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Montoro A.,Instituto Tecnico Agronomico Provincial ITAP | Sadras V.,South Australian Research And Development Institute
Acta Horticulturae

The aim of this work was to investigate the effect of elevated temperature, and its interaction with water supply, on stomata size and leaf photosynthesis in shiraz grapevine in Barossa Valley (South Australia) The experiment combined two thermal regimes (control and elevated day/night temperature) and two water regimes (irrigated and water deficit). Temperature regimes were control with background ambient temperature, and elevated day/night temperature achieved with an open-top heating system that combines passive heating on clear days, active heating on overcast days and during the night, and mobile panels that regulate the release of excess heat as necessary. Stomata size was measured in using the technique of nail polish and stickytape imprints from the abaxial epidermis. Stomatal length and width were measured s with at a magnification of × 200. Li-Cor 6400 was used (Li-Cor Environmental Sciences, Lincoln, Nebraska, USA) to measure photosynthetic rate. We found that elevated temperature increased stomata size and leaf photosynthesis in Shiraz grapevine. This response likely contributes to evaporative cooling and adaptation to elevated temperature. Source

Calleja J.F.,University of Oviedo | Recondo C.,University of Oviedo | Peon J.,University of Oviedo | Fernandez S.,University of Oviedo | And 2 more authors.
Remote Sensing

The broadband albedo values retrieved from satellite sensors are usually compared directly to ground measurements. Some authors have noted the necessity of high spatial resolution albedo estimates to fill the gap between ground measurements and satellite retrievals. In this respect, hyperspectral airborne data with high spatial resolution is a powerful tool. Here, a new operational method for the calculation of airborne broadband apparent albedo over the spectral range of 350-2500 nm is presented. This new method uses the Hemispherical Directional Reflectance Factor (HDRF) as a proxy for the narrowband albedo, assuming a Lambertian approximation. The broadband apparent albedo obtained is compared to that estimated using theapparent albedo equation devised for the Moderate Resolution Imaging Spectroradiometer (MODIS). Airborne data were collected using the Airborne Hyperspectral Scanner (AHS). Field data were acquired at three sites: A camelina field, a green grass field, and a vineyard. The HDRF can be used to approximate the narrowband albedo for all View Zenith Angle (VZA) values for flights parallel to the solar principal plane (SPP); for flights orthogonal to the SPP, discrepancies are observed when the VZA approaches -45°. Root Mean Square Error (RMSE) values in the range 0.009-0.018 were obtained using the new method, improving upon previous results over the same area (RMSEs of 0.01-0.03). The relative error in the albedo estimation using the new method is 12% for -36.2° < VZA < 40.8° in the case of flights parallel to the SPP and less than 15% for -13° < VZA < 45° and 45% for VZA = -45° for flights orthogonal to the SPP. The good performance of the new method lies in the use of the at-surface solar irradiance and the proposed integration method. © 2016 by the authors. Source

Montoro A.,Instituto Tecnico Agronomico Provincial ITAP | Lopez-Fuster P.,Instituto Tecnico Agronomico Provincial ITAP | Fereres E.,University of Cordoba, Spain
Irrigation Science

Irrigation scheduling services (ISS) provide farmers with recommendations on timing and amount of irrigation, thus contributing to improving on-farm water management. There are wide variations in the level of services, from providing regional water use guidelines to local, on-farm advisory services. An ISS (ISS-ITAP) was created in 1988 in Albacete, Central Spain, a province encompassing 100,000 ha which are irrigated mostly with groundwater. The ISS-ITAP first offered general information on crop water requirements (ET), and after 1994 field-specific scheduling services were provided to growers. By 2005 the ISS-ITAP had expanded its services to over 33,500 ha, corresponding to about 30% of the irrigable area. The evolution of irrigation performance in a number of individual farms was followed over 10 years, and it was found that the proportion of fields which were adequately irrigated increased from 50 to over 70% in that period. Meanwhile, the proportion of deficit-irrigated fields declined from 20 to 10%, while the proportion of over-irrigated fields which also had initially decreased from 20 to 10%, went back to 20% at the end of the study period. To assess the benefits and costs of the ISS-ITAP, a comparison of the yields achieved in the scheduled farms against those obtained in the rest of the province was carried out. When the Service was evaluated in economic terms, using information from 2003, the pay-back was 2 years and the internal rate of return was 59.1%, highlighting the high returns on the public funds invested by ISS-ITAP to provide irrigation advisory service to growers in the Albacete province. © 2010 Springer-Verlag. Source

Manas F.,Instituto Tecnico Agronomico Provincial ITAP | Lopez-Fuster P.,Instituto Tecnico Agronomico Provincial ITAP | Lopez-Urrea R.,ITAP
Acta Horticulturae

The effects of six different levels of water depths, applied during the growing season, on the production (yield) of mature almond trees were evaluated during four consecutive years in Albacete (Central Spain). The irrigation treatments applied were: T1, no irrigation with the exception of one irrigation needed to keep the trees alive; T2, which was irrigated by applying 25% of potential crop evapotranspiration (ETc) during the whole season (sustained deficit irrigation, SDI); T3, regulated deficit irrigation (RDI) treatment received 50% of ETc, however during the kernelfilling period irrigation was 15% of ETc; T4, SDI treatment which was irrigated by applying 50% of ETc; T5, RDI treatment received 100% of ETc, however during the kernel-filling period irrigation was 20% of ETc and T6, which was irrigated to satisfy the entire demand of ETc. Results indicate that, statistically there were significant differences (P<0.05) in yield and irrigation water use efficiency (WUEI) among treatments. The optimum yield response was observed in treatment T6 during the four years of the study period and reached an average maximum yield of about 1,260 kg ha-1. There were no significant differences (P>0.05) in almond production and WUEI between RDI and SDI strategies. Although yield reductions for treatments T4 and T5 were significant (23% for T4 and 31% for T5 less than T6), the water savings obtained (50% for T4 and 55% for T5 of that applied with respect to T6) may encourage the adoption of SDI and RDI strategies in areas where a large portion of irrigation water comes from aquifers that are threatened by over exploitation. Source

Lopez-Urrea R.,Instituto Tecnico Agronomico Provincial ITAP | Montoro A.,Instituto Tecnico Agronomico Provincial ITAP | Manas F.,Instituto Tecnico Agronomico Provincial ITAP | Lopez-Fuster P.,Instituto Tecnico Agronomico Provincial ITAP | Fereres E.,University of Cordoba, Spain
Agricultural Water Management

Vineyard irrigation management based on knowledge of the crop water requirements, is critical in the semi-arid zones for improving fruit quality and production stability as prerequisites for obtaining wines of high quality. The aim of this study was to quantify the water use of a mature Vitis vinifera cv. Tempranillo vineyard grown for wine production without soil water limitations during three growing seasons (2007-2009). The experimental work was carried out in the lysimeter facilities located in Albacete (Central Spain). In 1999, a weighing lysimeter with an overall resolution of 250g was installed in the center of a vineyard (100m×100m). A monolith of undisturbed soil was placed inside the lysimeter tank, which was 3m×3m and 1.7m deep. Two vines under drip irrigation were planted in the lysimeter, each one occupying 4.5m 2, the same area as the vines in the rest of the plot. To schedule irrigation, ET c values were calculated from daily mass loss minus drainage loss, and water was applied to replace the loss, thus, maintaining non-limiting soil water conditions. Seasonal grapevine evapotranspiration (ET) measured in the lysimeter was 550mm in 2007, 377mm in 2008 and 505mm in 2009. The lower ET c values in 2008 were directly related to a smaller canopy in that year caused by a late frost. In the three study years, maximum average K c values reached values of approximately 0.75, 0.60 and 0.70, respectively from veraison to harvest and were related to maximum canopy cover values of 45, 33 and 40 percent, respectively. The dual crop coefficient approach was used to separate crop transpiration (K cb) from soil evaporation (K e). As canopy increased, K cb values increased and K e values decreased from veraison to harvest stage. Linear relationships were found between the lysimeter K cb and the canopy cover (CC) for the three seasons, and a single relationship that related K cb to growing degree-days (GDD) was established (K cb=0.0004×GDD+0.093; R 2=0.97) allowing extrapolation of our results to other areas. © 2012 Elsevier B.V. Source

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