Impacts of agricultural intensification on soil erosion and sustainability of olive groves in Alentejo (Portugal)

Abstract

Context: Olive groves are key features of Iberian Mediterranean landscapes. With the intensification of olive grove production, some negative environmental impacts on soils must be considered to achieve farm sustainability. Objectives: To estimate, theoretically and empirically, soil erosion in olive groves of Alentejo (Portugal) considering different planting densities and soil managements (i.e. conventional, integrated, organic), and related impacts on soil loss and farm sustainability. Methods: Soil erosion was empirically calculated using sediment traps. Soil loss was modelled using the Universal Soil Loss Equation (USLE) model. The impact of erosion on farm sustainability was assessed by simulating future projections to 100 and 500 years. Results: An overestimation of theoretical erosion rates for all olive management models compared to the empirical results was observed. Plant cover strongly contributed to reduce soil loss. Temporal simulations based on experimental data showed a longer sustainability of intensive groves than expected according to theoretical values. Conclusions: Despite the negative impacts of intensive agriculture, this study highlights that it is essential to consider soil management impacts on erosion, an aspect that influences farm sustainability, regardless of planting density. Future studies should expand our experiments across a wider sample and locations of olive groves, to better discern how olive sustainability is impacted by different agricultural management options and decisions.