes as a key indicator group) to determine effects at a higher trophic level within the soil food web which is influenced by, and has impact on SOM, and its impact and further interactions with other soil constituents. All of the above are intimately bound to the activities of SMB. The second major thrust of the project seeks to understand the mechanisms by which those interactions develop and their outcomes are expressed at the larger scale. The research will provide an improved ability to determine the location of specific microbial activities and functions, and the roles that changing community structures (resulting from managerial or other changes) have on SOM transformations, nutrient and gaseous fluxes and general soil resilience. An essential part of this will be to use information obtained on the location of activities at the microscale to help to define spatial and temporal variability when the outcomes of these activities are expressed at the larger scale. New approaches to the mechanistic aspects of the control over the microbial ecology of the systems of interest will be required and will include the utilisation of novel markers to define substrate sources, SMB location and contribution to activities.

Summary

unavailable

Committee	Closed Committee - Agri-food (AF)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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