Evaluation of three incubation designs for mineralization kinetics of organic materials in soil

Carbon (C) mineralization was assessed during incubations of a Mediterranea n sandy soil amended with various organic by-products covering a wide range of C and nitrogen (N) contents. The laboratory incubation systems consist in measuring continuously the soil respiration (as CO2-C) in closed chamber s, or less current, in pre-storing soil containers in semi-open chambers un til transferred and measured for CO2-C evolved in closed 'measuring-jars'. The latest were improved, the new designs permitting to test a much greater number of by-products with a minimum handling. No significant differences were found between the results obtained by the different incubation systems . The storage systems using pre-storage of soils gave reproducible cumulati ve CO2- C curves. Results obtained with the pre-storage systems could be co mpared confidently to C mineralization data from studies using permanent cl osed chambers. One of them was specially reliable and can thus be recommend ed for long-term incubation experiments.