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Free University of Bozen-Bolzano

02 Apr 2019 18:00–19:30

series of lectures @ unibz | The pitfalls of water potential measurements ....

... to schedule irrigation

Speaker Dr. Omar García-Tejera

Date 02 Apr 2019 18:00 - 19:30

Location Room BZ D1.03, Universitätsplatz 1 - Piazza Università, 1, 39100 Bozen-Bolzano

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Water potential (¿) has been traditionally used to establish thresholds for irrigation scheduling. The underlying idea is that a change in ¿ induces a concomitant variation in transpiration (T). However, according to the catenary hypothesis, such relation is modulated by the global resistance of the system (R) (the soil-plant-atmosphere continuum, SPAC). These three terms ¿, T, and R, are not linearly related. As a consequence, the analysis of the response of one of them when the other two change is not straightforward. To assist in the study of the relations between ¿, T and R, a SPAC model with a multi-compartment solution was used. The model was previously validated for olive and almond trees under different levels of water stress, allowing the modification of R through changes in the leaf-root area relations. The simulation results show that ¿ varied at field capacity or permanent wilting point for the different LA:RA ratios. The results indicate that the ¿ threshold for irrigation obtained in one experiment may only be applied to other sites if R is the same; otherwise, the ¿-T relation will be different and hence the irrigation threshold.