Pretreatment of soil samples before NO3-N analysis.

Storage of sandy, loam and clay soil samples at 35 deg C or 70 deg C for 2-3 days reduced the NO3-N level in the soils. Freezing (-20 deg C), refrigeration (-4 deg C) or storage at room temperature for 2-3 days had little effect on NO3-N levels, although low or room temperature storage for 2 months increased NO3-N levels in the loam and clay soils. Freezing or refrigeration of the sandy soil for 2 months reduced NO3-N levels, while long storage at room temperature markedly increased NO3-N levels in this highly organic soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)