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determination of plant water requirement from sap flow measurement and modeling

Daily sap flow rate in an East and West trunk of olive tree ... Water relations and gas exchange in olive trees under regulated deficit irrigation and partial rootzone ...

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determination of plant water requirement from sap flow measurement and modeling

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    1. Determination of Plant Water Requirement from Sap Flow Measurement and Modeling

    Protected Horticulture & Environmental Control. Lab. Ta The Hung

    2. Contents

    Introduction Sap flow measurement Mathematical modeling Summary

    Surplus or deficit irrigation can have opposite consequences; Surplus irrigation can lead to leaching of nutrients that causes environmental problems. Water deficit can deleteriously affect potential growth. Introduction How much irrigation water should be applied ? When irrigation water should be applied ? Researchers & farmers Water requirement Irrigation schedule Yield & quality WR = Et + (PW) WR : Water requirement of plant Et : Leaf transpiration (PW) : stored water in plant (negligible) About 99% of plant water uptake is lost through transpiration Determination of plant water requirement There are two ways to calculate transpiration Penman-Monteith formula (Monteith 1981) Priestley-Taylor formula (Priestley and Taylor 1972) Pan Method (Allen et al., 1998) Weighing lysimeter Field chamber methods Monitoring of water balance in soil Sap flow measurements Transpiration Direct measurement Mathematical modeling Field chamber method These methods deduce the crop transpiration from the variation of the air humidity measurement but which also modify the microclimate. Direct measurement of transpiration This method is able to predict crop water use efficiency, drainage, groundwater recharge and nutrient loss by leaching Disturb the soil Weighing lysimeter Direct measurement of transpiration This method does not modify the plant’s environment, but provides accurate results only for a sufficiently long time lapse of several days Monitoring of water balance in soil ETc = P + I - ?S – D ± R Etc: the evapotranspiration of the crop P: rain I: irrigation ?S: soil water content variation between two dates D: drainage R: runoff Direct measurement of transpiration Sap flow measurement Easy use Continuous monitoring over a period of time as short as necessary They are not supposed to induce modification of the environment Measurement of transpiration term only Advantages Direct measurement of transpiration F: mass of flow rate of sap Qf: heat uptake Cp: specific heat capacity of sap dT: increase in sap temperature across the heater amount of sap flow = amount of transpiration Sap flow measurement Diurnal and daily sap flow were greatly affected by soil water available (potted banana plant) (Lu et al., 2002) Diurnal courses of sap flow and gravimetric water loss closed and opened circles represent different leaf sample The regression line with a zero intercept is for both sample leaves combined (solid line) Lotus plant Sap flow (ml/h) (Takagi et al., 2006) Comparison of sap flow rate (Fp) with transpiration rate (Trw) by weighing lysimeter Transpiration T0: closed symbols T1: opened symbols T0: plants were irrigated daily from DOY 275 T1: plants were not irrigated during 6 days (DOY 275-281) The relationship between SF and TR in both treatments, which was close to 1:1 young Lemon tree (Ortuno et al., 2005) Sap flow (l/d) TR (l/d) Relationship between daily sap flow rates (SF) and daily transpiration rates (TR) measured by weighing lysimeter T0: plants were irrigated daily above crop water requirements from DOY 194 to 260 T1: plants were not irrigated from DOY 194 to 244 (50 days) T0: closed symbols T1: opened symbols In some cases (water stress, high evaporative demand, etc.) sap flow can temporarily be higher or lower than the transpiration level (Ortuno et al., 2006) Sap flow (l/d) DOY Daily sap flow of Lemon tree under well-watered and stress condition Day of experiment EL for each of the active fronds The percentage contribution to total LAI and the corresponding contribution to total whole-plant water use Need to characterize frond water use behavior with respect to size and age in situation where fronds are used to estimate whole –plant water use (Wasantha et al., 2009) Daily changes in sapflow rate at the various plant parts of palm The sap flow in stems of the 2nd and 4th clusters and the leaf petioles fully unfolded above the 4th clusters resulted in positive values The direction of sap flow in stem of 3rd cluster was intermittently changed (Kim et al., 2008) Sap flow (mml/h) Time of day (hr) Daily changes in sapflow rate at the various plant parts of hydroponically grown tomato 232 234 236 238 240 242 244 DOY (Ferna’ndez et al., 2006) Daily sap flow rate in an East and West trunk of olive tree Normalized sap flow in an E and W branch of Sequoiasempervirens Normalized sap flow in an E and W branch of Sequoiadendron giganteum (Stephen et al., 2008) Some lags are found in some trees and not others Normalized sap flow in an E and W branch and stem of two tree species LE : Evapotranspiration Rn : the net radiation G : the soil heat flux (es - ea) : the vapour pressure deficit of the air ra : the mean air density at constant pressure cp : the specific heat of the air ? : the slope of the saturation vapour pressure temperature relationship g : the psychrometric constant rs and ra : the (bulk) surface and aerodynamic resistances. p : the air density ? : the psychrometric coefficience Calculating a climatic demand Determine a crop coefficient function Penman-Monteith formula Mathematical model ?T = A(1- Exp(-KLAI))G + BLAI*VPD T : Crop transpiration rate (kg m-2 s-1 ) G : Inside solar radiation (W m-2 ) VPD : Inside air vapour pressure deficit (kPa) LAI: Leaf area index (m2 m-2 ) K : The light extinction coefficient ? : The vapourization heat of water (2.45 Kj kg-1 ) A,B : Values of equation parameters (A, dimensionless; B, W m-2 kpa-1 ) (Baille et al., 2004) Crop transpiration was estimated from the Penman-Monteith equation VPD = vpsat - vpair Radiation from below Radiation from above Canopy e-KLAI = Ra/Rb Modified psychrometric chart Vapor pressure (psi) Vapor pressure (Kpa) Temperature (C) Temperature (F) Autumn Spring ?Ts = A(1- Exp(-KLAI))G + BLAI *VPD A, B were determined statistical regression with data sets of measured transpiration rate on one hand , and solar radiation, VPD and LAI on the other hand (Medrano et al., 2005) Comparison of observed transpiration by weighing lysimeter and estimated transpiration by penman- monteith equation There was a close relationship between both parameters. Sap flow measurements are conditioned by ET0 when the soil water content in large scale is not a limiting factor (Nicolas et al., 2005) Sap flow (tree/d) ETo(mm/h) apricot tree The relationship between daily sap flow (SF) and daily evapotranspiration (ETo) by Penman Monteith equation Summary Sap flow can evaluate plant transpiration and sensitively to daily plant water tress. A simple equation was derived from the Penman-monteith equation to predict plant evopotranspiration. The relationship among transpiration, sap flow and modeling. References Evangelina Medrano, Pilar Lorenzo, Mari’a Cruz Sa’nchez-Guerrero, Juan Ignacio Montero, 2005. Evaluation and modeling of greenhouse cucumber-crop transpiration under high and low radiation conditions. Sci. Hort. 105, 163-175. Fernanda Ortuno M., Yelitza Garcıa-Orellana, Wenceslao Conejero, M. Carmen Ruiz-Sanchez, Juan Jos Alarcon, and Arturo Torrecillas, 2006. Stem and leaf water potentials, gas exchange, sap flow, and trunk diameter fluctuations for detecting water stress in lemon trees. The Trees. 20, 1-8. J. E. Ferna´ndez A. Di´az-Espejo J. M. Infante P. Dura´n M. J. Palomo V. Chamorro I. F. Giro´n L. Villagarci´a, 2006. Water relations and gas exchange in olive trees under regulated deficit irrigation and partial rootzone drying. 284. 273-291. Ki Deog Kim, Eung Ho Lee, Jae Wook Lee, Il Hwan Cho, Boheum Mun, Byoung Yil Lee Jung Eek Son, and Changhoo Chun, 2008. Daily Changes in Rates of Nutrient and Water Uptake, Xylem Sap Exudate, and Sapflow of Hydroponically Grown Tomatoes. 49 (4), 209-215 Ortuno M.F., J.J. Alarcona, E. Nicolasa, A. Torrecillasa, 2005. Sap flow and trunk diameter fluctuations of young lemon trees under water stress and rewatering. Environmental and Experimental Botany 54:155– 162. Ortuno M.F., Y. Garcı-Orellana, W. Conejero, M.C. Ruiz-Sanchez, O. Mounzer, J.J. Alarcon and A. Torrecillas, 2006. Relationships between climatic variables and sap flow, stem water potential and maximum daily trunk shrinkage in lemon trees. Plant and Soil 279, 229–242. Rosanne Chabot, Sami Bouarfa, Daniel Zimner, Ce’dric Chaumont, Sylvain Moreau, 2005. Evaluation of the sap flow determined with a heat blnce method to measure the transpiration of a sugarcane canopy. Agri. Water Manage. 75, 10-24. Stephen S. O. Burges. Todd E. Dawson, 2008. Using branch and basal trunk sap flow measurements to estimate whole plant water capacitance: a caution. Plant Soil. 305, 5-13. Tomo’omi Kumagai, Sayaka Aoki, Hisami Nagasawa, Tetsuya Mabuchi, Katsuyoshi Kubota, Sachiko Inoue, Yasuhiro Utsumi, Kyoichi Otsuki, 2005,. Effects of tree-to-tree and radial variations on sap flow estimates of transpiration in Japanese cedar. Agri. For. Meteorol. 135, 110-116. Takagi K., Y. Harazono, Shin-ichi Noguchi, A. Miyata, M. Mano, and M. Komine, 2006. Evaluation of the transpiration rate of lotus using the stem heat-balance method. Aquatic Botany 85, 129–136. Wasantha S. Madurapperuma, Timothy M. Bleby, Sephen S.Q. Burgess, 2009. Evaluation of sap methods to determine water use by cultivated palms. Eviron. Exp. Bot. 66, 372-380.   Thanks and Regards
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