Changes in potential denitrification and respiration during the cold storage of soils

The denitrification potential in moderately fertilized soil sampled four ti mes during 1995 decreased significantly after cold storage, at 4 +/- 2 degr eesC for 1 week. Prolonged storage (up to 24 weeks) resulted in a further d ecrease of denitrification potential which dropped to 38-54 % of the origin al values. Similarly, denitrification potential decreased substantially dur ing the first week of storage in differently fertilized soils. After 24 wee ks of storage, denitrification potential dropped to 29-55 % of that in fres h soils. The effects of storage at 4 +/- 2 degreesC on denitrification pote ntial and respiration (determined as carbon dioxide evolution) were in gene ral the same in moderately fertilized soils from four different sites: in a ll soils, depression of both the denitrification potential and potential re spiration was found after 8 weeks. However, the extent to which the paramet ers were decreased differed from case to case. Not only the duration and st orage conditions but also unidentified soil parameters are important for th e persistence of biological activity in stored soils.