Proposed Revision to the Fao Procedure for Estimating Crop Water Requirements

Allen, Ross; Smith, M.; Pereira, L. S.; Pruitt, William O.

doi:10.17660/actahortic.1997.449.2

Cited by 191 publications

(325 citation statements)

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“…A determinação da área foliar é um dos principais parâmetros a serem analisados no crescimento vegetal das plantas, visto estar relacionada com diversos processos fisiológicos, tais como fotossíntese, respiração e transpiração (COSTA, 1999), além de servir para estimar a necessidade hídrica da cultura (ALLEN et al, 1996). Sua avaliação, durante todo o ciclo da cultura, é de extrema importância para que se possa modelar o crescimento e o desenvolvimento da planta e, em consequência, a produtividade e a produção total da cultura (TERUEL, 1995).…”

Section: Introductionunclassified

Níveis de irrigação na cultura do Kalanchoe cultivado em ambiente protegido

Parizi¹,

Peiter²,

Robaina³

et al. 2010

Cienc. Rural

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Section: Introductionunclassified

Níveis de irrigação na cultura do Kalanchoe cultivado em ambiente protegido

Parizi¹,

Peiter²,

Robaina³

et al. 2010

Cienc. Rural

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show abstract

“…The amount of evapotranspiration depends heavily on the level of solar radiation, and this relationship is taken into account by various computational models (Doorenbos, Pruitt 1977;Hargreaves, Samani 1985;Allen 1993;Ley et al 1994;Allen et al 1996;Xing et al 2008). The pattern of variation in evapotranspiration during the growing season and the shape of the curve describing the level of radiation per unit of temperature indicate that in order to estimate ETo only by means of mean air temperature, the coefficient α should not be a fixed value but a variable (α˷) for the individual months of the growing season.…”

Section: Resultsmentioning

confidence: 99%

A new approach to the method of drawing the Gaussen-Walter climate diagram

Treder

Klamkowski

Wójcik

2018

Meteorol. Hydrol. Water Manage.

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Abstract. In traditional climate diagrams a fixed coefficient (α) between temperature and precipitation has been adopted. It has been shown, however, that such an approach does not correctly describe the conditions of the climatic balance in Poland for the entire growing season. In this paper, a different solution to this problem is proposedthe introduction of a variable coefficient for individual months. The analysis of patterns of climatic variables over the year supports the hypothesis that in order to estimate ETo only by means of mean air temperature (ETo = α·T), the coefficient α should be variable for the individual months of the vegetative period. The values of the coefficient were empirically determined for use in calculating daily and monthly ETo. The newly proposed coefficients α were different from those determined with the standard climate diagram (published by Walter, Lieth 1967). The introduction of the variable value α into the computational model markedly improved the quality of the estimation of ETo.The mean bias errors determined for the estimation of ETo on the basis of temperature and the changing value of α were considerably lower than for the estimation of ETo with a fixed value of α. This provides the possibility of a more accurate presentation of periods of both excess and shortage of precipitation.

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“…The model performs water balance computations by estimating the input and output quantities of water to the soil reservoir as presented in (Allen et al, 1998 (Allen et al, 1998). The model calculates ETc by multiplying crop Kc (provided in the data base of the model) by the calculated value of ETo.…”

Section: Model Descriptionmentioning

confidence: 99%

“…When the model shows that there is only 15.0 mm in the root zone, it will be the time to apply the second irrigation. This value is based on the publish value of soil water depletion fraction in FAO book number 56 (Allen et al, 1998), where soil water depletion fraction equal to 0.55 for both wheat and maize.…”

Section: Model Descriptionmentioning

confidence: 99%

“…Crop water consumptive use (WCU), it is also defines as crop evapotranspiration (ETc) consists of two components, namely ETo and crop coefficients (Kc). ETo is the total amount lost from the field by both soil evaporation and plant transpiration (Allen et al, 1998). Accurate estimation of ETo is an important factor to attain prop water management.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Irrigation Scheduling Calculator (Isc) to Improve Water Management on Field Level in Egypt

Ouda¹

2017

Journal of Water Security

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Abstract. The developed model is MS excel sheet called "Irrigation Scheduling Calculator, ISC". The model requires to input daily weather data to calculate daily evapotranspiration using Penman-Monteith equation. The model calculates water depletion from the root zone to determine when to irrigate and how much water should be applied. The charge from irrigation pump is used to calculate how many hours should the farmer run the pump to deliver the needed amount of water. ISC model was used to developed irrigation schedule for wheat and maize planted in El-Gharbia governorate. The developed schedules were compared to the actual schedules for both crops. Furthermore, CropSyst model was calibrated for both crops and run using the developed schedules by ISC model. The simulation results indicated that the calculated irrigation amount by ISC model for wheat was lower than actual schedule by 6.0 mm. Furthermore, the simulated wheat productivity by CropSyst was higher than measured grain and biological by 2%. Similarly, the calculated applied irrigation amount by ISC model for maize was lower than actual schedule by 79.0 mm and the productivity was not changed.

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Proposed Revision to the Fao Procedure for Estimating Crop Water Requirements

Cited by 191 publications

References 0 publications

Níveis de irrigação na cultura do Kalanchoe cultivado em ambiente protegido

Níveis de irrigação na cultura do Kalanchoe cultivado em ambiente protegido

A new approach to the method of drawing the Gaussen-Walter climate diagram

Irrigation Scheduling Calculator (Isc) to Improve Water Management on Field Level in Egypt

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