Changes of Soil Aggregate Stability as a Result of the Effect of Freeze-thaw Cycles

Abstract

The objective of the present research was to assess the changes in soil erodibility during the non-vegetation period as one of the factors affecting the snowmelt erosion. The temperature fluctuation was simulated with the use of a climatic chamber ex situ. The soil surface was for simplicity reasons considered without any plant or snow cover. The paper deals with the rate of soil erodibility determination – the soil erodibility should increase due to the decrease of soil aggregate stability depending on the number of freeze-thaw cycles and initial soil moisture. Soil samples (taken from three sites) were subjected to freeze-thaw cycles under laboratory conditions. Changes in soil agreggate stability were monitored as one of the main soil characteristics which determine the soil erodibility. Two methods were used to determine the soil macroaggregate stability (soil aggregate fraction 1-2 mm): standard single-sieve method of wet sieving (Kemper et Rosenau, 1986), and dry aggregate analysis using a set of flat sieves with a diameter of 1 mm and 0.5 mm. The results of each method are controversial. Intended hypothesis has not been clearly confirmed.The objective of the present research was to assess the changes in soil erodibility during the non-vegetation period as one of the factors affecting the snowmelt erosion. The temperature fluctuation was simulated with the use of a climatic chamber ex situ. The soil surface was for simplicity reasons considered without any plant or snow cover. The paper deals with the rate of soil erodibility determination – the soil erodibility should increase due to the decrease of soil aggregate stability depending on the number of freeze-thaw cycles and initial soil moisture. Soil samples (taken from three sites) were subjected to freeze-thaw cycles under laboratory conditions. Changes in soil agreggate stability were monitored as one of the main soil characteristics which determine the soil erodibility. Two methods were used to determine the soil macroaggregate stability (soil aggregate fraction 1-2 mm): standard single-sieve method of wet sieving (Kemper et Rosenau, 1986), and dry aggregate analysis using a set of flat sieves with a diameter of 1 mm and 0.5 mm. The results of each method are controversial. Intended hypothesis has not been clearly confirmed.