Long-Range Low-Power Soil Water Content Monitoring System for Precision Agriculture

World population growth and desertification are increasing the food demand. Food production must increase to ensure food security in the following years. Smart agriculture tries to improve food production thanks to the adoption of electronic sensors to monitor and control fruit and vegetable crops. Another critical point in agriculture is the use of potable water. Precision irrigation strategies can be implemented to reduce water waste and increase crop production. This paper proposes a long-range, low-power sensor node to monitor soil water content. It is possible to place multiple sensor nodes in the field and use the gathered data to determine the most suitable irrigation strategy. The node communicates thanks to the LoRa protocol and it can also be used in remote areas where it is impossible to have an internet connection

Aquifer recharge in the Piedmont Alpine zone: Historical trends and future scenarios

The spatial and temporal variability of air temperature, precipitation, actual evapotranspiration (AET) and their related water balance components, as well as their responses to anthropogenic climate change, provide fundamental information for an effective management of water resources and for a proactive involvement of users and stakeholders, in order to develop and apply adaptation and mitigation strategies at the local level. In this study, using an interdisciplinary research approach tailored to water management needs, we evaluate the past, present and future quantity of water potentially available for drinking supply in the water catchments feeding the about 2.3 million inhabitants of the Turin metropolitan area (the former Province of Turin, north-western Italy), considering climatologies at the quarterly and yearly timescales. Observed daily maximum surface air temperature and precipitation data from 1959 to 2017 were analysed to assess historical trends, their significance and the possible cross-correlations between the water balance components. Regional climate model (RCM) simulations from a small ensemble were analysed to provide mid-century projections of the difference between precipitation and AET for the area of interest in the future CMIP5 scenarios RCP4.5 (stabilization) and RCP8.5 (business as usual). Temporal and spatial variations in recharge were approximated with variations of drainage. The impact of irrigation, and of snowpack variability, on the latter was also assessed. The other terms of water balance were disregarded because they are affected by higher uncertainty. The analysis over the historical period indicated that the driest area of the study region displayed significant negative annual (and spring) trends of both precipitation and drainage. Results from field experiments were used to model irrigation, and we found that relatively wetter watersheds in the northern and in the southern parts behave differently, with a significant increase of AET due to irrigation. The analysis of future projections suggested almost stationary conditions for annual data. Regarding quarterly data, a slight decrease in summer drainage was found in three out of five models in both emission scenarios. The RCM ensemble exhibits a large spread in the representation of the future drainage trends. The large interannual variability of precipitation was also quantified and identified as a relevant risk factor for water management, expected to play a major role also in future decades

Electromagnetic and self-potential investigation to detect seepage of irrigation canals

We adopted electromagnetic induction (EMI) and self-potential measurements along irrigation canal bank in order to detect groundwater seepage. The EMI methods is sensitive to the electrical conductivity of the subsoil, that is affected by the salt and clay content and water content. The depth of investigation depends on the soil electrical conductivity, the geometry of the instrument and the frequency of the electromagnetic field. The experimental data refers to anintegrated survey along a transect on an irrigation canals (400 m) .We acquired broadband electromagnetic data using a Profiler EMP400 (GSSI), with coil separation of 1.22 m and a bandwidth ranging from 1 to 15 kHz. The self-potential measurements were performed with a fixed electrode and a moving electrode along the same transect of EMI measurements. The interval spacing among self-potential measurements was 2 m. Visual inspection of the canal permitted to compare the evidence of seepage losses with the geophysical anomalies. The results of self-potential measurements show peaks of electrical potential at the same position of electrical conductivity anomalies. Integration of the EMI survey and SP measurements is useful to detect seepage losses from canals: a more detailed analysis of self potential anomalies is required to reduce "false" alarms