Water stability of soil aggregates and their ability to sequester carbon in soils of vineyards in Slovakia

Abstract

Soil water-stable aggregation is an important process for carbon sequestration and is a key factor controlling soil sustainability and resilience; therefore, the objectives of the present study were to (1) evaluate the differences in soil organic matter state, its specific and labile fractions and their importance in the formation of water-stable aggregates in vineyard soils differing in their genesis and texture under different soil management (vineyard rows – tilled and grassed in-between strips), and (2) estimate the ability of the vineyard soils to sequester soil organic carbon (SOC) into water-stable macro-aggregates (WSAma). The results showed that the WSAma content of the soils ranged from 47% to 97%. Soils with grasses had a higher SOC and labile carbon (CL) contents than the bulk soil and, as a result, the higher total WSAma content. Soils ranged in a decreasing order in their ability to sequester SOC and CL from bulk soil to WSAma: Haplic and Stagni-Haplic Luvisols > Calcaric Fluvisol = Rendzic Leptosol > Haplic and Luvi-Haplic Chernozem > Dystric and Eutric Cambisols. Our results showed that the maximum ratio of SOC content in WSAma to that in bulk soil was 1.0 at the maximum WSAma content regardless of the soil type. An increase in the ratio above this threshold value (1.0) resulted in a decrease in WSAma content.