Treatment of Steep and Clayey Soils with Olive Pruning Residues for Conservation Purposes: Hydrological Monitoring and Modelling Approaches

This study evaluates and models the hydrological response of a steep and clayey olive grove of Southern Italy under three Soil Management Practices (SMPs, mechanical tillage “MT”, mulching with 3500 kg/ha of pruning residues “M”, and standard protection of soil “SP”). The saturated hydraulic conductivity, Ksat, surface runoff and soil loss have been evaluated after 26 natural rainfalls at the plot scale throughout two years. Moreover, the accuracy of the SCS-CN and USLE-M models in predicting runoff volume and soil loss has been evaluated for the three SMPs. The MT showed the lowest Ksat (on average 45%, compared to SP), and the highest runoff coefficient (+9%) and soil loss (+130%). M increased the Ksat by 26%, and reduced runoff coefficients and soil loss (-13% and -43%, respectively) compared to SP. The SCS-CN model was accurate in predicting runoff for all SMPs, and its performance increased after CN calibration. The erosion predictions using USLE-M running with default C-factors were inaccurate. Calibration of this parameter gave a good prediction performance, especially in M plots.