Soil sample conservation from field to lab for heterotrophic respiration assessment

Author(s)

Lucas, Yves ^[1] ; Santin, Roberta Clemente ^[2] ; da Silva, Wilson T. L. ^[3] ; Merdy, Patricia ^[1] ; Melfi, Adolpho Jose ^[4] ; Ribeiro Pereira, Osvaldo Jose ^[4] ; Montes, Celia Regina ^[2]

Affiliation

^[1] Univ Toulon & Var, Aix Marseille Univ, CNRS, IM2NP, F-83041 Toulon 9 - France

^[2] Univ Sao Paulo, Ctr Energia Nucl Agr, CENA USP, NUPEGEL USP, Av Centenario 303, BR-13416903 Piracicaba, SP - Brazil

^[3] Embrapa Instrumentacao, R 15 Novembro 1452, Sao Carlos, SP - Brazil

^[4] Univ Sao Paulo, Inst Energia & Ambiente, IEE USP, Nucleo Pesquisa Geoquim & Geofis Litosfera, NUPEGE, Av Prof Luciano Gualberto 1289, BR-05508010 Sao Paulo - Brazil

• Document type: Journal article
• Source: METHODSX; v. 7, 2020.
• Web of Science Citations: 0

Abstract

We evaluated (1) whether the sample transport time could lead to a significant loss of carbon through microbial respiration and to a change of measured respiration rates, which can be a problem in areas difficult to access, with a long travel time from field to laboratory; (2) whether the method used to quantify heterotrophic respiration for agricultural soils is adequate for horizons that remain always water-saturated or close to saturation. Surface horizons and deep Bh of Amazonian podzols were sampled and kept under refrigeration to maintain moisture of sampling time. Incubations of aliquot of the same sample were initiated on the sampling day and 3, 6, 9 and 12 days after sampling. Other aliquots were conducted on a tension table to given water potential (60 cm H2O) prior to incubation. Soil samples, whether disturbed or not, should not be dried but kept at sampling moisture in semi-open plastic bags under refrigeration at 4 degrees C, respiration monitoring must be conducted without prior water potential adjustment. In such conditions,12 days between sampling and beginning of measurement did not affected respiration results. The method used for agricultural soils gave different results and does not make sense for soils under perudic moisture regime. (C) 2020 The Authors. Published by Elsevier B.V. (AU)

• FAPESP's process: 12/51469-6 - Modelling the dynamics of equatorial forest soil deep carbon in changing environments - C-PROFOR
• Grantee: Adolpho José Melfi
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 11/03250-2 - Quantification and dynamics of carbon associated with deep spodic horizons of Amazon Forest soils, towards possible climatic changed
• Grantee: Célia Regina Montes
• Support Opportunities: Regular Research Grants