Analyzing long-term soil erosion in a ridge-shaped persimmon plantation in eastern Spain by means of ISUM measurements

Graft unions of cultivated plants have been used as passive bio-indicators to assess long-term soil erosion rates. By taking complementary topographical measures in inter-row areas, soil erosion can be more accurately estimated as done with the Improved Stock Unearthing Method (ISUM) in vineyards. As vines are not the only plants that are grafted, ISUM could be also applied to other crops. Most fruit trees are planted in ridges and our objective was to test if ISUM could be applied in a ridge planted persimmon plantation. This update in the methodology will allow the scientific community to expand measurements that will contribute to assessing soil erosion processes in intensive and non-sustainable plantations, where soil erosion is a key factor of land degradation. To achieve this goal, we carried out the research in a persimmon orchard plantation located in Canals municipality, Valencia, eastern Spain. The current soil surface and mobilized soils were estimated using ArcGIS, MATLAB, and SolidWorks software. The data showed soil erosion of 55.9, 50.4, and 50.2 Mg ha(-1) yr(-1), using ArcGIS, MATLAB, and SolidWorks, respectively. In the inter-row areas, soil erosion reached 58.9 Mg ha(-1) yr(-1) with mean IS factor of 1.5. In the row areas, soil erosion was 37.2 Mg ha(-1) yr(-1). Overall soil erosion rates ranged from 34.5 to 69.6 Mg ha(-1) yr(-1). We discuss the effect of tillage and ridges on soil redistribution, and the contribution of ISUM to improve scientific knowledge due to its long-term assessment. We concluded that soil erosion in the orchard was extremely high, non-sustainable and that there is a need to apply soil conservation strategies.