This study aims to test plant-based sensors for their efficiency in determining nectarine water status in a modern high-density orchard.

Alessio Scalisi from the University of Palermo (Italy) is working with Dr Mark O’Connell and Dr Dario Stefanelli at the Stonefruit Field Laboratory (Tatura) over the 2017/18 season.

Climate changes are leading to shortages of water worldwide, affecting traditional horticultural management strategies. Improved understanding of crop water requirements, coupled with irrigation automation play a key role for water saving in future fruit crop production. However, although automated, irrigation is often neither efficient nor timely in responding to seasonal changes in tree water need.

Measurements are underway on ‘September Bright’ nectarines grafted on Elberta rootstock, and trained to an open Tatura system (2222 tree/ha). Fruit gauges and leaf turgor pressure probes are mounted on trees subjected to four different irrigation levels: 100, 40, 20 and 0% of ETc at different fruit growth stages. Fruit relative growth rate (RGR) and leaf turgor pressure (Lp) dynamics are being studied and compared to midday stem water potential (Ψstem), the reference method for plant water status detection. Relationships between plant water status indexes (RGR, Lp and Ψstem) and vegetative growth (trunk cross-sectional area, lateral strength and pruning weight), fruiting behaviour, fruit size, light interception and leaf gas exchange will be presented and discussed with respect to irrigation management.

Alessio Scalisi in the stonefruit orchard

Fruit gauge on ‘September Bright’ nectarines

Leaf turgor pressure probe