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This is the peer reviewed version of the following article: Heinemeyer, A. and Bene, C. Di and Lloyd, A.R. and Tortorella, D. and Baxter, R. and Huntley, B. and Gelsomino, A. and Ineson, P. (2011) 'Soil respiration : implications of the plant-soil continuum and respiration chamber collar-insertion depth on measurement and modelling of soil CO2 e ux rates in three ecosystems.', European journal of soil science., 62 (1). pp. 82-94, which has been published in nal form at http://dx.doi.org/10.1111/j.1365-2389.2010.01331.x. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. fluxes. We hypothesized that total soil respiration is frequently under-estimated because soil 30 collar insertions sever surface roots, which coupled to the preferential practice of taking 31 daytime measurements, lead to the autotrophic (root-derived) component frequently being 32 missed. We measured root distribution and soil CO 2 efflux in three contrasting ecosystems: a 33Lodgepole pine (Pinus contorta) plantation, an upland heather-dominated peatland and a 34 lowland sheep-grazed grassland, where we combined shallow surface collars with collars at 35 different soil insertion depths for occasional and continuous hourly flux measurements. Collar 36 insertion by only a few centimetres reduced total soil CO 2 efflux in all three ecosystems by an 37 average of 15% but at times up to 30 to 50%, and was directly proportional to the quantity of 38 cut fine roots. Most reduction occurred in the shallow-rooted peatland system and least in the 39 deep-rooted grassland. In the forest and grassland, soil temperatures explained most of the 40 deep collar (i.e. largely heterotrophic) variation and did not relate to the root-derived (i.e.

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Soil solarization, alone or combined with organic amendment, is an increasingly attractive approach for managing soil-borne plant pathogens in agricultural soils. Even though it consists in a relatively mild heating treatment, the increased soil temperature may strongly affect soil microbial processes and nutrients dynamics. This study aimed to investigate the impact of solarization, either with or without addition of farmyard manure, in soil dynamics of various C, N and P pools. Changes in total C, N and P contents and in some functionally-related labile pools (soil microbial biomass C and N, K 2 SO 4 -extractable C and N, basal respiration, KCl-exchangeable ammonium and nitrate, and water-soluble P) were followed across a 72-day field soil solarization experiment carried out during a summer period on a clay loam soil in Southern Italy. Soil physico-chemical properties (temperature, moisture content and pH) were also monitored. The average soil temperature at 8-cm depth in solarized soils approached 55°C as compared to 35°C found in nonsolarized soil. Two-way ANOVA (solarizationÂorganic amendment) showed that both factors significantly affected most of the above variables, being the highest influence exerted by the organic amendment. With no manure addition, solarization did not significantly affect soil total C, N and P pools. Whereas soil pH, microbial biomass and, at a greater extent, K 2 SO 4 -extractable N and KCl-exchangeable ammonium were greatly affected. An increased release of water-soluble P was also found in solarized soils. Yet, solarization altered the quality of soluble organic residues released in soil as it lowered the C-to-N ratio of both soil microbial biomass and K 2 SO 4 -extractable organic substrates. Additionally, in solarized soils the metabolic quotient (qCO 2 ) significantly increased while the microbial biomass C-to-total organic C ratio (microbial quotient) decreased over the whole time course. We argued that soil solarization promoted the mineralization of readily decomposable pools of the native soil organic matter (e.g. the microbial biomass) thus rendering larger, at least over a short-term, the available fraction of some soil mineral nutrients, namely N and P forms. However, over a longer prospective solarization may lead to an over-exploitation of labile organic resources in agricultural soils. Manure addition greatly increased the levels of both total and labile C, N and P pools. Thus, addition of organic amendments could represent an important strategy to protect agricultural lands from excessive soil resources exploitation and to maintain soil fertility while enhancing pest control.