Conservation scenarios for olive farming on sloping land in de Mediterranean

Research output: Thesisinternal PhD, WU


The future of olive farming on sloping land in the Mediterranean is uncertain. Sloping and Mountainous Olive Production Systems (SMOPS) that have been sustainable for ages have in a relatively short time frame witnessed major changes. Although remnants of many of these traditional landscapes still exist today, the general trend is different. Demographic changes of the rural population, integration in the market economy with its competitive character, and technological innovation have drastically changed both the local economy, its agricultural production systems and – as a consequence – its environment. As a result of differential developments, there is now a stratification of SMOPS. While some production systems can continue to compete on global markets, other mostly traditional olive groves will need to rely on other than productive functions only. Of an increasing number of functions, the importance is recognised by stakeholder groups at various levels or by society as a whole. This awareness also extends to those systems that continue to be economical, but which need special attention to conserve functions that could get lost in the process of intensification. The present research project searches to develop an integrated methodology addressing these problems and to assess its performance for different scenarios of SMOPS. It addresses the following objectives: 1.      Making an inventory of SMOPS and their natural resource conservation issues; 2.      Developing a function assessment methodology and analyzing the various functions of SMOPS; 3.      Taking soil conservation as an example function, exploring the importance of soil erosion in SMOPS and assess how it can be controlled; 4.      Developing scenarios based on a set of core functions identified by stakeholders; 5.      Optimizing environmental and social performance of SMOPS in conservation scenarios The first objective is embarked upon in Chapters 2 and 3. While olive production is an important agricultural activity throughout the Mediterranean, soil erosion is one of the environmental key problems in this zone. Due to their location on sloping land, erosive rainfall patterns, erodible soils and deficient ground cover, erosion risk in olive production areas is high. Chapter 2 identifies those areas where olive cultivation can be considered to be SMOPS, and inventories soil and water conservation options for olive orchards with particular reference to five important production areas: Eastern Andalusia (Spain), North-eastern Portugal, Southern Italy, Crete (Greece) and Central-West Tunisia.  Chapter 3 analyses the link between SMOPS and natural resource management issues in more detail. It starts off with the notion that a wide variety of olive plantation systems exists throughout the Mediterranean, especially in sloping and mountainous areas. Recent drivers of change, including the widespread introduction of mechanisation, increased use of (chemical) inputs and (drip-)irrigation have still augmented this variety. It is postulated that the various systems have very different resource use patterns and environmental and social performances. Based on a comprehensive case study in six study areas: Trás-os-Montes (Portugal), Córdoba and Granada/Jaén (both in Spain), Haffouz (Tunisia), Basilicata/Salerno (Italy) and West-Crete (Greece), a cluster analysis is applied to classify 28 SMOPS distinguished regionally. This analysis resulted in the classification of 6 types of SMOPS along an intensity of production gradient: 1) very extensive, 2) traditional extensive, 3) semi-intensive low input, 4) semi-intensive high input, 5) intensive, and 6) organic. Natural resources management options to address soil erosion, low biodiversity, wildfire risk and excessive water use are explored for each of these systems. Chapter 4 presents one of the distinguished SMOPS types in detail: traditional extensive (or simply: traditional) olive orchards account for a large share of the area under olives in the Mediterranean, particularly in marginal areas. Traditional SMOPS are characterised as a low-intensity production system, associated with old (sometimes very old) trees, grown at a low density, giving small yields and receiving low inputs of labour and materials. During the OLIVERO project, traditional olive production systems were identified and described in five target areas: Trás-os-Montes (Portugal), Córdoba and Granada/Jaén (Spain), Basilicata/Salerno (Italy), and West-Crete (Greece); the latter of which was in a supra-regional classification later reclassified as a semi-intensive low input SMOPS (Chapter 3). Though traditional SMOPS provide multiple environmental services, their economic viability has become an issue, especially in southern Europe where EU policies favour more intensive and competitive systems. Orchards that have not been intensified seem to be threatened by the recent reform of the EU olive and olive oil policy, as income support, now decoupled from production, is based on past production in a four-year reference period. As a consequence, traditional olive growing is at risk of abandonment. Chapter 4 concludes that the viability of these systems is only assured if reduced opportunity costs for family labour are accepted and the olive growing is part-time, and recommends some private and public interventions to prevent its abandonment. While Chapter 4 anticipates on the functions of traditional olive groves, a framework for the analysis of the multiple functions of SMOPS (Objective 2) is presented in Chapter 5. Multifunctionality in agriculture has in the last decade received a lot of attention from researchers and policy-makers. Focusing on a case study about SMOPS in north-eastern Portugal, methods are discussed on how to deal with studying multiple functions of agro-ecosystems. The “House of Functions” is presented as a function assessment method. By depicting performance of ecological, productive, economic, social and cultural functions on axes together forming the silhouette of a house, the method could supposedly appeal to a wide range of actors. In the case study, we conclude that regional SMOPS particularly fall short in supplying ecological functions. They do however contribute significantly to the local economy, generate employment and perform an important cultural role in maintaining the landscape, and are thus a key to regional development and to stop outmigration of the population. Policy-makers could use the function assessment tool to design effective cross-compliance rules and relevant agri-environmental measures (AEM) to enhance ecological and social functions, and to communicate ideas to other stakeholders. As such, it can reinforce decision-making by visualizing trends, development alternatives or scenarios. The role of research in this method is facilitating dialogue between stakeholder groups and feeding the process with relevant indicators. Chapter 6 subsequently focuses on a single function: soil conservation, and explores how well olive groves perform this function (Objective 3). A literature review provides a pessimistic view of the capacity of SMOPS to conserve the soil, with some average regional soil loss values supposedly as high as 40 – 100 ton ha-1 y-1. These figures are based on empirical models that apply a simple multiplication of adverse environmental factors such as steep slopes, erodible soils and low vegetation cover. We present experimental data from rainfall simulations, runoff plot studies and field assessment of erosion symptoms that challenge this view. We point at the effects of surface roughness from tillage, rock fragment cover on steep slopes, orchard undergrowth, slope irregularities, vegetative strips, and of erosion resulting mainly from infrequent high intensity rainfall events, and (erroneous) upscaling of experimental results. Although these factors act and/or interact at different scales, taken together they provide an argument for indicating more precisely when, where and for whom erosion constitutes a problem. Combining the findings from our individual experiments, Chapter 6 concludes that tillage applied judiciously in selected locations of an orchard might reduce erosion. Localised erosion may still be controlled at field level by vegetative strips. Our results suggest that average soil erosion rates are unlikely to surpass 10 ton ha-1 y-1, which is nevertheless still more than the soil renewal by weathering (about 1 ton ha-1 y-1). Any recommendations for improved soil management should ideally be tested at the appropriate scale and should capture the climatic (rainfall) conditions under which they are intended to mitigate soil erosion problems. This brings us to Chapter 7, which concentrates on scenario development with stakeholders for olive orchards in the five Olivero target areas (Objective 4). The first step in scenario development is in fact the establishment of a typology of SMOPS (Chapter 3), as their future perspectives differ. The next step is to perform a SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis. Departing from the SWOT, a general overview is given of the medium- and long-term prospects. These have been validated by experts from the olive sector and foresee changes towards abandonment, intensification and organic production. On balance, the changes could lead to lower production of some target areas in future. An analysis of major external factors affecting the future development of SMOPS indicates there will be labour shortages and increased wage rates, reduced subsidies and constant or rising olive oil prices. On the basis of these assumptions, four future scenarios are developed for the five target areas, with the help of a Linear Programming (LP) simulation model. The results are presented for two target areas. For the Trás-os-Montes target area in Portugal, three of the four tested scenarios point to a high level of abandonment, while in the most positive scenario the areas under semi-intensive low input and organic SMOPS increase. In the Granada/Jaén target area in Spain, all scenarios hint at intensification, and only the orchards on the steepest slopes are likely to be abandoned.  The direction and extent of environmental effects (erosion, fire risk, pollution, water use and biodiversity) differ per scenario, as do the extent of cross-compliance and AEM. In Chapter 8, the LP model and scenarios of Chapter 7 are taken as a point of departure for a further methodological development and optimization of environmental and social performance of SMOPS (Objective 5). It presents alternative (multiple) goal programming (GP) models that take into account two perspectives: a farmer’s and that of the society at large. The two perspectives represent hierarchical levels mutually dependent on each other to achieve best performance of the SMOPS from their perspective. A weighted GP model from a farmer’s perspective – in short WGP (F), in which income represents half of the total weight of criteria, scored best on income and environmental and social objectives under all scenarios. Further analysis using the WGP (F) model showed that the scenarios have an important effect on SMOPS performance from a farmer’s, but not from a societal perspective. Current cross-compliance conditions and AEM give more incentives to reduce the negative environmental impact of (intensive) farming than to enhance the positive functions of traditional agriculture or reduce the negative effects of abandonment. SMOPS under more constrained and disadvantaged positions are burdened with additional policy requirements, while those with intensification potential (under favourable conditions) are not and may opt to participate in attractive AEM schemes. The effectiveness of cross-compliance and AEM can be improved by: a) removing substantial overlap between them; b) shifting focus of cross-compliance conditions more to intensive SMOPS, e.g. by the inclusion of IPM, or design additional conditions for them; c) shifting focus of AEM more to extensive SMOPS or design additional measures for them, e.g. by inclusion of biodiversity aims; and d) increase incentives for farmers to adhere to or comply with the policies, for example by giving awards to ‘good’ farmers. Chapter 9 recapitalizes the findings from previous chapters. It argues that with the full integration of the olive sector in the single farm payment scheme, an opportunity has been missed to promote low intensity olive farming. What functions are valued is context-dependent and science plays a facilitating role. The concept of conservation scenario is coined as an iterative learning process to facilitate adaptation to factors beyond decision-makers’ control. After all, we better build a house on a solid foundation of knowledge…  
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
  • Stroosnijder, Leo, Promotor
  • de Graaff, Jan, Co-promotor
Award date7 Sep 2007
Place of Publication[S.l.]
Print ISBNs9789085047179
Publication statusPublished - 2007


  • olea europaea
  • olives
  • production
  • sloping land
  • mediterranean region
  • conservation
  • erosion
  • sustainability
  • agroecosystems

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