Grapevine water use and the crop coefficient are linear functions of the shaded area measured beneath the canopy

Williams, Larry E.; Ayars, James E.

doi:10.1016/j.agrformet.2005.07.010

Cited by 298 publications

(202 citation statements)

References 18 publications

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“…Camargo and Pereira (1994) recommend that Kc be estimated as 1.2 times the fraction of ground shaded by coffee trees around noontime to allow for values above 1.0, the limit for completely shaded ground area, and for seasonal leaf area changes. Similarly, the water use for a grapevine orchard (Williams and Ayars, 2005) and for an isolated peach tree (Goodwin et al, 2006) was found to be linearly related to the shaded area casted on the ground beneath the canopy around noontime. For grapevines Kc was linearly related to the leaf area index (L) up to 4.5 (Williams et al, 2003;Williams and Ayars, 2005;Netzer et al, 2009).…”

Section: Methodsmentioning

confidence: 99%

“…Similarly, the water use for a grapevine orchard (Williams and Ayars, 2005) and for an isolated peach tree (Goodwin et al, 2006) was found to be linearly related to the shaded area casted on the ground beneath the canopy around noontime. For grapevines Kc was linearly related to the leaf area index (L) up to 4.5 (Williams et al, 2003;Williams and Ayars, 2005;Netzer et al, 2009). Theoretically it is more correct to use L then shaded area as it represents the ratio of the total canopy leaf area to the planted area (Ritchie and Burnett, 1971;Fuchs et al, 1987;Al-Kaisi et al, 1989).…”

Section: Methodsmentioning

confidence: 99%

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Coffee crop coefficient for precision irrigation based on leaf area index

Pereira¹,

Camargo

Nova³

2011

Bragantia

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Crop coefficient (Kc) for coffee plantations was found to be linearly related to the leaf area index (L) up to 3, i.e., Kc = b L. The basic assumption is that for irrigated trees the water use per unit leaf area (ET LA) is equal to the reference evapotranspiration (ETo) expressed also on a unit leaf area basis of the reference surface (ET LA = ETo/Lo). As recommended by FAO-56 the leaf area index (Lo) for the hypothetical reference surface (grass) is equal to 2.88, then the most likely value is b = Lo-1 = 2.88-1 = 0.347. However, for L > 3 (completely covered ground surface) Kc decreased from a peak value (~1.05) tending to an asymptotic low value around 0.7 for L > 6, but the linear model gives unrealistic Kc estimates; tentatively the empirical function Kc = 1.8 L-0.5 is offered here as an initial guess due to the lack of experimental results for the interval 3.5 <L < 5.5. To become operational under commercial fields it is necessary to estimate the leaf area per coffee tree (LA, m² tree-1), and based on a very limited set of data, LA was estimated as a function of planting density (PD, trees ha-1), i.e., LA = 88.38 - 8.63 Ln (PD). Alternatively, L (< 3.4) can be computed directly as a function of canopy volume (for V < 1.2 m³).

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Coffee crop coefficient for precision irrigation based on leaf area index

Pereira¹,

Camargo

Nova³

2011

Bragantia

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“…Accordingly, K c for table grape vineyards for the initial, mid-season, and end-season stages would be 0.30, 0.95, and 0.75 for an effective ground cover of 50%, and 0.30, 1.10, and 0.85 for an effective ground cover of 70% (Allen and Pereira 2009). Pruning and trellis system have also been reported to modify the K c (Williams and Ayars 2005a). Williams et al (2003) and Williams and Ayars (2005a) reported mid-season K c values for Thompson Seedless grapevines in California under a head training system ranging from about 0.90-1.30 when ground cover ranged from 60 to 75%.…”

Section: Introductionmentioning

confidence: 99%

“…Seasonal ET depends upon environmental conditions, characteristics of the crops (such as trellis system and row spacing in vineyards), and cultural practices (such as canopy and irrigation management). Seasonal table grape ET has been reported to range from 687 to 1,350 mm (Williams et al 2003;Williams and Ayars 2005a;Netzer et al 2009;Rodriguez et al 2010). Different techniques have been used to measure or to estimate table grape ET and crop coefficients: weighing lysimeters (Williams and Ayars 2005a;Williams et al 2003), drainage lysimeters (Vieira de Azevedo et al 2008;Netzer et al 2009), Bowen ratio (Rana et al 2004;Texeira et al 2007), and eddy covariance (Rodriguez et al 2010).…”

Section: Introductionmentioning

confidence: 99%

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Evapotranspiration of grapevine trained to a gable trellis system under netting and black plastic mulching

Moratiel

Martı́nez-Cob

2011

Irrig Sci

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Spatial and diurnal below canopy evaporation in a desert vineyard: Measurements and modeling

Kool

Ben‐Gal

Agam

et al. 2014

Water Resources Research

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Evaporation from the soil surface (E) can be a significant source of water loss in arid areas. In sparsely vegetated systems, E is expected to be a function of soil, climate, irrigation regime, precipitation patterns, and plant canopy development and will therefore change dynamically at both daily and seasonal time scales. The objectives of this research were to quantify E in an isolated, drip-irrigated vineyard in an arid environment and to simulate below canopy E using the HYDRUS (2-D/3-D) model. Specific focus was on variations of E both temporally and spatially across the inter-row. Continuous above canopy measurements, made in a commercial vineyard, included evapotranspiration, solar radiation, air temperature and humidity, and wind speed and direction. Short-term intensive measurements below the canopy included actual and potential E and solar radiation along transects between adjacent vine-rows. Potential and actual E below the canopy were highly variable, both diurnally and with distance from the vine-row, as a result of shading and distinct wetted areas typical to drip irrigation. While the magnitude of actual E was mostly determined by soil water content, diurnal patterns depended strongly on position relative to the vine-row due to variable shading patterns. HYDRUS (2-D/3-D) successfully simulated the magnitude, diurnal patterns, and spatial distribution of E, including expected deviations as a result of variability in soil saturated hydraulic conductivity.

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Grapevine water use and the crop coefficient are linear functions of the shaded area measured beneath the canopy

Cited by 298 publications

References 18 publications

Coffee crop coefficient for precision irrigation based on leaf area index

Coffee crop coefficient for precision irrigation based on leaf area index

Evapotranspiration of grapevine trained to a gable trellis system under netting and black plastic mulching

Spatial and diurnal below canopy evaporation in a desert vineyard: Measurements and modeling

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