The feasibility of using canopy temperature (T c ) measured with a hand-operated infrared thermographic camera as a water stress indicator was evaluated in the field during two seasons on citrus and persimmon trees subjected to different levels of deficit irrigation. In both species, which differ in leaf anatomy and stomatal response to environmental conditions, T c was compared with midday stem water potential ( s ) measurements. In persimmon trees, leaf stomatal conductance (g s ) was also measured. T c was the most sensitive indicator of plant water status particularly due to the lower tree-to-tree variability as compared to  s and g s . On the other hand, in citrus trees T c was not always affected by plant water stress. Only in the second experimental season, when air vapour pressure deficit values were below 2.7 kPa and images were also taken from above the canopies, deficit-irrigated trees had higher T c than the control ones, this difference being at most 1.7 ºC. Overall, the results show that hand-operated thermographic cameras can be used to detect plant water stress in both fruit tree species.Nevertheless, the use of T c measurements to detect plant water stress appears to be more precise in persimmon than in orange citrus. This might be because persimmon trees have larger leaf size which determines higher canopy resistance allowing for higher increases in canopy temperature in response to water stress via stomatal closure.3

Leaf temperature is a physiological trait that can be used for monitoring plant water status. Nowadays, by means of thermography, canopy temperature can be remotely determined. In this sense, it is crucial to automatically process the images. In the present work, a methodology for the automatic analysis of frontal images taken on individual trees was developed. The procedure can be used when cameras take at the same time thermal and visible scenes, so it is not necessary to reference the images. In this way, during the processing in batch, no operator participated. The procedure was developed by means of a non supervised classification of the visible image from which the presence of sky and soil could be detected. In case of existence, a mask was performed for the extraction of intermediate pixels to calculate canopy temperature by means of the thermal image. At the same time, sunlit and shady leaves could be detected and isolated. Thus, the procedure allowed to separately determine canopy temperature either of the more exposed part of the canopy or of the shaded portion. The methodology developed was validated using images taken in several regulated deficit irrigation trials in Persimmon and two citrus cultivars (Clementina de Nules and Navel Lane-Late).Overall, results indicated that similar canopy temperatures were calculated either by means of the automatic process or the manual procedure. The procedure developed allows to drastically reduce the time needed for image analysis also considering that no operator participation was required. This tool will facilitate further investigations in course for assessing the feasibility of thermography for detecting plant water status in woody perennial crops with discontinuous canopies. Preliminary results reported indicate that the type of crop evaluated has an important influence in the results obtained from termographic imagery. Thus, in Persimmon trees there were good 3 correlations between canopy temperature and plant water status while, in Clementina de Nules and Navel Lane-Late citrus cultivars canopy temperature differences among trees could not be related with tree-to-tree variation in plant water status.

Elsevier Ballester, C.; Castel, J.; Jiménez Bello, MA.; Castel Sánchez, JR.; Intrigliolo Molina, DS. (2013). Thermographic measurement of canopy temperature is a useful tool for predicting water deficit effects on fruit weight in citrus trees. Agricultural Water Management. 122:1-6. doi:10.1016/j.agwat.2013.02.005. ψ s and g s . However, when T c was obtained from thermal imaging, there was a good correlation with ψ s in days of relatively high water stress (i.e. when ψ s differences among treatments were > 1.0 MPa). The average fruit weight at harvest was significantly correlated with all the stress indicators, and the best correlation was that of thermographic T c followed by ψ s and g s . Overall, results showed that in citrus trees T c measurement obtained from thermal imaging is a good tool to predict the effect of water deficit on fresh fruit weight. THERMOGRAPHIC MEASUREMENT OF CANOPY TEMPERATURE IS A USEFUL TOOL FOR PREDICTING WATER DEFICIT EFFECTS ON FRUIT WEIGHT IN CITRUS TREESC

With the aim of reducing energy consumption and improve water use in pressurised irrigation systems, the methodology for grouping intakes of pressurised irrigation networks into sectors to minimize energy consumption developed by Jimenez Bello et al.(2010a) was modified to allow irrigation intakes to operate the scheduled time according to crop water needs instead of operating in restricted irrigation periods of the same length. Moreover a method was developed to detect the maximum number of intakes that can operate without extra energy in the case the source has enough head to at least feed some of them. These methods were applied to a Mediterranean irrigation system, where the total cropped area was orchards, mainly citrus. In this case study, water was allocated to two different groups of intakes, one fed by gravity and the other one by pumps. A saving of 36.3 % was achieved, by increasing the total volume supplied by gravity, by decreasing the injection pump head and by improving the pump performance. Therefore all intakes operate just the strict irrigation time at the minimum required pressure. Dear Editor:The work we submit for reviewing to Agricultural Water Management is the fourth manuscript of a serial that deals about energy, water and fertilizer management in pressurized irrigation networks. In the previous ones, a methodology to schedule irrigation intakes in pressurized networks minimizing energy consumption was introduced and validated.In the present work, this methodology has been extended to apply just the crop water requirements by allowing to operate irrigation intakes the proper irrigation time. Moreover a new method has been deployed to increase the volume applied by gravity.The methodology has been applied to a real study case that represents a characteristic Mediterranean modernized irrigation district.The authors belong to several research institutes from the Universitat Politècnica de València (UPV), SpainThank you for receiving our work.Best regards.Miguel Angel Jimémez Bello With the aim of reducing energy consumption and improve water use in pressurised irrigation 13 systems, the methodology for grouping intakes of pressurised irrigation networks into sectors 14 to minimize energy consumption developed by Jimenez Bello et al.(2010a) was modified to 15 allow irrigation intakes to operate the scheduled time according to crop water needs instead of 16 operating in restricted irrigation periods of the same length. Moreover a method was 17 developed to detect the maximum number of intakes that can operate without extra energy in 18 the case the source has enough head to at least feed some of them. 19These methods were applied to a Mediterranean irrigation system, where the total cropped 20 area was orchards, mainly citrus. In this case study, water was allocated to two different 21 groups of intakes, one fed by gravity and the other one by pumps. A saving of 36.3 % was 22 achieved, by increasing the total volume supplied by gravity, by decreasing the injection 23 pump head and by...

Grouping irrigation intakes into sectors that operate in scheduled shifts allows the irrigation network to be operated in a more efficient way from an energy point of view. In the case of systems where water is supplied by pump units, the criteria used so far to create the irrigation sectors do not guarantee that pumping sets work in the most efficient manner, despite the use of Variable Frequency Drives.With that purpose in mind, a new methodology using a Genetic Algorithm and the hydraulic network model has been developed to group intakes into sectors in order to minimize energy consumption. It has been applied to a study case. Several scenarios have been run and compared with the study case by means of energy performance indicators. Results show the existing improvement margin in the system energy performance. At the same time, operational network conditions improve due to minimum required pressure at consumption points is guaranteed.Suggested Reviewers:Opposed Reviewers:1 A methodology for grouping irrigation intakes into sectors to minimize the energy consumption in pressurised irrigation networks. AbstractGrouping irrigation intakes into sectors that operate in scheduled shifts allows the irrigation

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