DYNAMICS OF SOIL STRUCTURE PARAMETERS IN LOAMY SOILS OF SLOVAKIA

Abstract

Studies on the structure of loamy soils were carried out in several fields located on loamy calcaric Chernozem, loamy haplic and mollic Fluvisols in the north-west part of the Danube lowland (Slovakia). The aims of the studies were to evaluate: (1) the overall and dynamics of the soil structure parameters with dependence on soil types, and (2) the relationships between soil parameters and soil structure parameters. The results showed that soil structure parameters varied in time and soil types. Overall, the best soil structure according to vulnerability coefficient (Kv), index of aggregate stability (Sw) and crusting index (Ic) was in mollic Fluvisol > haplic Fluvisol > calcaric Chernozem. The results of the dynamics of structural parameters such as: Kv, Sw and Ic were very similar. The most favourable soil structure evaluated according to the percentage of aggregate destruction (PAD) was in mollic Fluvisol > calcaric Chernozem > haplic Fluvisol. When all soils were assessed together, the negative significant correlations were observed between the Kv and contents of soil organic carbon (r = -0.634, P ≤ 0.01, n = 18), hot- (r = -0.732, P ≤ 0.001, n = 18) and cold-water soluble carbon (r = 0.670, P ≤ 0.01, n = 18) as well as C HA :C FA ratio (r = 0.615, P ≤ 0.01, n = 18). The same trend was observed between Ic and soil organic matter (SOM) parameters. Higher stability of SOM positively affected stabilization of macroaggregates (r = 0.520, P ≤ 0.05, n = 18). If all loamy soils were assessed separately, we detected negative significant correlations between Ic and soil organic carbon (calcaric Chernozem: r = -0.998, P ≤ 0.001, n = 6; haplic Fluvisol: r = -0.997, P ≤ 0.001, n = 6; mollic Fluvisol: r = -0.995, P ≤ 0.001, n = 6). In mollic Fluvisol, values of Kv and Ic increased with higher labile carbon contents as well as higher stability of SOM positively affected stabilization of macroaggregates.