Comparison of Micromorphometric Characteristics of Aggregates from Noneroded and Moderately Eroded Typical Chernozem in a Laboratory Experiment

Resumo

The aim of this study was to develop an approach to assessing the impact of rill erosion on aggregates of typical chernozem aggregates in a laboratory experiment with flume. Aggregates from the plow horizons of noneroded and moderately eroded typical chernozem (Haplic Chernozem (Loamic, Aric, Pachic) and Haplic Chernozem (Loamic, Aric)) of Kursk region (Russia) were analyzed. Micromorphometric parameters of the aggregates of the same sizes untreated by water and transported by water flow were statistically compared. These aggregates were initially air-dry or capillary-wetted. Photos of thin sections were processed using Skyscan CT-analyser program to obtain quantitative micromorphometric parameters: form factor (FF) and roundness (Rdn). Then, the coefficient of aggregate surface unevenness (U) was calculated. As a result, it was found that aggregates from the noneroded soil changed stronger under the influence of a shallow-water flow, if the soil before the experiment was dry. This was confirmed by significant statistical differences in all the studied parameters. The change in parameters of aggregates from the moderately eroded typical chernozem depended on the soil structure rather than on the sample moistening before the experiment. A comparison of aggregates treated with shallow-water flow showed that their characteristics are affected both by the initial state of the soil and by the degree of its erosion. The degree of roundness was the most representative parameter, as the largest number of statistically significant differences was found.