Area characterisation:
The Montilla-Moriles PDO encompasses 5,000 hectares of vineyards with an average farm size of 2.3 hectares. The terrain features laminar soil structures with slopes requiring consideration for erosion management. The climate brings high-intensity rainfall events in autumn and spring that cause significant soil wash-away, with gullies being typical features of the landscape. Most vineyards use traditional management without trellis systems, which complicates cover crop implementation. The average vineyard operates on moderate slopes with trellis systems and no irrigation for modelling purposes.
Objective:
To compare the profitability and cost-effectiveness of three soil management scenarios (conventional tillage, temporary cover crops, permanent cover crops) in Montilla-Moriles vineyards, incorporating both private on-site erosion costs borne by farmers and social off-site costs borne by society, to inform policy decisions about agri-environmental subsidies for erosion control.
Context:
Challenges addressed
The measure addresses environmental management of soil erosion on sloping vineyards, which also drains nutrients, organic matter and soil biodiversity.
Financing:
Costs of NbS
Switching from conventional tillage to permanent cover crops between vine rows across about 5,000 ha raises management costs by about EUR 166 per ha per year (2023 prices).
Potential impacts/benefits:
Cover crops cut the amount of soil lost from each hectare every year, keeping nutrients, organic matter and water in the vineyard. This also avoids off-site damage from sediment and protects soil biodiversity and the ecosystem services it supports. Counting the social costs of erosion on and off the farm, cover crops avoid losses of about EUR 367 per ha per year (2023 prices).
Benefit–cost ratio
This gives a BCR of 2.21, even before cultural and aesthetic benefits are valued. For individual winegrowers, however, private savings alone do not cover the extra costs.
Actions:
- Field surveys conducted across sixteen vineyards (eight for each of the two most common soil management techniques) to collect topographic, soil, cover and management information.
- Daily climate data for 16 years (2000-2015) obtained from nearby weather stations.
- The ORUSCAL tool calibrated using strategy incorporating soil moisture subfactor to assess erosion risk under different management scenarios.
- Policy Analysis Matrix constructed using farm budgets adjusted for inflation to 2016 values, incorporating input-output prices, subsidies, and monetised erosion costs from literature.
- Sensitivity analysis conducted on output prices, labour costs, variable machinery costs and erosion costs.
Contacts:
Study overview
Montilla-Moriles is a Protected Designation of Origin (PDO) wine region in Andalusia, southern Spain, comprising approximately 5,000 hectares of vineyards managed by around 2,000 winegrowers. The region produces 276,000 hectolitres of white wine annually, with 90% sold on the domestic market. Vineyards are typically situated on slopes where bare soil management predominates, intensifying erosion and leading to significant losses of nutrients, organic matter, water and soil biodiversity.
The region experiences a semi-continental Mediterranean climate with an average annual precipitation of 604 mm and a mean annual temperature of 17.2°C. Soils are predominantly Luvisols and Cambisols with high carbonate content. Despite the erosion risk, only about 10% of vineyards currently use temporary vegetation cover during autumn and winter months. The economic situation for winegrowers is challenging as grapes are sold mostly to cooperatives at low prices (approximately €0.30 per kilogram), and the region faces competition from both Jerez wines and more profitable olive and almond orchards.
Research conducted through the VineDivers project compared three soil management scenarios using the ORUSCAL erosion model and Policy Analysis Matrix: conventional tillage (bare soil), temporary cover crops during autumn-winter, and permanent cover crops throughout the year. The study incorporated both private on-site costs borne by farmers and social off-site costs affecting broader society, including infrastructure damage and environmental impacts.