Agricultural drainage water that has seeped into tile drainage systems can cause nitrogen and phosphorus pollution of the surface water bodies. Constructed wetlands (CWs) can help mitigate the effects of agricultural non-point sources of pollution and remove different pollutants from tile drainage water. In this study, hydrological and water quality data of a Northern Italian CW that has been treating agricultural drainage water since 2000 were considered to assess its ability to mitigate nitrogen and phosphorus pollution. The effects of such long-term operation on the nutrients and heavy metals that eventually accumulate in CW plants and sediments were also analysed. Since 2003, the CW has received different inflows with different nutrient loads due to several operation modes. However, on average, the outflow load has been 50% lower than the inflow one; thus, it can be said that the system has proved itself to be a viable option for tile drainage water treatment. It was found that the concentration of nitrogen and phosphorus in the plant tissues varied, whereas the nitrogen content of the soil increased more than 2.5 times. Heavy metals were found accumulated in the plant root systems and uniformly distributed throughout a 60 cm soil profile at levels suitable for private and public green areas, according to the Italian law

Proximal soil sensors are taking hold in the understanding of soil hydrogeological processes involved in precision agriculture. In this context, permanently installed gamma ray spectroscopy stations represent one of the best space-time trade off methods at field scale. This study proved the feasibility and reliability of soil water content monitoring through a seven-month continuous acquisition of terrestrial gamma radiation in a tomato test field. By employing a 1 L sodium iodide detector placed at a height of 2.25 m, we investigated the gamma signal coming from an area having a ~25 m radius and from a depth of approximately 30 cm. Experimental values, inferred after a calibration measurement and corrected for the presence of biomass, were corroborated with gravimetric data acquired under different soil moisture conditions, giving an average absolute discrepancy of about 2%. A quantitative comparison was carried out with data simulated by AquaCrop, CRITeRIA, and IRRINET soil-crop system models. The different goodness of fit obtained in bare soil condition and during the vegetated period highlighted that CRITeRIA showed the best agreement with the experimental data over the entire data-taking period while, in presence of the tomato crop, IRRINET provided the best results.

The aim of this paper was to investigate the effects of two different irrigation strategies, regulated deficit irrigation, RDI and partial root drying, PRD using surface freshwater (SW) and brackish treated waste water (TWW) for tomato for the year 2015. The field experiment was carried at CER experimental farm in the Bologna Italy. The field experiment showed close crop yields under the two irrigation strategies and two water qualities. The SALTMED modelling results illustrated that the model can simulate reasonably well the soil moisture content, soil salinity, dry matter and final crop yields. Both field observations and model results indicated that water saving irrigation strategies like PRD (Partial Root-zone Drying) and RDI (Regulated Deficit Irrigation) almost produced similar crop yields and total dry matter with freshwater as with treated waste water irrigation. However, PRD used between 15 to 17% less water than RDI excluding the rainfall. Water productivity as was calculated from rainfall and irrigated water was slightly higher for the PRD in comparison with the RDI irrigation strategy. Such PRD irrigation strategies have huge potential to reduce cost and water consumption that could be used to irrigate more land to meet the future food demand.

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Soil moisture is a crucial parameter to determine the crop water requirement for irrigation. The soil moisture deficit (SMD) of the root zone is an indicator that can be used to determine the exact crop water requirement. Application of the recent technology of COsmic-ray Soil Moisture Observation System (Cosmos) provides continuous, integrated, area-based values, with a measurement radius of up to 400 m, whilst being non-invasive.In a field experiment in Italy, the Cosmos probe was used over a mixed crop area during the cropping seasons of 2014 and 2015. The results showed that soil moisture values obtained by Cosmos were comparable with those obtained for the top 0-60 cm layer soil moisture measured by sensors, soil cores, profile probes and with values simulated by the SALTMED model. This indicates that the Cosmos probe's effective depth of sensing is within the top 0-60 cm. Knowing that almost 80% of the crop root system is accommodated within the top 0-60 cm, the Cosmos measurement could be useful for monitoring the soil water status and SMD in the root zone in irrigated agriculture. The Cosmos system could be made operational for irrigation managers to determine when and how much to irrigate. Copyright © 2017 John Wiley & Sons, Ltd. RÉSUMÉ L'humidité du sol est un paramètre crucial pour déterminer les besoins en eau d'une culture irriguée. Le déficit d'humidité du sol de la zone de racine (SMD) est un indicateur qui peut être utilisé pour déterminer le besoin en eau exact d'une récolte. L'application de la technologie récente du système d'observation de l'humidité du sol à rayonnement COsmic (Cosmos) fournit des valeurs continues, intégrées, zonales, avec un rayon de mesure de jusqu'à 400 m, tout en étant non invasive.Dans une expérience de terrain en Italie, la sonde COSMOS a été utilisée sur une zone de cultures mixtes pendant les saisons de 2014 et 2015. Les résultats ont montré que les valeurs d'humidité du sol obtenues par Cosmos étaient comparables à celles obtenues pour les 60 premiers centimètres du sol par des capteurs, des prélèvements de sol, des sondes à profils humidimétriques, des résultats de simulation par le modèle SALTMED. C 0 est donc dans cette zone où se situe la profondeur effective de détection de la sonde Cosmos; sachant que près de 80% du système racinaire se situe également dans cette zone, la mesure Cosmos pourrait être utile pour surveiller l'état de l'eau du sol et le SMD dans la zone la zone racinaire en vue d'une application dans l'agriculture irriguée. Le système COSMOS pourrait être rendu opérationnel pour les gestionnaires de l'irrigation afin de déterminer quand irriguer et en quelle quantité.