The effect of organic matter on aggregation under different soil management practices in a vineyard in an extremely humid year

Soil organic matter is an important agent responsible for binding soil mineral particles together and creating soil structure stability. Soil management can modify the content of soil organic matter and soil structure stability. Therefore, the aim of this study was to evaluate the effect of soil organic matter on soil structure stability under different soil management practices in Rendzic Leptosol, in an extremely humid year. In 2006, an experiment of the different management practices in a productive vineyard was established in the locality of Nitra-Dražovce (Slovakia). The following treatments were established: 1. control (grass without fertilization), 2. T (tillage), 3. T + FM (tillage + farmyard manure), 4. G + NPK3 (grass + NPK 120–55–195 kg·ha− 1), and 5. G + NPK1 (grass + NPK 80–35–135 kg·ha− 1). Soil samples were collected every month, during the year 2010. The results showed that the aggregation process and soil structure stability were mainly dependent on the stable form of soil organic matter or the physically protected soil organic matter inside of aggregates in all soil management practices in a vineyard. In the treatment with plowed farmyard manure, the soil structure stability decreased, during 2010. In this case, humic substances stability had a statistically significant influence on soil structure stability. The lower the values of color quotient of humic substances in soil were, the lesser was the decrease in soil structure stability.