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Effects of some extreme rainfall events on Hydrological and Soil Erosion Processes in Tilled and Grassed Vineyards
Full text linkVineyards soils are especially threatened by the risk of soil compaction and soil erosion, with negative consequences for wine production and provisioning of ecosystem services. Indeed, adopting proper soil management in vineyards is crucial to avoid water losses and erosion by runoff, thus improving water infiltration. The use of cover crops in vineyards is widely considered as an effective agricultural conservation measure, providing reduction of runoff and erosion processes and several other ecosystem services. Within the IN-GEST SOIL project, a preliminary study was conducted in a sloping vineyard located in Piedmont, NW Italy, in order to assess the role of permanent grass cover in protecting the vineyard's soil from degradation, especially in relation to soil compaction due to machinery traffic and soil erosion. Rainfall characteristics, runoff and its turbidity, soil erosion, and soil water content were hourly measured during extreme events occurred in the last two years (2020 and 2021), in two different inter-row soil managements: 26 runoff events were recorded, 5 of which due to extreme rainfall with more than 100 mm in the autumn/winter period. Results show how the soil management adopted in a trafficked vineyard strongly influences the infiltration and water retention capacity of the soil and the risk of erosion. Indeed, the grass cover halves the runoff by more than 5 times and reduces the soil erosion by more than 25 times, compared to conventional tillage. Extreme rainfall events were responsible for more than 3⁄4 of the runoff and 95% of the soil eroded in the period (> 5 t/ha), highlighting the need to improve the environmental sustainability of these agricultural systems, considering the challenge of climate change, with forecasts indicating increasing temperatures and decreasing rainfall in the Mediterranean region associated with extreme events such as drought and intense rainfall
Temporal variability of soil management effects on soil hydrological properties, runoff and erosion at the field scale in a hillslope vineyard, North-West Italy
Full text linkSoil management in vineyard inter-rows has a great influence on soil hydraulic conductivity and bulk density, and, consequently, on runoff and soil erosion processes at the field scale. The maintenance of bare soil in vineyard inter-rows with tillage, as well as the tractor traffic, are known to expose the soil to
compaction, reduction of soil water holding capacity and increase of runoff and erosion. The use of grass cover is one of the most common and effective practices in order to reduce such threats. It is therefore important to relate rainfall characteristics, soil properties and response in terms of runoff and soil
erosion, from yearly to seasonal and to single event temporal scales. The objective of this work is to quantify the temporal variability of the effects of two different kind of inter-row management on soil hydrological properties, runoff and erosion in vineyards. For this reason two vineyard field-scale plots in
the Alto Monferrato vine-growing area (Piedmont, NW Italy) were monitored in two years. The inter-rows were managed with conventional tillage (CT) and grass cover (GC), respectively. Fifteen series of infiltration tests were carried out during a 2-year period of observation (October 2012 to November
2014). In order to take into account the effect of tractors traffic, the tests were done on the track, and outside the track. Furthermore, a dataset of 29 rainfall-runoff events covering a wide range of topsoil characteristics was collected in the two plots, along with soil water content and runoff discharge monitoring, and determination of sediment yield in case of erosive events. An optical disdrometer installed in the plots provided also 1-min rainfall intensity data. In summer, just one month after tillage,
CT soil showed very low hydraulic conductivity, so storms were able to cause Hortonian runoff and soil losses up to 5.7 Mg ha1. In autumn and winter very high saturation-excess runoff was observed in CT, that reached 83% of the precipitation. Runoff in the grass cover plot was mainly due to saturation of the
topsoil, and the annual reduction of runoff in the GC plot was about 63%. Soil erosion up to 1.2 Mg ha1 in a single event was observed in the GC vineyard in winter. In each year of observation, most of the erosion occurred during a single event, while the total annual erosion was up to 9 times higher in the CT
treatment than in the GC
Year-round variability of field-saturated hydraulic conductivity and runoff in tilled and grassed vineyards
Full text linkThe soil management adopted in vineyard inter-rows has a great influence on soil hydraulic properties, and, consequently, on runoff at the field scale. Conventional management with tillage is adopted by vine-growers to improve the soil water recharge during winter. Nevertheless, this practice is known to increase runoff and soil erosion in steep areas, especially in mechanized vineyards, thus grass cover is adopted to reduce these negative impacts. The year-round values of field-saturated hydraulic conductivity and of the field-scale runoff were measured in vineyard plots from November, 2012 to March, 2016 in the Alto Monferrato vine-growing area (Piedmont, NW Italy). Field-saturated hydraulic conductivity values were obtained by 110 infiltration measurements. The tests were carried out by adopting the Simplified Falling Head methodology in two adjacent vineyards plots, where inter-rows were managed with conventional tillage (CT) and grass cover (GC), respectively. The runoff, the soil temperature and the soil water content in the two plots have also been recorded. As it was expected, the tillage increased the field-saturated hydraulic conductivity with respect to the plot with permanent grass cover. However, this effect was only temporary, since a decrease in field-saturated hydraulic conductivity was observed as a consequence of cumulative precipitation and tractor passages after the tillage operations. The field-saturated hydraulic conductivity ranged between 9 and 9119 mm h-1 in the tilled plot and between 4 and 1775 mm h-1 in the plot with grass cover. The response of the plots to precipitation events, in terms of runoff also varied considerably. Generally, during most of the events, the runoff in the tilled plot resulted higher (up to nearly 20 times) than in the grassed one. The grass cover was less effective in occasion of large precipitation events during the wet seasons than in other months
The contribution of W-band radar monitoring for understanding of runoff and soil erosion response at field scale
Full text linkVegetation cover has a great influence on hydrological response at field scale, and, consequently, on runoff and soil erosion processes. The maintenance of bare soil in vineyard inter-rows with tillage, as well as the tractor traffic, are known to expose the soil to compaction, reduction of soil water holding capacity and increase of runoff and erosion. The use of grass cover is one of the most common and effective practices in order to reduce such threats. Rain-driven runoff (RO) and soil loss (SL) at sites with different cover have been investigated over last decades. It has been found that RO and SL often correlate with rain properties. This correlation, however, is highly variable among different sites and also for different time periods. In many studies rain is represented only by a few parameters such as e.g. maximum intensity and total precipitation. Size of rain drops is rarely analysed, although it is important for an accurate estimation of kinetic energy of rain. Polarimetric millimetre-wavelength radars are one of the instruments capable of drop size measurements. In contrast to in-situ rain sensors, such radars have much larger sampling area and can estimate range profiles of drop size distributions with high spatial and temporal resolution. The objective of this work is to relate runoff and soil erosion to rain properties based on traditional monitoring techniques complemented by observations from a radar. With this aim, a site in the Alto Monferrato vine-growing area (Piedmont, NW Italy) was equipped with a 94-GHz radar in June 2023. The site has two vineyard-field-scale plots with inter-rows managed with conventional tillage (CT) and grass cover (GC), respectively. The radar is located about 100 m from the plots. The radar elevation was set to 30° so that the radar samples rain above the plots. During the summer and autumn seasons of 2023, 26 rain and 13 runoff events were observed. The preliminary results of the conventional analysis show that in this period runoff is directly related to erosivity index (EI30) both in CT and GC plots, and, only in GC treatment to maximum rainfall intensity over 10 minutes and antecedent rainfall in previous 7 days. Maximum rainfall intensity over 30 and 60 minutes, on the contrary, has a negative direct proportion with runoff. Soil erosion for both treatments was also directly related also with maximum rainfall intensity over 10 minutes and antecedent rainfall in previous 7 days and, in addition has a negative proportion with rainfall energy. It should be noted the relevant role played by rainfall intensity over short time interval and the antecedent rainfall, resulting in increased soil moisture. Relationships are different from those obtained in the same site in a previous study, reflecting the peculiarity of summer 2023, characterized by few rainfall events occurred on very dry soil. Information obtained from W-Band radar monitoring allows to investigate relationships in a deeper way among rainfall characteristics and generation of runoff and soil erosion
“Estimating soil surface roughness by proximal sensing for soil erosion modeling implementation at field scale”
Full text linkSoil Surface Roughness (SSR) is a physical feature of soil microtopography, which is strongly influenced by tillage practices and plays a key role in hydrological and soil erosion processes. Therefore, surface roughness indices are required when using models to estimate soil erosion rates, where tabular values or direct measurements can be used. Field measurements often imply out-of-date and time-consuming methods, such as the pin meter and the roller chain, providing inaccurate indices. A novel technique for SSR measurement has been adopted, employing an RGB-Depth camera to produce a small-scale Digital Elevation Model of the soil surface, in order to extrapolate roughness indices. Canopy cover coverage (CC) of the cover crop was also detected from the camera's images. The values obtained for SSR and CC indices were implemented in the MMF (Morgan-Morgan-Finney) model, to validate the reliability of the proposed methodology by comparing the models' results for sediment yields with long-term soil erosion measurements in sloping vineyards in NW Italy. The performance of the model in predicting soil losses was satisfactory to good for a vineyard plot with inter-rows managed with recurrent tillage, and it was improved using spatialized soil roughness input data with respect to a uniform value. Performance for plot with permanent ground cover was not so good, however it was also improved using spatialized data. The measured values were also useful to obtain C-factor for RUSLE application, to be used instead of tabular values
Effects of inter-annual climate variability on grape harvest timing in rainfed hilly vineyards of piedmont (NW Italy)
Full text linkThe current scenario of global warming impacts viticulture, influencing grape and wine quality. A study was carried out in the “Basso Monferrato” region, a rainfed hilly vine-growing area in NW Italy, to investigate the relationships between climate variables and grape harvest dates. The dates of harvest for some local wine grape varieties were recorded from 1962 to 2019 in the Vezzolano Experimental Farm and surrounding vineyards. Three series of climate data were investigated by means of trend analysis for temperature variables, Huglin index, and precipitation during the growing period. A significant trend was found for temperature variables (positive) and harvest dates (negative), indicating anticipation of harvest beginning from 11.6 to 34.2 days in the 58-years study period, depending on the variety. The influence of increasing temperature and Huglin index in anticipating the harvest period, particularly the harvest beginning, was also highly significant for all the considered varieties and vineyards in the Monferrato area. Implication under a climate warming scenario, the relevance of having available continuous and homogeneous datasets and possible future studies were also discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Large-scale, real-time monitoring of Soil Moisture dynamics with Cosmic Rays
No full textThe availability of soil water resources is regulated by soil features such as texture, structure and soil organic content. It is challenging to establish the expected water reservoir dynamic boundaries, due to soil natural complexity which develops significant variability even within small areas. A solution to this issue is Cosmic-Rays Neutron Sensing (CRNS). It offers the capability to monitor the actual water content dynamics of an entire field yearround, using a single non-invasive sensor. Importantly, CRNS averages over soil variability, positioning itself at a spatial scale that bridges the gap between point measurements and satellite data1. Information obtained by CRNS can be integrated with other techniques such as point-scale measurements, sampling campaigns and satellites passes. When combined with pedological knowledge of the sites, this provides a more comprehensive and reliable picture of water content dynamics at different scales. This approach enhances our understanding of soil water resources and informs better management strategies
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