Open Source evaluation of kilometric indexes of abundance.

Kilometric Abundance Index (KAI) is a common measure used in wildlife studies because it allows a straightforward comparison of species abundance in different sites or at different times. KAI expresses the ratio of the total number of individuals (or of signs of presence) observed along a transect by the total transect length covered at each site. v.transect.kia is a new tool for GRASS GIS, developed for automating the evaluation of KAI, reducing the risk of manual errors especially when handling large datasets. It can also split the transects according to one environmental variable (typically habitat type) and evaluate true 3D transect length. It calculates KAI using a point map of sightings and saves the results in the attribute table, the output can be displayed in any GIS or used for further statistical analysis. The tool has been tested on field data from Northern Italy for mountain hare (Lepus timidus), allowing a first wide-area estimate

Turbulence integral length and footprint dimension with reference to experimental data measured over maize cultivation in Po Valley, Italy

The atmospheric turbulence in the planetary boundary layer (PBL) governs the mass and energy exchange over the soil-vegetation-atmosphere system. Micrometeorological stations based on the eddy-covariance technique have been recently developed for the assessment of latent and sensible heat fluxes through high frequency measurements of the fluctuating component of wind velocity, temperature and air water content in the PBL. Correct interpretation of such measurements requires assessment of the actual source area (footprint) contributing to the eddy fluxes (latent and sensible heat). Many different approaches have been developed to estimate the source area function but there is no general consensus on the accuracy and applicability of these methods. The objective of this work is to demonstrate the existence of a relationship between the representative source area for eddy covariance measurements, and the large eddies responsible for the transport of turbulent kinetic energy (TKE). Moreover, the energy balance closure was used to analyze the possible effects of the different lengths of the source area on the heat fluxes. A series of measurements were carried out in a micrometeorological eddy covariance station located in a maize field in Landriano in Po Valley (PV), Italy. The results show that the dimension of the large eddies is tightly bound to the footprint size, leading to a new approach to study the eddy covariance measure based on the assessment of the turbulence scale.La turbulencia atmosférica en la capa límite planetaria (PBL, por sus siglas en inglés) gobierna el intercambio de masa y energía en el sistema suelo-vegetación-atmósfera. Actualmente existen estaciones micrometeorológicas basadas en la técnica de covarianza turbulenta para la evaluación de los flujos de calor latente y sensible a través de la medición de las fluctuaciones de la componente vertical de la velocidad del viento, de la temperatura y del vapor de agua en la PBL. La interpretación correcta de estas mediciones requiere de la correcta evaluación del área de origen donde se generan los flujos turbulentos. Se han desarrollado muchos enfoques diferentes para calcular esta área de origen, pero no existe ningún consenso general sobre la precisión y la aplicabilidad de esos métodos. El objetivo de este trabajo es demostrar que existe una relación entre el área de origen típica que afecta al instrumental y los torbellinos que son responsables del transporte de la energía cinética turbulenta (TKE, por sus siglas en inglés). Se realizó una serie de mediciones con una estación micrometeorológica situada en un campo de maíz en Landriano, en el valle del Po, Italia. Los resultados demuestran que la dimensión de los torbellinos está en estrecha relación con la dimensión del área de origen, proponiendo un nuevo enfoque para el estudio de la covarianza turbulenta con base en en las dimensiones de los torbellinos

Managing and Planning Water Resources for Irrigation: Smart-Irrigation Systems for Providing Sustainable Agriculture and Maintaining Ecosystem Services

Smart-irrigation systems are a hot topic in irrigation management. Satellite imaging, sensors and controls, communication technologies and irrigation decision models are readily available. The price of the required technology is being reduced year after year, and its implementation in agriculture gives real-time information that allows for more accurate management of water resources. Even so, the adaptation of existing technologies to particular situations that the irrigation management is facing in different agro-environmental contexts is needed. This Special Issue addresses the application of different smart-irrigation technologies in four different research areas: (1) remote sensing-based estimates of crop evapotranspiration, (2) Information and Communication Technologies (ICTs) for smart-irrigation, (3) precision irrigation models and controls, and (4) the price of natural resources. The nine papers presented in this special issue cover a wide range of practical applications, and this editorial summarizes each of them

The potential of a coordinated system of gates for flood irrigation management in paddy rice farm

Rice is one of the most important staple foods in the world. In Europe, Italy is the main producer of rice, with almost all production concentrated in the northeast of the country. Traditionally, rice is grown in fields that are flooded from before planting until just before harvest. This water management technique requires a great deal of labour for farmers who have to manually adjust the inlet and outlet gates to maintain a constant ponding water level in the fields, especially when there is fluctuation of water supply at the farm inlet, for example as a result of rainfall. In addition, the practice of flood irrigation is very water-intensive. New technologies based on remotely and automatically controlled gates are being studied to increase the efficiency of this irrigation method. The objective of this work is to explore the potential of a coordinated and intelligent system of gates for efficient farm irrigation management and ponding water level maintenance. Based on information and measurements from a real case study consisting of a 40-hectare paddy rice farm located in northern Italy, where automatic gates and water level sensors were placed at strategic points of the farm canals and fields, respectively, a proportional-integral (PI) and a non-linear model predictive control (NMPC) of water levels were implemented and compared through modelling and simulation experiments. The results show that the proportional-integral control reproduces the actions that the farmer uses when faced with situations of surplus of water in the fields or a shortage of water in the farm canal. In particular, the general coordination of the gates is lost, and the individual binomial field-gate prevails as an independent system in the farmer's operation. Conversely, non-linear predictive control coordinates the gate operation to obtain a uniform ponding water level in the fields when there is a shortage of water, or significant water conservation when there is an excess of water as a result of rainfall. In conclusion, a nonlinear predictive control model seems to be a suitable strategy to advance irrigation management in rice farms, allowing rice farmers to continue the tradition of flooding while increasing its performance

A procedure for designing natural water retention measures in new development areas under hydraulic-hydrologic invariance constraints

In recent years, in Italy and elsewhere, regional regulations based on hydraulic-hydrologic invariance (HHI) principles have taken hold, especially for new development areas. Natural water retention measures (NWRMs) are among the most interesting options to provide the storage and infiltration capacities that are needed to achieve the HHI objectives. A procedure for the design of NWRMs in new development areas under HHI constraints is presented and is based on a simple combination of Soil Conservation Service Curve Number (SCS-CN) method for determining rainfall excess and lag-time method for simulating runoff propagation. Three types of NWRMs can be considered: rain barrels, drainage wells and drainage trenches; five types of synthetic hyetographs can be selected and three different approaches for the determination of critical storm duration applied. The results obtained by applying the procedure in a new development area located in northern Italy are illustrated and some general conclusions are drawn. It clearly emerges that practitioners should pay particular attention to the correct determination of design storm duration in order to avoid large underestimations of NWRMs size. Moreover, different combinations of the three NWRMs can provide the required reduction of peak of runoff after the transformation, but it appears that drainage trenches are more effective with respect to harvesting systems in reducing the peak runoff value

Evaluating longitudinal dispersion of scalars in rural channels of agro‐urban environments

In agro-urban environments, the water resource conveyed by rural channels is susceptible to a gradual impoverishment due to the continuous combined sewer overfow release, constituting a pending and urgent issue for water management companies and the entire community. Reliable one-dimensional longitudinal dispersion coefcients D are required to model and study the hydrodynamics and water quality patterns at the scale of rural channel networks. Empirical formulas are usually adopted to estimate D but the accuracy in the prediction could be questionable. In order to identify which are the most suitable formulas to determine D in rural channels, feld tracer measurements were carried out in three rural channels with typical geometry and confguration. The obtained D values were then compared with the most commonly used predicting formulas that the literature provides. The accuracy of the predictors was further checked by simulating diferent fow rates inside the tested channels by using a one-dimensional hydraulic model. Starting from the obtained results, indications and guidelines to choose the most suitable formulas to predict D in rural channels were provided. These indications should be followed when developing realistic quality models in the agro-urban environments, especially in those cases where direct measurements of the longitudinal dispersion coefcient D are not available

Analyzing the Gap between Irrigation Water Requirement and Supply at the District Scale

Agriculture is the world's largest consumer of freshwater and it is now well established that freshwater availability is decreasing in many parts of the world (particularly in the Mediterranean region) as a direct result of global climate change. Therefore reducing the gap between the effective irrigation water requirements and the water supplies to irrigated areas is a key challenge to support the adaptation of agricultural systems to future climate and water scarcity conditions. In this work, an agro-hydrological model was used to assess this gap in seven pressurized irrigation districts (ranging from about 200 to 3000 ha in size) located in the Padana plain (i.e. the largest irrigated region in the EU). Specifically, daily irrigation water requirements estimated by the IdrAgra model (https://idragra.unimi.it/resources/) were compared with the observed water supplies at the head of each district for the period 2016-2022 including wet, medium and dry rainy seasons. Detailed land use and soil information, irrigation efficiency maps, agro-meterological and remote sensing data have been integrated into the model to provide highly accurate irrigation water requirement estimates. The results show that a mismatch between water supplies and actual irrigation water requirements occurs quite often, with water supplies often exceeding crop water requirements in the wet seasons and falling short in the dry seasons. Part of this mismatch is due to the rigidity of water management criteria (e.g., fixed irrigation scheduling between plots within the district, lack of rapid adaptation of water supply to irrigation demand), which makes it difficult to align water distribution with real irrigation needs. The analysis of these results has shown that there is a margin for reducing the gap between supply and demand in the seven study districts through the improvement of irrigation management practices that we believe could be applied elsewhere in similar irrigation contexts

Impact of land preparation on water saving in border irrigation

Border irrigation is still the most widely surface irrigation technique used for watering row crops worldwide, including the Padana Plain where it is mainly used to irrigate forage crops. Observations in the Lombardy Padana Plain show that a considerable amount of water, up to 3000 m3/ha, is used during each irrigation event, often resulting in excessive irrigation. This practice is unsustain-able in the long term due to declining surface water supplies. Research suggests that improved management of irrigation timing and land preparation can lead to significant reductions in water use. This work investigates the potential water savings that could be achieved by op-timising land preparation on a 2 ha irregular boundary field traditionally irrigated at 2300 m3/ha per irrigation event. Using detailed topographic data and the Irri-Surf2D model, scenarios such as using laser levelling to improve slopes, intro-ducing ridges and adjusting irrigation timing were investigated. The results showed that effective land preparation could save up to 47% of water per irriga-tion event. These results show how it is possible to increase the sustainability of border irrigation while keeping this technique alive in the Padana plain