Storage of air-dry soil samples at 0 degrees C or at room temperature before analysis does not affect bicarbonate soil-test phosphorus

Abstract

Five levels of phosphorus (P), as powdered single superphosphate, were incubated in moist soil (field capacity) for 42 days at 50°C in six different soils collected from south-western Australia. The soils were then air-dried for 7 days. Some subsamples of air-dry soil were stored for 180 days at 0°C in a cold room. Other subsamples were stored at fluctuating room temperature (18–25°C) in a laboratory and were sampled at 30, 60, 120, 150 and 180 days after storage to measure bicarbonate-extractable P (soil-test P) by the Olsen and Colwell procedures. No changes in soil-test P were detected while air-dry soil samples were stored at 0°C or room temperature.