Semi-empirical approach for estimating actual evapotranspiration in Greece

Poulovassilis, A.; Anadranistakis, M.; Liakatas, A.; Alexandris, Stavros; Kerkides, P.

doi:10.1016/s0378-3774(01)00121-4

Cited by 21 publications

(26 citation statements)

References 8 publications

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“…In such conditions, plant sensors are preferable, but, thus far, not a single variable is recommended for general use; nor are the identified thresholds considered valid for the entire cropping season [10,19]. Poulovassilis et al [76] and Casadesús et al [74] reported that the lack of effective and affordable methods for a representative assessment of water status in heterogeneous plots is an important practical limitation. Consequently, both feed-forward and feed-back approaches are required.…”

Section: Criteria For Irrigation Scheduling: Physical Support To the mentioning

confidence: 99%

Stress Coefficients for Soil Water Balance Combined with Water Stress Indicators for Irrigation Scheduling of Woody Crops

Ferreira

2017

Horticulturae

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There are several causes for the failure of empirical models to estimate soil water depletion and to calculate irrigation depths, and the problem is particularly critical in tall, uneven, deficit irrigated (DI) crops in Mediterranean climates. Locally measured indicators that quantify water status are useful for addressing those causes and providing feed-back information for improving the adequacy of simple models. Because of their high aerodynamic resistance, the canopy conductance of woody crops is an important factor in determining evapotranspiration (ET), and accurate stress coefficient (Ks) values are needed to quantify the impact of stomatal closure on ET. A brief overview of basic general principles for irrigation scheduling is presented with emphasis on DI applications that require Ks modelling. The limitations of existing technology related to scheduling of woody crops are discussed, including the shortcomings of plant-based approaches. In relation to soil water deficit and/or predawn leaf water potential, several woody crop Ks functions are presented in a secondary analysis. Whenever the total and readily available water data were available, a simple Ks model was tested. The ultimate aim of this discussion is to illustrate the central concept: that a combination of simple ET models and water stress indicators is required for scheduling irrigation of deep-rooted woody crops.

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Section: Criteria For Irrigation Scheduling: Physical Support To the mentioning

confidence: 99%

Stress Coefficients for Soil Water Balance Combined with Water Stress Indicators for Irrigation Scheduling of Woody Crops

Ferreira

2017

Horticulturae

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“…The standard United Nations Food and Agricultural Organization Drainage Paper 56 [2] method, which employs a standardized version of the Penman-Monteith approach, was used and adjusted to correct for actual ET due to limiting of soil moisture. The correction was via an exponential function proposed by Poulovassilis et al [51], where the decay rate is a function of average moisture content and potential evapotranspiration . Wu et al [52] showed that for mature corn crops, nearly 90% of the roots are distributed within top 60-cm depth.…”

Section: Drying Phase Simulationmentioning

confidence: 99%

Modeling Soil Moisture Profiles in Irrigated Fields by the Principle of Maximum Entropy

Mishra

Ellenburg

Al‐Hamdan

et al. 2015

Entropy

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Vertical soil moisture profiles based on the principle of maximum entropy (POME) were validated using field and model data and applied to guide an irrigation cycle over a maize field in north central Alabama (USA). The results demonstrate that a simple two-constraint entropy model under the assumption of a uniform initial soil moisture distribution can simulate most soil moisture profiles that occur in the particular soil and climate regime that prevails in the study area. The results of the irrigation simulation demonstrated that the POME model produced a very efficient irrigation strategy with minimal losses (about 1.9% of total applied water). However, the results for finely-textured (silty clay) soils were problematic in that some plant stress did develop due to insufficient applied water. Soil moisture states in these soils fell to around 31% of available moisture content, but only on the last day of the drying side of the irrigation cycle. Overall, the POME approach showed promise as a general strategy to guide irrigation in humid environments, such as the Southeastern United States.

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“…The crop coefficient and reference evapotranspiration (K c -ET o ) approach has been successfully applied to wheat in many locations (Abdelhadi et al, 2000;Allen, 2000;Kang et al, 2000;Liu et al, 2002, Poulovassilis et al, 2001Sepaskhah and Andam, 2001). Crop ET can also be estimated through reference ET, soil-moisture content, and leaf area index (LAI) (Kendy et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Perceptive research on wheat evapotranspiration in Pakistan

Laghari

Lashari

Memon

2008

Irrigation and Drainage

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The Mehran model is developed based on the FAO-56 modified Penman-Monteith equation for computing reference and crop evapotranspiration with dual crop coefficients. Evapotranspiration (ET) of wheat in three field experiments with management-allowed depletion (MAD) of 45, 55 and 65% was observed through gypsum block readings and a drainage lysimeter. The seasonal crop ETs were observed as 363, 359 and 332 mm, and were computed as 383, 369 and 355 mm. The corresponding water use efficiencies (WUEs) were ascertained as 14.1, 15.0 and 13.4 kg (ha mm)À1 . The highest crop WUE was achieved with MAD at 55%; therefore, this research is more focused upon in the paper. The model relatively overestimated seasonal ET by 2.8%. Weekly root length and daily soil-moisture measurements revealed that wheat extracts most of its moisture from the 0-50 cm soil profile. When practising either scientific or traditional irrigation scheduling in the country, a seasonal water amount of 370 mm is suggested for wheat to achieve optimum yield and WUE.Statistical analysis (R 2 ¼ 0.90, T ¼ 2.09, and F ¼ 999) showed good correlation between computed and actual seasonal ETs of crop with an experimental MAD of 55%. The Mehran model is found to be quite versatile and can be successfully used as a decision support system (DSS) for irrigation scheduling of wheat in Pakistan. L'analyse statistique (R 2 ¼ 0.90, T ¼ 2.09, et F ¼ 999) a montré la bonne corrélation entre l'évapotranspiration saisonnière calculée et réellement mesurée pour une irrigation rationnée à 55%. Le modèle de Mehran apparaît tout à fait souple et peut être employé avec succès en tant que système interactif d'aide à la décision pour le pilotage de l'irrigation du blé au Pakistan.

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Semi-empirical approach for estimating actual evapotranspiration in Greece

Cited by 21 publications

References 8 publications

Stress Coefficients for Soil Water Balance Combined with Water Stress Indicators for Irrigation Scheduling of Woody Crops

Stress Coefficients for Soil Water Balance Combined with Water Stress Indicators for Irrigation Scheduling of Woody Crops

Modeling Soil Moisture Profiles in Irrigated Fields by the Principle of Maximum Entropy

Perceptive research on wheat evapotranspiration in Pakistan

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