Ant Community Is Not Influenced by the Addition of Olive Mill Pomace Compost in Two Different Olive Crop Managements

SIMPLE SUMMARY: Olive oil production is the main economic interest in olive orchards, but this industrial process generates large amounts of a by-product called ‘alperujo’, which is very negative to the environment. When composted, it generates a product useful for fertilizing many crops, and the objective of the work was to evaluate its impact on the ant community in two diverse types of olive crop management: a superintensive grove (no-tillage, with a cover crop, irrigated) and a traditional grove (tillage, no cover crop, rain-fed). The main conclusion was that the addition of compost did not alter the presence of ants and the composition of the species in each grove, but the type of management could have influenced the abundance of ants (much more abundant in the superintensive than in the traditional grove) and, secondarily, the composition of the species. ABSTRACT: Industrial production of olive oil generates large amounts of solid waste called ‘alperujo’. Its compost can fertilize many crops, especially olives. Furthermore, superintensive orchards are increasing their surface globally due to higher production and savings in different costs. Ants are considered an important part of the arthropod community in olive orchards and could even play a significant role in pest control. The tree canopy and ground were sampled to compare the ant assemblage in plots fertilized with compost and mineral products in two groves with different types of crop management (superintensive and traditional) over two years. The numbers of ants in both types of fertilization in each grove were not statistically different (p > 0.05), indicating that the type of fertilization did not have a significant impact on its populations in the ground or in the canopy, but the number of individuals was significantly higher in the superintensive grove than in the traditional grove (both in the ground and in the canopy, p < 0.01). The most frequent species in the ground were Pheidole pallidula, Plagiolepis smitzii and Aphaenogaster senilis (superintensive grove) and Pheidole pallidula, Tetramorium gr semilaeve, Plagiolepis pygmaea, and Tapinoma nigerrimum (traditional grove). In the canopy, the most frequent species were Plagiolepis spp. in both groves. Differences in ant densities and species between the groves could be due to the different management, especially of the soil, but it must be confirmed using more replicas and longer periods of study.