摘要
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Irrigation practices in areas featuring ample fluctuations in summer precipitations require to develop easy-handling water management strategies to define time of application and water volumes to be used. Thus monitoring soil wate...
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Irrigation practices in areas featuring ample fluctuations in summer precipitations require to develop easy-handling water management strategies to define time of application and water volumes to be used. Thus monitoring soil water content (SWC) underneath vine canopy by a capacitance probe was tested as a tool for control irrigation and tracking vine physiological performance along the season and under uncertain meteorological conditions in the Marche (central Italy). Control not-irrigated plots (I0) were compared to RDI treatments based on the restitution of 33% (I1) or 70% (I2) of crop evapotranspiration of the previous week. Grapevines were irrigated when midday leaf water potential ( Psi l) was about -0.9 MPa, net photosynthesis (P<sub>n</sub>) was still high (11 micro mol m<sup>-2</sup> s<sup>-1</sup>) and SWC in the first 0.6 m depth underneath vine canopy have reached the wilting point (WP) threshold. After drip-irrigation, P<sub>n</sub>, Psi l and Psi s values increased in RDI treatments compared to control I0 vines. SWC underneath the row raised to values close to the field water capacity (FWC). From the end of July till harvest, in mid-September, Psi l decreased around -1.1 MPa, SWC in the first 0.6 m depth lowered below WP, while P<sub>n</sub> remained above 8 micro mol m<sup>-2</sup> s<sup>-1</sup> in all treatments. Thus water absorption during berry ripening took place mainly in deep soil layers in all tested treatments. Strict linear correlations were found among indicators of water status ( Psi l, Psi s and SWC), that, in turn, resulted correlated with P<sub>n</sub>. In our trial the linear correlation between SWC and P<sub>n</sub> accounted for 69% of the total variability. SWC, easily monitored in the field by DIVINER2000 capacitance probe, was a good indicator of vine water status and physiological performance. All Grapevines experienced only moderate water stress, thus RDI treatments slightly affected yield and grape composition.
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