Articles
WATER RELATIONS AND YIELD OF PEACH TREES UNDER HIGH EVAPORATIVE DEMAND CONDITIONS
Article number
537_34
Pages
299 – 304
Language
Abstract
The effect of watering restrictions on yield and quality of peaches of the late producing cultivar « Carnival » has been studied.
The experiment was carried out in a production orchard located in Mornag near Tunis which has 555 trees/ha and was grown using a vase system.
Ratios between total water supplied and Penman-Monteith reference evapotranspiration ([I+P]/ETo) were used for irrigation scheduling.
Over the three phases of fruit growth I, II and III, average values of ETo were successively 5.6, 6.7 and 6.6 mm/day.
The corresponding ratios of the wettest plot (control,0) were respectively 0.43, 0.60 and 0.91. Irrigation was reduced by one third for treatment (1) during phases I,II, (2) during phase III , and (3) during all phases.
Measurements were made of water potentials of the leaf ( ψl) and xylem (
x), yield and total soluble solids (°Brix). Results show that unlike l, x was correlated with the daily values of ([I+P]/ETo). Mid-day x varied typically from -1.0 to -1.3 MPa for the control and from -1.3 to -1.7 MPa for the least irrigated treatment (3). Total soluble contents of fruits increased linearly with decreasing ([I+P]/ETo) ratios.
However, variable reductions in yield have been observed for the treatments under water restrictions.
With reference to the control, irrigation reduction during phase I and II gave the second best yield.
Whereas treatment (2) gave the lowest yield and saved only 80mm of irrigation.
Constant reduction in water supply from fruit set to the end of harvest helped save more than 200 mm with less than a 10 % drop in yield.
Long-term consequences should be investigated.
The experiment was carried out in a production orchard located in Mornag near Tunis which has 555 trees/ha and was grown using a vase system.
Ratios between total water supplied and Penman-Monteith reference evapotranspiration ([I+P]/ETo) were used for irrigation scheduling.
Over the three phases of fruit growth I, II and III, average values of ETo were successively 5.6, 6.7 and 6.6 mm/day.
The corresponding ratios of the wettest plot (control,0) were respectively 0.43, 0.60 and 0.91. Irrigation was reduced by one third for treatment (1) during phases I,II, (2) during phase III , and (3) during all phases.
Measurements were made of water potentials of the leaf ( ψl) and xylem (
x), yield and total soluble solids (°Brix). Results show that unlike l, x was correlated with the daily values of ([I+P]/ETo). Mid-day x varied typically from -1.0 to -1.3 MPa for the control and from -1.3 to -1.7 MPa for the least irrigated treatment (3). Total soluble contents of fruits increased linearly with decreasing ([I+P]/ETo) ratios.However, variable reductions in yield have been observed for the treatments under water restrictions.
With reference to the control, irrigation reduction during phase I and II gave the second best yield.
Whereas treatment (2) gave the lowest yield and saved only 80mm of irrigation.
Constant reduction in water supply from fruit set to the end of harvest helped save more than 200 mm with less than a 10 % drop in yield.
Long-term consequences should be investigated.
Authors
N. Ben Mechlia, A. Sahli, R. Zitouna
Keywords
Prunus persica, irrigation, leaf water potential, xylem water potential, yield
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