Effect of low‐temperature storage on the extractable nutrient ions in soils

Low‐temperature storage gave significant increases in the amounts of extractable ammonium‐nitrogen and phosphorus in four soil types. The changes in nitrate‐nitrogen and particularly in potassium and calcium were less pronounced and varied according to the soil studied. The effects were generally greater in the organic soils. Low‐temperature storage of soils which had been air‐dried previously caused similar changes. In view of these findings it is considered that deep‐freeze storage should not be used when extractable nutrients are to be determined.