|Novák, TJ; Incze, J; Spohn, M; Glina, B; Giani, L: Soil and vegetation transformation in abandoned vineyards of the Tokaj Nagy-Hill, Hungary, Catena, 123, 88-98 (2014), doi:10.1016/j.catena.2014.07.017|
Two chronosequences, one south (S-sequence) and one southwest (SW-sequence) with differing times since their abandonment (193, 142, 101, 63, 39 and 14 years), were studied on Tokaj Nagy-Hill. The sites were investigated in respect of vegetation characteristics, soil physico-chemical characteristics, total organic carbon stocks (TOC stocks), accumulation rates of total organic carbon (TOC accumulation rates), and soil profiles, which were classified according to the World Reference Base (WRB) 2007. The S-sequence was 25–35% sloped and strongly eroded, and the SW-sequence was 17–25% sloped and moderately eroded. Vegetation development at the S-sequence resulted in shrub-grassland mosaics, supplemented by protected herb species and forest development at the earliest abandonment. The SW-sequence was predominantly covered by forest vegetation, and trees were absent at the 63 and 14 year old abandonment sites. Soils of the S-sequence show shallow remnants of loess cover with redeposited soil materials containing 15–65% skeletal volcanic rock of weathering products coated by secondary calcium carbonates. The SW-sequence profiles are developed on deep loess or loess derivatives. The calcium-carbonate content was higher in profiles of the S-sequence (18.1 ± 10.4%) than in the SW-sequence (6.7 ± 2.7%); consequently, the pH of the topsoil was higher in the S-sequence, and correlated significantly negatively with the age of abandonment in both sequences (r= −0.893; p= 0.01 in S, and r= −0.739; p= 0.05 in SW). TOC stocks of the top 6 cm soil layers were higher in the S slope (1.82 ± 0.71 kg m−2) than in the SW-sequence (0.95 ± 0.49 kg m−2), and correlated significantly positively with the duration of abandonment. When calculated for the whole profile, TOC stocks were similar in both S- and SW-sequences (S: 8.21 ± 3.31 kg m−2; SW: 8.24 ± 6.01 kg m−2). The TOC accumulation rates of the top 6 cm soil layers exhibited 18.9 ± 10.0 g C m−2 y−1 in the S and 7.0 ± 4.2 g C m−2 y−1 in the SW-sequence. Sites with the same age of abandonment showed different vegetation and soil features in both chronosequences, indicating that time is not the most decisive factor in soil transformation processes after abandonment of viticulture on Tokaj Nagy-Hill. Additional directing factors were slope steepness and exposition.