Evolution of soil organic carbon in an olive orchard under arid climate

Soil organic carbon (SOC) variation was followed in an olive orchard covering 134 ha during six years. Spatial and temporal variation models were adapted and developed in order to detect heterogeneity of SOC spatial distribution and mineralization rate. These parameters allow adaptation of cultural practices, i.e. organic fertilization, to field reality. Indeed, the detection of spatial variability of SOC identified zones needing urgent organic fertilization. Moreover, the variability of SOC mineralization rate facilitated the choice of the organic fertilizer type. The spatial variability and temporal variation of SOC were assessed and modeled. At the orchard level SOC shown an important spatial variation (CV = 28%) following the spherical distribution model. The developed models for temporal variation was calibrated and validated and gave acceptable results (R2 = 0.79). These kinds of models can be used as decision support systems for fertilization and soil fertility management and are necessary for impact of this management forecasting and long-term strategy implementation at orchard level.

► Soil organic carbon of an arid soil was spatially modeled in one olive orchard.
► Soil organic carbon mineralization rate was described precisely in one olive orchard.
► A simple model was adapted to forecast SOC evolution.
► Combination of spatial and temporal models give a precise picture of the situation.