Year-round variability of field-saturated hydraulic conductivity and runoff in tilled and grassed vineyards

The 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 Role of the Minor Hydrographic System in Increasing the Ecological Network

This contribution describes the definition of the structure of the local ecological network. It was carried out as part of the support activities for the construc-tion of the new urban plan of Mappano (Turin, Italy). The knowledge of the minor hydrographic system in Mappano allowed the construction of the structural map of the local ecological network, which contemplates the structural elements of the network (primary ecological network), the contiguous portions to the structural elements (areas with ecological functionality areas where it is a priority to intervene to increase ecological network), the areas of possible expansion of the network, i.e., areas with residual ecological functionality. However, there it is possible to carry out interven-tions useful for the protection of habitats and species of interest for conservation of biodiversity. Peripheral strips and connecting corridors, consisting of minor water canals, have therefore made it possible to better define the areas of possible expansion of the network: wetlands and marshes, in these relevant areas, represent stepping-stones of fundamental importance for rest and reproduction of many species and which need to be safeguarded in the design of the new local urban plan

Evaluation of Turbulent Fluxes on a mountain slope

Studies about turbulent exchanges, momentum and mass transfer and energy balance on mountain slopes allow a better comprehension of the interactions between soil and atmosphere in complex orography. In addition, if long periods of observations are considered, the evolution of energy and mass fluxes can be derived. This is useful for model delicate ecosystems such as in the highlands. Furthermore, the study on carbon dioxide fluxes can be related to the increase of greenhouse gas. The eddy-covariance technique has some critical points: one of the most important is related to the relative uncertainty in the fluxes estimation when there are bad weather or low-wind and nocturnal conditions. Our aim is divided into two parts: in the first one, the meandering was explored. In the second part, we compared two approaches, the planar fit and the double rotation techniques for the computation of turbulent fluxes. Because of the high number of low-wind speed conditions (LWS), we investigated the “meandering”: in LWS conditions, wind speed components and scalars such as temperature can show oscillations visible in the auto-correlation function of the signals. In these cases, turbulent fluxes estimation may be difficult. We analysed 11 months of data collected at 10 Hz, considering a 1-hour time scale, with the identification of surface-layer parameters. Meandering phenomenon was explored following the works of Mortarini et al. (2013, 2015). We evaluated also the impact of clear-sky conditions on our data. We observed the validity of the formula for spectral analysis proposed in the aforementioned papers in most part of the analysed hours. Meandering conditions occur in 305 hours over more than 8000, especially during winter and night, although there are diurnal episodes. Meteorological conditions seem to play some role on the local phenomena because, although no certain relationship between stability and meandering parameters was found, the sky was cloudy in most part of meandering hours. In the second part, 30-minutes turbulent fluxes (sensible heat flux, latent heat flux and mass fluxes of water vapour and carbon dioxide) were determined using planar fit and double rotation techniques and the eddy-covariance technique use was tested for our site having a slope of about 26. Then, computation of the energy balance was done. We made comparisons between estimated and measured data and considerations on sensible and latent heat fluxes, then energy and mass fluxes and net radiation were computed also at the daily scale. We found that anemometer rotations improve robustness of computation and the difference between planar fit and double rotation is not so high in fluxes computations. Planar fit seems to give more reliable values. Considering the ground heat flux, G, we obtained a better approximation of energy balance. In particular, the computation of the energy balance ratio (EBR) showed that in general the balance is better during the daytime, while the seasons in which the energy balance is nearer to closure are summer and autumn