In-depth analysis of soil management and farmers’ perceptions of related risks in two olive grove areas in southern Spain

José A Gómez,Ana Sánchez Montero,Gema Guzmán,María-Auxiliadora Soriano

doi:10.1016/j.iswcr.2021.01.003

Abstract

This manuscript presents a questionnaire-based study aimed to provide a detailed analysis on the different soil management carried out by olive farmers in two representative olive-growing areas in southern Spain (Cordoba and Estepa), their perceptions on cover crop use and the possible influence of the different types of farms and farmers’ typologies on these perceptions. Our results show a relatively large variability of soil management, with fourteen options, as a result of a combination of different alternatives for bare soil and cover crops with the use or not of pruning residues, but with a great similarity between both areas. The results indicate a high adoption of soil conservation measures in the two study areas, with 63% of farmers using cover crops and 80% a mulch of pruning residues, higher than that reported in previous studies in Southern Spain, and a trend of lower use of these techniques by less experienced and younger farmers. This high penetration of soil conservation measures resulted in a significant reduction of soil erosion risk, as indicated by the relatively low values for the cover and management factor (C) of RUSLE, also calculated and presented in this study, but also the possibility of focusing further efforts on farmers with less experience. Our results indicate the persistence of a minor, but relevant, percentage of farmers using bare soil management (37%) and no mulching (20%), with a moderate concern on the impact of soil erosion on soil degradation and provision of ecosystem services. This suggests the need to concentrate efforts also on this cluster of farmers to enhance the success of what seems to be a remarkable expansion of the use of soil conservation measures in recent decades in Southern Spain, but also in similar areas in the Mediterranean basin.

Highlights

Olive trees cover approximately 10.5 Mha worldwide (FAOSTAT, 2020)
This indicates again that there is a cluster of olive farmers to whom training and awareness efforts to enhance the adoption of soil management practices best adapted to the provision of ecosystems services, should be focused - probably with a different, or complementary, approach than the one followed to date. It is apparent from the limitations perceived by farmers in this study, that efforts to enhance the availability at a lower cost of seed for cover crops, and facilitating the use of mowers, for farmers combining them with pruning residues, should be given priority in RþDþi future efforts of soil conservation in olive groves. This manuscript presents the results of a detailed analysis of different soil management carried out by farmers in two representative olive-growing areas in southern Spain (Cordoba and Estepa)
The results indicate a high incorporation of soil conservation measures in both olive-growing areas, 63% of farmers using cover crops and 80% a mulch of pruning residues, higher than those presented in previous studies in Andalusia (Southern Spain)

Summary

Introduction

Olive trees cover approximately 10.5 Mha worldwide (FAOSTAT, 2020). This area is larger than the cultivated area of other widely distributed woody crops such as vineyards or apple trees, 7.2 and 4.9 Mha respectively, smaller than the area devoted to field crops for vegetable oils like soybean or sunflower, 124.9 and 27.5 Mha, respectively (FAOSTAT, 2020). Due to the climatic requirements of olive trees, around 95% of the total area is cultivated in the Mediterranean basin and seven countries concentrate 84% of the olive grove area (Spain, Tunisia, Italy, Morocco, Greece, Turkey and Syria, in order of decreasing extension). In these countries olive is a major cash crop, having municipalities where olive groves occupy more than 70% of all available land (e.g. some areas in southern Spain, REDIAM, 2020). Olive acreage has grown steadily over the last decades worldwide, with an average annual increase of 5.7% since the early 1960’s (FAOSTAT, 2020) as a response to the increasing demand for olive oil In parallel to this market success, olive cultivation has been associated with several sustainability problems Among these sustainability issues are a reduction of biodiversity, overexploitation of water resources, decreasing profitability for farmers, offsite contamination, and soil degradation by accelerated water erosion processes (Gomez, 2009)

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Results

Discussion

Conclusion