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Better knowledge of the evapotranspiration and carbon exchange of fruit trees is needed to optimize the trade-off between water use and carbon assimilation and to better understand the role of agriculture in the biogeochemical cycles. In this work, we measured water and carbon fluxes with eddy covariance and transpiration with sap flow in a drip-irrigated peach orchard of 70% ground cover located in southern Spain for 2 years. The empirically measured crop coefficient (Kc) under good watering conditions in the summer ranged from 1 to 1.1. The daytime net ecosystem exchange (NEE) flux of the orchard averaged 30 g CO2 m2 day−1 during the period of maximum activity in July. The daytime ecosystem water use efficiency (WUE) of the orchard reached a minimum in late June, flattened around 4 g CO2 L−1 throughout the summer, and increased in autumn, but was unaffected by fruit removal or post-harvest irrigation reduction imposed by the farm (30% reduction). The response of instantaneous peach ecosystem WUE to VPD was also investigated. Both Kc, NEE, leaf water potential and stomatal conductance decreased sharply after harvest. Transpiration data from some purposely over-irrigated experimental trees demonstrated that the post-harvest alterations we found were not caused by fruit removal, but are result of mild water stress originated by the irrigation reduction. Hence, the often-observed alterations in water relations after harvest in well-watered trees were not observed in this experiment. This work adds insight on peach irrigation efficiency and on the contribution of orchards to agricultural carbon budgets., This study was funded by the project CONSOLIDER-RIDECO [grant number CSD2006-00067], of the Spanish Ministry of Science and Education through European Union ERDF funds.

Induction motors (IM) are susceptible to mechanical failures with severe consequences for production lines; hence, detection and classification of IM faults have been of great interest for researchers in last years. Broken rotor bars (BRB) are one of the most difficult faults to detect, since this fault does not give any indication of deterioration increasing significantly the production costs; hence, it is quite important to detect them in early states. Several methodologies have been proposed to extract information about the motor condition relying on motor-current-signature analysis (MCSA); however, they usually require high-computational-complexity algorithms to reach trustworthy result. In this work, a novel methodology for early detection and classification of BRB faults in IM is proposed. This methodology consists of obtaining two spectrograms using fixed-width windows, which are segmented through Otsu algorithm to visualize the time evolution of fault frequencies. The fault severity classification is performed through Kurtosis computation from non-stationary components. Obtained results from real experimentation validate the proposed-method high efficiency, reaching an overall 100% accuracy on detecting and classifying half, one, two BRBs, and healthy condition.

This article is part of the Research Topic: Advances in Oil Crops Research—Classical and New Approaches to Achieve Sustainable Productivity.-- Edited by: Dragana Miladinović, Johann Vollmann, Leire Molinero-Ruiz and Mariela Torres., Several simulation models of the olive crop have been formulated so far, but none of them is capable of analyzing the impact of environmental conditions and management practices on water relations, growth and productivity under both well-irrigated and water-limiting irrigation strategies. This paper presents and tests OliveCan, a process-oriented model conceived for those purposes. In short, OliveCan is composed of three main model components simulating the principal elements of the water and carbon balances of olive orchards and the impacts of some management operations. To assess its predictive power, OliveCan was tested against independent data collected in two 3-year field experiments conducted in Córdoba, Spain, each of them applying different irrigation treatments. An acceptable level of agreement was found between measured and simulated values of seasonal evapotranspiration (ET, range 393 to 1016 mm year-1; RMSE of 89 mm year-1), daily transpiration (Ep, range 0.14–3.63 mm d-1; RMSE of 0.32 mm d-1) and oil yield (Yoil, range 13–357 g m-2; RMSE of 63 g m-2). Finally, knowledge gaps identified during the formulation of the model and further testing needs are discussed, highlighting that there is additional room for improving its robustness. It is concluded that OliveCan has a strong potential as a simulation platform for a variety of research applications., The research leading to these results has received funding from Ministerio de Economía y Competitividad (Grant Nos. AGL-2010-20766 and AGL2015-69822), from Junta de Andalucía (Grant No. P08-AGR-04202), from the European Community’s Seven Framework Programme-FP7 (KBBE.2013.1.4-09) under Grant Agreement No. 613817. 2013–2016 “MODelling vegetation response to EXTREMe Events” (MODEXTREME, modextreme.org) and from ERA-NET FACCE SURPLUS (Grant No. 652615, project OLIVE-MIRACLE), the latter co-funded by INIA (PCIN-2015-259). Besides, ÁL-B was funded by a postdoctoral fellowship (‘Juan de la Cierva-Formación 2015’ Programme, FJCI-2015-24109) from Ministerio de Economía y Competitividad.

The aim of this study was to assess the effect of different irrigation strategies in virgin olive oil (VOO) composition and quality of cv. Cobrançosa, integrated in a protected denomination of origin of >Azeite de Trás-os-Montes> in the Northeast of Portugal. Three irrigation treatments were applied: T2-full irrigation that received a seasonal water equivalent to 100% of estimated crop evapotranspiration (ETc), T1-continuous deficit irrigation (30% ETc) and T0- rainfed treatment. Data were collected from two consecutive crop years (2005-2006). Irrigation regimes had a minor effect on standard quality indices (free fatty acids, peroxide value, K232 and K270) of VOO and in fatty acid composition. Total polyphenols decreased up to treatment T2, and were strongly related to the water stress integral, suggesting that the effect of irrigation on this variable occurs along the crop season and not just during the oil accumulation phase. A strategy of continuous deficit irrigation with only 30% of maximum ETc may have an advantageous effect, as it increased oil yield to more than double that of rainfed conditions while VOO quality was similar., This study was supported by project AGRO 175 of AGRO-INIA program of Ministério da Agricultura (Portugal) and Fundação para a Ciência e a Tecnologia do Ministério da Ciência, Tecnologia e do Ensino Superior (Portugal) which supported a PhD grant (SFRH/BD/18441/2004).

The impact of extreme events (such as prolonged droughts, heat waves, cold shocks and frost) is poorly represented by most of the existing yield forecasting systems. Two new model-based approaches that account for the impact of extreme weather events on crop production are presented as a way to improve yield forecasts, both based on the Crop Growth Monitoring System (CGMS) of the European Commission. A first approach includes simple relations – consistent with the degree of complexity of the most generic crop simulators – to explicitly model the impact of these events on leaf development and yield formation. A second approach is a hybrid system which adds selected agro-climatic indicators (accounting for drought and cold/heat stress) to the previous one. The new proposed methods, together with the CGMS-standard approach and a system exclusively based on selected agro-climatic indicators, were evaluated in a comparative fashion for their forecasting reliability. The four systems were assessed for the main micro- and macro-thermal cereal crops grown in highly productive European countries. The workflow included the statistical post-processing of model outputs aggregated at national level with historical series (1995–2013) of official yields, followed by a cross-validation for forecasting events triggered at flowering, maturity and at an intermediate stage. With the system based on agro-climatic indicators, satisfactory performances were limited to microthermal crops grown in Mediterranean environments (i.e. crop production systems mainly driven by rainfall distribution). Compared to CGMS-standard system, the newly proposed approaches increased the forecasting reliability in 94% of the combinations crop × country × forecasting moment. In particular, the explicit simulation of the impact of extreme events explained a large part of the inter-annual variability (up to +44% for spring barley in Poland), while the addition of agro-climatic indicators to the workflow mostly added accuracy to an already satisfactory forecasting system., Part of the methodology of this study has been funded under the European Community's Seventh Framework Programme (FP7/2007-2013), grant agreement no. 613817 (MODEXTREME, Modelling vegetation response to extreme events, http://modextreme.org).

A model of potential olive oil production is presented, based on a three-dimensional model of canopy photosynthesis and respiration and dynamic distribution of assimilates among organs. The model is used to analyse the effects of planting density (high and super-high density orchards with 408 and 1667 trees ha−1, respectively) and climate change (ΔT of 4 °C and CO2 concentration of 740 ppm) on olive oil production. To evaluate its predictive power, the simulations were tested with published measurements of leaf area, growth and yield for a high density olive orchard cv. ‘Arbequina’ in Cordoba, Spain. The model slightly overestimated (less than 7%) the different measurements reported in the experiment. For all simulations, the maximum yields obtained were in agreement with literature. Simulations showed that climate change had a very small effect on yields due to compensation of the negative and positive effects of temperature and CO2 on photosynthesis and respiration. However, high temperatures led to some sterile years due to lack of vernalization. The model predicts that super-high density olive orchards achieve higher potential yields than high-density systems and that maximum yields are reached on the third year of the orchard. The advantage of a higher density is a higher interception of solar radiation, especially during the first years of the orchard. In all the simulations, the model predicted a small decrease of the radiation use efficiency for oil production with the age of the orchard as well as an important inter-annual variability (range of 0.11–0.19 g (MJ PAR)−1), indicating that the use of a constant radiation use efficiency may not be adequate to predict oil production., The authors gratefully acknowledge the financial support of the Junta de Andalucía (project P08-AGR-04202). Part of this work was financed by the European Union (FP7) KBBE-CALL 7, Grant Agreement no. 613817 “Modeling Vegetation Response to Extreme Events—MODEXTREME”. While the model was developed, Alejandro Morales held a postgraduate fellowship granted by the Fundacion Caja Madrid.

This study introduces a novel methodology for early detection of stator short circuit faults in induction motors by using autoregressive (AR) model. The proposed algorithm is based on instantaneous space phasor (ISP) module of stator currents, which are mapped toα-βstator-fixed reference frame; then, the module is obtained, and the coefficients of the AR model for such module are estimated and evaluated by order selection criterion, which is used as fault signature. For comparative purposes, a spectral analysis of the ISP module by Discrete Fourier Transform (DFT) is performed; a comparison of both methodologies is obtained. To demonstrate the suitability of the proposed methodology for detecting and quantifying incipient short circuit stator faults, an induction motor was altered to induce different-degree fault scenarios during experimentation.

Sapwood thermal properties and water content (Fw) natural variations affect the accuracy of heat pulse sap flow methods, as they are typically set as constants or calculated during zero flow conditions. In a first experiment, a characterisation of both thermal properties and some of their determining anatomical and functional factors was conducted on several fruit tree species assessing the reliability of different methodologies. Besides that, a second experiment was carried out to evaluate the errors of heat pulse methods arising from ignoring Fw variations. To do so, desorption curves were constructed, allowing the substitution of Fw changes with those of water potential (Ψ). Results of the first experiment showed considerable differences between species in both the thermal, anatomical and functional properties of sapwood. Apart from that, discrepancies between the methods applied to determine thermal properties were also found and their implications for some heat pulse methods are discussed. The analysis conducted for the second experiment indicated that large errors in sap flux density (J) determinations might occur when daily and seasonal variations of Ψ (and hence of Fw) are disregarded. The extent of these errors was influenced by the species and heat pulse technique. Thus, the heat ratio and Tmax were, respectively, the least and most vulnerable methods to errors in J determinations associated with changes in Fw., This work was funded by the Andalusian Regional Government (Junta de Andalucía, Project P10-AGR-6456), by the Spanish Ministry of Natural, Rural and Marine Environment (MMARM, Project AGL-2010-20766) and European Regional Development Fund (ERDF). In addition, we thank the Spanish Research Council (CSIC) predoctoral JAE program for the PhD funding granted to the first author.

This study provides insight into the assessment of the spatio-temporal trends of chlorophyll fluorescence, narrow-band physiological indices, and structural indices acquired with a hyperspectral imager flown over a flux tower in a canopy characterized by small seasonal structural changes and a heterogeneous architecture. A total of seven flights between summer and autumn were conducted with a hyperspectral camera that captured 30cm resolution imagery and 260 spectral bands in the 400-900nm region. This enabled the identification of pure-vegetation tree crown pixels around an eddy covariance flux tower without shadow components or background effects. The hyperspectral imagery was used to study the temporal patterns of canopy fluorescence and reflectance indices related to physiology and canopy structure. The seasonal trends observed in the airborne indices and fluorescence and their relationship with gross primary production (GPP) demonstrated that vegetation indices mostly related to structure such as the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI) yielded non-significant relationships (r2=0.17; p>0.05) due to the small structural changes in the canopy through the season. By contrast, physiological indices related to chlorophyll content (TCARI/OSAVI), light use efficiency (PRI570), and canopy chlorophyll fluorescence calculated through the Fraunhofer Line Depth principle (FLD3) showed a similar seasonal trend to that of GPP measured at the same time of the flights (r2 in the range 0.75-0.84; p0.05) to the physiological indicators such as TCARI/OSAVI, PRI570 and fluorescence. The spatial variability of the hyperspectral indices investigated through the coefficient of variation (CV) showed that fluorescence around the tower varied up to 17% at the time of the maximum stress (summer), while LAIp showed little variation during that time (CV=1.8%). After the summer stress period, the CV for fluorescence and chlorophyll content decreased in autumn down to 9%. This study demonstrates that small physiological changes occurring in an evergreen canopy were still captured by remote sensing physiological indices and high-resolution airborne fluorescence. These indicators are required for GPP monitoring when the vegetation dynamics are not captured by remote sensing structural indices. © 2012 Elsevier Inc., The authors gratefully acknowledge the financial support from the Spanish Ministry of Science and Education (MEC) for projects AGL2009-13105, CONSOLIDER RIDECO (CSD2006-67) and from the Regional Government of Andalusia for project P08-AGR-04202.

This study was conducted to model the fraction of intercepted photosynthetically active radiation (fIPAR) in heterogeneous row-structured orchards, and to develop methodologies for accurate mapping of the instantaneous fIPAR at field scale using remote sensing imagery. The generation of high-resolution maps delineating the spatial variation of the radiation interception is critical for precision agriculture purposes such as adjusting management actions and harvesting in homogeneous within-field areas. Scaling-up and model inversion methods were investigated to estimate fIPAR using the 3D radiative transfer model, Forest Light Interaction Model (FLIGHT). The model was tested against airborne and field measurements of canopy reflectance and fIPAR acquired on two commercial peach and citrus orchards, where study plots showing a gradient in the canopy structure were selected. High-resolution airborne multi-spectral imagery was acquired at 10 nm bandwidth and 150 mm spatial resolution using a miniaturized multi-spectral camera on board an unmanned aerial vehicle (UAV). In addition, simulations of the land surface bidirectional reflectance were conducted to understand the relationships between canopy architecture and fIPAR. Input parameters used for the canopy model, such as the leaf and soil optical properties, canopy architecture, and sun geometry were studied in order to assess the effect of these inputs on canopy reflectance, vegetation indices and fIPAR. The 3D canopy model approach used to simulate the discontinuous row-tree canopies yielded spectral RMSE values below 0. 03 (visible region) and below 0. 05 (near-infrared) when compared against airborne canopy reflectance imagery acquired over the sites under study. The FLIGHT model assessment conducted for fIPAR estimation against field measurements yielded RMSE values below 0. 08. The simulations conducted suggested the usefulness of these modeling methods in heterogeneous row-structured orchards, and the high sensitivity of the normalized difference vegetation index and fIPAR to background, row orientation, percentage cover and sun geometry. Mapping fIPAR from high-resolution airborne imagery through scaling-up and model inversion methods conducted with the 3D model yielded RMSE error values below 0. 09 for the scaling-up approach, and below 0. 10 for the model inversion conducted with a look-up table. The generation of intercepted radiation maps in row-structured tree orchards is demonstrated to be feasible using a miniaturized multi-spectral camera on board UAV platforms for precision agriculture purposes. © 2012 Springer Science+Business Media, LLC., Financial support from the Spanish Ministry of Science and Innovation (MCI) for the projects AGL2009-13105, CONSOLIDER CSD2006-67, and AGL2003-01468 is gratefully acknowledged, as well as the Junta de Andalucía-Excelencia AGR-595 and FEDER. M.L. Guillén-Climent was supported by a grant JAE of CSIC, co-funded by the European Social Fund.

Little information is available on carbon exchange of olive orchards despite their agronomical and ecological importance. Measurements of CO 2 and water vapour exchange were performed during 2006 and 2007 with large closed chambers in an olive orchard in Cordoba (Spain) under two irrigation regimes, full and regulated deficit irrigation.Canopy assimilation was higher for full (10.8-21.3gCO 2m -2day -1) than for deficit irrigation (5.1-17.4gCO 2m -2day -1). Forty-five percent of gross assimilation was lost in respiration being root respiration less than 30% of total respiration. Water use efficiency (WUE) typically decreased from maximum values around 30gCO 2L -1 soon after sunrise to 2-7gCO 2L -1 in the afternoon when vapour pressure deficit typically exceeded 5kPa. While water stress improved instantaneous WUE only slightly, the effect was dramatic for daily values. The measurements allowed the calibration of a model coupling canopy conductance and assimilation that showed a seasonal variation in the parameters suggesting changes in the physiology of olive trees. The improvement of WUE in olive trees under water stress supports the adoption of deficit irrigation in olive orchards although further research is required to prevent negative side effects. © 2012 Elsevier B.V., The authors gratefully acknowledge the financial support of the Ministerio de Educación y Ciencia of Spain (project AGL2004-05717), Consejeria de Ciencia e Innovación Junta de Andalucia (project P08-AGR-04202), and of the European Regional Development Fund (ERDF).

The compensation heat pulse (CHP) method is widely used to estimate sap flow and transpiration in conducting organs of woody plants. Previous studies have reported a natural azimuthal variability in sap flow, which could have practical implications in locating the CHP probes and integrating their output. Sap flow of several olive trees (Olea europaea L. cv. 'Arbequina') previously grown under different irrigation treatments were monitored by the CHP method, and their xylem anatomical characteristics were analyzed from wood samples taken at the same location in which the probes were installed. A significant azimuthal variability in the sap flow was found in a well-irrigated olive tree monitored by eight CHP probes. The azimuthal variability was well related to crown architecture, but poorly to azimuthal differences in the xylem anatomical characteristics. Well-irrigated and deficit-irrigated olive trees showed similar xylem anatomical characteristics, but they differed in xylem growth and in the ratio of nocturnal-to-diurnal sap flow (N/D index). The results of this work indicate that transpiration cannot be accurately estimated by the CHP method in olive trees if a small number of sensors are employed and that the N/D index could be used as a sensitive water status indicator. © The Author 2010. Published by Oxford University Press. All rights reserved., This work was financed by grant no. CSD2006-00067 (Consolider-RIDECO) of Ministerio de Ciencia e Innovación (Spain).

We measured eddy covariance fluxes of CO2 and H2O over a flat irrigated olive orchard during growth, in different periods from Leaf Area Index (LAI) of 0.3–1.9; measurements of soil respiration were also collected. The daily net ecosystem exchange flux (FNEE) was practically zero at LAI around 0.4 or when the orchard intercepted 11% of the incoming daily radiation; at the end of the experiment, with LAI of 1.9 (and the fraction of intercepted daily radiation close to 0.5), FNEE was around 10 g CO2 m−2 day−1. The night-time ecosystem respiration (Reco), calculated from eddy fluxes in well-mixed night conditions, show a clear but non-linear dependence with LAI; it ranged from 0.05 to 0.15 mg CO2 m−2 s−1 (in average), being the lower limit ideally close to the heterotrophic soil respiration at the site. The gross primary production flux (FGPP) was linearly related to LAI within the LAI range of this experiment (with 11 g CO2 m−2 day−1 increments per unit of LAI) and to the fraction of intercepted radiation. The maximum rates of FGPP (0.75 mg CO2 m−2 s−1) were obtained in the summer mornings of 2002, at LAI close to 1.9. FGPP was strongly modulated by vapour pressure deficit (VPD) through the canopy conductance, even in absence of water stress. Hence, especially in the summer, the maximum rates of carbon assimilation are reached always before noon. The daily course of FGPP shows a two-phase pattern, first related to irradiance and then to canopy conductance. The water use efficiency (WUE) was, in average, 3.8, 6.3 and 7 g CO2 L−1 in 1999, 2001 and 2002, respectively, with maxima always in the early morning. Hourly WUE was strongly related to VPD (WUE = −10.25 + 22.52 × VPD−0.34). Our results suggest that drip irrigated orchards in general, and olive in particular, deserve specific carbon exchange and carbon budget studies and cannot be easily included in other biomes., This work was funded by project AGL2004-05717 of Spanish Ministry of Science (Ministerio de Educación y Ciencia).

The larvae of scarab beetles, known as “white grubs” and belonging to the genera Phyllophaga and Anomala (Coleoptera: Scarabaeidae), are regarded as soil-dwelling pests in Mexico. During a survey conducted to find pathogenic bacteria with the potential to control scarab larvae, a native Serratia sp. (strain Mor4.1) was isolated from a dead third-instar Phyllophaga blanchardi larva collected from a cornfield in Tres Marías, Morelos, Mexico. Oral bioassays using healthy P. blanchardi larvae fed with the Mor4.1 isolate showed that this strain was able to cause an antifeeding effect and a significant loss of weight. Mortality was observed for P. blanchardi , P. trichodes , and P. obsoleta in a multidose experiment. The Mor4.1 isolate also caused 100% mortality 24 h after intracoelomic inoculation of the larvae of P. blanchardi , P. ravida , Anomala donovani and the lepidopteran insect Manduca sexta . Oral and injection bioassays were performed with concentrated culture broths of the Mor4.1 isolate to search for disease symptoms and mortality caused by extracellular proteins. The results have shown that Mor4.1 broths produce significant antifeeding effects and mortality. Mor4.1 broths treated with proteinase K lost the ability to cause disease symptoms and mortality, in both the oral and the injection bioassays, suggesting the involvement of toxic proteins in the disease. The Mor4.1 isolate was identified as a putative Serratia entomophila Mor4.1 strain based on numerical taxonomy and phylogenetic analyses done with the 16S rRNA gene sequence. The potential of S. entomophila Mor4.1 and its toxins to be used in an integrated pest management program is discussed.

We tested the hypothesis that the transpiration (λEp) of high-coupled canopies, such as olive groves, may be calculated on a daily basis with sufficient precision by the Penman–Monteith ‘big leaf’ equation, by a model of bulk daily canopy conductance (gc) capable of scaling for canopy dimension. Given the limited data required, such a model could replace the standard approach (ET0 × Kc) for calculating olive water requirements, enhancing the precision of estimates. We developed a specific model of daily gc for unstressed olive canopies that was calibrated by transpiration measurements obtained by water balance from a 2-year experiment in a mature orchard with λEp ranging from 0.6 (February 1993) to 11.5 (July 1994) MJ m–2 day–1 and where leaf area index (L) changed from 1.25 to 2.5. The model uses the intercepted fraction of daily PAR and a linear function of average daytime temperature. The model was validated with λEp data collected by eddy covariance in a 3-year experiment conducted in a growing orchard that differed in L and cultivar from the one used in the calibration. The gc model, when used in the Penman–Monteith equation, gave very good daily λEp predictions for all seasons during 3 years, ranging from 0.5 (November 1998) to 5.5 (June 2000) MJ m–2 day–1, indicating that the goals of dealing with the dependence of olive gc on L and of simulating the seasonal variations in gc were achieved. A comparison with the Jarvis gc model, calibrated with 2 months of measured gc hourly data, showed that the gc model developed here performed better than the Jarvis model for the 3-year dataset. The exception to this was the period in which the Jarvis model was calibrated. This indicates that (1) the Jarvis model did not account for the seasonal variations in gc of the olive trees; and (2) the spatial and temporal scale assumptions required in the calibration of gc generate seasonal errors in the simulated bulk daily λEp for this crop. The applicability of this bulk gc model is restricted to well watered olive canopies and to the one-layer approach of calculating λEp but it could be adapted to rain-fed canopies in the future.

An investigation of the detection of water stress in non-homogeneous crop canopies such as orchards using high-spatial resolution remote sensing thermal imagery is presented. An airborne campaign was conducted with the Airborne Hyperspectral Scanner (AHS) acquiring imagery in 38 spectral bands in the 0.43–12.5 mm spectral range at 2.5 m spatial resolution. The AHS sensor was flown at 7:30, 9:30 and 12:30 GMT in 25 July 2004 over an olive orchard with three different water-deficit irrigation treatments to study the spatial and diurnal variability of temperature as a function of water stress. A total of 10 AHS bands located within the thermal-infrared region were assessed for the retrieval of the land surface temperature using the split-window algorithm, separating pure crowns from shadows and sunlit soil pixels using the reflectance bands. Ground truth validation was conducted with infrared thermal sensors placed on top of the trees for continuous thermal data acquisition. Crown temperature (Tc), crown minus air temperature (Tc Ta), and relative temperature difference to well-irrigated trees (Tc TR, where TR is the mean temperature of the well-irrigated trees) were calculated from the ground sensors and from the AHS imagery at the crown spatial resolution. Correlation coefficients for Tc TR between ground IRT sensors and airborne image-based AHS estimations were R2 = 0.50 (7:30 GMT), R2 = 0.45 (9:30 GMT) and R2 = 0.57 (12:30 GMT). Relationships between leaf water potential and crown Tc Ta measured with the airborne sensor obtained determination coefficients of R2 = 0.62 (7:30 GMT), R2 = 0.35 (9:30 GMT) and R2 = 0.25 (12:30 GMT). Images of Tc Ta and Tc TR for the entire field were obtained at the three times during the day of the overflight, showing the spatial and temporal distribution of the thermal variability as a function of the water deficit irrigation schemes., Financial support from the Spanish Ministry of Science and Technology (MCyT) for the projects AGL2002-04407-C03 and AGL2003-01468, and financial support to P.J. Zarco-Tejada from the Ramo´n y Cajal (MCyT) and Averroes (JA) programs are gratefully acknowledged.

Leaf area loss is a typical damage of fungal and insect attacks or hail. In this work growth responses to defoliation were analysed by removing 50% of leaf area at different phenological stages in sunflower (Helianthus annuus L.). Plants defoliated at head-visible stage showed an increased single leaf area which partly compensated the reduction in light interception during the season, while later treatments, during pre-anthesis and complete anthesis, did not show increased single leaf area but a delayed leaf senescence. A decrease in biomass accumulation was observed particularly in pre-anthesis treated plants. Results were implemented into the crop model OILCROP-SUN 6.0 to assess the impact of compensation on growth and yield. It was concluded that leaf area recovery should be incorporated into the growth models for a reliable simulation of yield after partial defoliation. (C) 2002 Elsevier Science B.V. All rights reserved.

Effects of increasing carbon dioxide concentration [CO2] on wheat vary depending on water supply and climatic conditions, which are difficult to estimate. Crop simulation models are often used to predict the impact of global atmospheric changes on food production. However, models have rarely been tested for effects on crops of [CO2] and drought for different climatic conditions due to limited data available from field experiments. Simulations of the effects of elevated [CO2] and drought on spring wheat (Triticum aestivum L.) from three crop simulation models (LINTULCC2, AFRCWHEAT2, Sirius), which differ in structure and mechanistic detail, were compared with observations. These were from 2 years of free-air carbon dioxide enrichment (FACE) experiments in Maricopa, Arizona and 2 years of standardised (in crop management and soil conditions) open-top chamber (OTC) experiments in Braunschweig and Giessen, Germany. In a simulation exercise, models were used to assess the possible impact of increased [CO2] on wheat yields measured between 1987 and 1999 at one farm site in the drought prone region of Andalucia, south Spain. The models simulated well final biomass (BM), grain yield (GY), cumulative evapotranspiration (ET) and water use efficiency (WUE) of wheat grown in the FACE experiments but simulations were unsatisfactory for OTC experiments. Radiation use efficiency (RUE) and yield responses to [CO2] and drought were on average higher in OTC than in FACE experiments. However, there was large variation among OTC experiments. Plant growth in OTCs was probably modified by several factors related to plot size, the use (or not use) of border plants, airflow pattern, modification of radiation balance and/or restriction of rooting volume that were not included in the models. Variation in farm yields in south Spain was partly explained by the models, but sources of unexplained yield variation could not be identified and were most likely related to effects of pests and diseases that were not included in the models. Simulated GY in south Spain increased in the range between 30 and 65% due to doubling [CO2]. The simulated increase was larger when a [CO2]×drought interaction was assumed (LINTULCC2, AFRCWHEAT2) than when it was not (Sirius). It was concluded that crop simulation models are able to reproduce wheat growth and yield for different [CO2] and drought treatments in a field environment. However, there is still uncertainty about the combined effects of [CO2] and drought including the timing of drought stress and about relationships that determine yield variation at farm and larger scales that require further investigation including model testing.

The authors thank Dr. M. Pastor for providing access to the experimental orchards., Evaporation from the soil (E s) beneath an olive orchard was characterised in a semi-arid Mediterranean climate (Córdoba, Spain). First, the microlysimeter method was modified to measure accurately E s beneath tree orchards. The variability in irradiance reaching the soil beneath the orchard caused spatial variations in E s during both evaporation stages. In the first days of the drying cycle, E s was higher for high irradiance locations but the opposite occurred the subsequent days, although daily differences in E s between locations progressively declined. For the energy-limiting stage, linear relationships between E s values and incident photosynthetically active radiation were found for different times throughout the season. The slopes of the relationships were similar, but their intercepts differed substantially, showing the importance of a variable aerodynamic component in determining E s. A simple functional model was formulated to estimate E s at daily time steps. During the energy-limiting stage, E s is calculated as the sum of the equilibrium evaporation at the soil surface and an aerodynamic term, derived from the Penman equation. For the falling rate stage, Ritchie's (1972) approach is adopted for the E s calculations. The model was successfully tested in an orchard of 6×6 m spacing, typical of intensive olive orchards, under a wide range of evaporative demand conditions. Trees covered around 36% of the soil surface. The model predicted an average seasonal E s of 286 mm, which represents around one third of the estimated olive evapotranspiration and about 50% of the average seasonal rainfall of the area., This work was funded by grant OLI96-2212 of the Comisión Interministerial de Ciencia y Tecnología, Ministerio de Educación y Cultura, Spain. S. Bonachela received financial support form CSIC, Spain.

High early vigour (plant dry matter in the early development stages) in sunflower may be a desirable character under water-limited environments as it may contribute to higher transpiration efficiency and reduced soil evaporation. However a high early vigour causes a more rapid use of soil water, which may threaten crop water supply during seed filling. This is also influenced by the seasonal pattern of rainfall and genotype season length. The objective of this research was to simulate the performance of cultivars of sunflower differing in season length and early vigour under a Mediterranean climate. A simulation model of the sunflower crop, OILCROP-SUN, was modified and used to find the optimum combination of early vigour and season length of the genotypes for different environments. Field experiments were carried out during 1992, 1993 and 1994 in Cordoba, Spain (38°N). Sunflower populations with similar genetic background but with differences in early vigour were used to study the association of this trait with other characters and with the genetic parameters required to run the model. Changes in early vigour were simulated by modifying leaf growth rate in the model. The field experiments showed that high early vigour, as measured by stem volume 425°Cd after emergence, is not related to reduced root growth and is not associated with season length. Simulations showed that the highest seed yield is obtained using genotypes with high early vigour, provided that their season length is long enough for the growing conditions

[EN] This work present a group of tools based on the fast Fourier transform (FFT) and Haar, Daubechies and Coiflet discrete wavelet transform (DWT), using the Park's instantaneous space phasor module (ISP) of the three phase induction machine stator currents for electric stator and rotor fault diagnosis. A simulation and experimental validation for inter-turn stator short-circuit electric fault and end-ring broken rotor fault diagnosis was performed. The main objective of the work is to perform a non invasive electric fault diagnosis to avoid economical losses in the industrial process using the advantages of spectral and wavelet tools., [ES] En este trabajo se presenta un conjunto de herramientas basadas en la transformada rápida de Fourier (TRF) y la transformada discreta ondeleta (TDO) Haar, Daubechies y Coiflet utilizando el módulo del vector espacial instantáneo (VEI) de las corrientes de estator del motor de inducción trifásico para diagnosticar fallas en el estator y en el rotor. Se efectúa un estudio en simulación y una validación experimental de fallas eléctricas del estator para cortocircuito entre espiras de un mismo devanado y problemas de fisura de barra y anillo de cortocircuito de rotor. El objetivo del trabajo es contar con una herramienta de tipo no invasiva que permita efectuar el diagnóstico de fallas incipientes (con un carácter preventivo) con el fin de evitar pérdidas económicas importantes en diferentes procesos industriales que utilizan máquinas de inducción aprovechando para ello las virtudes que ofrece la TRF y la TDO mediante el análisis de las firmas de corriente del estator del motor de inducción (MI), así como el diagnóstico de fallas drásticas con fines correctivos., Este trabajo fue financiado por programa de Doctorado en Ciencias de la Ingeniería del Instituto Tecnológico de Aguascalientes, el apoyo del proyecto PROMEP/ITA/103.5/13/8890 y con recursos del convenio PROMEP/UASLP/CARepPrel-15 y C14- FAI-04-42.42