30 research outputs found

    Evapotranspiration simulated by CRITERIA and AquaCrop models in stony soils

    Get PDF
    The performance of a water balance model is also based on the ability to correctly perform simulations in heterogeneous soils. The objective of this paper is to test CRITERIA and AquaCrop models in order to evaluate their suitability in estimating evapotranspiration at the field scale in two types of soil in the Mediterranean region: non-stony and stony soil. The first step of the work was to calibrate both models under the non-stony conditions. The models were calibrated by using observations on wheat crop (leaf area index or canopy cover, and phenological stages as a function of degree days) and pedo-climatic measurements. The second step consisted in the analysing the impact of the soil type on the models performances by comparing simulated and measured values. The outputs retained in the analysis were soil water content (at the daily scale) and crop evapotranspiration (at two time scales: daily and crop season). The model performances were evaluated through four statistical tests: normalised difference (D%) at the seasonal time scale; and relative root mean square error (RRMSE), efficiency index (EF), coefficient of determination (r2) at the daily scale. At the seasonal scale, values of D% were less than 15% in stony and on-stony soils, indicating a good performance attained by both models. At the daily scale, the RRMSE values (2) indicate the inadequacy of AquaCrop to simulate correctly daily evapotranspiration. The higher performance of CRITERIA model to simulate daily evapotranspiration in stony soils, is due to the soil submodel, which requires the percentage skeleton as an input, while AquaCrop model takes into account the presence of skeleton by reducing the soil volume

    evapotranspiration of tomato simulated with the criteria model

    Get PDF
    The CRITERIA model simulates crop development and water dynamics in agricultural soils at different spatial scales. The objective of this paper was to test CRITERIA in order to evaluate the suitability of the model as a tool for scheduling irrigation at field scale. The first step of the work was to validate this hypothesis, by means of calibration and validation of CRITERIA on processing tomato in two experimental sites in Southern Italy (Rutigliano and Foggia) for the years 2007 and 2008 under different irrigation regimes. The irrigation treatments were: i) absence of plant water stress (the control treatments set up for both years and sites), ii) moderately stressed (applied in Rutigliano for 2007), and iii) severely stressed (applied in Foggia for 2008). The second step consisted in the evaluation of the expected impact of different irrigation regimes on daily actual evapotranspiration. For model calibration, the 2007 data of the control treatment was used, whereas in the validation process of actual evapotranspiration, the other part of the dataset was used. The observed data were crop evapotranspiration, agrometeorological data, leaf area index, physical-chemical and hydrological characteristics of soil, phenological stages and irrigation management. In order to evaluate model performance we used three statistical indicators to compare simulated and measured values of actual evapotranspiration: the normalized differences of seasonal values are less than 10% for all treatments; the model efficiency index on the typical period between two irrigations (4 days) was positive for all treatments, with the best values in the Foggia site, for both the irrigated and the severely stressed experiments; the relative root mean square error (RRMSE) was smaller than 20% in both the control treatments, but higher than 30% for the stressed treatments. The increase in RRMSE for the stressed experiments is due to CRITERIA simulating a crop in good soil water conditions and, as a consequence, with a larger evapotranspiration demand with respect to water stressed crop. Therefore, we can consider CRITERIA as a suitable tool to manage irrigations of processed tomato, especially for the full irrigation regime; an improvement can be reached by simulating the impact of water stress conditions on the eco-physiological parameters of the crop, in order to use the model also under deficit irrigation regimes

    Productivity of energy sorghum irrigated with reclaimed wastewaters

    Get PDF
    The sustainability of biomass sorghum ( Sorghum bicolor L. Moench.) in the Mediterranean environment is linked to the possibility of increasing crop productivity by using conventional clean water and wastewater irrigation. An experimental setup was arranged in Southern Italy during 2012 and 2013 seasons to determine the potential productivity of biomass sorghum irrigated with conventional water at different irrigation regimes (100 and 50% of calculated evapotranspiration) and different types of municipal wastewater. During the sorghum growing season, the crop development (biomass and leaf are index) and the soil water content were monitored for all irrigation treatments. The data obtained showed that the dry biomass of sorghum irrigated with the deficit treatment (17 t ha –1 ) was lower compared with conventionally irrigated sorghum. For both seasons and under full irrigated conditions, sorghum irrigated with wastewater produced on average more dry biomass (23 t ha –1 ) than the crop irrigated with conventional water (20.5 t ha –1 ), using the same irrigation volumes

    Bioenergy productivity of sugar beet irrigated with reclaimed wastewaters

    Get PDF
    The use of treated wastewater to irrigate the sugar beet (Beta Vulgaris L. var. saccharifera) for bioethanol could play a strategic role to contrast the use of natural water resources and increase the productivity of the crop. The 2-year experiment (2013-2014) was performed on sugar beet irrigated with fresh water and wastewater at different steps of the reclamation process (secondary and tertiary treatments). The data obtained showed that the root sugar beet yield and ethanol production under fresh water treatment (52.2 Mg ha–1 and 5446 L ha–1) were lower respect to that obtained from the secondary and tertiary wastewater treatments (66.7 Mg ha–1 and 6785 L ha–1, and 58.7 Mg h–1 and 6164 L ha–1, respectively), with the same irrigation volumes. These results can depend on the higher quantity of nutrient uptake when wastewater is used for irrigation. In particular, the average N applied (as nitrate and ammonium) with irrigation during the growing seasons (2013 and 2014) was corresponding to the supply of 4, 28 and 20 kg ha–1, for the fresh water, secondary, and tertiary wastewater treatments, respectively

    Inverse Modeling for MEG/EEG data

    Full text link
    We provide an overview of the state-of-the-art for mathematical methods that are used to reconstruct brain activity from neurophysiological data. After a brief introduction on the mathematics of the forward problem, we discuss standard and recently proposed regularization methods, as well as Monte Carlo techniques for Bayesian inference. We classify the inverse methods based on the underlying source model, and discuss advantages and disadvantages. Finally we describe an application to the pre-surgical evaluation of epileptic patients.Comment: 15 pages, 1 figur

    Patients' perceptions of quality of care delivery by urology residents: A nationwide study

    Get PDF
    Objective To present the results of a nationwide survey among urological patients to evaluate their perception of the quality of care provided by residents. Methods An anonymous survey was distributed to patients who were referred to 22 Italian academic institutions. The survey aimed to investigate the professional figure of the urology resident as perceived by the patient. Results A total of 2587 patients were enrolled in this study. In all, 51.6% of patients were able to correctly identify a urology resident; however, almost 40% of respondents discriminated residents from fully trained urologists based exclusively on their young age. Overall, 98.2% patients rated the service provided by the resident as at least sufficient. Urology trainees were considered by more than 50% of the patients interviewed to have good communication skills, expertise and willingness. Overall, patients showed an excellent willingness to be managed by urology residents. The percentage of patients not available for this purpose showed an increasing trend that directly correlated with the difficulty of the procedure. Approximately 5-10% of patients were not willing to be managed by residents for simple procedures such as clinical visits, cystoscopy or sonography, and up to a third of patients were not prepared to undergo any surgical procedure performed by residents during steps in major surgery, even if the residents were adequately tutored. Conclusions Our data showed that patients have a good willingness to be managed by residents during their training, especially for medium- to low-difficulty procedures. Furthermore, the majority of patients interviewed rated the residents' care delivery as sufficient. Urology trainees were considered to have good communication skills, expertise and willingness

    Orchard Floor Management Affects Tree Functionality, Productivity and Water Consumption of a Late Ripening Peach Orchard under Semi-Arid Conditions

    No full text
    Semi-arid conditions are favorable for the cultivation of late ripening peach cultivars; however, seasonal water scarcity and reduction in soil biological fertility, heightened by improper soil management, are jeopardizing this important sector. In the present two-year study, four soil managements were compared on a late ripening peach orchard: (i) completely tilled (control); (ii) mulched with reusable reflective plastic film; (iii) mulching with a Leguminosae cover-crop flattened after peach fruit set; (iv) completely tilled, supplying the water volumes of the plastic mulched treatment, supposed to be lower than the control. Comparison was performed for soil features, water use, tree functionality, fruit growth, fruit quality, yield and water productivity. Even receiving about 50% of the regular irrigation, reusable reflective mulching reduced water loss and soil carbon over mineralization, not affecting (sometimes increasing) net carbon assimilation, yield, and fruit size and increasing water productivity. The flattening technique should be refined in the last part of the season as in hot and dry areas with clay soils and low organic matter, soil cracking increased water evaporation predisposing the orchard at water stress. The development and implementation of appropriate soil management strategies could be pivotal for making peach production economically and environmentally sustainable

    Dimensioning the Irrigation Variables for Table Grape Vineyards in Litho-soils

    No full text
    The pedo-climatic and farm characteristics of Bari’s hinterland have allowed for the diffusion of prestigious table viticulture. The typical “tendone” vineyard structure is set up after managing the surface of the soil. The karstic nature of the region and the thermo-rainfall trend during the vegetative season impede the vineyard from producing adequately without irrigation. Given the importance of water contributions to table grapes, it is necessary to correctly measure the water variables for economic and environmental reasons. Farmers often irrigate according to “fixed” turns and volumes, against the rules of “good irrigation practice” which consider monitoring the water status of the soil or plant as a prerequisite of irrigation scheduling. During this experiment, two methods of irrigation management were compared: “fixed-turn” and “on demand”. For “on demand” irrigation, the irrigation volume is calculated on the basis of the soil water status (estimated according to the “water balance” method described in the “Paper n. 56 FAO”) and the irrigation is scheduled on the basis of the experimental relationship between “pre-dawn” leaf water potential and the water available in the soil. For this comparison, data from a 2-year “on farm” experimentation, in an area typical of table grape cultivation in Southern Italy, have been used. The results obtained show that, in respect to the “fixed-turn” management, the “on demand” management allows for a 20% reduction in water volumes, without compromising production. The water balance method proved to be a promising criterion for irrigation scheduling in these shallow soils, rich in stones (litho-soils). This only held true when the depth of the soil layer explored by the root system was defined by the “equivalent depth” and not by the actual soil’s depth

    Increasing the effective use of water in green asparagus through deficit irrigation strategies

    No full text
    A six-year study was carried out to assess the effects of deficit (DI) and regulated deficit irrigation (RDI) strategies on yield and water use efficiency of two hybrids of asparagus (Asparagus officinalis L., hybrids Grande and Italo), in a typical semi-arid Mediterranean environment of Southern Italy. The experimental setup consisted of full irrigation (IRR; restoration of 100% of the crop evapotranspiration ET c ), DI (restoration of 50% of ET c from the first fern flush until the end of the growing season) and two RDI (1: no irrigation supply from the first fern flush, crop development stage more sensitive to water stress, until end of the growing season, RDI 1 ; 2: no irrigation supply from the second fern flush until the end of the growing season, RDI 2 ) treatments. The relationships between yield and water regimes in the multi-year dataset were analyzed using linear mixed effect models (LMM) taking into account residual autocorrelation and comparing different variance-covariance structures. Irrigation treatments affected significantly the asparagus productivity. The six-year average yield was highest under IRR treatment (6.4 t ha −1 ) and lowest under RDI 1 treatment (4.4 t ha −1 ). In comparison with IRR treatment, DI reduced ET c by 20% and yield by 13% (6-season average). Six-year average yields were similar in DI and RDI 2 treatments (5.6 and 5.4 t ha −1 , respectively). Asparagus yield varied with hybrid. Italo hybrid showed higher yield performances (5.6 t ha −1 ) respect to Grande (5.3 t ha −1 ). The soil water deficit tolerance, assessed through the “yield response factor” (Ky of the marketable yield), was 0.61 and this value indicates that asparagus is mildly negatively affected by sub-optimal irrigation regimes. On the contrary, irrigation water use efficiency (WUE I ) was clearly affected by the experimental treatment. WUE I was higher (2.8 kg m −3 ) if asparagus experiences the soil water shortage during the first fern flush (RDI 1 ). Operatively, full irrigation maximizes asparagus marketable yield, while reduced irrigation volume (DI or RDI 2 treatments) seems a promising strategy, since it allowed reducing on average the irrigation volume supplies by 34% with asparagus marketable yield loss by 13%
    corecore