EFFECT OF FREEZING ON THE FREE AMINO ACIDS IN SOIL

Abstract

Five soils were subjected to temperatures of 1° and −14 °C for 3 weeks. Freezing caused a marked increase in the total amount of free amino acids extracted. The amounts of free amino acids released were greater in soils where decomposition of organic matter was more complete. While prolonged storage of soil at 1 °C had no measurable effect on the free amino acids released, storage over a long period at −14 °C decreased the free amino acid content. Equilibration of wetted soil at room temperature prior to storage at cold temperatures decreased the extractable free amino acids. The data support the contention that part of the effect of soil freezing on the acceleration of microbial activity is due to release of available energy sources.