No abstract

No abstract

Winemaking in Chile is a long tradition that is recognized around the world. It is especially important in the Maule region where more than 40% of the total wine in the country is produced. However, there is a lack of studies related to soil erosion in vineyards in Chile, especially considering the extreme rainfall events that occur in the country. This research estimates soil erosion mobilization rates before and after a rainy season between April 2020 and May 2020 using the "improved stock unearthing method" on two inter-row plots in a vineyard located in the Maule region of Chile. This method relies on the graft union as a bioindicator for assessing soil surface-level changes. Maps of the soil surface were obtained to show how soil depletion and accumulation points within the inter-row areas could be detected. It has been estimated that a total soil mobilization of 85.7 and 130 Mg ha yr À1 had occurred in the inter-row areas 1 and 2, respectively, since the establishment of the plantation. However, a single rain event mobilized soil at rates of 5.5 and 3.5 Mg ha yr À1 , respectively, in the inter-row areas 1 and 2. We have demonstrated that erosive processes present in the study area exceed the rates of soil formation and the tolerable rates of erosion on a global scale. The results allow re-thinking of agricultural practices and management of soil systems to improve the sustainability of conventional Chilean vineyards and their soils.erosion, improved stock unearthing method, sustainable agriculture, vineyards | INTRODUCTIONGlobally, about a third of the total arable land has been lost in the last 40 years due to erosion, and at an alarming loss rate of more than 10 million ha per year (FAO, 2015). Many recent investigations estimated that cultivated soils show severe or moderate degradation due to the absence of vegetation cover and the use of herbicides (Cerdà,

Chestnut cultivation is a type of traditional centennial exploitation in southern areas of Extremadura. Currently, chestnut is in danger of extinction due to the effects of climate change, some diseases (e.g. Cryphonectria parasitica) and land mismanagement. The high temporal variability of rainfall leads to soil erosion in chestnut cultivation. New forms of management are proposed to try, among other things, to reduce soil losses. This study quantifies soil losses in areas under tree canopies and open areas considering two different age plantations; 1990s and 1960s. To achieve the proposed goal 18 erosion plots were installed as paired plots under tree canopies and open areas in both plantations. The total amount of rainfall per event, tree cover, bare soil, runoff coefficient and sediment concentration were also measured in every plot. The results showed that the highest percentage of bare soil (> 45%) coincides with the period of greatest tree cover (> 75%). The open areas and the youngest plantation showed soil losses higher than the areas under the tree and the oldest plantation. In addition, soil losses increase as higher percentages of bare soil are recorded. We conclude that the size of the trees and a better soil stability in older plantations help reduce soil losses.

<p>Watering ponds are the main source of drinking water supply for livestock in the rangelands of the SW Iberian Peninsula. Most of these ponds consist of small earth dams which collect surface runoff from intermittent streams, with pond sizes rarely exceeding 1 ha. Understanding the hydrological functioning of this type of infrastructures is crucial for an efficient water management in extensive livestock farms, especially in semi-arid areas, where water resources are often scarce.</p><p>In this line, we have analysed the temporal patterns of water availability in a sample of representative livestock watering ponds in the SW Iberian Peninsula, being the objectives (1) to determine the influence of temporal rainfall variability on water availability in the ponds; (2) to examine the influence of factors such as pond size and catchment area on the effectiveness of the ponds, understood as their capacity to keep water during dry periods; and (3) to suggest minimum values for those factors, which can serve as a guide for the design of watering ponds in comparable rangeland areas. The applied methodology was primarily based on the analysis of aerial photographs and rainfall data available from public sources, requiring only few field measurements, and could therefore be used in areas with data scarcity.</p><p>High correlation coefficients were obtained between the water availability observed in the ponds and the antecedent rainfall at several time scales, evidencing the principal role of precipitation in the hydrological dynamics of these infrastructures in the study area. The accumulation periods (AP) of antecedent rainfall that best explained the hydrological response of the ponds depended largely on pond size. In those ponds whose maximum flooded area (A<sub>max</sub>) was less than 2000 m<sup>2</sup>, water availability in the ponds was greatly influenced by AP between 2 and 5 months, while for the ponds larger than 2000 m<sup>2</sup>, the best correlations were obtained for AP greater than 6 months. These results highlight the key role of the size of the ponds in their effectiveness. Thus, since the dry season usually lasts in the study area for 3-4 months, the large ponds (A<sub>max</sub> > 2000 m<sup>2</sup>) could remain operational throughout the summer, if it rains enough during the wet season and if their watersheds are large enough to allow a sufficiently high pond water level to be reached at the end of the wet season. In relation to the latter, the analyses carried out led us to suggest, for the study area, a minimum value of the catchment-area/pond-capacity ratio around 100 m<sup>-1</sup>.</p><p>Moreover, the analysis of the water availability observed in the ponds under drought conditions (i.e., with an antecedent rainfall substantially lower than normal for the corresponding time of year) revealed a high vulnerability to droughts in most of the ponds, which limits their use as the sole source of water supply in many farms.</p>