Simulation of automatic control of an irrigation canal

Improved water management and efficient investment in the modernization of irrigation schemes are essential measures in many countries to satisfy the increasing demand for water. Automatic control of the main canals is one method for increasing the efficiency and flexibility of irrigation systems. In 2005, one canal in the irrigation scheme ‘Sector BXII del Bajo Guadalquivir’ was monitored. This canal is representative of irrigation schemes in Southern Spain; it is divided into four pools and supplies an area of 5,154 ha. Ultrasonic sensors and pressure transducers were used to record the opening of gates and water levels at the upstream and downstream ends of each canal pool. Using the recorded data and the SIC (Simulation of Irrigation Canals) hydraulic model, two canal control options (local upstream control and distant downstream control) were evaluated using a Proportional-Integral control algorithm. First, the SIC model was calibrated and validated under steady-state conditions. Then the proportional and integral gains of the PI algorithm were calibrated. The controllers were tested using theoretical demand changes (constant outflow followed by a sudden demand increase or decrease) and real demand changes generated on the basis of a spatially distributed crop water balance that included a number of sources of variability (random and not random) in the determination of field irrigation timing and depth. The results obtained show that only the distant downstream controller was able, quickly and automatically, to adjust the canal dynamics to the varying water demands; it achieved this efficiently and with few spills at the canal tail, even when there were sudden and significant flow variations

Effects of the Irrigation Modernization in Spain 2002-2015

Regions and basins suffering from water scarcity have promoted the modernization of irrigation systems, defined as irrigation efficiency enhancement as a measure for the adaptation to a growing demand and a limited supply of water resources. In the period 2002–2015, Spain carried out an intense irrigation modernization process with the aim of achieving significant water savings and higher flexibility and to guarantee supply, among other favourable outcomes (e.g. environmental and socio-economic). Nevertheless, certain unfavourable effects of irrigation modernization also need to be discussed. This study analyses these effects in Spain based upon a DPSIR (Driving forces, Pressures, States, Impacts, and Responses) framework and a wide-ranging review of the existing empirical literature. Our findings are highly relevant to inform decision-makers in the planning of future irrigation modernization programmes worldwide

Is the von Krmn constant affected by sediment suspension?

Is the von Krmn constant affected by sediment suspension? The presence of suspended sediment in channels and fluvial streams has been known for decades to affect turbulence transfer mechanism in sediment-laden flows, and, therefore, the transport and fate of sediments that determine the bathymetry of natural water courses. This study explores the density stratification effects on the turbulent velocity profile and its impact on the transport of sediment. There is as yet no consensus in the scientific community on the effect of sediment suspension on the von Krmn parameter, . Two different theories based on the empirical log-wake velocity profile are currently under debate: One supports a universal value of =0.41 and a strength of the wake, , that is affected by suspended sediment. The other suggests that both and could vary with suspended sediment. These different theories result in a conceptual problem regarding the effect of suspended sediment on , which has divided the research area. In this study, a new mixing length theory is proposed to describe theoretically the turbulent velocity profile. The analytical approach provides added insight defining as a turbulent parameter which varies with the distance to the bed in sediment-laden flows. The theory is compared with previous experimental data and simulations using a k-turbulence closure to the Reynolds averaged Navier Stokes equations model. The mixing length model indicates that the two contradictory theories incorporate the stratified flow effect into a different component of the log-wake law. The results of this work show that the log-wake fit with a reduced is the physically coherent approximation. © 2012. American Geophysical Union. All Rights Reserved.This research was partially funded by the project P08-AGR-03925 (Junta de Andalucía).Peer Reviewe

Decision Support Tool for the Optimal Sizing of Solar Irrigation Systems

Solar photovoltaic (PV) irrigation is increasingly used in agriculture, driven by its low operation cost and virtually zero emissions, providing electricity access in rural areas. However, the high investment cost requires an optimal design. The objective of this work was to develop a user-friendly tool to optimally size a PV generator that satisfies crop irrigation needs under local constrictions. The ODSIS (Optimal Design of Solar Irrigation System) tool, was organized in three calculation modules, preceded by two complements, which determine the daily crop irrigation needs and power demand of the pumping system. Then, the first module sizes the PV plant, considering a multiplication factor, and provides the PV production potential throughout each day of the season. The second and third modules evaluate the total investment cost and equivalent greenhouse gas emissions avoided by comparison with traditional energy sources. This tool was applied to a case study in Senegal for which a multiplication factor of 1.4 was obtained for the optimal PV plant size. Between 22% to 64% of the investment cost corresponded to the PV pumping system, depending on the irrigation technique. The use of PV energy in the case study would represent an annual economic saving for the farmer after 5 to 8 years of payback period, avoiding the emission of between 29.8 and 37.9 tCO2eq/year for the case study area

Pumpage Reduction by using Variable Rate Irrigation to Mine Undepleted Soil Water

Conventional irrigation schedules are typically based on portions of the field where root zones hold the least available soil water. This leaves undepleted available water in areas with larger water holding capacities. The undepleted water could be used through variable-rate irrigation (VRI) management; however, the benefits of VRI without in-field mapping are unexamined. In this research, the field-averaged amount of undepleted available soil water in the root zone was calculated from the NRCS Soil Survey Geographic database for 49,224 center-pivot irrigated fields in Nebraska. Potential reductions in pumpage from mining undepleted available water were then estimated. Results of the analysis show that widespread adoption of zone control VRI technology based only on the pumping savings from mining undepleted available water may be unwarranted for current VRI costs and average pumping energy expenses in the Central Plains ($0.0026 m-3 to$0.0947 m-3). Pumpage reductions exceeded 51 mm year-1 for only 2% of the fields and exceeded 25 mm year-1 for 13% of the fields; thus, reductions may be small compared to annual pumpage requirements. If VRI were im-plemented on all fields with a potential pumpage reduction greater than 51 or 25 mm year-1, the volume of pumpage reduction would be approximately 0.35% or 1.3%, respectively, of the total irrigation pumpage in Nebraska. These data may be a conservative estimate of pumpage reduction in fields where the measured variability in soil properties exceeds that described by the NRCS Soil Survey, or if undepleted water is mined early in the season and the soil water profile is refilled by precipitation, allowing undepleted water to be mined again. Adoption of zone control VRI is most feasible for fields where the pumpage reduction from VRI is large and pumping costs are above normal. Pivot fields with high un-depleted water were sparsely distributed across Nebraska and were often located along streams and or in associated alluvial areas. The prevalence of fields with large quantities of undepleted water differed among and within soil associations. We were unable to assign feasibility of VRI based on the soil association, as the occurrence of undepleted water varied significantly within a soil association. These findings should assist producers and other entities interested in VRI technology; however, pumpage reduction through use of undepleted soil water is only one benefit of VRI technology and management. Producers are encouraged to consider all potential benefits when analyzing VRI investments

Exploring TanDEM-X Interferometric Products for Crop-Type Mapping

The application of satellite single-pass interferometric data to crop-type mapping is demonstrated for the first time in this work. A set of nine TanDEM-X dual-pol pairs of images acquired during its science phase, from June to August 2015, is exploited for this purpose. An agricultural site located in Sevilla (Spain), composed of fields of 13 different crop species, is employed for validation. Sets of input features formed by polarimetric and interferometric observables are tested for crop classification, including single-pass coherence and repeat-pass coherence formed by consecutive images. The backscattering coefficient at HH and VV channels and the correlation between channels form the set of polarimetric features employed as a reference set upon which the added value of interferometric coherence is evaluated. The inclusion of single-pass coherence as feature improves by 2% the overall accuracy (OA) with respect to the reference case, reaching 92%. More importantly, in single-pol configurations OA increases by 10% for the HH channel and by 8% for the VV channel, reaching 87% and 88%, respectively. Repeat-pass coherence also improves the classification performance, but with final scores slightly worse than with single-pass coherence. However, it improves the individual performance of the backscattering coefficient by 6–7%. Furthermore, in products evaluated at field level the dual-pol repeat-pass coherence features provide the same score as single-pass coherence features (overall accuracy above 94%). Consequently, the contribution of interferometry, both single-pass and repeat-pass, to crop-type mapping is proved.This work was funded by the Spanish Ministry of Science and Innovation, the State Agency of Research (AEI) and the European Funds for Regional Development (EFRD) under Project TEC2017-85244-C2-1-P, and by the European Commission, H2020 Programme, under Project MOSES (Managing crOp water Saving with Enterprise Services)

El papel de la investigación para identificar oportunidades de mejora del regadío en Mauritania

Ponencia presentada en el I Congreso en Investigación en Agricultura para el desarrollo, celebrado en Madrid el 17 y 18 de octubre de 2011.-- Gómez Macpherson, H. et. al.La producción agrícola de Mauritania se concentra en el valle del río Senegal donde también se concentra gran parte de la población. Sólo un 0,5 % de la superficie mauritana es cultivable, y la tradicional dependencia de la agricultura pluvial ha provocado una alta inseguridad alimentaria; algo que quedó patente con las hambrunas causadas por los ciclos de sequía de los años 70. Los estados ribereños del río Senegal se organizaron entonces para desarrollar zonas regables con el objetivo de la seguridad alimentaria. En Mauritania, el regadío se orientó de forma exclusiva al cultivo del arroz, prácticamente desconocido en la zona. La ricicultura convive con sistemas tradicionales (pluviales y basados en el ciclo anual de inundación-recesión del río), pero el regadío es el sistema que garantiza la producción año a año. Sorprende por tanto que dos tercios de la superficie inicialmente regada se hayan abandonado. Esta paradoja fue el origen de la colaboración entre el Ministerio de Desarrollo Rural de Mauritania, el Instituto de Agricultura Sostenible y la Universidad Politécnica de Cataluña, concretada en proyectos financiados por AECID, y que tiene como objetivo ahondar en las razones del abandono del regadío y en buscar fórmulas para atajarlo. La colaboración se ha realizado sobre tres ejes principales: 1) comprender la interacción del regadío con los sistemas tradicionales de secano y de recesión de inundaciones; 2) diagnosticar el funcionamiento de los pequeños perímetros de riego; y 3) evaluar cultivos alternativos al arroz en términos de productividad de la tierra y del agua. Entre los cultivos regados de interés potencial se identificó el sorgo por ser del gusto de los habitantes del valle y cultivarse tradicionalmente en secano y tras la recesión del agua en suelos inundados.Los autores agradecen a los técnicos de campo y agricultores mauritanos por el trabajo realizado y al MDR y AECID por la financiación.Peer Reviewe

Opportunities of super high-density olive orchard to improve soil quality: Management guidelines for application of pruning residues

Applying pruning residues in the lanes of olive groves has become a popular practice because it is economical and accrues benefits for soil and water management. This study presents an analysis of the impact of different rates of pruning residue on soil properties, in particular related with soil quality. Over 4 annual campaigns, chopped pruning residues used as a mulch were analyzed in terms of composition, coverage and moisture content to evaluate their effects on the amount of soil organic carbon (−10 cm and −20 cm) and CO2 emissions, temperature and moisture. The experiment was carried out in a super-intensive olive orchard in Cordoba (SE, Spain) and used four amounts of fresh pruning residue: 7.5 t ha⁻1(T1), 15.0 t ha⁻1 (T2) and 30.0 t ha⁻1 (T3), with a control T0 = 0.0 t ha1.Mulch mean leaf fraction was 46.0 ± 17.5% (±SD) and initial water content, 24.8 ± 8.6%. The mulching benefits for soil moisture were observed in amounts of pruning residue >7.5 t ha⁻1, which are only produced in super-intensive olive groves or in orchards with high tree densities. The low impact of the treatments on soil moisture was explained by the dramatic annual variations in residue moisture contents, caused by the regimes of high temperatures and rainfall-evapotranspiration deficits inherent to the Mediterranean Basin climate. Thus, the mulching capacity only resulted efficient when the residues were still humid in spring. In addition, 15.0 t ha⁻1 of pruning residues was the threshold to provide significant increases in soil organic carbon at depths of 0–20 cm. Thus, accumulating pruning residue in lanes at rates of over 15 t ha⁻1 (T2 and T3) is more convenient than a uniform distribution with lower amounts, due to the low mineralization rates occurring during warm seasons and the larger inputs of OM increasing the annual balance of SOC

The 12-item World Health Organization Disability Assessment Schedule II (WHO-DAS II): a nonparametric item response analysis

<p>Abstract</p> <p>Background</p> <p>Previous studies have analyzed the psychometric properties of the World Health Organization Disability Assessment Schedule II (WHO-DAS II) using classical omnibus measures of scale quality. These analyses are sample dependent and do not model item responses as a function of the underlying trait level. The main objective of this study was to examine the effectiveness of the WHO-DAS II items and their options in discriminating between changes in the underlying disability level by means of item response analyses. We also explored differential item functioning (DIF) in men and women.</p> <p>Methods</p> <p>The participants were 3615 adult general practice patients from 17 regions of Spain, with a first diagnosed major depressive episode. The 12-item WHO-DAS II was administered by the general practitioners during the consultation. We used a non-parametric item response method (Kernel-Smoothing) implemented with the TestGraf software to examine the effectiveness of each item (item characteristic curves) and their options (option characteristic curves) in discriminating between changes in the underliying disability level. We examined composite DIF to know whether women had a higher probability than men of endorsing each item.</p> <p>Results</p> <p>Item response analyses indicated that the twelve items forming the WHO-DAS II perform very well. All items were determined to provide good discrimination across varying standardized levels of the trait. The items also had option characteristic curves that showed good discrimination, given that each increasing option became more likely than the previous as a function of increasing trait level. No gender-related DIF was found on any of the items.</p> <p>Conclusions</p> <p>All WHO-DAS II items were very good at assessing overall disability. Our results supported the appropriateness of the weights assigned to response option categories and showed an absence of gender differences in item functioning.</p

Meta-analysis of ciltacabtagene autoleucel versus physician’s choice therapy for the treatment of patients with relapsed or refractory multiple myeloma

[Objective]: In the absence of head-to-head trials, indirect treatment comparisons (ITCs) between ciltacabtagene autoleucel (cilta-cel; in CARTITUDE-1) and treatments used in real-world clinical practice (physician’s choice of treatment [PCT]), were previously conducted. We conducted multiple meta-analyses using available ITC data to consolidate the effectiveness of cilta-cel versus PCT for patients with triple-class exposed relapsed or refractory multiple myeloma (RRMM). [Methods]: Five ITCs were assessed for similarity to ensure robust comparisons using meta-analysis. Effectiveness outcomes were overall survival (OS), progression-free survival (PFS), time to next treatment (TTNT), and overall response rate (ORR). A robust variance estimator was used to account for the use of CARTITUDE-1 in each pairwise ITC. Analyses were conducted in both treated and enrolled populations of CARTITUDE-1. [Results]: Four ITCs were combined for evaluation of OS. Results were statistically significantly in favor of cilta-cel versus PCT in treated patients (hazard ratio [HR]: 0.24, 95% confidence interval [CI]: 0.22–0.26). Three ITCs were combined for evaluation of PFS and TTNT. Cilta-cel reduced the risk of progression and receiving a subsequent treatment by 80% (HR: 0.20 [95% CI: 0.06, 0.70]) and 83% (HR: 0.17 [95% CI: 0.12, 0.26]), respectively. Three ITCs were combined for evaluation of ORR. Cilta-cel increased the odds of achieving an overall response by 86-times versus PCT in treated patients. Findings were consistent in the enrolled populations and across sensitivity analyses. [Conclusions]: Evaluating multiple indirect comparisons, cilta-cel demonstrated a significantly superior advantage over PCT, highlighting its effectiveness as a therapy in patients with triple-class exposed RRMM.The CARTITUDE-1 study and these analyses were funded by Janssen Research & Development, LLC, and Legend Biotech, Inc. Medical writing support was provided by EVERSANA and funded by Janssen Global Services, LLC