Journal article
Ratios of C, N and P in soil water direct microbial immobilisation–mineralisation and N availability in nutrient amended sandy soils in southwestern Australia
Agriculture, Ecosystems & Environment, Vol.127(1-2), pp.93-99
2008
Abstract
Microbial processes regulate soil nutrient availability to plants through mineralisation and immobilisation. It is less clear why in some circumstances microbial activity results in net-immobilisation of nutrients, in others net-mineralisation. In this study, we used a full combination of C, N and P (7 treatments and a control), which resulted in a wide range of C/N (1-167) and C/P (7-651) ratios in two sandy soils of southwestern Australia, to test microbial response to the amendments in relation to N-immobilisation and -mineralisation behaviour. After 5 days of amended incubation, soil water N was measured and net-immobilisation or -mineralisation estimated as the difference in soil water N before and after incubation. Microbial respiration, soil water C and P concentrations were also monitored. Microbial respiration was generally coupled with net-N-immobilisation. While all C-supply treatments such as C, CN, CP and CNP resulted in net-N-immobilisation, the "non-C" amendments including N, P and NP and the blank favoured net-N-mineralisation. Overall, C/N ratio appears more critical than C/P in directing microbial N-immobilisation/mineralisation hence the soil water N, with N remaining in soil water decreasing exponentially with increasing initial C/N. Such an inverse relationship was, however, tied to non-P-limiting conditions. It is suggested that the immediate availability of C, N, and P and their relative supply compared to that of the cell physiological demands may underlie microbial responses, and in the short-term, determine the direction of the two opposing microbial processes, N-mineralisation and -immobilisation
Details
- Title
- Ratios of C, N and P in soil water direct microbial immobilisation–mineralisation and N availability in nutrient amended sandy soils in southwestern Australia
- Authors/Creators
- S. Qiu (Author/Creator) - Murdoch UniversityA.J. McComb (Author/Creator) - Murdoch UniversityR.W. Bell (Author/Creator) - Murdoch University
- Publication Details
- Agriculture, Ecosystems & Environment, Vol.127(1-2), pp.93-99
- Publisher
- Elsevier BV
- Identifiers
- 991005545269207891
- Copyright
- © 2008 Elsevier B.V.
- Murdoch Affiliation
- School of Environmental Science
- Language
- English
- Resource Type
- Journal article
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Source: InCites
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- Citation topics
- 3 Agriculture, Environment & Ecology
- 3.45 Soil Science
- 3.45.112 Soil Carbon Dynamics
- Web Of Science research areas
- Agriculture, Multidisciplinary
- Ecology
- Environmental Sciences
- ESI research areas
- Environment/Ecology