Is the hillslope position relevant for runoff and soil loss activation under high rainfall conditions in vineyards?

Abstract

In agricultural lands, the way in which slope position affects the detachment of material and the runoff generation is not clear. There are complex interactions between slope position, slope gradient and a series of soil characteristics, and their impact on runoff generation and soil erosion may vary from site to site. We designed an experiment to investigate the initial hydrological responces of soils located on different slope positions (footslope, backslope and shoulder) in runoff and soil detachment generation. To achieve these goals, 25 high-intensity low frequency rainfall events were simulated in experiments with a return period of 5 years, on 0.25m2 circular plots to measure the detachment along a hillslope in the Celler del Roure vineyards in Eastern Spain. The results of this investigation showed that soil erosion rates (3Mgha−1h−1) were high and there were no significant differences between sites in relation to slope position; all the plots generated runoff (runoff coefficient of 24.8%). These results allow us to conclude that soil detachment and runoff generation in Mediterranean vineyards, where tillage is millennia-old management practice, could be also evenly distributed. Therefore, the used management practices in these vineyards contribute to creating net source areas of runoff and erosion with no areas that could act as a sink under intensive rainfall events. Based on our research and a literature review, we propose to implement nature-based solutions that would contribute to reducing soil erosion in agricultural land by creating sink areas in the form of hedgerows, ponds, or vegetation strips where the surface wash deposits and water can sediment and infiltrate. We also discussed other management practices contributing to reduction of erosion,such as mulching and inter-row crops. We state that there is an urgent need to apply strategies to reduce soil loss in vineyards.