Estimating Non-Sustainable Soil Erosion Rates in the Tierra de Barros Vineyards (Extremadura, Spain) Using an ISUM Update

Abstract

Monitoring soil erosion processes and measuring soil and water yields allow supplying key information to achieve land degradation neutrality challenges. Vineyards are one of the most affected agricultural territories by soil erosion due to human and natural factors. However, the spatial variability of soil erosion, the number of sampling points, and plot size necessary to estimate accurate soil erosion rates remains unclear. In this research, we determine how many inter-rows should be surveyed to estimate the soil mobilization rates in the viticulture area of Tierra de Barros (Extremadura, SW Spain) using the Improved Stock Unearthing Method (ISUM). This method uses the graft union of the vines as a passive biomarker of the soil surface level changes since the time of plantation and inter-row measures. ISUM was applied to three inter-row and four rows of vines (5904 sampling points) in order to determine how many surfaces and transects must be surveyed as all the previous surveys were done with only one inter-row. The results showed average values of soil depletion reaching −11.4, −11.8, and −11.5 cm for the inter-rows 1, 2, and 3, respectively. The current soil surface level descended 11.6 cm in 20 years. The inter-rows 1, 2, and 3 with a total area of 302.4 m 2 each one (2016 points) recorded 71.4, 70.8, and 74.0 Mg ha −1 yr −1 , respectively. With the maximum number of sampling points (5904), 71.2 Mg ha −1 yr −1 were obtained. The spatial variability of the soil erosion was shown to be very small, with no statistically significant differences among inter-rows. This could be due to the effect of the soil profile homogenization as a consequence of the intense tillage. This research shows the potential predictability of ISUM in order to give an overall overview of the soil erosion process for vineyards that follow the same soil management system. We conclude that measuring one inter-row is enough to get an overview of soil erosion processes in vineyards when the vines are under the same intense tillage management and topographical conditions. Moreover, we demonstrated the high erosion rates in a vineyard within the viticultural region of the Tierra de Barros, which could be representative for similar vineyards with similar topographical conditions, soil properties, and a possible non-sustainable soil management system.

Effect of plot size and precipitation magnitudes on the activation of soil erosion processes using simulated rainfall experiments in vineyards

“…In the past, soil loss and surface runoff have also been studied using different plot sizes by researchers in other countries investigating vineyards (Rodrigo-Comino et al, 2019) and other land uses, such as grasslands and subtropical environments (Thomaz and Vestena, 2012;Mayerhofer et al, 2017). We have reported that runoff on a small plot was about 30% higher in our experiments than on large plots, but that the soil loss was approximately the same for small and large plots under natural rainfall.…”

“…It is clear that different results might be obtained when the plot size increases. In vineyards, tests were recently carried out by Rodrigo-Comino et al (2019) using ISUM (Improved Stock Unearthing Method) in the viticultural area of Tierra de Barros (Extremadura, Spain). The authors demonstrated that measurements of soil loss on plots from 300 to 900 m 2 in size, may result in differences of about 3 t ha −1 yr −1 .…”

The 3Ps (Profit, Planet, and People) of Sustainability amidst Climate Change: A South African Grape and Wine Perspective

“…Research has suggested that soil loss in vineyards is above the level that amounts to tolerable soil loss, less so for older vineyards with more organic matter content and higher bulk density in relation to younger vineyards [125] Moreover, accurately measuring soil loss in vineyards is fraught with difficulties, because different methodologies available tend to give different results. Thus, there is a need to improve the accuracy of measurements [126]. However, research has shown that there are various practices to mitigate the effects of soil erosion such as terracing, sediment fences, check dams, grass margins, contour farming, and the use of cover crops [127,128].…”

A Bibliometric Analysis on Land Degradation: Current Status, Development, and Future Directions

“…Accurately monitoring soil erosion processes and measuring soil and water yields can provide key information for achieving land-degradation neutrality. For example, Rodrigo-Comino [17] considers vineyards to be one of the agricultural areas most subject to human and natural factors. However, the spatial variability of soil erosion, the number of sampling points, and the size of the plot required to accurately estimate soil erosion rates remain unclear.…”

“…However, the spatial variability of soil erosion, the number of sampling points, and the size of the plot required to accurately estimate soil erosion rates remain unclear. In view of this, Rodrigo-Comino [17] used the improved stock unearthing method (ISUM) to analyze the soil erosion rate of Tierra de Barros (Extremadura, Spain). The results of the study found that the spatial differences in soil erosion were small, and the differences between rows were not statistically significant.…”