Livro das Actas - advid

SAP FLOW AND VARIATION ON STEM DIAMETER
TO DETERMINE THE WINEGRAPE WATER STATUS
Manuel OLIVEIRA 1 ; Carlos CASTRO 2 ; Maria José CORREIA 3 ; Rui
COSTA4 4 ; Ana Alexandra OLIVEIRA 5
ABSTRACT
Vineyards in Northwestern Portugal are often subjected to intense water stress that may cause them
damage and Irrigation when properly managed can play an important role in fruit yield and quality.
To manage the vineyard water supply we need indicators that permit the assessment of the plant
water status along the growing season. We hypothesized that simultaneous readings of sap flow
and variation of the stem diameter of plants in the field might constitute a reliable indicator of the
water status, eventually, representative of the vineyard. In 2011 a number of plants were fitted of
sap flow meters and dendrometers. Half of the plants were irrigated and the other rainfed. The sap
flow rate and the stem diameter variation were studied during the growing season. The results of
2012 are presented and discussed here. The stem diameter variation is a sensitive indicator that can
be used for management decisions but its cost and sampling limitations might prevent its use at
field scale.
Key words: Vitis vinifera, stem diameter, sap flow, Cumulative Sum
1 - INTRODUCTION
Monitoring of plant water status in field grown grapevines does allow diagnosing the
onset and severity of water stress so as to schedule irrigation according to the actual
plant needs (Patakas et al., 2005). Recently, that diagnose in fruit tree orchards and vineyards
is frequently based on changes in the stem diameter (Doltra et al., 2007) or from
sap-flow records (Fernandez et. al., 2008; Poblete-Echeverria et al., 2012). Plant growth
is a sensitive indicator of water stress and it has been demonstrated that trends in trunk
1 CITAB – Agronomy, UTAD, Vila Real. mto@utad.pt;
2 Agronomy, UTAD, Vila Real. ccastro@utad.pt;
3 Agronomy, UTAD, Vila Real, mjosec@utad.pt;
4 Agronomy, UTAD, Vila Real, ruicosta@utad.pt;
5 Agronomy, UTAD, Vila Real. anaolive@utad.pt
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