Liguria's terraced hillsides represent one of the most labour-intensive agricultural landscapes in Italy. The dry-stone terrace walls — called ciàn in the local dialect of the Cinque Terre — were built over many centuries to convert steep coastal slopes into viable growing surfaces for vines, olives, and kitchen gardens. The soil on these terraces is largely artificial in the engineering sense: it was carried up the hill or redistributed from natural accumulation points on the slope, retained by the stone walls, and maintained over generations through intensive management.
From the mid-20th century, large-scale abandonment of terrace cultivation — driven by the economic unattractiveness of hillside farming relative to coastal tourism and light industry — left many terrace systems unmaintained. Wall collapses, erosion, and the progressive deterioration of the accumulated soil layer followed. Soil recovery on these surfaces, where recovery has been attempted, presents a distinct set of challenges that differ markedly from the flat-field fallow dynamics of Tuscany or the Po Valley.
Composition and Characteristics of Terrace Soils
Studies conducted by the University of Genoa's Department of Earth Sciences in the 2000s characterised the soil profiles on maintained and abandoned terraces in the Cinque Terre area. Active terraces under vine cultivation showed a shallow but moderately well-structured topsoil (typically 20–35 cm) with organic matter content maintained by regular addition of composted grape marc, olive prunings, and — historically — seaweed collected from the shore and carried up the slopes.
The mineral base was typically coarse schist-derived sand and gravel, with low clay content and rapid drainage. This made the terraces productive for drought-adapted crops but highly vulnerable to nutrient leaching when organic matter additions ceased. On abandoned terraces, organic matter levels dropped to below 1% in topsoil samples taken 10–15 years post-abandonment, compared to 2.8–4% on actively managed terraces in the same area.
The Role of Seaweed Additions
Pre-modern Ligurian terrace farming had a characteristic nutrient input that is largely absent from documented mainland Italian rotation systems: regular application of collected seaweed (poseidonia and sargasso) from the local beaches. Census records from several Cinque Terre villages from the 18th and 19th centuries include references to organised seasonal seaweed collection as part of agricultural preparatory work. The seaweed served both as a mineral supplement — particularly for potassium — and as a mulch that reduced moisture loss from the coarse terrace soils during the dry summer months.
This input ceased as commercial fertilisers became available in the early 20th century and as the collection of seaweed became impractical with the reduction in agricultural labour. Its absence, combined with reduced organic amendments generally, is cited in the University of Genoa soil surveys as a contributing factor to the observed organic matter decline on marginal and abandoned terraces.
Abandonment Dynamics and Erosion Patterns
When terrace maintenance ceases, the sequence of deterioration is relatively predictable based on documented cases in the Cinque Terre, the Ligurian Riviera di Levante, and the Val di Vara inland zone. The first phase — typically within two to five years of abandonment — involves the emergence of spontaneous vegetation: annual grasses, brambles, and scrub. This provides some erosion protection but exerts root pressure on wall joints.
Wall collapse tends to begin at weak points — typically where drainage outlets have become blocked or where the foundation stone has shifted on the clay-rich subsoil that underlies some terrace sections. A single wall collapse can trigger a cascade, since each terrace depends on the structural integrity of the one above it to retain the soil load. Documented collapse events in the Cinque Terre National Park, particularly those accelerated by heavy autumn rainfall, have removed entire terrace sequences within a single storm.
"The loss of a wall is rarely the loss of one wall. On a slope of 35 degrees, the load transfer means the next terrace receives what the collapsed one was holding."
From a land survey report, Parco Nazionale delle Cinque Terre, 2012
Documented Recovery Techniques
Recovery of abandoned terraces, where it has been systematically attempted, follows a sequence that addresses structural, soil physical, and soil chemical conditions in that order.
Wall Reconstruction and Drainage Restoration
Without intact retaining walls, soil recovery is temporary. The dry-stone wall rebuilding work recorded in Cinque Terre recovery projects — supported in part by the Parco Nazionale and Regional funds — documents wall reconstruction costs averaging 90–130 euros per linear metre at 2020 prices, almost entirely representing skilled labour. Qualified muretti a secco wall builders are increasingly scarce; the technique is classified as Intangible Cultural Heritage by UNESCO as of 2018, partly in recognition of this knowledge-loss risk.
Drainage restoration involves clearing the bocchette — small outlet channels built into the lower wall courses — which typically require cleaning of accumulated fine sediment and root material. Blocked drainage causes waterlogging behind the wall face, which is the principal cause of frost-related wall instability in the higher inland terraces.
Soil Physical Recovery
On terraces where wall integrity has been restored but the soil surface has been disturbed by vegetation clearance or partial erosion, the primary intervention is mechanical loosening of the compacted upper layer. On narrow terraces where mechanised equipment cannot access, this is done by hand with a zappa or fork. Wider lower-slope terraces in the Val di Vara area have occasionally been accessible to a walking-tractor-mounted rotavator.
Deep compaction from 15 years of natural vegetation mat and root penetration creates a distinct hardpan layer at the depth where the old plough layer once ended — typically at 20–25 cm on vine terraces. Breaking this layer is reported as essential before any cover crop or re-establishment crop can develop adequate root structure. Trials in the Cinque Terre area from 2015–2019, conducted in cooperation with CREA's liguri branch, found that terraces receiving deep mechanical loosening before cover crop establishment showed significantly better recovery in topsoil structure after two seasons than those receiving only surface scarification.
Organic Matter Rebuilding and Cover Crops
Rebuilding organic matter on recovered terraces has been approached through several documented pathways. Green manure crops — principally phacelia, field mustard, and vetches — were trialled on accessible terraces in the Cinque Terre recovery programme from 2016. These crops are turned in before seeding to seed, returning biomass directly to the soil. On the coarse terrace soils, where organic matter mineralisation is rapid, a single green manure crop produces visible improvement in soil structure within one growing season, though the organic matter percentage returns to baseline rapidly without repeated inputs.
The reintroduction of composted seaweed — sourced now from certified coastal collection rather than informal beach gathering — was piloted on three terraces in the Vernazza area in 2018. Initial results showed a measurable improvement in cation exchange capacity in topsoil samples after one application cycle, consistent with the potassium and mineral content of the material.
Long-Term Prospects and Current Status
The scale of abandoned terrace in Liguria — estimated at 70–80% of the historic terrace area by regional land use surveys published in the 2010s — means that systematic recovery across the whole landscape is not realistic within current economic and demographic constraints. What has been attempted is concentrated on the most visible, culturally significant zones (Cinque Terre) and on terraces where vine or olive production can generate sufficient returns to service the ongoing maintenance cost.
Research published in the FAO Soils Portal and in the European Journal of Agronomy (2021) documents the Ligurian terrace case as an example of a landscape where agricultural abandonment has produced soil degradation on a scale comparable to active erosion in equivalent rainfall zones without terracing. The comparison highlights that the terrace system itself, while requiring maintenance, was performing significant soil conservation work that has been lost with abandonment.