The use of olive mill pomace compost increases the population of certain ground/soil organisms in olive groves

Olive is one of the largest crops in Spain, primarily for oil extraction from drupes. This process produces a by-product called ‘alperujo’, which can be composted and used as fertilizer. This study investigated the impact of ‘alperujo’ compost on ground/soil invertebrate inhabitants compared to mineral fertilization in two groves with different crop management types (superintensive and traditional) during 2021 and 2022. Anystidae/Erythraeidae (Acari; Trombidiformes) and Acari (Other) were more abundant in the compost treatment in both groves, but significant only in the superintensive grove. Some other ground/soil inhabitants, such as Anthicidae (Coleoptera), Araneae, and Gastropoda were generally more present in the compost treatment of the superintensive grove. No significant effect of fertiliser treatment was observed for other ground/soil organisms. Future studies with more replicas and over a longer period of time should be performed to confirm these results, but they can be considered of interest to push forward the implementation of ‘alperujo’ compost in the olive fertilization, favouring a circular economy and a sustainable agriculture.