Pig Slurry Management in Mediterranean Agriculture Under Real Farming Conditions: A Case Study in Southern Spain

Abstract

Pig slurry management is a challenge in livestock-intensive agricultural areas, where sustainable reuse requires field applications to be translated into measurable and controllable doses. This study evaluated a field-adapted calibration procedure for pig slurry application in a Mediterranean cereal field in southern Spain, particularly for spreading equipment without built-in dose-control systems. Slurry delivery was quantified by direct field collection and weighing and related to the number of tractor passes. Three management scenarios were evaluated: a non-amended control, one pass per application event, and two passes per application event. Soil properties were monitored before slurry application and during two subsequent sampling campaigns. Short-term responses were mainly observed in soil chemical properties, with increases in organic matter and total nitrogen after application and transient changes in available nutrients, whereas the evaluated physical properties showed temporal variation without a consistent slurry-specific pattern. Increasing slurry application did not consistently result in proportional or more persistent soil responses. Given the limited field replication, these findings should be interpreted as exploratory. Overall, the proposed calibration procedure provides a practical framework for converting tractor passes into measurable slurry and nutrient applications that can be adapted to local equipment, slurry characteristics, agronomic requirements, and regulatory conditions.