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The partitioning of crop canopy water may affect soil water distribution and this may in turn affect sprinkler irrigation application efficiency. The aim of this work was to develop a methodology to evaluate spatial and temporal soil water content distribution in the case of sprinkler irrigation application efficiency considering stemflow. Time domain reflectometry (TDR) soil moisture monitoring was carried out on eight soil water sensor locations for both center pivot and traveling big gun irrigation in different phenological and tillage cases. The two case studies were chosen because they show the two opposite limits of the methodology's application. Two water distribution estimation methods were employed: raw measured soil moisture and model simulation of the infiltration process. The infiltration process was modeled by means of the two-dimensional (2D) Richard's equation. The simulations were calibrated on the data measured at eight soil water sensor locations. The stemflow and surface runoff conveyed in the interrow by hilling were obtained as additional model-fitting parameters. During center pivot irrigation, 34% of the water delivered in the interrow was conveyed in the row. During traveling big gun irrigation. 88% of the water delivered in the row was conveyed in the interrow. Soil water distributions calculated from measured data overestimated irrigation application efficiency by approximately 15%. The spatial and temporal soil water content distribution obtained from simulation of the water infiltration process allowed mass balance closure in both case studies. The proposed simulation method evaluated stemflow effects on the water distribution profile, leading to accurate application efficiency calculations. [ABSTRACT FROM AUTHOR]

Abstract: Climate models predict a general future increase in air temperatures and, therefore, an augmentation of water requirements for agricultural purposes. However, without an appropriate management of the water resource, the competition between agriculture and other sectors risk to worsen the water scarcity crisis. Reducing the losses from irrigation canals will surely improve the efficiency of the irrigation systems, but lining the irrigation channels is an extremely expensive procedure sustainable only in the presence of h gh losses. Moreover, the two most known methods for determining losses from irri ation canals (inflow-outflow and ponding test) are quite expensive and time-consuming. In this context, the EM (Electromagnetic Induction) system has been used for decades for mapping soil properties: it is a fast and user friendly technique, easy for field applications and not excessively expensive. In this study we verified the usefulness of the EM system to determine the presence of leakage of irrigation canals. To this aim we selected three canals in the Piedmont plain (northwest of Italy) representatives of the most common regional typologies. Electrical conductivity values, collected using an EM device, were combined with data measured with traditional techniques such as inflow-outflow measurements (acoustic Doppler profiler and propeller flow meter), and soil water content measurements (TDR - Time Domain Reflectometer). EM electrical conductivity measurements were performed at different discharges values in permanent flow, h nce, at different water leve heights. The two replications were necessaries to investigate the variation of electrical conductivity versus the water level height. Results show that EM allows detecting seepage losses. Namely, these las s cause a lowering of the soi electrical conductivit*y values in steady conditions of soil water content. [Copyright &y& Elsevier]

Abstract: Understanding and characterizing the soil moisture spatial variability and its relevant physical controls is a main challenge in hydrological sciences. In this work we examine the spatial variability characteristics of soil moisture data at 0-30cm depth collected over three years (2006-2008) on a plot (about 200 m2) in Grugliasco (Po Plain, Northern Italy) by means of 21 Time Domain Reflectometry probes. The plot is divided into two subplots: one covered by grapevine plants, the other covered homogeneously by grass. The site is almost flat and the soil is sandy. The characteristics of the site allow to isolate he contribution of soil hydraulic properties and land use to soil moisture variability. Examination of the data shows higher soil moisture values in the vineyard han in the meadow, implying the influence of vegetation cover during the growing season; correspondingly, the spatial soil moisture variability is systematically lower in the vineyard than in the meadow. Evaluation of the main physical controls on the spatia mean and the variability of soil moisture is carried out by using a simple bucket model, forced by using local rainfal and evapotranspiration data. The model is calibrated by using mean soil moisture daily time series over one year for the two sites. The model accuracy is verified for the other two years, showing a relatively good prediction capability The model is also shown to be able to capture the main differences between the two sites in terms of spatia variability. [Copyright &y& Elsevier]

Abstract: Agricultural management influences the rainfall-runoff processes and has relevant effect on soil erosion, especially on hillslope vineyards. Mechanization in the inter-row is particularly important in this issues. Vegetation cover, soil structure modification and crust formation dramatically influence the overland flow. In this work ponded infiltration measurements in relation both to soil water content measurements and to long time series of rainfall-runoff were performed. In fact in the case of event scale mathematical models, soil hydrology theory provides the methods to evaluate some key parameters. First of all a long time series of rainfall-runoff data measured by the IMAMOTER-CNR-Torino was analyzed in order to quantify the soil management effects in the Regione Piemonte experimental vineyards “Tenuta Cannona”. Then temporal variability of hydraulic conductivity and soil water content were measured in different soil surface conditions in relation to vineyard management. The analysis of the runoff data set and the infiltration tests showed how the increase in infiltration in tilled inter-rows was limited to rainfall events that occurred immediately after tillage, whilst the grass cover assured better reduction of runoff and higher hydraulic conductivity on a wider temporal scale. [Copyright &y& Elsevier]

Soil erosion is affected by rainfall temporal patterns and intensity variability. In vineyards, machine traffic is implemented with particular intensity from late spring to harvest, and it is responsible for soil compaction, which likely affects soil hydraulic properties, runoff, and soil erosion. Additionally, the hydraulic and physical properties of soil are highly influenced by vineyards' inter-rows soil management. The effects on soil compaction and both hydrological and erosional processes of machine traffic were investigated on a sloping vineyard with different inter-row soil managements (tillage and permanent grass cover) in the Alto Monferrato area (Piedmont, NW Italy). During the investigation (November 2016–October 2018), soil water content, rainfall, runoff, and soil erosion were continuously monitored. Field-saturated hydraulic conductivity, soil penetration resistance, and bulk density were recorded periodically in portions of inter-rows affected and not affected by the machine traffic. Very different yearly precipitation characterized the observed period, leading to higher bulk density and lower infiltration rates in the wetter year, especially in the tilled vineyard, whereas soil penetration resistance was generally higher in the grassed plot and in drier conditions. In the wet year, management with grass cover considerably reduced runoff (−76%) and soil loss (−83%) compared to tillage and in the dry season. Those results highlight the need to limit the tractor traffic, in order to reduce negative effects due to soil compaction, especially in tilled inter-rows. [ABSTRACT FROM AUTHOR]

• The abandoned pastures are increasingly important ecosystems in the Alps. • The model Hydrus 1D with double vegetation (DV, grassland and shrubland) fits the observed actual evapotranspiration (ETa). • The occurring shrub encroachment of grassland increased ETa at the site, if compared to simulations with only grassland. • Vapor pressure deficit drives ETa deviations (observations - DV simulations and between single vegetation simulations). • Wider-scale hydrological models should include information about the isohydric or anisohydric behavior of vegetation. This study analyzes the effect of shrub encroachment on actual evapotranspiration (ETa), a still poorly studied phenomenon in the Alps. The effect of shrub encroachment is investigated on an Alpine grassland in Western Italy using both data and a soil hydrological model (Hydrus 1D), which is used to model three different land covers: grassland, shrubland, and a mixture of the two land covers with a novel double vegetation approach recently introduced. Four growing seasons of eddy covariance measurements are used as an approximate reference for the interpretation and consistency of the model outputs. Also, the impact of meteorological inter-annual variability and of different environmental conditions on both modeled and measured evapotranspiration is analyzed. The modeling results show that the model is able to capture the inter-annual variability of ETa. The double vegetation approach suggests that the percentage of total transpiration flux assigned to the shrubland is between 20 and 60 %. Single-vegetation simulations show that shrubs lead to an enhancement of ETa equal to + 27.1 %, +26.0 %, +26.8 %, and + 23.9 % (range 2014–2017) compared to grassland, which could lead to an alteration of the hydrological cycle. Moreover, chambers measurements of shrubs transpiration show a good agreement with the eddy covariance measurement, suggesting that the ecosystem's behavior is already close to a shrubland, which yields an increased ETa if compared to grassland. The evaporative index from the modeled shrubland is higher (range +24–27 %) than the case of a modeled grassland. Finally, ETa and the evaporative fraction (EF) are in the energy-limited regime in most cases. This result was obtained from the analysis of the relationship between ETa (and EF) and either meteorological variables or soil water content including the simulated one in the 0–100 cm horizon. The following analysis, more focused on micrometeorological variables, namely vapor pressure deficit, net radiation, wind speed, air temperature, and ground heat flux, indicates that ETa is mostly affected by the vapor pressure deficit. [ABSTRACT FROM AUTHOR]

In recent years, our understanding of snow gliding and glide-snow avalanches has improved; however, the contributing factors are still poorly understood and difficult to measure. In particular, the role of soil properties has not been considered as much as other environmental parameters (e.g. air temperature). Focusing on soil properties we established a monitoring site in the Italian Alps, in the release zone of a WSW-facing avalanche path. The area is typically characterized by intense snow gliding that results in the formation of large glide cracks, often leading to the release of a glide-snow avalanche. The site was equipped with four glide-snow shoes to measure snow gliding movement. Temperature and water content sensors were located at the snow-soil interface and at different depths within the soil. Meteorological data were recorded by a nearby automatic weather station, and snowpack properties were evaluated using manual snow profiles and SNOWPACK simulations; additionally, soils were characterized with special emphasis on the physical properties of the upper soil horizons. During two monitoring seasons, we registered a cold-temperature event characterized by gradual and continuous snow gliding and three warm-temperature events with glide-crack formation and evolution, in one case resulting in a glide-snow avalanche. Univariate (Mann-Witney U test) and multivariate (Classification Trees) analyses allowed us to find significant differences between gliding and non-gliding periods, and confirmed the importance of distinguishing between cold and warm-temperature events. In particular, for warm-temperature events we found that the most significant parameters were a large snow depth, strong settlement and high air temperature. For cold-temperature events we found that, together with a large snow depth, the volumetric liquid water content, both at the snow-soil interface and within the soil, played a fundamental role. Moreover, for the cold-temperature events we found a strong correlation between daily glide rates and the soil volumetric liquid water content, with an exponential relationship at the snow-soil interface and at 5 cm depth within the soil. These results highlight the relationship between the snow gliding process and the soil conditions, which have been identified among the main environmental factors related to the development of snow gliding. [ABSTRACT FROM AUTHOR]

Summary: We test the ability of three box models () to describe soil moisture dynamics in a regularly monitored experimental site in northwestern Italy. The models include increasingly complex representations of leakage and evapotranspiration processes. We force the models with the local rainfall, and we determine model parameters with a least-square minimization procedure. We study separately summer and annual dynamics. When we use the models to reproduce annual dynamics, we include a simple representation of the annual cycle of evapotranspiration. We test the models both in simulation mode, estimating their parameters from the same data used to verify them, and in forecast mode, determining the model parameters from one period, and using them to forecast soil water dynamics in a different period. The results indicate that simple box models can estimate soil water dynamics at midlatitudes, using rainfall as the only meteorological driver. The models displaying the best performances include the representation of leakage and evapotranspiration as nonlinear functions of soil water content. [ABSTRACT FROM AUTHOR]